Final Product Of Thermal Decomposition Research Articles

Synthesis, structure, and thermal stability of new one-dimensional rubidium coordination supramolecular compound

New one-dimensional rubidium dipicolinate hydrate, Rb(Hpdc)(H2pdc)·2H2O, Rb-pdc (H2pdc = pyridine-2,6-dicarboxylic acid) has been grown via hydrothermal method. Single crystal X‐ray diffraction indicates that Rb-pdc reveal a zigzag chain structure, and is composed of RbO7N2 polyhedra, 2,6-pdc ligand, and H2O. Rb-pdc crystallizes in the triclinic space group P1¯ (No.2) with unit cell of a = 6.9050(4) Å, b = 10.9237(7) Å, c = 11.3319(7) Å, α = 94.014(2)°, β = 90.591(2) , γ = 99.6870(10)°, V = 840.28(9) Å3, Z = 2. The observed Rb–O and Rb–N bond distances are 2.904(4)–3.545(4) Å and 3.112(3)–3.159(4) Å, respectively. H-bonds incorporate the chains in Rb-pdc into a 2D (along [1,0,0] direction) network topology. Thermogravimetric analysis (TGA) and powder X-ray diffraction measured at different temperatures show that Rb-pdc exhibits three steps of weight losses, and Rb2O as the final thermal decomposition product is demonstrated. Also, elemental analysis (EA) and infrared (IR) spectrum are performed to identify the chemical composition and characterized bonding.

SYNTHESIS AND STUDIES OF Cu(II),Ni(II),Co(II) COMPLEXES WITH bis(SALICILIDEN)HYDRAZON

New complexes of Cu(II), Co(II), and Ni(II) with bis(salicylidene)hydrazone have been obtained. It has been shown that bis(salicylidene)hydrazone forms bi-nuclear complexes with the ions of these metals. The structure and physicochemical properties of these complexes have been studied by IR, UV spec-troscopy, EPR and thermogravimetric analysis. IR spectra show that coordination of ligand with metal ion is carried out through oxygen atom of phenolic group and nitrogen atom of C=N group. In the elec-tronic spectra of the ligand there are absorption bands of the aromatic ring transition at ~240 and 290 nm (related to π→π* and n- π transitions). The absorption bands at 340 and 380 nm can be attributed to the absorption of the azomethine group conjugated to the benzene ring. On the basis of thermogravimetric analysis the stages of thermal decomposition of synthesized complexes and the composition of solid reaction products obtained at these stages have been determined. It has been shown that the final products of thermal decomposition consist of Co, Ni, Cu oxides. In the EPR spectrum of the copper complex a very weakly asymmetric signal with g=2.10 is observed, which may indicate a tetrahedral (pseudotetrahedral) structure of the complex

Thermally Induced Solid-Phase Quasi-Intramolecular Redox Reactions of [Hexakis(urea-O)iron(III)] Permanganate: An Easy Reaction Route to Prepare Potential (Fe,Mn)Ox Catalysts for CO2 Hydrogenation.

Research on new reaction routes and precursors to prepare catalysts for CO2 hydrogenation has enormous importance. Here, we report on the preparation of the permanganate salt of the urea-coordinated iron(III), [hexakis(urea-O)iron(III)]permanganate ([Fe(urea-O)6](MnO4)3) via an affordable synthesis route and preliminarily demonstrate the catalytic activity of its (Fe,Mn)Ox thermal decomposition products in CO2 hydrogenation. [Fe(urea-O)6](MnO4)3 contains O-coordinated urea ligands in octahedral propeller-like arrangement around the Fe3+ cation. There are extended hydrogen bond interactions between the permanganate ions and the hydrogen atoms of the urea ligands. These hydrogen bonds serve as reaction centers and have unique roles in the solid-phase quasi-intramolecular redox reaction of the urea ligand and the permanganate anion below the temperature of ligand loss of the complex cation. The decomposition mechanism of the urea ligand (ammonia elimination with the formation of isocyanuric acid and biuret) has been clarified. In an inert atmosphere, the final thermal decomposition product was manganese-containing wuestite, (Fe,Mn)O, at 800 °C, whereas in ambient air, two types of bixbyite (Fe,Mn)2O3 as well as jacobsite (Fe,Mn)T-4(Fe,Mn)OC-62O4), with overall Fe to Mn stoichiometry of 1:3, were formed. These final products were obtained regardless of the different atmospheres applied during thermal treatments up to 350 °C. Disordered bixbyite formed first with inhomogeneous Fe and Mn distribution and double-size supercell and then transformed gradually into common bixbyite with regular structure (and with 1:3 Fe to Mn ratio) upon increasing the temperature and heating time. The (Fe,Mn)Ox intermediates formed under various conditions showed catalytic effect in the CO2 hydrogenation reaction with <57.6% CO2 conversions and <39.3% hydrocarbon yields. As a mild solid-phase oxidant, hexakis(urea-O)iron(III) permanganate, was found to be selective in the transformation of (un)substituted benzylic alcohols into benzaldehydes and benzonitriles.

Evolution of Ephemeral Phosphate Minerals on Planetary Environments

The detection of ammonium-bearing compounds in meteorites, comets, and in Earth’s geologic record is challenging due to the volatilization of ammonia during heating. Struvite (MgNH4PO4·6H2O) is an ammonium-bearing phosphate mineral considered to be relevant to the origin of organophosphates on the early Earth, and it is possible that this mineral may have formed on the early Earth and in meteorites in favorable environments. However, in contrast to other phosphate minerals such as those within the apatite mineral group, there is little evidence of struvite on the early Earth and no detection of it in meteorites, where such high-N (nitrogen) and low-H2O conditions may be more commonplace. Here, we demonstrate that struvite quickly loses ammonia and transforms into a new suite of minerals; hence, this mineral is ephemeral. This ephemerality is demonstrated by the thermal decomposition reactions of struvite that lead to the mineral newberyite (MgHPO4·3H2O), an acidic phosphate mineral. Both struvite and newberyite transform into magnesium pyrophosphate and magnesium triphosphate, which are the final products of thermal decomposition (T > 200 °C). However, magnesium pyrophosphate itself reacts with calcium-bearing minerals such as calcite or gypsum and transforms into orthophosphate minerals and polyphosphate salts. Such reactions could have occurred in meteorites as well as on the early Earth. The present research helps identify how ephemeral—but prebiotically relevant—minerals may be lost from the geologic record, but still could have played a role in the development of life.

Synthesis, structure, spectroscopy, thermal analysis and electron spin resonance of classical paddle–wheel binuclear and unusual polynuclear copper(II) compounds with benzoate and salicylamide

Two copper(II)benzoate compounds formulated in a fashion type of [Cux[RCOO]yLz] which are compound 1 or [Cu(C6H5COO)2(C6H5(OH)CONH2)]2 and compound 2 or [Cu(C6H5COO)(H2O)2]n·n(C6H5COO)·nH2O, {where (C6H5COO) = benzoate or (C6H5(OH)CONH2) = salicylamide}, have been successfully synthesized and characterized. Single crystal X-ray diffraction results confirmed the triclinic unit cell with a space group of P1¯ of the classical paddle–wheel binuclear compound 1 and the monoclinic unit cell with a space group of C2/c of polynuclear compound 2. Novel binuclear 1 has salicylamide as ancillary ligand and consists of a distorted square pyramidal [CuO4 + O] chromophore. Polynuclear 2 consists of the monomeric [Cu(C6H5CO)(H2O)2]n+ moiety which is furthered tribridged by coordinated ligands, generated the octahedral [CuO4 + O2] core and the polymeric [Cu(C6H5CO)(H2O)2]n+ chain. Compound 2 is stabilized by water and benzoate counter parts via CH⋯O and CH⋯π weak hydrogen bondings. The Fourier-Transform infrared spectrometer as well as the solid state ultraviolet visible spectra confirmed their components, geometries and weak interactions. The thermogravimetry analysis of compounds 1 and 2 started with the releasing of water molecules and were followed by the decompositions of the organic ligands. The thermograms also indicated the strong and extensive hydrogen bond interactions. The final thermal decomposition products were copper oxide. The electron spin resonance (ESR) spectra measured at room temperature illustrating the signals of triplet. The broader field ESR spectra of 2 than 1 are also noticed.

New zinc(II) 3-aminobenzoates with bioactive ligands: Synthesis, thermal, spectral and antimicrobial properties

Zinc(II) 3-aminobenzoate (3-NH2benz) as well as four new coordination compounds containing ligands L (thiourea – tu, nicotinamide – nad; isonicotinamide – inad; N,N-diethylnicotinamide – dnad) with general formula of [Zn(3-NH2benz)2L2] were synthesized and characterized by elemental analysis and IR spectroscopy. Thermoanalytical methods (TG/DTG, DTA) were used in order to compare the thermal decomposition of synthesized compounds with previously prepared 2- and 4-aminobenzoates. The intermediates and the final product of thermal decomposition were proved by spectroscopic methods. The antimicrobial activity of the zinc(II) 3-aminobenzoate complexes against various strains of bacteria, yeasts and filamentous fungi was determined and compared with 2- and 4-aminobenzoates as well. According to obtained results complexes with thiourea and N,N-diethylnicotinamide exhibit activity towards filamentous fungi R. oryzae, and A. Alternata, yeast C. Albicans, as well as bacteria S. aureus.

Structure transformations in nickel oxalate dihydrate NiC2O4·2H2O and nickel formate dihydrate Ni(HCO2)2·2H2O during thermal decomposition

Structure and thermolysis of NiC2O4·2H2O (I) and Ni(HCO2)2·2H2O (II) were studied for the precipitated powders from the water solutions of precursors. The compound (I) has a disordered structure (C2/c, a=11.7916(5), b= 5.31798(14), c= 9.7806(7) Å, β = 127.014(6)°, V= 489.73(4)Å3) which is described via the displacement vector applied to the basis atoms and the part of the shifted atoms. Thermal dehydration of (I) leads to formation of the disordered β-NiC2O4 (III), the structure of which (P21/n, a=5.8294(9), b= 5.1685(13), c= 5.2712(4) Å, β = 117.793(12)°, V= 140.50(5)Å3) was refined from the powder diffraction. Oxalates (I) and (III) are both characterized by the essential part of the shifted atoms causing the extinction of some lines in XRPD pattern. The final product of thermal decomposition of (I) in air is NiO, whereas thermolysis of (II) leads to formation of Ni/NiO mixture. The content of Ni in the latter depends on the thickness of the decaying layer in the sample because the gaseous products of the reaction prevent the oxidation of the nickel formed initially.

A novel three-dimensional SrII coordination polymer based on benzene-1,2,4,5-tetracarboxylate: hydrothermal synthesis, crystal structure and spectroscopic and thermal studies.

Coordination of the anions of benzenecarboxylic acids with metal cations leads to coordination polymers with various structural features. Very few examples of strontium-based structures have been reported. A new three-dimensional coordination polymer, namely poly[aqua(μ12-benzene-1,2,4,5-tetracarboxylato)distrontium(II)], [Sr2(C10H2O8)(H2O)]n, has been synthesized under hydrothermal conditions and characterized by thermal analysis, vibrational spectroscopy (Raman and IR), single-crystal X-ray diffraction and powder X-ray diffraction. The coordination geometries around the two independent SrII ions can be described as a distorted dodecahedron and a distorted monocapped square antiprism. The compound features a three-dimensional structure containing inorganic motifs, with two-dimensional layers connected through organic linkers, and possesses a topologic structure of a binodal (6,12) connected alb net with the Schläfli symbol {415}2{448.618}. The final product of thermal decomposition is strontium oxide (SrO).

Experimental investigations of thermal stability of some morpholinecarbamic acid complexes of copper(II) and zinc(II)

Some new carbamates, viz. M(MorphcbmH)2X2 (MorphcbmH = morpholinecarbamic acid, M = Cu, X = Cl, ClO4,NO3; M = Zn, X = Cl, ClO4, NO3, CH3COO and X2 = SO4), have been synthesized and investigated. Compounds were characterized by elemental analysis, molar conductance, FT infrared, fluorescence, NMR (1H and 13C) and solution electronic absorption spectral studies. Room temperature field-dependent magnetic susceptibility measurements, PXRD spectral and cyclic voltametric studies were also conducted. Chelating bidentate mode of coordination of ligand, MorphcbmH with four coordination around metal ion has been proposed. Ligand and its compounds have also been studied using non-isothermal thermogravimetric analysis and differential scanning calorimetric analytical techniques which inferred formation of metal oxide/MCO3 as final thermal decomposition products. Compounds were screened against the lipase enzyme for assaying their enzyme activity and were found to retard the lipase activity from 48.16 to 0.044 µmol mL−1 min−1.

Thermogravimetric study on preparation of NiTiO3 in different reaction times

The thermodynamic properties of the fabrication of NiTiO3 material in different reaction times are reported. The design of this material is accessible through a new efficient sol–gel methods, utilizing Ni(Ac)2·4H2O and Ti(OiPr)4 as starting materials for the formation of NiTiO3 final product through thermal decomposition. The thermogravimetric (TG) and differential scanning calorimetric (DSC) techniques were used to analyze the reaction of Ni(Ac)2·4H2O and Ti(OiPr)4, which produces precursor materials at 0.5, 1, 2, 24, 48 and 72 h of reaction times, as well as the thermal stability of these precursors and the final product. The DSC data show an exothermic phenomenon of releasing large amount of energy of −1393 J/g at T Peak 655 K due to the first event of decomposition started at T Onset 607 K and finished at T Endset 663 K for the precursor materials obtained at 0.5 h of reaction, showing the presence of starting materials in this precursor. A similar exothermic behavior was observed in the sample of 1 h of reaction time and was vanished in the materials obtained at 2–72 h of reaction, indicating the influence of the time on the completion of reaction and formation of NiTiO3 crystalline phase as final product of thermal decomposition. In addition, using the information obtained from the TG/DSC, XRD and FTIR analyses, the optimum temperature for the thermal decomposition of the precursor materials to NiTiO3 with fairly high crystallinity was also determined and discussed.

The thermal decomposition of silver dinitramide AgN(NO2)2

Silver dinitramide AgN(NO2)2 was prepared, and its structure was characterized by UV–Visible absorption spectra, Fourier transform infrared (FT-IR) spectra and Fourier transform Raman spectra. Its thermal decomposition process was investigated by differential scanning calorimetry and thermogravimetric analysis coupled with the gas analysis by FT-IR (EGA-FT-IR). The intermediate and final products of thermal decomposition were analyzed by FT-IR, Raman spectra and X-ray diffraction. Kissinger method and Ozawa methods were used to calculate apparent activation energy Ea, the pre-exponential constant lg A and linear correlation coefficient r. The results showed that the degradation process of AgN(NO2)2 could be divided into two stages. The first one with a mass loss of 21.86 % took place in 408–483 K, in which N2O was released and the intermediate product of thermal decomposition was AgNO3. The second stage with a mass loss of 28.24 % occurred in 483–800 K. In this process, gases NO2 and O2 were evolved and Ag was the final product of thermal decomposition. Kissinger method results: Ea = 66.59 kJ mol−1, lg A = 7.21 min−1 and r = 0.9913. Ozawa method results: Ea = 70.53 kJ mol−1, r = 0.9987.

Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

The differences between thermal and vibrational properties of [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2 are reported. The differential scanning calorimetry revealed that tetraamminenickel(II) perrhenate exhibits, in the temperature range of 300–140 K, one phase transition at ca. T hc = 188 K (on heating) and T cc = 185 K (on cooling). In the case of hexaamminenickel(II) perrhenate, no phase transition was observed in the same temperature region. Thermogravimetric measurements showed that the decomposition proceeds in the two main stages. In the first stage, a complete deammination takes place and next Re2O7 is released. TG measurements showed that NH3 molecules are not equivalently bonded to central atom. The final and intermediate products of decomposition were analysed by means of infrared spectroscopy. The final product of thermal decomposition of both compounds is nickel(II) oxide. The analysis of far infrared spectra revealed that anions in [Ni(NH3)6](ReO4)2 have disturbed tetrahedral symmetry, whereas in [Ni(NH3)4](ReO4)2 they seem to form polymeric chains. The variation of the activation energies of the deammination and decomposition steps of [Ni(NH3)6](ReO4)2 was calculated through the model-free isoconversional Kissinger–Akahira–Sunose method and model-free Kissinger method. Infrared spectra were calculated by the DFT method and quite a good agreement with the experimental data was obtained.

Thermal decomposition study of HAuCl4·3H2O and AgNO3 as precursors for plasmonic metal nanoparticles

Thermal decomposition of HAuCl4·3H2O and AgNO3, as precursors for Au and Ag nanoparticles, respectively, was monitored by coupled TG–DTA with TG/EGA–FTIR and EGA–MS techniques in a flowing 80 %Ar + 20 %O2 and Ar atmospheres in the temperature range of 30–600 °C. The intermediate and final products of thermal decomposition were analysed by ex situ XRD and FTIR techniques. The thermal degradation of HAuCl4·3H2O starts immediately after melting at 75 °C and takes place in three steps in the temperature range of 75–320 °C with total mass loss of 49.4 and 49.7 % in artificial air and Ar atmospheres, respectively. EGA by MS and FTIR revealed a simultaneous release of H2O and HCl in the temperature range of 75–235 °C. EGA by MS revealed a release of Cl2 at around 225 °C and in the interval of 250–320 °C. According to the XRD analysis, the main solid product in the end of the first decomposition step at 190 °C is AuCl3; in the end of the second decomposition step at 240 °C is AuCl and the final product at 320 °C is Au. The thermal decomposition of AgNO3 takes place in a single step in the temperature range of 360–515 °C with a total mass loss of 39.0 and 37.8 % in flowing artificial air and Ar atmospheres, respectively. According to EGA–MS and EGA–FTIR the main evolved gases are NO2, NO and O2. The final product of the thermal decomposition at 600 °C is Ag irrespective of the atmosphere.

Synthesis, thermal, spectral and biological properties of zinc(II) 4-hydroxybenzoate complexes

New zinc(II) 4-aminobenzoate complex compounds with general formula [Zn(4-NH2benz)2L2]·nH2O, where 4-NH2benz = 4-aminobenzoate; L = nicotinamide (nad), isonicotinamide (inad), N-methylnicotinamide (mnad), thiourea (tu), urea (u), theophylline (tph), and caffeine (caf); n = 0–2; were synthesised and characterised by elemental analysis, thermal analysis, and IR spectroscopy. The thermal behaviour of prepared compounds was studied by TG/DTG and DTA methods in argon atmosphere. During the thermal decomposition, organic ligand, carbon monoxide, carbon dioxide, and aniline were evolved. The final solid product of the thermal decomposition was zinc oxide. The volatile gaseous products were proved by mass spectrometry. Solid intermediate product and the final product of thermal decomposition were identified by IR spectroscopy and X-ray powder diffraction method. It was solved crystal structure of polymeric [Zn(4-NH2benz)2], where the coordination environment around zinc(II) atom is an unsymmetrical distorted trigonal bipyramidal with chromophore ZnO3N2. The antimicrobial activity of zinc(II) carboxylate compounds was tested against various strains of bacteria, yeasts, and filamentous fungi (S. aureus, E. coli, C. albicans, R. oryzae, A. alternata, M. gypseum). The presence of zinc in complexes led to the increase their antimicrobial activity in comparison with free 4-aminobenzoic acid and ligands.

Novel complexes of Co2+, Ni2+, and Cu2+ with N-(phosphonomethyl)aminosuccinic acid

Complexes of Co2+, Ni2+, and Cu2+ with N-(phosphonomethyl)aminosuccinic acid (H4PMAS) of general formula Na2MPMAS·nH2O [M=Co(II), Ni(II), Cu(II), n—number of water molecules] were synthesized. Based on interpretation of diffusion reflectance spectroscopy, structure of all complexes is based on distorted octahedral. Analysis of IR spectra of Co(II), Ni(II), and Cu(II) N-(phosphonomethyl)aminosuccinates demonstrated that metal ions are coordinated to the ligand through nitrogen atom of the imino group, oxygen atoms of the α- and β-carboxyl groups as well as oxygen atom of the phosphonic group of the H4PMAS. We demonstrated that thermal stability of complexes increases in sequence Cu(II) < Ni(II) < Co(II), obviously as a result of change over from the dimeric to polymeric character of the initial complex. Complete decomposition of ligand occurs at these temperatures and is accompanied by release of H2O, CO2, and NO2. The final products of thermal decomposition of the complexes are mixtures of oxides and phosphates of respective metals.

Bimetallic poly- and oligo-nuclear complexes based on a rhodium(III) metalloligand

Interaction of trans-[Rh(i-Nic)4Cl2]3− anions (i-Nic− – isonicotinate anion) with Cuaq2+ and Coaq2+ cations in water has afforded complex salts Co3[Rh(i-Nic)4Cl2]2·17H2O (1) and Cu3[Rh(i-Nic)4Cl2]2·14H2O (2). Oligonuclear character of 1 and 2 has been established. A coordination polymer Cu5[Rh(i-Nic)4Cl2]2(i-Nic)2(OH)2·2H2O (3) has been crystallized by hydrothermal treatment of 2 at 160°C, and its structure was determined by X-ray structural analysis. EPR data for the complexes has been collected and interpreted. Thermal decomposition of the salts was studied by c-DTA. Bimetallic alloys rhodium–copper and rhodium–cobalt have been obtained as final products of thermal decomposition.

Synthesis, structure, solid-state thermolysis, and catalytic properties of binuclear Ce, Nd, Eu, and Gd cymantrenecarboxylate complexes with DMSO

New rare-earth cymantrenecarboxylate complexes [Ln2(μ,η2-O2CCym)2(μ2-O2CCym)2-(η2-O2CCym)2(DMSO)4] (Cym = (η5-C5H4)Mn(CO)3, Ln = Ce (1), Nd (2), Eu (3), Gd (4)) were synthesized and characterized by X-ray diffraction. In dimeric structures 1–4, two of four bridging carboxylates are chelating-bridging, and Ln atoms have coordination number 9. The catalytic activity of complex 2 in the polymerization of 2,3-dimethyl-1,3-butadiene was investigated. The thermal decomposition of the synthesized compounds was studied by DSC and TGA. According to the X-ray powder diffraction data, the final thermal decomposition product of 1 in air consists of CeO2 and Mn3O4. Under the same conditions, complexes 2–4 afford mixtures of LnMn2O5 and Mn2O3.

Thermal decomposition behavior of praseodymium oxides, hydroxides, and carbonates

Thermal decomposition behavior was studied for Pr6O11, Pr2O3, Pr(OH3), and Pr2(CO3)3 · xH2O. In the course of transformation, the intermediate species were different for each starting material, as well as the surface area and morphology of the final thermal decomposition products. During thermal decomposition in the temperature range of 200°C up to 1400°C, mass losses for each species were attributed to the removal of hydroxide and carbonate species based on changes in the infrared bands for each powder for hydroxide groups at ≃3600 cm−1 and carbonate groups at ≃1300–1500 cm−1. X-ray diffraction analysis identified the final decomposition product at 1400°C for each species as Pr6O11 regardless of the starting material. A decrease in surface area and increase in equivalent particle radius for each final Pr6O11 product is attributed to sintering. The presence of hydroxyl and carbonate groups in the Pr6O11, Pr2O3, Pr(OH3), and Pr2 (CO3)3 · xH2O precursor dictate the morphology of thermally decomposed Pr6O11.

Thermoanalytical investigations of niobium(V) complexes of 4-isopropylphenol

Thermal behaviour of newly synthesized niobium(V) aryloxides of composition [NbCl5−n (OC6H4CH(CH3)2-4) n ] (where n = 1 → 5) synthesized by the reactions of niobium pentachloride with 4-isopropylphenol in predetermined molar ratios in carbon tetrachloride has been studied by thermogravimetric (TG) and differential thermal analysis (DTA) techniques. The results showed that thermal decomposition of complex of composition [NbCl4(OC6H4CH(CH3)2-4)] resulted in the formation of NbOCl3 as the ultimate decompositional product while all other complexes yielded Nb2O5 as the final product of thermal decomposition. From the mathematical analysis of TG data, the kinetic and thermodynamic parameters viz. energy of activation, frequency factor, entropy of activation, etc. have been evaluated using Coats–Redfern equation.

Thermal properties of solid complexes with biologically important heterocyclic ligands

Thermogravimetry (TG) and derivative thermogravimetry (DTG) have been applied to the investigation of the thermal behavior of the compounds Cu(2-Clbz)2(denia)2(H2O)2 (I), Cu(2-Brbz)2(denia)2(H2O)2 (II), and Cu(3-Brbz)2(denia)2(H2O)1 (III), where 2-Clbz and 2-Brbz and 3-Brbz = 2-chloro-, 2-bromo- and 3-bromobenzoate anions, denia = N,N-diethylnicotinamide, H2O = water molecules. Thermal decomposition of all studied compounds proceeds in three steps. Heating of the compounds first results in the release of water molecules. The final product of thermal decomposition of studied complexes was CuO. The thermal stability of the complexes can be ordered in the sequence: (II) < (I) < (III). IR data suggest unidentate coordination of benzoate anions to Cu(II) in complexes (I)–(III).