Here are the proofs of your article. [610243]

Dear Author,
Here are the proofs of your article.
• You can submit your corrections online , via e-mail or by fax.
• For online submission please insert your corrections in the online correction form. Always
indicate the line number to which the correction refers.
• You can also insert your corrections in the proof PDF and email the annotated PDF.
• For fax submission, please ensure that your corrections are clearly legible. Use a fine black
pen and write the correction in the margin, not too close to the edge of the page.
• Remember to note the journal title , article number , and your name when sending your
response via e-mail or fax.
•Check the metadata sheet to make sure that the header information, especially author names
and the corresponding affiliations are correctly shown.
•Check the questions that may have arisen during copy editing and insert your answers/
corrections.
•Check that the text is complete and that all figures, tables and their legends are included. Also
check the accuracy of special characters, equations, and electronic supplementary material if
applicable. If necessary refer to the Edited manuscript .
•The publication of inaccurate data such as dosages and units can have serious consequences.
Please take particular care that all such details are correct.
•Please do not make changes that involve only matters of style. We have generally introduced
forms that follow the journal’s style.
Substantial changes in content, e.g., new results, corrected values, title and authorship are not
allowed without the approval of the responsible editor. In such a case, please contact the
Editorial Office and return his/her consent together with the proof.
• If we do not receive your corrections within 48 hours , we will send you a reminder.
• Your article will be published Online First approximately one week after receipt of your
corrected proofs. This is the official first publication citable with the DOI. Further changes
are, therefore, not possible.
• The printed version will follow in a forthcoming issue.
Please note
After online publication, subscribers (personal/institutional) to this journal will have access to the
complete article via the DOI using the URL: http://dx.doi.org/[DOI].
If you would like to know when your article has been published online, take advantage of our free
alert service. For registration and further information go to: http://www.link.springer.com.
Due to the electronic nature of the procedure, the manuscript and the original figures will only be
returned to you on special request. When you return your corrections, please inform us if you would
like to have these documents returned.

Metadata of the article that will be visualized in
OnlineFirst
Please note: Images will appear in color online but will be printed in black and white.
ArticleTitle Thermal and spectroscopic analysis of Co(II)–Fe(III) polyglyoxylate obtained through the reaction of
ethylene glycol with metal nitrates
Article Sub-Title
Article CopyRight Akadémiai Kiadó, Budapest, Hungary
(This will be the copyright line in the final PDF)
Journal Name Journal of Thermal Analysis and Calorimetry
Corresponding Author Family Name Pascariu
Particle
Given Name Mihai-Cosmin
Suffix
Division Faculty of Pharmacy
Organization “Vasile Goldiș” Western University of Arad
Address 86 Liviu Rebreanu, 310414, Arad, Romania
Division Faculty of Medicine
Organization “Victor Babeș” University of Medicine and Pharmacy of Timișoara
Address 2 Eftimie Murgu Sq., 300041, Timisoara, Romania
Division
Organization National Institute of Research and Development for Electrochemistry and
Condensed Matter – INCEMC
Address 144 Dr. Aurel Păunescu-Podeanu, 300569, Timisoara, Romania
Phone
Fax
Email mihai.cosmin.pascariu@gmail.com
URL
ORCID
Corresponding Author Family Name Muntean
Particle
Given Name Cornelia
Suffix
Division Faculty of Industrial Chemistry and Environmental Engineering
Organization Politehnica University of Timișoara
Address 6 Vasile Pârvan Blvd., 300223, Timisoara, Romania
Division Research Institute for Renewable Energy
Organization Politehnica University of Timișoara
Address 2 Victoriei Sq., 300006, Timisoara, Romania
Phone
Fax
Email cornelia.muntean@upt.ro
URL
ORCID

Author Family Name Niculescu
Particle
Given Name Mircea
Suffix
Division Faculty of Industrial Chemistry and Environmental Engineering
Organization Politehnica University of Timișoara
Address 6 Vasile Pârvan Blvd., 300223, Timisoara, Romania
Phone
Fax
Email
URL
ORCID
Author Family Name Sasca
Particle
Given Name Viorel
Suffix
Division
Organization Institute of Chemistry Timișoara of Romanian Academy
Address 24 Mihai Viteazul Blvd., 300223, Timisoara, Romania
Phone
Fax
Email
URL
ORCID
Author Family Name Lupa
Particle
Given Name Lavinia
Suffix
Division Faculty of Industrial Chemistry and Environmental Engineering
Organization Politehnica University of Timișoara
Address 6 Vasile Pârvan Blvd., 300223, Timisoara, Romania
Phone
Fax
Email
URL
ORCID
Author Family Name Milea
Particle
Given Name Marius-Silviu
Suffix
Division Faculty of Industrial Chemistry and Environmental Engineering
Organization Politehnica University of Timișoara
Address 6 Vasile Pârvan Blvd., 300223, Timisoara, Romania
Phone
Fax

Email
URL
ORCID
Author Family Name Bîrzescu
Particle
Given Name Mihail
Suffix
Division Faculty of Industrial Chemistry and Environmental Engineering
Organization Politehnica University of Timișoara
Address 6 Vasile Pârvan Blvd., 300223, Timisoara, Romania
Phone
Fax
Email
URL
ORCID
ScheduleReceived 9 June 2016
Revised
Accepted 19 December 2016
Abstract The synthesis and thermal and spectroscopic studies of a new CoII–FeIII heteropolynuclear coordination
compound are presented. The in situ oxidation product of ethylene glycol plays the role of ligand. Under
specific working conditions, the reaction of ethylene glycol with FeIII and CoII nitrates in dilute acid
solutions occurs with the oxidation of the former to glyoxylic acid, coordinated to the CoII and FeIII cations
as glyoxylate anion (C 2H2O4 2−), with simultaneous isolation of the heteropolynuclear coordination
compound. In order to separate and identify the ligand, the synthesized coordination compound, having the
composition formula Co 4Fe10(L)9(OH) 20(H2O)32·14H 2O, where L is the glyoxylate anion, has been treated
with R–H cationite (Purolite C-100). After the retention of the metal cations, the resulting glyoxylic acid
was confirmed by measuring its physical constants, by specific reactions and through spectroscopic
methods. The synthesized coordination compound was characterized by physical–chemical analysis,
electronic spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) and
thermal analysis. Cobalt ferrite impurified with ferric oxide was obtained following the thermal
decomposition of CoII–FeIII polyhydroxoglyoxylate. The oxides obtained through thermolysis were studied
by FTIR, XRD, scanning electron microscopy (SEM) and elemental analysis.
Keywords (separated by '-') CoII–FeIII polyhydroxoglyoxylate – Heteropolynuclear coordination compound – Glyoxylic acid – Cobalt
ferrite – Thermal analysis – X-ray diffractometry
Footnote Information Mihail Bîrzescu: Deceased in 2012.

UNCORRECTEDPROOF12
3Thermal and spectroscopic analysis of Co(II) –Fe(III)
4polyglyoxylate obtained through the reaction of ethylene glycol
5with metal nitrates
6Mircea Niculescu1·Mihai-Cosmin Pascariu2,3,4·Cornelia Muntean1,5·
7Viorel Sasca6·Lavinia Lupa1·Marius-Silviu Milea1·Mihail BŸrzescu1
8 Received: 9 June 2016 / Accepted: 19 December 2016
9©Akade ´miai Kiado ´, Budapest, Hungary 2016
10 Abstract The synthesis and thermal and spectroscopic
11 studies of a new CoII–FeIIIheteropolynuclear coordination
12 compound are presented. The in situ oxidation product of
13 ethylene glycol plays the role of ligand. Under specific
14 working conditions, the reaction of ethylene glycol with FeIII
15 and CoIInitrates in dilute acid solutions occurs with the
16 oxidation of the former to glyoxylic acid, coordinated to the
17 CoIIand FeIIIcations as glyoxylate anion (C 2H2O42−), with
18 simultaneous isolation of the heteropolynuclear coordina-
19 tion compound. In order to separate and identify the ligand,
20 the synthesized coordination compound, having the com-
21 position formula Co 4Fe10(L)9(OH) 20(H2O)32·14H 2O, where22 Lis the glyoxylate anion, has been treated with R–H cationite
23 (Purolite C-100). After the retention of the metal cations, the
24 resulting glyoxylic acid was confirmed by measuring its
25 physical constants, by specific reactions and through spec-
26 troscopic methods. The synthesized coordination compound
27 was characterized by physical–chemical analysis, electronic
28 spectroscopy, Fourier transform infrared spectroscopy
29 (FTIR), X-ray diffractometry (XRD) and thermal analysis.
30 Cobalt ferrite impurified with ferric oxide was obtained
31 following the thermal decomposition of CoII–FeIIIpolyhy-
32 droxoglyoxylate. The oxides obtained through thermolysis
33 were studied by FTIR, XRD, scanning electron microscopy
34 (SEM) and elemental analysis. 35
36 Keywords CoII–FeIIIpolyhydroxoglyoxylate ·
37 Heteropolynuclear coordination compound · Glyoxylic
38 acid · Cobalt ferrite · Thermal analysis · X-ray
39 diffractometry
40 Introduction
41 Starting with the nineteenth century and up until present
42 day, the mono- and polynuclear coordination compounds
43 that possess carboxylic acids and their derivatives as
44 ligands gained a notable place in the coordination chem-
45 istry [ 1–6]. Besides their theoretical interest, these complex
46 combinations are used in the chemical industry (heteroge-
47 neous chemical catalysis, electrocatalysis, preparation of
48 special oxidic systems and ceramic pigments), electrical
49 engineering, information technology, pharmaceutical areas
50 and others [ 7–14].
51 The classical methods of obtaining such coordination
52 compounds involve the aqueous treatment of metal salts with
53 carboxylic acids or carboxylates. Depending on the cation
54 involved, the precipitation of the coordination compoundA1 Mihail Bı ˆrzescu: Deceased in 2012.
A2&Mihai-Cosmin Pascariu
A3 mihai.cosmin.pascariu@gmail.com
A4&Cornelia Muntean
A5 cornelia.muntean@upt.ro
A61Faculty of Industrial Chemistry and Environmental
A7 Engineering, Politehnica University of Timis ¸oara, 6 Vasile
A8 Pa ˆrvan Blvd., 300223 Timisoara, Romania
A92Faculty of Pharmacy, “Vasile Goldis ¸” Western University of
A10 Arad, 86 Liviu Rebreanu, 310414 Arad, Romania
A113Faculty of Medicine, “Victor Babes ¸” University of Medicine
A12 and Pharmacy of Timis ¸oara, 2 Eftimie Murgu Sq.,
A13 300041 Timisoara, Romania
A144National Institute of Research and Development for
A15 Electrochemistry and Condensed Matter – INCEMC, 144 Dr.
A16 Aurel Pa ˘unescu-Podeanu, 300569 Timisoara, Romania
A175Research Institute for Renewable Energy, Politehnica
A18 University of Timis ¸oara, 2 Victoriei Sq., 300006 Timisoara,
A19 Romania
A206Institute of Chemistry Timis ¸oara of Romanian Academy, 24
A21 Mihai Viteazul Blvd., 300223 Timisoara, Romania
AQ1
AQ2
123
Journal : Large 10973 Dispatch : 28-12-2016 Pages : 10
Article No. : 6079LE TYPESET
MS Code : JTAC-D-16-00782 CP DISK44
J Therm Anal Calorim
DOI 10.1007/s10973-016-6079-1Author Proof

UNCORRECTEDPROOF55 takes place at certain pH values, established with or without
56 the addition of alkaline hydroxides [ 15–17].
57 A number of new, unconventional methods have been
58 developed in order to obtain oxidic systems with special
59 structures and properties, which are required by the modern
60 technologies. One of these, which gained popularity start-
61 ing with the 1990s, uses polynuclear coordination
62 compounds with the glyoxylate anion as ligand, obtained
63 by a new protocol [ 18,19].
64 Polyols can be oxidized to aldehydes, carboxylic acids
65 or compounds with mixed functions, depending on the
66 oxidizing agents and the working conditions, as already
67 established in the literature [ 20–24]. Thus, 1,2-ethanediol
68 (ethylene glycol, EG) can be oxidized to glycolic aldehyde,
69 glyoxal, glycolic, glyoxylic and oxalic acids. In a strongly
70 acidic environment and with energetic oxidizers, a
71 degradative oxidation of EG, which proceeds with the
72 breaking of the C–C bond, takes place, and formaldehyde,
73 formic acid and carbon dioxide are obtained [ 25–27].
74 In order to obtain only one of these oxidation products,
75 some well-defined working conditions are required. These
76 include an adequate oxidizing agent, concentration of
77 reactants, acidity, temperature and heating rate [ 27].
78 The literature [ 28] mentions that the glyoxylic acid is
79 obtained through the mild oxidation of EG with a nitric
80 acid solution. In addition, Knetsch and Groeneveld [ 29]
81 obtained the Cu(EG) 2(NO 3)2combination by concentrating
82 through evaporation a solution containing 0.01 mol [Cu
83 (OH 2)6](NO 3)2dissolved in 0.02 mol EG. The highly
84 hygroscopic combination rapidly decomposes with the
85 release of NO 2. Although this process has not been studied
86 in depth by the two authors, Bı ˆrzescu [ 19] later showed that
87 a redox reaction takes place between EG and the NO 3−ions
88 during the evaporation of the respective solution.
89 A series of homo- and heteropolynuclear glyoxylates have
90 been obtained and characterized by means of a new method
91 elaborated by the later author. The method is based on the
92 oxidation of EG to the glyoxylate dianion, C 2H2O42−(GA), by
93 some metal nitrates, during the heating of their aqueous solu-
94 tion. The oxidation reaction is car ried out in the absence of other
95 reagents, simultaneously with t he isolation of the correspond-
96 ing solid glyoxylates. The yield of the synthesis exceeds 80%.
97 The aerobic thermal conversion of the homopolynuclear
98 MIIglyoxylates, namely [MC 2H2O4(OH 2)2]n(M=Mn,
99 Co, Ni) and [CuC 2H2O4·0.5H 2O]n, allowed for the prepa-
100 ration of some (nonstoichiometric) metal oxides containing
101 the metal at different oxidation states: α-Mn 2O3−x,C o 3O4
102+xor NiO 1+x, and CuO or Cu 2O, respectively [ 19]. These
103 oxides are obtained at relatively low temperatures (300–
104 400°C) with a high degree of reproducibility.
105 After establishing the conditions for the production of
106 nickel and cobalt nonstoichiometric oxides, an original
107 method of obtaining anodes with electrocatalytic active films108 was elaborated [ 19,30]. The thus obtained anodes can be used
109 for oxygen discharge during electrolysis of alkaline solutions.
110 This paper is part of a series of studies concerned with
111 the elaboration of new methods for obtaining coordination
112 compounds through the oxidation of diols with metal
113 nitrates [ 31–45]. A large variety of coordination com-
114 pounds was prepared by this original synthesis procedure.
115 The obtained compounds decompose to simple or mixed
116 oxides at relatively low temperatures. The main objective
117 of this research is to highlight the importance of the pre-
118 cursor’s nature in the synthesis of simple and mixed metal
119 oxides with different properties and applications.
120 In the present paper, the preparation of CoII–FeIII
121 polyhydroxoglyoxylate from an aqueous EG/cobalt(II)
122 nitrate/iron(III) nitrate system is presented from the syn-
123 thesis–structure relationship viewpoint. In addition, a novel
124 method, which can be used as an alternative way for the
125 synthesis of the glyoxylic acid through the decomposition
126 of this new coordination compound, is also described.
127 Experimental
128 Materials and methods
129 The reagents, all acquired from commercial sources, were
130 of analytical grade. EG, Co(NO 3)2.6H 2O and Fe(NO 3)3·9-
131 H2O (Merck) had a minimum purity of 99% w/w. A
132 0.1 mol L−1nitric acid solution was used.
133 The coordination compound was characterized using the
134 following methods: Fourier transform infrared spec-
135 troscopy (FTIR), electronic spectroscopy (diffuse
136 reflectance technique), X-ray diffractometry (XRD), ther-
137 mal analysis and chemical analyses.
138 The FTIR spectra were recorded using KBr pellets on a
139 Jasco FT/IR-410 spectrometer, in the 400–4000 cm−1
140 range, while the diffuse reflectance spectrum was recorded
141 with a PerkinElmer Lambda 950 spectrophotometer, using
142 Spectralon®(a sintered polytetrafluoroethylene material) as
143 reflection standard.
144 TG, DTG and DTA curves were recorded on a Mettler
145 TGA/SDTA 851/LF1100 thermoanalyzer system in the 25–
146 1000 °C temperature range, with a heating rate of 10 °
147 C min−1. The measurements were taken in dynamic air
148 atmosphere at a flow rate of 0.05 L min−1, using 150- μL
149 alumina crucibles and samples of about 30 mg.
150 The XRD patterns were recorded at room temperature
151 using a Rigaku Ultima IV diffractometer with CuK αradi-
152 ation ( λ=1.5406 A ˚). The average crystallite size ( d) and
153 the phase proportions in the samples were calculated using
154 the whole pattern profile fitting (WPPF) method. The
155 instrument influence was subtracted using the diffraction
156 pattern of a Si standard recorded in the same conditions.M. Niculescu et al.
123
Journal : Large 10973 Dispatch : 28-12-2016 Pages : 10
Article No. : 6079LE TYPESET
MS Code : JTAC-D-16-00782 CP DISK44
Author Proof

UNCORRECTEDPROOF157 The solid-state decomposition products formed during
158 heating were also obtained in a Nabertherm LE 6/10B150
159 oven by using the same temperature regime as for the
160 thermal analysis. The obtained powders were characterized
161 by FTIR, XRD and scanning electron microscopy (SEM).
162 The surface morphology was studied by SEM, using a
163 FEI Quanta FEG 250 instrument.
164 Synthesis of the coordination compound
165 and separation of glyoxylic acid
166 The synthesis of the complex compound is based on the
167 oxidation of EG by CoIIand FeIIInitrates in a diol–water
168 mixture, with the simultaneous isolation of the coordina-
169 tion compound from the reaction system.
170 An aqueous solution of Co(NO 3)2·6H 2O, Fe(NO 3)3·9-
171 H2O and EG, in the 1:2:2 molar ratio, was prepared. A few
172 drops of aqueous nitric acid were also added to set the pH
173 value at 3.0. This mixture was gradually heated up to 90 °C
174 in a thermostat. The reaction was considered as complete
175 when the gas evolution has ceased.
176 The solid, powdery reaction product was purified by
177 refluxing in an acetone–water (5:1 v/v) mixture. The sus-
178 pension was then filtered, and the reddish brown solid was
179 washed with acetone and finally maintained in air until
180 constant mass (in order for the complex compound to
181 stabilize itself as hydrate, by retaining from the atmosphere
182 the necessary lattice water). The yield was 65% (based on
183 EG). The metal nitrates were entirely consumed during the
184 synthesis of the coordination compound. This was verified
185 by treating a sample with concentrated sulfuric acid, when
186 no release of brown vapors was observed. A negative result
187 was also obtained for the ring reaction (no intensely brown-
188 colored [Fe(H 2O)5NO]SO 4was obtained in the reaction
189 with FeSO 4and H 2SO4). The Braccio reaction was nega-
190 tive as well (no NO/C0
3or NO/C0
2anions were shown by the
191 antipyrine test, so the oxidizing action of the nitrate anion
192 did not cause its reduction to the nitrite anion).
193 In order to separate and identify the ligand, the aqueous
194 suspension of the obtained coordination compound was
195 treated with R–H cationite. After the retention of the metal
196 cations, the resulting acidic solution was lyophilized and a
197 white, crystalline solid was obtained.
198 Results and discussion
199 Identification of the ligand through physical –
200 chemical analysis
201 The obtained lyophilization product is the ligand in its
202 protonated form, which was identified by specific reactions
203 and physical measurements. This is a highly water-soluble204 product, with a poor solubility in alcohols and ethylic ether,
205 and with a 98 °C melting point. The physical properties of
206 the lyophilization product and the following analyses lead
207 to the conclusion that this substance is glyoxylic acid.
208 In the FTIR spectrum of the lyophilization product
209 (Fig. 1), we can observe the bands characteristic of the two
210 forms of the glyoxylic acid, which exist in equilibrium:
HCO/C0COOH țH2O/C10HOðȚ2HC/C0COOH
glyoxylic acid I ðȚ hydrated glyoxylic acid II ðȚð1Ț
212 212 The broad band in the range of 3200–3600 cm−1, with a
213 maximum at 3390 cm−1, is attributed to the stretching of the
214 two different sorts of O–H bond—the one in the acid group
215 and the simple “alcohol” type in the hydrated aldehyde group
216 (II). The sharp band at 1731 cm−1is assigned to the ν(C=O)
217 vibration. The band at 1629 cm−1is attributed to the asym-
218 metric vibration of the carboxylate group. The band with
219 maximum at 1380 cm−1is assigned to the νsym(OCO) sym-
220 metric vibration. The band with maximum at 1232 cm−1can
221 be attributed to the coupling between a stretching vibration,
222 ν(CO), and a bending vibration, δ(OH). The two bands at
223 1089 and 993 cm−1are assigned to the hydrated aldehyde
224 [gem-diol, CH(OH) 2]. The band with maximum at 661 cm−1
225 is attributed to the δ(OCO) bending vibration [ 46–48].
226 The chemical investigation of the lyophilization product
227 was carried out through specific redox, color and precipi-
228 tation reactions. Firstly, the reaction with silver oxide
229 (Ag 2O) produced metallic silver. Secondly, the reaction
230 with metallic zinc gave glycolic acid. Thirdly, after the
231 reaction with indole or pyrogallol in concentrated sulfuric
232 acid, a red or, respectively, blue color occurred. Fourthly,
233 following the reaction with resorcinol, the lactone of the
234 2,2′,4,4′-tetraoxodyphenylacetic acid was formed in the
235 presence of sulfuric acid; the oxygen, in alkaline medium,
236 oxidized the lactone and a blue-violet color appeared.
237 Lastly, precipitates were obtained in the reactions with p-
238 nitrophenylhydrazine and 2,4-dinitrophenylhydrazine.
239 All these results are in good agreement with the litera-
240 ture data regarding glyoxylic acid [ 19,49,50].
241 Characterization of the coordination compound
242 The elemental analysis results (Table 1), as well as the
243 FTIR investigation, have indicated that the synthesized
244 coordination compound has the following empirical
245 chemical formula: CoFe 2.5(OH) 5(L)2.25(H2O)8·3.5H 2O,
246 where L is the glyoxylate dianion (C 2H2O42−).
247 These results, as well as those previously reported
248 concerning the oxidation of diols with metal nitrates
249 [30–33,40,49], suggest that the oxidation of EG with Fe
250 (NO 3)3and Co(NO 3)2proceeds, in our working conditions,
251 to glyoxylate anion, coordinated to FeIIIand CoIIions.Thermal and spectroscopic analysis of Co(II)–Fe(III) polyglyoxylate obtained through…
123
Journal : Large 10973 Dispatch : 28-12-2016 Pages : 10
Article No. : 6079LE TYPESET
MS Code : JTAC-D-16-00782 CP DISK44
Author Proof

UNCORRECTEDPROOF
252 Accordingly, we suggest the following mechanism for
253 the reaction between EG and these metal nitrates:
C2H3O/C0
4ț6e/C0ț7Hț/C10C2H4OHðȚ2+2 H 2O ð2Ț
255 255 NO/C0
3+3 e/C0ț4Hț!NOț2H2O ð3Ț
257 257 C2H4OHðȚ2ț2NO/C0
3țHț/C10C2H3O/C0
4ț2NOț2H2O
ð4Ț
259 259 Fe H 2OðȚ6/C2/C33țț2H2O/C10Fe OHðȚ2H2OðȚ4/C2/C3țț2H3Oț
ð5Ț
261 261 Co H 2OðȚ6/C2/C32ț/C10Co H 2OðȚ6/C2/C32țð6Ț
263 263 (in the working conditions, hydrolysis virtually does not
264 occur for the CoIIaquacation)
265 By summing Eqs. 4,5and 6, and considering the
266 interaction of the ligands with the metal cations, we obtain:
18 NO/C0
3ț4C oH 2OðȚ6/C2/C32țț10 Fe OH ðȚ2H2OðȚ4/C2/C3ț/C16/C17
ț9C 2H4OHðȚ2/C0!țxH2OCo4Fe10OHðȚ20C2H2O4 ðȚ9/C1xH2O
ț18 NO ț82 H 2O
ð7Ț
268 268 2NO gðȚ+O 2gðȚ ! 2NO 2gðȚ ð 8Ț
270 270 After analyzing the previous reactions, one may notice the
271 need for the presence of protons generated as seen in Eq. 5,
272 in order to potentiate the oxidation activity of the nitrate
273 ion, and the fact that FeIIIis a complex generator, being a
274 stronger Lewis acid than CoII.275 The suggested formula of the coordination compound,
276 as well as the information concerning its structure, will be
277 confirmed by the next results.
278 The diffuse reflectance spectrum of the coordination
279 compound shows the presence of the characteristic bands
280 for the hexacoordinated CoIIand FeIIIions in a (pseudo)
281 octahedral environment (Fig. 2).
282 The reflectance spectrum reveals at 330 nm the forbid-
283 den spin transition band,6A1g→4Eg(G), which is
284 attributed to the FeIIIion. The band located at 420 nm
285 (small shoulder) is due to the L→FeIIIcharge transfer. The
286 bands that appear in the 800–1100 nm range are also
287 attributed to the FeIIIion in a high-spin octahedral con-
288 figuration,6A1g→4T1g(G) [ 19,48].
289 Accordingly, the FeIIIion exists in the fundamental
290 state, t3
2ge2
g, high spin, the three ligands (HO–,Land H 2O)
291 being of low field and of similar strength.
292 The spin-allowed transition band,4T1g(F)→4T1g(P)
293 (ν3), located at 480 nm (shoulder), is characteristic of CoII
294 ion in a high-spin octahedral configuration ( t5
2ge2
g)[51].
295 Also, the absence of the band at 700 nm due to the
2964T1(P)←4A2transition, characteristic of tetracoordinated
297 CoII, shows that CoIIis hexacoordinated in the complex
298 compound. The relatively low intensity band that appears
299 at 1390 nm due to the6A1g→4T1g(G) ( ν1) transition is also
300 attributed to the CoIIion [ 52]. CoIIIions have not been
301 identified.
302 The overall shape of the electronic spectrum, together
303 with the width and asymmetry of the bands, are proofs for
3390
1731
1089123213801629
993
661
Wavenumber/cm–1Transmittance/%
3900 3400 2900 2400 1900 1400 900 40090
70
50
30
10
–10Fig. 1 FTIR spectrum of the
isolated glyoxylic acid
Table 1 Elemental analysis data of the coordination compound
Compound (empirical chemical formula) %C %H %Fe %Co
CoFe 2.5(L)2.25(OH) 5(H2O)8·3.5H 2O Found Calc. Found Calc. Found Calc. Found Calc.
7.68 7.79 4.54 4.69 19.98 20.19 8.62 8.51M. Niculescu et al.
123
Journal : Large 10973 Dispatch : 28-12-2016 Pages : 10
Article No. : 6079LE TYPESET
MS Code : JTAC-D-16-00782 CP DISK44
Author Proof

UNCORRECTEDPROOF304 the deformation of the octahedral coordination for both
305 metal cations.
306 In order to obtain further information regarding the
307 structure of the synthesized compound and the ligands
308 coordination, the FTIR spectrum was recorded in the 400–
309 4000 cm−1range (Fig. 3).
310 Table 2shows the characteristic FTIR bands for the
311 synthesized coordination compound and the corresponding
312 assignments.
313 The broad band in the 3200–3600 cm−1range, with a
314 maximum at 3411 cm−1, is attributed to the formation of
315 hydrogen bonds between the water molecules and the
316 hydroxyl groups [ 19,53]. The intense band at 1626 cm−1is
317 attributed to the asymmetrical vibration of the carboxylate
318 group, the value also showing that the carboxylate reso-
319 nance is maintained during complex formation and that the
320 metal–carboxylate bond has a predominantly ionic char-
321 acter [ 48].
322 The band with the maximum at 1384 cm−1is attributed
323 to the νsym(OCO) vibration. As the difference between
324 νasym and νsymis higher than 170 cm−1, we may conclude325 that the metal–carboxylate bond is preponderantly ionic
326 and that the carboxylate group acts as a bidentate ligand
327 [48,53]. In addition, the existence of the two bands for
328 νsym(OCO) can be explained through the octahedral
329 deformation. The band at 1320 cm−1confirms again that
330 the carboxylate group is acting as a bidentate ligand
331 [30,48]. The band at 1130 cm−1is attributed to the C–OH
332 vibration. The bands of weak intensity at 1027 and
333 1053 cm−1are assigned to the vibration of the OH bridge
334 group. The band at 826 cm−1is attributed to the δasym(-
335 OCO) vibration [ 46,47].
336 The synthesized reddish brown solid shows a remark-
337 able stability, due to the very strong hydrogen bonds
338 between adjacent layers; therefore, it is practically insol-
339 uble in water and in common organic solvents. In pure
340 state, its composition does not alter with time and it can
341 only be destroyed in a strong acidic medium or by treat-
342 ment with concentrated ammonia, when CoIIforms
343 ammine complexes.
344 These results, as well as the above-mentioned data,
345 suggest a polynuclear structure that corresponds to the
346 following formula:
347 [Co 4Fe10(C2H2O4)9(OH) 20(H2O)32]n·14nH 2O.
348 In order to be consistent with the elemental analysis
349 data, the distorted octahedral stereochemistry of CoIIand
350 FeIIIions and the bridging glyoxylate anion, we propose
351 the structure from Fig. 4for the synthesized
352 heteropolynuclear coordination compound.
353 Thermal decomposition of CoII–FeIII
354 polyhydroxoglyoxylate
355 In order to confirm the structural formula of the studied
356 coordination compound, as well as to establish the steps of
357 its thermal conversion and the decomposition products
200 400 600 800 1000 1200 1400 1600
Wavelength/nmReflectance/%60
50
40
30
20
10
0
Fig. 2 Diffuse reflectance spectrum of the coordination compound
Wavenumber/cm–13900 3400
3411
1626
15651384
1320
1130
701 826
645
593
2900 2400 1900 1400 900 400Transmittance/%100
80
60
40
20
0
Fig. 3 FTIR spectrum of the synthesized coordination compoundTable 2 Characteristic FTIR absorption bands for the coordination
compound, together with the corresponding assignments
Wavenumber/cm−1Assignment
3411 vs, b ν(OH)
1626 vs νasym(OCO)+δ(H2O*)
1565 m, sh Lattice water
1384 m νsym(OCO) and/or ν(C–C)
1320 m νsym(OCO) and/or δsym(OCO)
1130 m ν(C–O)+δ(Fe–OH)
826 w δasym(OCO)
701 m ρ(H2O*)
645 m Lattice water
593 m ν(Co–O)
sstrong ( vvery), bbroad, mmedium, wweak, shshoulder, H2O*
coordinated waterThermal and spectroscopic analysis of Co(II)–Fe(III) polyglyoxylate obtained through…
123
Journal : Large 10973 Dispatch : 28-12-2016 Pages : 10
Article No. : 6079LE TYPESET
MS Code : JTAC-D-16-00782 CP DISK44
Author Proof

UNCORRECTEDPROOF358 formed during heating, the thermoanalytical methods have
359 been used. The TG, DTG and DTA curves of the CoII–FeIII
360 polyhydroxoglyoxylate hydrate’s decomposition in
361 dynamic oxidative atmosphere are shown in Fig. 5.
362 The thermal decomposition reactions of CoII–FeIII
363 polyhydroxoglyoxylate were monitored by FTIR, XRD and
364 SEM. Figure 6shows the 400–2000 cm−1range FTIR
365 spectra of the thermal decomposition products.
366 The FTIR spectrum recorded for the residue obtained
367 through thermal decomposition of the polynuclear coordi-
368 nation compound in air at 350 °C (Fig. 6a) reveals the
369 disappearance of its characteristic bands, confirming its
370 degradation. The two sharp and strong bands at 1145 cm−1
371 and 1099 cm−1are assigned to the ν(C–O) stretching
372 vibration for CoCO 3, one of the compounds that are formed
373 during the thermal decomposition [ 54]. The bands at
374 1636 cm−1(m), 632 cm−1(s), 565 cm−1(m) and 490 cm−1375 (m) are assigned to Fe 2O3[53,54]. This FTIR spectrum
376 also reveals the characteristic absorption bands of CoFe 2O4
377 nanoparticles at about 612 cm−1(s) and 408 cm−1(m) due
378 to the Co–O and Fe–O stretching vibrations [ 51,54]. The
379 same bands, but more intense, are found in the FTIR
380 spectrum recorded for the residue obtained at 500 °C
381 (Fig. 6b).
382 The FTIR spectra of the thermal decomposition products
383 obtained at 800 °C (Fig. 6c) and 1000 °C (Fig. 6d) show the
384 bands at 607 cm−1(vs) and 401 cm−1(s), assigned to the
385 CoFe 2O4, and the characteristic bands of α-Fe2O3at
386 1637 cm−1(w) and 478 cm−1(w/m), which are the end-
387 products of the thermal decomposition [ 51,54]. The other
388 weak bands are not relevant to the decomposition of CoII–
389 FeIIIpolyhydroxoglyoxylate.
390 The XRD analysis, which is the most useful technique
391 for the identification of a crystalline structure, was
Fe Fe Fe
Fe Fe CoFeO
OO
O OOO OO O
O O OHCo CoOH
OH
OHOH
OHOH
OH2 OH2OH2 OH2 OH2
HH
HHH
HFig. 4 Proposed structure for
the heteropolynuclear
coordination compound
314 °C249 °C199 °C103 °C287 °C
380 °C 570 °C723 °C
760 °CTGDTGDTA217 °C158 °C318 °CII I III IV V VI Exo
0 200 400 600 800 1000
Temperature/°C100
90
80
70
60
50
40
30Mass/%
DTA/°C20
10
0
–10
–20
DTG/%/min
–2.52.5
0
–55Fig. 5 Thermoanalytical curves
for the aerobic decomposition of
CoII–FeIII
polyhydroxoglyoxylate hydrateM. Niculescu et al.
123
Journal : Large 10973 Dispatch : 28-12-2016 Pages : 10
Article No. : 6079LE TYPESET
MS Code : JTAC-D-16-00782 CP DISK44
Author Proof

UNCORRECTEDPROOF
392 employed to investigate the crystallinity and purity of the
393 solid products obtained by thermal conversion of the
394 polynuclear coordination compound in air. The XRD pat-
395 terns of the complex and of the powders obtained by its
396 annealing at 350, 500, 800 and 1000 °C are shown in
397 Fig.7.
398 Although in the complex’s pattern some weak diffrac-
399 tion peaks are present, the crystalline phase could not be
400 identified. The analyzed complex is a new compound, with
401 a low crystallization degree. The powder obtained by the
402 coordination compound’s annealing at 350 °C also has a
403 low crystallization degree, but the emergence of the spinel
404 phase was observed.
405 In addition to the lines of the cubic CoFe 2O4phase
406 (ICDD—International Centre for Diffraction Data file
407 00-022-1086), the diffraction lines of the rhombohedral α-
408 Fe2O3phase (01-089-0598) were also recorded in the
409 pattern of the sample annealed at 500 °C. The presence of
410 α-Fe2O3in the sample annealed at 500 °C shows that, at
411 350°C, the powder contains a mixture of spinel phases
412 (CoFe 2O4and γ-Fe2O3) whose lines overlap. Following the
413 annealing at 500 °C,γ-Fe2O3was converted to α-Fe2O3
414 [55–57]. In the diffraction pattern, the weak lines of
415 rhombohedral CoCO 3phase (00-011-0692) were also
416 recorded.417 The pattern of the powder obtained at 800 °C displays
418 only the diffraction lines of CoFe 2O4andα-Fe2O3, which
419 are present in the sample in proportions of 76% and 24%,
420 respectively. Both phases have the average crystallite size
421 din the nanometer range (39 nm for CoFe 2O4and 46 nm
422 forα-Fe2O3). The composition of the powder obtained at
423 1000°C is the same, containing both CoFe 2O4(78%) and
424 α-Fe2O3(22%), but the phases are better crystallized than
425 at 800 °C.
426 Regarding the thermoanalytical curves [ 58,59] pre-
427 sented in Fig. 5, we can now make the following
428 comments.
429 In the 20–287 °C temperature range, the TG and DTG
430 profiles show water removal in three steps, with maximum
431 rates at 103 °C (I, Eq. 9), 199 °C (II, Eq. 10) and 249 °C
432 (III, Eq. 11). The lattice water, the coordinated water and
433 additional water chemically obtained from the OH groups
434 are all lost up to around 287 °C (mass loss: found 33.36%,
435 calculated 32.44%). In this temperature range, the DTA
436 curve displays three broad endothermic peaks.
437 The coordinated water is bounded weaker to the CoII,
438 and the majority is lost in the second step. FeIIIis a much
439 stronger complex generator; therefore, water molecules
440 bind more strongly and are lost with greater difficulty in the
2000 1800 1600 1400 1200 1000 800 600
607
4014781637 1632408490565612632
4781637
401607109911451636
1144
1098
630
612
568
407723
484
400
Wavenumber/cm–1Transmittance/%
2000 1800 1600 1400 1200 1000 800 600 400
Wavenumber/cm–12000 1800 1600 1400 1200 1000 800 600 400
Wavenumber/cm–12000 1800 1600 1400 1200 1000 800 600 400
Wavenumber/cm–1
100
80
60
40
20
0Transmittance/%100
80
60
40
20
0Transmittance/%100
80
60
40
20
0Transmittance/%100
80
70
60
5090
(a)
(c) (d)(b)
Fig. 6 FTIR spectra of the thermal decomposition products at a350°C,b500°C,c800°C and d1000°CThermal and spectroscopic analysis of Co(II)–Fe(III) polyglyoxylate obtained through…
123
Journal : Large 10973 Dispatch : 28-12-2016 Pages : 10
Article No. : 6079LE TYPESET
MS Code : JTAC-D-16-00782 CP DISK44
Author Proof

UNCORRECTEDPROOF
441 third step, together with the water resulting from the OH
442 groups (when oxo bridges are formed).
443 The strong exothermic effect that characterizes step IV
444 (maximum at 318 °C) is due to the ligand combustion
445 (Eq. 12). In the sixth and final step (Eq. 14), a mixture of
446 CoFe 2O4spinel (predominant) and α-Fe2O3is formed447 (Fig. 7) (according to elemental analysis, calculated/found
448 %Co: 21.45/21.36; %Fe: 51.68/51.75). The final decom-
449 position product obtained at 1000 °C, which is a black
450 powder, has the same composition (cobalt ferrite and
451 hematite mixture), but it is better crystallized, as seen in
452 Fig. 7(total mass loss throughout the thermal decomposi-
453 tion: found 60.31%, calculated 60.35%).
454 To conclude, the registered TG, DTG and DTA curves
455 suggest that the following steps occur during the progres-
456 sive aerobic heating of CoII–FeIIIpolyhydroxoglyoxylate
457 hydrate:
Co4Fe10OHðȚ20C2H2O4 ðȚ9H2OðȚ32
/C114H 2OðsȚ /C0 !I20/C0158/C14C ðȚ /C014H2OCo4Fe10OHðȚ20C2H2O4 ðȚ9
H2OðȚ32ðsȚ
ð9Ț
459 459Co4Fe10OHðȚ20C2H2O4 ðȚ9H2OðȚ32ðsȚ /C0!II158/C0217/C14C ðȚ /C012H2O
Co4Fe10OHðȚ20C2H2O4 ðȚ9H2OðȚ20ðsȚ
ð10Ț
461 461Co4Fe10OHðȚ20C2H2O4 ðȚ9H2OðȚ20ðsȚ /C0!III217/C0287/C14C ðȚ /C024H2O
Co4Fe10O4OHðȚ12C2H2O4 ðȚ9ðsȚ
ð11Ț
463 463Co4Fe10O4OHðȚ12C2H2O4 ðȚ9ðsȚ /C0!IV287/C0380/C14C ðȚ ț9O2
2CoFe 2O4ðsȚț3c-Fe2O3ðsȚ+ 2CoCO 3ðsȚ+ 16CO 2ðgȚ
+ 15H 2OðgȚ
ð12Ț
465 4653c-Fe2O3ðsȚ/C0!V400/C0500/C14C ðȚ3a-Fe2O3ðsȚ ð13Ț
467 467a-Fe2O3ðsȚ+ CoCO 3ðsȚ /C0!VI570/C0760/C14C ðȚ /C0CO 2CoFe 2O4ðsȚð14Ț
2θ/°10 20 30 40 50 60 70 80Complex350 °C500 °C800 °C1000 °CIntensity/a.u.CoCO3α-Fe2O3CoFe2O4
Fig. 7 XRD patterns of the CoII–FeIIIpolyhydroxoglyoxylate and of
the powders obtained by annealing at 350, 500, 800 and 1000 °C
Fig. 8 SEM images of the powders obtained by CoII–FeIIIpolyhydroxoglyoxylate’s annealing at a350°C and b800°CM. Niculescu et al.
123
Journal : Large 10973 Dispatch : 28-12-2016 Pages : 10
Article No. : 6079LE TYPESET
MS Code : JTAC-D-16-00782 CP DISK44
Author Proof

UNCORRECTEDPROOF469 469 We can state that the processes observed on the TG curve
470 are global processes and that the proposed decomposition
471 steps represent a complex (macro)mechanism.
472 In order to obtain information about the surface mor-
473 phology and the particle size of the products obtained by
474 thermal decomposition of the polynuclear coordination
475 compound, SEM investigations [ 59] were performed. The
476 SEM images of the powder obtained at 350 °C (Fig. 8a)
477 show spherical morphology for the nanoparticles, with
478 their size being distributed between 15 and 25 nm. The
479 image of the powder obtained through the annealing of the
480 complex at 800 °C (Fig. 8b) shows bigger particles, with
481 their sizes distributed in a wider range (30–150 nm).
482 Conclusions
483 We have elaborated a new method for the synthesis of a
484 novel coordination compound, which is based on the oxi-
485 dation of ethylene glycol by cobalt(II) and iron(III) nitrates
486 in a diol–water mixture. The ethylene glycol’s oxidation
487 product, namely glyoxylic acid, is coordinated by the metal
488 cations in the form of glyoxylate dianion, and thus, the
489 stable complex compound, which is hardly soluble in
490 water, precipitates and is already isolated.
491 The coordination compound synthesized by this new
492 method is a heteropolynuclear combination, having the
493 formula [Co 4Fe10(L)9(OH) 20(H2O)32]n·14nH 2O. This
494 complex has been investigated by physical–chemical
495 analyses, thermal analysis (TG, DTG and DTA), electronic
496 and FTIR spectroscopy. All the experimental investigations
497 lead to the conclusion that this complex is characterized by
498 a (pseudo)octahedral configuration of the cobalt(II) and
499 iron(III) cations.
500 The thermal conversion product obtained at 800 °Ci sa
501 mixture of CoFe 2O4(predominant) and α-Fe2O3. The SEM
502 images showed spherical morphology of particles with
503 their size widely distributed between 30 and 150 nm.
504
505 References
506 1. Brezeanu M, Safarica E, Segal E, Patron L, Robu T. An analysis
507 of thermal decomposition of coordination polynuclear com-
508 pounds in Fe(III), Mn(II), Ni(II) systems. Rev Roum Chim.
509 1982;27:137–40.
510 2. Brezeanu M, Tatu E, Bocai S, Brezeanu O, Segal E, Patron L.
511 Non-isothermal decomposition kinetics of polynuclear coordi-
512 nation compounds. Thermochim Acta. 1984;78:351–5.
513 3. Nicholson GC. The thermal decomposition of ferrous oxalate
514 dehydrate. J Inorg Nucl Chem. 1967;29:1599–604.
515 4. Sadakane M, Takahashi C, Kato N, Ogihara H, Nodasaka Y, Doi
516 Y, Hinatsu Y, Ueda W. Three-dimensionally ordered macrop-
517 orous (3DOM) materials of spinel-type mixed iron oxides.518 Synthesis, structural characterization, and formation mechanism
519 of inverse opals with a skeleton structure. Bull Chem Soc Jpn.
520 2007;80:677–85.
521 5. Buta I, Ianasi C, Savii C, Cseh L, Bakardieva S, Linert W,
522 Costisor O. Synthesis and characterization of New Heterometallic
523 Cobalt-zinc oxalates linked by organic amines. Rev Chim
524 Buchar. 2014;65:416–20.
525 6. Pillar EA, Zhou R, Guzman MI. Heterogeneous oxidation of
526 catechol. J Phys Chem A. 2015;119:10349–59.
527 7. Gao Z, Cui F, Zeng S, Guo L, Shi J. A high surface area
528 superparamagnetic mesoporous spinel ferrite synthesized by a
529 template-free approach and its adsorptive property. Micropor
530 Mesopor Mater. 2010;132:188–95.
531 8. Urbanovici E, Segal E, Andruh M, Brezeanu M. Non-isothermal
532 decomposition kinetics of a mononuclear coordination compound
533 of Fe(II). Thermochim Acta. 1987;118:309–12.
534 9. Andruh M, Brezeanu M, Paraschivoiu I, Segal E. Thermal
535 behaviour of complex cation-complex anion-type coordination
536 compounds. Part I. Thermochim Acta. 1990;161:247–57.
537 10. Dragoe N, Andruh M, Meghea A, Segal E. Thermal behaviour of
538 complex cation-complex anion-type coordination compounds.
539 Part II. Thermochim Acta. 1990;161:259–66.
540 11. Dragoe N, Andruh M, Segal E. Thermal behaviour of complex
541 cation-complex anion type coordination compounds: part IV.
542 Thermochim Acta. 1991;176:241–8.
543 12. Cimpoes ¸u F, Andruh M, Segal E. Thermal behaviour of complex
544 cation-complex anion type coordination compounds: part V.
545 Thermochim Acta. 1991;177:93–100.
546 13. Ferbint ¸eanu M, Andruh M, Segal E. On the thermal behaviour of
547 two coordination compounds of Ni(II) and Co(II). Thermochim
548 Acta. 1991;178:241–8.
549 14. Teica ˘DT, Segal E, Andruh M. On the thermal decomposition of
550 some coordination compounds of copper(II) with benzoylpyri-
551 dine. Thermochim Acta. 1991;178:249–55.
552 15. Yang H, Zhang X, Tang A, Qiu G. Cobalt ferrite nanoparticles
553 prepared by coprecipitation/mechanochemical treatment. Chem
554 Lett. 2004;33:826–7.
555 16. Zhang K, Holloway T, Pradhan AK. Magnetic behavior of
556 nanocrystalline CoFe 2O4. J Magn Magn Mater. 2011;323:1616–
557 22.
558 17. Mohapatra S, Rout SR, Panda AB. One-pot synthesis of uniform
559 and spherically assembled functionalized MFe 2O4(M=Co, Mn,
560 Ni) nanoparticles. Colloids Surf A. 2011;384:453–60.
561 18. Bı ˆrzescu M, Cristea M, S ¸tefa ˘nescu M, Constantin G. Procedeu de
562 obținere a feritei de cobalt (Procedure for Obtaining Cobalt
563 Ferrite). Romanian Patent No. 102.501. IAEM, Timis ¸oara. 1990.
564 19. Bı ˆrzescu M. Combinat ¸ii complexe cu etilen glicol s ¸i produs ¸ii sa˘i
565 de oxidare (Complex combinations with ethylene glycol and its
566 oxidation products). Ph.D. Thesis. University of Bucharest. 1998
567 (in Romanian ).
568 20. Prati L, Rossi M. Gold on Carbon as a new catalyst for selective
569 liquid phase oxidation of diols. J Catal. 1998;176:552–60.
570 21. Porta F, Prati L, Rossi M, Coluccia S, Martra G. Metal sols as a
571 useful tool for heterogeneous gold catalyst preparation: reinvesti-
572 gation of a liquid phase oxidation. Catal Today. 2000;61:165–72.
573 22. Carrettin S, McMorn P, Johnston P, Griffin K, Hutchings GJ.
574 Selective oxidation of glycerol to glyceric acid using a gold
575 catalyst in aqueous sodium hydroxide. Chem Commun.
576 2002;7:696–7.
577 23. Niculescu M. Compus ¸i coordinativi cu liganzi produs ¸i de oxidare
578 a diolilor (Coordination compounds with oxidation products of
579 diols as ligands). Ph.D. Thesis. University Politehnica Timis ¸oara.
580 2004 ( in Romanian ).
581 24. Mehta G, Uma R. Ladderane-like motifs: solid state architecture
582 of trans-1,2-diphenyl-1-cyclobutene-3,4-diol dinitrate. Indian J
583 Chem Sect B Org Chem Incl Med Chem. 1999;38B:1154–8.AQ3Thermal and spectroscopic analysis of Co(II)–Fe(III) polyglyoxylate obtained through…
123
Journal : Large 10973 Dispatch : 28-12-2016 Pages : 10
Article No. : 6079LE TYPESET
MS Code : JTAC-D-16-00782 CP DISK44
Author Proof

UNCORRECTEDPROOF584 25. Ullmann’s encyclopedia of industrial chemistry, 6th ed., 2002.
585 26. Wiberg KB, Scha ¨fer H. Chromic acid oxidation of isopropyl
586 alcohol. The oxidation steps. J Am Chem Soc. 1969;91:933–6.
587 27. Ogata Y. Oxidations with nitric acid or nitrogen oxides. In:
588 Trahanovsky WS, editor. Oxidation in organic chemistry. Part C.
589 New York: Academic Press; 1978. p. 295–342.
590 28. Wilkinson G, Gillard RD, McCleverty JA, editors. Comprehen-
591 sive coordination chemistry. 1st ed. Oxford: Pergamon Press;
592 1987. p. 435–83.
593 29. Knetsch D, Groeneveld WL. Alcohols as ligands: part IV.
594 Complexes of ethylene glycol with some metal(II) sulfates and
595 nitrates. Recl Trav Chim Pays Bas. 1973;92:855–64.
596 30. Ra ˘doi I, Bı ˆrzescu M, Golumbioschi F, S ¸tefa ˘nescu M. Obt ¸inerea
597 de anozi cu pelicule electrocatalitice active din complecs ¸i met-
598 alici, folosit ¸i ıˆn electroliza apei (Obtaining anodes with
599 electrocatalytically active films from metal complexes, used in
600 water electrolysis). Rev Chim Buchar. 1985;36:832–6 (in
601 Romanian) .
602 31. Niculescu M, Bı ˆrzescu M, Budrugeac P, Segal E. Thermal and
603 structural investigation of the reaction between 1,2-propanediol
604 and Ni(NO 3)2·6H 2O. J Therm Anal Calorim. 2001;63:181–9.
605 32. Niculescu M, Bı ˆrzescu M, Budrugeac P, Segal E. Thermal and
606 structural investigation of the reaction between 1,2-propanediol
607 and Co(NO 3)2·6H 2O. J Therm Anal Calorim. 2001;65:881–9.
608 33. Niculescu M, Negrea P, Bı ˆrzescu M, Budrugeac P. Structural
609 investigations and thermal analysis of the coordination compound
610 obtained through the reaction of 1,3-propanediol with Co
611 (NO 3)2·6H 2O. Rev Roum Chim. 2003;48:997–1006.
612 34. Niculescu M, Dumitru R, Magda A, Bandur G, Sisu E. Noi
613 metode de ob ținere a unor acizi carboxilici prin reac ții de oxidare
614 a poliolilor cu azota ți de metal(II). I. Reac ții de oxidare a 1,2-
615 propandiolului cu azota ți de metal(II) (New methods to obtain
616 carboxylic acids by oxidation reactions of polyols with metal(II)
617 nitrates. I. Oxidation reactions of 1,2-propandiol with metal(II)
618 nitrates). Rev Chim Buchar. 2007;58:932–6 (in Romanian) .
619 35. Birzescu M, Niculescu M, Dumitru R, Budrugeac P, Segal E.
620 Copper(II) oxalate obtained through the reaction of 1,2-ethane-
621 diol with Cu(NO 3)2·3H 2O: structural investigations and thermal
622 analysis. J Therm Anal Calorim. 2008;94:297–303.
623 36. Niculescu M, Bı ˆrzescu M, Dumitru R, Sisu E, Budrugeac P. Co
624 (II)–Ni(II) heteropolynuclear coordination compound obtained
625 through the reaction of 1,2-propanediol with metallic nitrates as
626 precursor for mixed oxide of spinel type NiCo 2O4. Thermochim
627 Acta. 2009;493:1–5.
628 37. Birzescu M, Niculescu M, Dumitru R, Carp O, Segal E. Syn-
629 thesis, structural characterization and thermal analysis of the
630 cobalt(II) oxalate obtained through the reaction of 1,2-ethanediol
631 with Co(NO 3)2·6H 2O. J Therm Anal Calorim. 2009;96:979–86.
632 38. Niculescu M, Dumitru R, Magda A, Pode V. New methods to
633 obtain carboxylic acids by oxidation reactions of polyols with
634 metal(II) nitrates. II. Oxidation reactions of 1,3-propanediol with
635 metal(II) nitrates. Rev Chim Buchar. 2013;64:271–4.
636 39. Niculescu M, Budrugeac P. Structural characterization of nickel
637 oxide obtained by thermal decomposition of polynuclear coor-
638 dination compound [Ni 2(OH) 2(H3CCH(OH)
639 COO−)2(H2O)2·0.5H 2O]n. Rev Roum Chim. 2013;58:381–6.
640 40. Niculescu M, Ros ¸u D, Lede ți I, Milea M, Budrugeac P. Thermal
641 and spectroscopic studies of Ni(II)-Fe(III) heteropolynuclear
642 coordination compound obtained through the reaction of 1,2-
643 ethanediol with metallic nitrates. Rev Roum Chim. 2013;58:543–
644 52.
645 41. Niculescu M, Budrugeac P, Lede ți I, Pode V, Birzescu M. Syn-
646 thesis and characterization of the polynuclear coordination
647 compound obtained through the reaction of 1,3-propanediol with
648 Cu(NO 3)2·3H 2O. Rev Roum Chim. 2013;58:387–92.649 42. Niculescu M, Lede țiI ,B ı ˆrzescu M. New methods to obtain
650 carboxylic acids by oxidation reactions of 1,2-ethanediol with
651 metallic nitrates. J Organomet Chem. 2014;767:108–11.
652 43. Bı ˆrzescu M, Milea M, Ros ¸u D, Lede ți I, Rafaila ˘M, Sasca V,
653 Niculescu M. Synthesis and thermal analysis of the nickel(II)
654 oxalate obtained through the reaction of ethylene glycol with Ni
655 (NO 3)2·6H 2O. Rev Roum Chim. 2014;59:555–63.
656 44. Ros ¸u D, Bı ˆrzescu M, Milea MS, Pascariu MC, Sasca V, Nicu-
657 lescu M. Synthesis-structure relationship in the aqueous ethylene
658 glycol-iron(III) nitrate system. Rev Roum Chim. 2014;59:789–
659 96.
660 45. Niculescu M, Magda A, Jurca M, Costea L, Pode V. Thermal and
661 kinetic studies of the polynuclear coordination compound
662 obtained through the reaction of 1,3-propanediol with Ni
663 (NO 3)2·6H 2O. Rev Chim Buchar. 2015;66:1217–21.
664 46. Antti BM. The crystal and molecular structure of cis-Dichloro-bis
665 (1,2-ethanediol)manganese(II) [MnCl 2(C2H6O2)2]. Acta Chem
666 Scand. 1973;27:3513–22.
667 47. Nakamoto K, Morimoto Y, Martell AE. Infrared spectra of
668 aqueous solutions. I. Metal chelate compounds of amino acids.
669 J Am Chem Soc. 1961;83:4528–32.
670 48. Ekstro ¨m GN, McQuillan AJ. In situ infrared spectroscopy of
671 glyoxylic acid adsorption and photocatalysis on TiO 2in aqueous
672 solution. J Phys Chem B. 1999;03:10562–5.
673 49. Ștefa˘nescu M, Sasca V, Bı ˆrzescu M. Thermal behaviour of the
674 homopolynuclear glyoxylate complex combinations with Cu(II)
675 and Cr(III). J Therm Anal Calorim. 2003;72:515–24.
676 50. Sandulescu D. Manualul inginerului chimist (The book of the
677 chemical engineer), vol. Second. Bucharest: Editura Tehnica ˘;
678 1973 (in Romanian) .
679 51. Habibi MH, Parhizkar HJ. FTIR and UV–vis diffuse reflectance
680 spectroscopy studies of the wet chemical (WC) route synthesized
681 nano-structure CoFe 2O4from CoCl 2and FeCl 3. Spectrochim
682 Acta Part A. 2014;127:102–6.
683 52. Brezeanu M, Cristurean E, Antoniu A, Marinescu D, Andruh M.
684 Chimia metalelor (Chemistry of metals). Bucharest: Publishing
685 House of the Romanian Academy; 1990. p. 328–33 (in
686 Romanian) .
687 53. Spectral Database for Organic Compounds, SDBS, http://sdbs.db.
688 aist.go.jp/sdbs/cgi-bin/cre_index.cgi . Accessed 4 April 2016.
689 54. Bentley FF, Smithson LD, Rozek AL. Infrared spectra and
690 characteristic frequencies 700 to 300 cm−1. New York: Wiley;
691 1968.
692 55. Ștefa˘nescu M, Bozdog M, Muntean C, Ștefa˘nescu O, Vlase T.
693 Synthesis and magnetic properties of Co 1-xZnxFe2O4(x=01)
694 nanopowders by thermal decomposition of Co(II), Zn(II) and Fe
695 (III) carboxylates. J Magn Magn Mater. 2015;393:92–8.
696 56. Grigorie AC, Muntean C, Ștefa˘nescu M. Obtaining of γ-Fe2O3-
697 nanoparticles by thermal decomposition of polyethyleneglycol–
698 iron nitrate mixtures. Thermochim Acta. 2015;621:61–7.
699 57. Niculescu M, Sasca V, Muntean C, Milea MS, Ros ¸u D, Pascariu
700 MC, Sisu E, Ursoiu I, Pode V, Budrugeac P. Thermal behavior
701 studies of the homopolynuclear coordination compound iron(III)
702 polyoxalate. Thermochim Acta. 2016;623:36–42.
703 58. Zapała L, Kosin ´ska M, Woz ´nicka E, Byczyn ´ski Ł, Zapała W.
704 Synthesis, spectral and thermal study of La(III), Nd(III), Sm(III),
705 Eu(III), Gd(III) and Tb(III) complexes with mefenamic acid.
706 J Therm Anal Calorim. 2016;124:363–74.
707 59. Predoana L, Jitianu A, Preda S, Malic B, Zaharescu M. Thermal
708 behavior of Li–Co-citric acid water-based gels as precursors for
709 LiCoO 2powders. J Therm Anal Calorim. 2015;119:145–53.AQ4M. Niculescu et al.
123
Journal : Large 10973 Dispatch : 28-12-2016 Pages : 10
Article No. : 6079LE TYPESET
MS Code : JTAC-D-16-00782 CP DISK44
Author Proof

Journal : 10973
Article : 6079 123
the language of science
Author Query Form
Please ensure you fill out your response to the queries raised below and return this form along
with your corrections
Dear Author
During the process of typesetting your article, the following queries have arisen. Please check your typeset proof carefully
against the queries listed below and mark the necessary changes either directly on the proof/online grid or in the ‘Author’s
response’ area provided below
Query Details Required Author’s Response
AQ1 Please check and approve the edit made in the article title.
AQ2 Please check if the corresponding authors affiliations are correctly identified.
AQ3 Please check and confirm the inserted volume number is correctly identified for reference [22].
AQ4 Please provide the author names and initials for reference [25].Author Proof