Coordination compounds of cobalt,nickel, copper,and zinc with 2-bromo-3-phenylpropenal benzoylhydrazone and thiosemicarbazone

By X-ray structural analysis the crystal structure of 2-bromo-3-phenylpropenal benzoylhydrazone (HL) was determined. The molecule is not flat. In the crystal the HL molecules form infinite chains with reciprocal van der Waals interaction. 2-Bromo-3-phenylpropenal hydrazone (HL) and thiosemicarbazone (HL′) react with cobalt, nickel, copper and zinc chlorides, nitrates and acetates to form coordination compounds of the composition Cu(HL)(L)₂ [HL = C₆H₅-CH=CBr-CH=N-NH-C(O)-C₆H₅], MX₂·2 HL′·nH₂O [M = Co, Ni, Cu, Zn; X = Cl, NO₃, HL′ = C₆H₅-CH=CBr-CH=N-NH-C(S)-NH₂; n = 0–3], MX₂·HL·n H₂O [M = Ni, Cu; n = 0, 1], and ML′₂·nH₂O [M = Co, Ni, Zn; n = 0–3]. The same reactions in the presence of amines (A = C₅H₅N, 2-CH₃C₅H₄N, 3-CH₃C₅H₄N, 4-CH₃C₅H₄N) afford complexes of the composition CuALCl and MALX·n H₂O [M = Cu, Ni; X = Cl, NO₃; n = 0–2]. Structure of the coordination node in the amine-containing copper derivatives is polynuclear, in complexes Cu(HL)(L)₂ is octahedral, in other compounds it is tetrahedral. The azomethines (HL and HL′) in these complexes behave as bidentate N,O and N,S ligands. Thermolysis of the complexes includes a step of dehydration (60–90°C) and complete thermal decomposition (430–590°C).     

Coordination compounds of cobalt, nickel, copper and zinc with thiosemicarbazone and 3-phenylpropenal semicarbazone

Hydrates of 3-phenylpropenal thiosemicarbazone (HL·H₂O) and semicarbazone (HL′·H₂O) react in methanol with cobalt, nickel, copper, and zinc chlorides, nitrates, and acetates to form coordination compounds MX₂·2HL·nSolv [M = Co, Ni, Cu, Zn; X = Cl, NO₃; HL = C₆H₅CH=CH-CH=N-NHC(O)NH₂; n = 0–3; Solv = H₂O, CH₃OH], CuX₂·HL·nH₂O [M = Ni, Cu; n = 0, 1], ML₂·nH₂O and ML′·nH₂O [M = Co, Ni, Zn; HL′ = C₆H₅CH=CH-CH=N-NHC(O)NH₂; n = 0–3]. In the presence of amines (A = C₅H₅N, 2-CH₃C₅H₄N, 3-CH₃C₅H₄N, and 4-CH₃C₅H₄N) these reactions yield the complexes Cu(A)LCl·CH₃OH and M(A)LX·nH₂O [M = Cu, Ni; X = Cl, NO₃; n = 0–2]. The copper complexes with the amine ligands are of polynuclear structure, and other complexes are monomeric. Carbazones (HL and HL′) are included in the complexes as bidentate N,S-and N,O-ligands. The thermolysis of the complexes involves the stages of removing solvent crystallization molecules (70–90°C), deaquation (150–170°C), and full thermal decomposition (500–580°C).     

Cobalt and nickel coordination polymers containing 3-pyridylnicotinamide and five-membered ring dicarboxylates

Cobalt and nickel coordination polymers containing the conformationally flexible 3-pyridylnicotinamide (3-pna) ligand and a five-membered ring-based dicarboxylate ligand have been prepared and structurally characterized via single-crystal X-ray diffraction. [Co(tpdc)(3-pna)]_n (1) was prepared using 2,5-thiophenedicarboxylic acid (H₂tpdc). This material shows a 2-D layer structure containing {Co₂(OCO)₂} dimers linked by tpdc and 3-pna ligands. Compound 1 manifests an underlying 3,5-connected (4²6)(4²6⁷8) 3,5L2 topology. The isostructural pair of solids [Co(D-cam)(3-pna)(H₂O)₂]_n (2) and [Ni(D-cam)(3-pna)(H₂O)₂]_n (3) was obtained from the chiral D-camphorate (D-cam) ligand. These two materials possess acentric ribbon coordination polymer motifs. Compound 1 manifests antiferromagnetic coupling concomitant with Kramers doublet formation. Thermal properties of these materials are also discussed.     

Crystal structures of 3-phenylpropenal thiosemicarbazone and its nickel and zinc chelates

3-Phenylpropenal thiosemicarbazone hydrate C₆H₅-HC=CH-CH=N-NH-C(S)-NH₂ · H₂O (HL · H₂O, I) and two chelates [Ni(L)₂] · nCH₃OH (II) and [Zn(L)₂] (III) are studied by X-ray diffraction. The crystals of I are orthorhombic: a = 6.227(1) Å, b = 7.763(2) Å, c = 25.585(5) Å, β = 90°, space group P2₁2₁2₁, Z = 4, R = 0.0426. A nonplanar molecule of I has an E conformation. The crystals of II are triclinic: a = 6.551(2) Å, b = 10.752(3) Å, c = 10.885(3) Å, α = 64.751(5)°, β = 82.753(5)°, γ = 89.857(5)°, space group, Z = 1, R = 0.0661. In a centrosymmetric molecule of II, the central atom coordinates two deprotonated ligands L through the immine nitrogen atom and thioamide sulfur atom at the vertices of a distorted square. The crystals of III are monoclinic: a = 25.342(2) Å, b = 9.150(2) Å, c = 21.340(3) Å, α = 90°, β = 111.84(2)°, γ = 90°, space group C2/c, Z = 8, R = 0.0556. In a molecule of complex III, two deprotonated bidentate ligands L are coordinated by the zinc ion through the immine nitrogen atoms and thioamide sulfur atoms to form a distorted tetrahedron at the central atom. In both II and III, ligand L after coordination by the metal ion changes the E conformation with respect to the N(1)-C(2) bond for the Z conformation. In crystals I-III, molecules are packed to form infinite layers parallel to the planes (001) and (010).     

Cobalt(II), nickel(II) and zinc(II) coordination compounds derived from aromatic amines

The structural and spectroscopic characterization of coordination compounds of four aromatic amines derived from benzimidazole, 2-aminobenzimidazole (L1), 1-(S-methylcarbodithioate)-2-aminobenzimidazole (L2), 2-(2-aminophenyl)-1H-benzimidazole (L3) and 6,6-dimethyl-5H-benzimidazolyl[1,2-c]quinazoline (L4) are reported. Cobalt(II) [Co(L1)₂(CH₃COO)₂] (1) and nickel(II) [Ni(L1)₂(CH₃COO)₂] (2) acetate coordination compounds of L1 are discussed. The synthesis and the X-ray crystal structure of the new 1-(S-methylcarbodithioate)-2-aminobenzimidazole (L2) is informed, together with its cobalt(II) [Co(L2)₂Cl₂] (3), [Co(L2)₂Br₂] (4) and zinc(II) [Co(L2)₂Cl₂] (5), [Zn(L2)₂Br₂] (6) coordination compounds. In these compounds the imidazolic nitrogen is coordinated to the metal center, while the ArNH₂ and the S-methylcarbodithioate groups do not participate as coordination sites. A co-crystal of L1 and L2 is analyzed. Structural analyses of the coordination compounds of L3 showed that this ligand behaves as a bidentate ligand through the aniline and the imidazole groups forming six membered rings in the cobalt(II) [Co(L3)Cl₂] (7) and zinc(II) [Zn(L3)Cl₂] (8) compounds, as well as the nickel(II) nitrate [Ni(L3)₂(H₂O)₂](NO₃)₂ (9). The quinazoline L4 was produced by insertion of one acetone molecule and water elimination in L3, its X-ray crystal diffraction analysis, as well as that of its zinc(II) coordination compound [Zn(L4)₂Cl₂] (10), are discussed.     

Structure and properties of bivalent nickel and copper complexes with pyrazine-amide-thioether coordination: stabilization of trivalent nickel

Acyclic pyrazine-2-carboxamide and thioether containing hexadentate ligand 1,4-bis[o-(pyrazine-2-carboxamidophenyl)]-1,4-dithiobutane (H(2)bpzctb), in its deprotonated form, has afforded light brown [Ni(II)(bpzctb)](1)(S=1) and green [Cu(II)(bpzctb)](2)(S=1/2) complexes. The crystal structures of 1.CH(3)OH and 2.CH(2)Cl(2) revealed that in these complexes the ligand coordinates in a hexadentate mode, affording examples of distorted octahedral M(II)N(2)(pyrazine)N'(2)(amide)S(2)(thioether) coordination. Each complex exhibits in CH(2)Cl(2) a reversible to quasireversible cyclic voltammetric response, corresponding to the Ni(III)/Ni(II)(1) and Cu(II)/Cu(I)(2) redox process. The E(1/2) values reveal that the complexes of bpzctb(2-) are uniformly more anodic by approximately 0.2 V than those of the corresponding complexes with the analogous pyridine ligand, 1,4-bis[o-(pyridine-2-carboxamidophenyl)]-1,4-dithiobutane (H(2)bpctb), attesting that compared to pyridine, pyrazine is a better stabilizer of the Ni(ii) or Cu(i) state. Coulometric oxidation of the previously reported complex [Ni(II)(bpctb)] and 1 generates [Ni(III)(bpctb)](+) and [Ni(III)(bpzctb)](+) species, which exhibit a LMCT transition in the 470--480 nm region and axial EPR spectra corresponding to a tetragonally elongated octahedral geometry. Complex 2 exhibits EPR spectra characteristic of the d(z(2)) ground state.     

Iron,nickel and zinc malates coordination compounds cynthesis,characterization and thermal behaviour

The coordinations compounds (NH₄)[Fe(C₄H₄O₅)(OH)₂]·0.5H₂O, [Ni(C₄H₄O₅)]·3H₂O and [Zn(C₄H₄O₅)]·5H₂O were synthesized by a precipitation method and characterized by chemical analysis, spectral (IR, UV-VIS) and magnetical investigations. In the range 50-600°C stepped thermal decompositions occur with formation of anhydrous malates, malonates, oxoacetates (iron and nickel compounds) and hydroxocarbonate (Zn compound) as intermediates observed by FT-IR spectroscopy. α-Fe₂O₃, NiO and ZnO constitute the final decomposition products. This revised version was published online in July 2006 with corrections to the Cover Date.     

Isomerism of copper(II) coordination compounds with hydroxamic acids

The structure of Cu^II complexes with hydroxamic acids Cu[R¹N(O)−(O)CR²]₂, where R¹=Ph, R²=Me; R¹=Me, R²=Ph, was studied by ESR spectroscopy. In toluene solutions and low-temperature glasses, the complexes exist as two forms, which were identified ascis-andtrans-isomers. The proportions of the isomers were determined. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 726–729, April, 1999.     

Synthesis of copper(II) coordination compounds with benzoxazine derivatives

Copper(II) complexes with 1,2-dihydro-4H-3,1-benzoxazine (HL) derivatives, CuLOH, were prepared by anodic electrosynthesis. The use of an amalgamated copper anode resulted in an increase in the electrosynthesis rate. It follows from the IR spectra of the products that the benzoxazine ring in the ligand molecule is opened upon complexation, while a six-membered chelate ring involving the oxygen atom of the deprotonated phenol group and the imine nitrogen atom is formed.     

Cobalt, zinc, and nickel complexes of a diatopic heteroscorpionate ligand: building blocks for coordination polymers

New binuclear complexes of Co(II), Zn(II), and Ni(II) derived from a diatopic heteroscorpionate ligand, (4-carboxyphenyl)bis(3,5-dimethylpyrazolyl)methane (L4c), have been synthesized and characterized by X-ray diffraction, ESI-MS, IR, UV-vis spectroscopy, and magnetic susceptibility. These building blocks have been subsequently used for the construction of higher order metallosupramolecular architectures.     

Heteronuclear coordination compounds of copper and cobalt in urethane-yielding reactions

Heteronuclear coordination compounds capable of catalyzing the low-temperature dissociation of urethane groups were synthesized on the basis of copper and cobalt chlorides. The study was performed with an urethane prepolymer produced from oligoester diol and 2,4-toluylene diisocyanate. It was found that the dissociation of urethane groups in the prepolymer is accompanied by formation of carbodiimides and release of 2,4-toluylene diisocyanate. As a result of the subsequent redox interaction, Cu(II) ions are mostly converted to Cu(I), and the involvement of isocyanate groups in the para-position into the reaction processes leads to formation of azoaromatic derivatives. It is shown that their coordination binding by Co(II) ions strongly affects both the supramolecular organization of polyurethanes and a set of their physicomechanical properties.     

Demetallation of coordination compounds of nickel with tetradentate ligands based on S-substituted isothiosemicarbazides

The passage of dry gaseous hydrogen chloride through chloroform solutions or acetone suspensions of S-substituted N¹,N⁴-di(salicylidene)isothiosemicarbazidates of nickel (Ni(LRR)) has led to a demetallization reaction with the liberation in the free state of S-substituted N¹,N⁴-di(salicylidene)isothiosemicarbazides with the general formula N₂LRR (where R is H and R is CH₃ (I); R is H and R is C₂H₅ (II); R is H and R is C₃H₇ (III); R is H and R is C₇H₇ (IV); and R is CH₃ and R is CH₃ (V)). The IR spectra of (I-IV) each showed bands characteristic for an aromatic ring and groups in the 1600–1500 cm^–1 region, with a band of the deformation vibrations of an OH group at 1300 cm^–1. The PMR spectra in CDCl₃ each had two singlets at 12.15-11.25 and 9.00-8.36 ppm which were assigned, respectively, to the protons of an OH group and those of a =CH group. A multiplet in the 7.70-6.83 ppm region belonged to the protons of benzene rings. In the region of lower fields there were the signals of the substituents R and R. In the mass spectra of (I-V), the peaks of the molecular ions, and also the characteristic fragments OH, R, SR, and HSR have been detected.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 21, No. 5, pp. 604–608, September–October, 1985.     

Thermal properties of solid nickel(II) coordination compounds

The paper deals with the chemical and physical factors influencing the stoichiometry of thermal decomposition of solid coordination compounds. Nickel(II) coordination compounds were used as examples: the problem of the relationship between the structure of the initial compound (and of its intermediates) and the stoichiometry of thermal decomposition is discussed; experimental conditions are shown to affect this decomposition, and the conceptions of the apparent and real stoichiometries of thermal decomposition are discussed. The results obtained may have a more general meaning.

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Zusammenfassung Der Beitrag befa\t sich mit den chemischen und physikalischen Faktoren, welche die Stöchiometrie der thermischen Zersetzung fester Koordinationsverbindungen beeinflussen. Koordinationsverbindungen von Nickel(II) wurden als Beispiel eingesetzt; das Problem des Zusammenhanges zwischen Struktur der Ausgangsverbindung (und seiner IntermediÄrprodukte) und der Stöchiometrie der thermischen Zersetzung wird erörtert; die die Zersetzung beeinflussenden Versuchsbedingungen werden gezeigt und das Konzept der sogenannten scheinbaren und tatsÄchlichen Stöchiometrie der thermischen Zersetzung wird beschrieben. Die erhaltenen Ergebnisse dürften von allgemeinerer Bedeutung sein.

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Résumé L'article considère les facteurs chimiques et physiques qui influencent la stchiométrie des réactions de décomposition thermique des composés de coordination solides. Les composés de coordination du nickel(II) ont été choisis pour illustrer le problème des relations entre la structure du composé initial (et de ses intermédiaires) et la stchiométrie de la réaction de décomposition thermique. On montre que les conditions expérimentales influencent la décomposition et on discute le principe des réactions stchiométriques de décomposition thermique dites «apparentes» et «réelles». Les résultats obtenus sont probablement de portée plus générale.

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Reported at the 7th Seminar on Modern Methods in Inorganic Chemistry. Harmonia-Bratislava, 1977.     

On the structure of copper(II) coordination compounds with L-histidine

Quantum chemical calculations are performed for the spatial and electron structure of complex compounds of L-histidine and its ionized forms with copper(II) for a variety of compositions within the density functional theory (DFT) using the B3LYP functional and 6-311G(d) basis. The solvent (water) is considered within the PCM approximation. EPR spectroscopy is used to study the equilibrium in the copper(II)–L-histidine system in an aqueous solution at рН 2–11. A comparison between the theoretical calculations and the EPR spectra suggests the following geometry for the coordination environment of the copper(II) ion in the complex compounds: CuHLL–square-planar coordination; CuL₂, CuHLL′, and CuLL′–distorted square pyramid; and CuL₂′–octahedral environment.     

Thermal properties of solid nickel(II) coordination compounds

The paper deals with the chemical and physical factors influencing the thermal octahedral square planar changes of nickel(II) complexes in the solid phase. The relationship between these transformations and the tetragonal distortion of the octahedral ligand field is discussed. Depending on the coordination of the ligands, these transformations can be divided into two groups: octahedral monomer square planar monomer, and octahedral polymer square planar monomer changes. Attention is directed only to octahedral and square planat Ni(II) complexes (square planar complexes with chromophores [NiN₄], [NiN₂O₂] and [NiO₄]), which can be isolated in the solid state before and after heating. The possibility of such a configurational change seems to be dependent upon the thermal stabilities of the initial and final complexes, the electronic and steric properties of the ligands, the complexing ability of the central atom, and particularly the equatorial-axial interactions of the ligands via the central atom.

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Zusammenfassung Vorliegende Arbeit befasst sich mit den chemischen und physikalischen Faktoren, die den thermischen Übergang oktaedrisch-rechteckig planar der Festkörperphase von Nickel(II) komplexen beeinflussen. Es werden die Beziehungen zwischen dieser Transformation und der tetragonalen Verzerrung oktaedrischer Ligandenfelder besprochen. Entsprechend der Koordinierung der Liganden können diese Transformationen in zwei Gruppen eingeteilt werden: monomer oktaedrisch-monomer rechteckig planar sowie polymer oktaedrisch-monomer rechteckig planare. Hier werden nur solche oktaedrische und rechteckig planare Ni(II)komplexe (rechteckig planare Komplexe mit (NiN₄)-, (NiN₂O₂)- und (NiO₄)-Chromophoren) betrachtet, die sowohl vor als auch nach dem Erhitzen in fester Form isoliert werden können. Die Möglichkeit solcher Konfigurationsübergange scheint von der thermischen Stabilität der Ausgangs- und Produktekomplexe, von elektronischen und sterischen Eigenschaften der Liganden, von der Komplexbildungsstärke des Zentralatomes und hauptsächlich von den äquatorial-axialen Wechselwirkungen der Liganden gegenüber dem Zentralatom abzuhängen.

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, . . , : . - ( [NiN₄], [NiN₂O₂] [NiO₂]), . , , , , , — .

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Part A: J. Thermal Anal., 16 (1979) 213.     

Spectroscopic studies on some azo compounds and their cobalt, copper and nickel complexes

Synthesis and characterization of [o-carboxy phenylazo] moiety of barbituric acid, thiobarbituric acid, thiouracil, citrazinic acid, and disodium chromotropate and their complexes derived from cobalt (II), nickel (II), and copper (II) salts were done. The stereochemistry and the mode of bonding of the complexes were achieved based on elemental analysis, NMR, UV-Vis, IR and ESR. The dissociation constants of the free azo ligands are evaluated by spectrophotometric methods.     

Three 1-D molybdenum(V) phosphates with copper/nickel coordination cations

Three 1-D reduced molybdenum(V) phosphates, [Ni(OH)₂][Na₂(H₂O)₃]₂{Ni[(MoO₂)₆(OH)₃(HPO₄)₃(PO₄)]₂}?·?2C₆H₁₄N₂?·?2H₃O?·?5H₂O (1), [Ni(H₂O)₂][K(H₂O)₅]₂{Ni[(MoO₂)₆(OH)₃(HPO₄)₃(PO₄)]₂}?·?2C₆H₁₄N₂?·?2H₃O?·?4H₂O (2), and [Cu(H₂O)₂][Na(H₂O)₅]₂{Cu[(MoO₂)₆(OH)₃(HPO₄)₃(PO₄)]₂}?·?2C₆H₁₄N₂?·?2H₃O?·?4H₂O (3), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. The crystallographic analysis reveals that 1 is based on {Ni[Mo₆O₁₂(OH)₃(HPO₄)₃(PO₄)]₂} clusters connected through {[Ni(OH)₂][Na₂(H₂O)₃]₂} pentanuclear mixed-metal cluster units to yield unusual 1-D chains along the c-axis, which further form 3-D supramolecular networks via hydrogen-bonding. Compounds 2 and 3 are heterogeneous isostructural compounds. Both are built from M[Mo₆P₄]₂ (M?=?Ni or Cu) blocks as the structural motif combined with [MO₄(H₂O)₂] (M?=?Ni or Cu) octahedra to form 1-D chains, where M[Mo₆P₄]₂ (M?=?Ni or Cu) is bonded by [M′(H₂O)₅] (M′?=?K or Na). Furthermore, bulk carbon paste electrode modified with 1 (1-CPE) displays good electrocatalytic activity toward reduction of nitrite or bromate.     

Synthesis,structure and properties of complex compounds of cobalt,nickel, copper and zinc with 2-formylpyridine semicarbazone

2-Formylpyridine semicarbazone L reacts with cobalt, nickel, copper and zinc chlorides, nitrates and perchlorites to form coordination compounds of compositions ML₂X₂·nH₂O (M=Co, Ni, Cu, Zn; X = Cl, NO₃, ClO₄; L = NC₅H₄-CH=N-NH-C(O)-NH₂; n = 0, 1) and CuLX₂·nH₂O (X = Cl, Br, NO₃; n = 0−0.5). Complex CuL(NO₃)₂ has polynuclear, CuLX₂·0.5H₂O (X = Cl, Br), binuclear, and other compounds, mononuclear structures. Azomethine L behaves in them as tridental N,N,O-ligand. Thermolysis of these complexes proceeds through such stages as dehydration (80–95°C), deactivation (145–155°C) and complete theral degradation (170–590°C). Complexes CuLX₂·nH₂O (X = Cl, NO₃; n = 0−0.5) were established to inhibit in vitro the growth and reproduction of 100% of cancer cells of human mieloid leukaemia HL-60 at 10⁻⁴ M concentration. At 10⁻⁵ M concentration they inhibit only 10% of cells, and at 10⁻⁶ M concentration they do not possess anticancer activity.     

The thermal,spectral and magnetic studies ofp-tolylacetic acid compounds of cobalt,nickel and copper

The preparation and some properties of complexes ofp-tolylacetic acid with cobalt, nickel and copper are described. Magnetic measurements, electronic and far infrared spectra show that the metal complexes have octahedral structures. Infrared spectra indicate that coordination takes place through the carboxyl group to the metal ions and that the water molecule in each of the complexes is present as water of crystallisation. Thermogravimetry studies also show that the water molecules in each of the complexes do not form a coordinate bond with the metal ion. Differential thermal analysis show that the dehydration processes are accompanied by endothermic reactions. In each case the anhydrous metal complex undergoes an exothermic reaction to give the metal oxide.This work was supported by the Carnegie Trust for the Universities of Scotland and the Hungarian OTKA foundation (T-4096).