Synthesis and characterization of N -(alky(aryl)carbamothioyl)cyclohexanecarboxamide derivatives and their Ni(II) and Cu(II) complexes

N-(R-carbamothioyl)cyclohexanecarboxamides (R: diethyl, di-n-propyl, di-n-butyl, diphenyl and morpholine-4) and their Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analyses, FT-IR and NMR methods. N-(diethylcarbamothioyl)cyclohexanecarboxamide, HL¹, C₁₂H₂₂N₂OS, crystallizes in the orthorhombic space group P2₁2₁2₁, with Z = 4, and unit cell parameters, a = 6.6925(13) Å, b = 9.0457(18) Å, c = 22.728(5) Å. The conformation of the HL¹ molecule with respect to the thiocarbonyl and carbonyl moieties is twisted, as reflected by the torsion angles O1–C6–N2–C5, C6–N2–C5–N1 and S1–C5–N2–C6 of 1.68°, ?67.47° and 115.50°, respectively. The structure of HL¹ also shows a delocalization of the π electrons of the thiocarbonyl group over the C–N bonds. The ring puckering analysis shows that the cyclohexane ring has a chair conformation. The bis(N-(morpholine-4-carbonothioyl)cyclohexane carboxamido)nickel(II) complex, Ni(L⁵)₂, C₂₄H₃₈N₄NiO₄S₂, crystallizes in the monoclinic space group P2₁/c, with Z = 4, and unit cell parameters, a = 16.919(3) Å, b = 8.3659(17) Å, c = 19.654(4) Å, β = 107.43(3)°. Ni(L⁵)₂ is a cis-complex with a slightly distorted square-planar coordination of the central nickel by two oxygen and two sulfur atoms.     

Synthesis,characterization and crystal structures of Nickel(II) complexes containing sterically hindering Benzimidazole ligands

The synthesis, characterization, and crystal structures of two Ni(II) complexes with N,N-bis[2-(2′-benzimidazolyl)ethyl]amine (bbiea) (1) and N,N-bis[2-(1′-methyl-2′-benzimidazolyl)ethyl]amine (bmbea) (2) are reported. The nickel complex Ni(bbiea)(O₂C₂H₃)(ClO₄) (3) crystallizes in the space group C2/c, with a = 35.830(7), b = 14.130(3), c = 10.756(2)?Å, and β = 103.04(3)°. Compound 4, Ni(bmbea)(NO₃)₂, crystallizes in the space group P2₁/c, with a = 17.024(5), b = 16.516(4), c = 8.692(2)?Å, and β = 91.31(2)°. In 3, the bbiea ligand is coordinated to the Ni(II) ion in a facial conformation, whereas the bmbea ligand in 4 adopts meridonal geometry. Both complexes contain a single benzimidazole chelate and the remaining coordination sites are occupied by solvent molecules and/or counterions. Reactions involving large excesses of ligand-to-metal and different solvents produced only the mono-chelated complexes 3 and 4. No evidence for formation of bis-chelated complexes with Ni(II) was observed by MALDI-TOF and ESI-mass spectroscopy. Ligand field parameters for 3 and 4 were determined to be 9606 and 9862?cm^?1, respectively.     

Synthesis and characterization of copper(II), nickel(II) and cobalt(II) complexes with novel thiourea derivatives

A novel series of thiourea derivatives, namely, N,N-diphenyl-N-(4-phenyl-benzoyl)thiourea (HL¹), N,N-diphenyl-N-(4-chloro-benzoyl)thiourea (HL²) and N,N-di-n-propyl-N-(4-chloro-benzoyl)thiourea (HL³), and its metal complexes has been prepared and characterised by elemental analysis, i.r. spectroscopy, ¹H-n.m.r. spectroscopy, mass spectrometry and single crystal X-ray diffraction. The ligand coordinates to Ni^II, Cu^II and Co^II in a bidentate manner yielding essentially neutral complexes of the type cis-[ML₂]. N.m.r. spectra and single crystal X-ray diffraction analysis revealed the presence of a distorted tetrahedral coordination ML₂ complex.     

Synthesis and characterization of Cu(II) and Ni(II) complexes of some 4-bromo- N -(di(alkyl/aryl)carbamothioyl) benzamide derivatives

4-Bromo-N-(di-R-carbamothioyl)benzamide (R = methyl, ethyl, n-propyl, n-butyl and phenyl) ligands and their Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analyses, FT-IR and ¹H-NMR spectroscopy. The crystal and molecular structure of bis(4-bromo-N-(di-n-propylcarbamothioyl)benzamido)nickel(II) has been determined from single crystal X-ray diffraction data. It crystallizes in the triclinic, space group P 1, Z = 2 with a = 9.286(2) Å, b = 13.215(3) Å, c = 14.125(3) Å, α = 64.180(5)°, β = 85.483(6)°, γ = 83.067(5)°, V = 1548.3(7) ų and D _Calcd = 1.594 mg m^?3. Loss of the N–H proton resonance and the N–H stretching vibration and the shift of the ν _C=O and ν _C=S stretching vibrations confirm formation of the metal complexes. These studies have shown that the metal complexes are neutral cis-[ML₂].     

Synthesis,crystal structure,and electrochemistry of [Co{(Me-sal)2dien}(N3)] and [Co{(Me-sal)2dpt}(N3)]

The structure, spectroscopic, and electrochemical properties of [Co{(Me-sal)₂dien}(N₃)] and [Co{(Me-sal)₂dpt}(N₃)], where (Me-sal)₂dien = 2,2′-[1,1′-(3-azapentane-1,5-diyldinitrilo)diethylidyne] diphenolate and (Me-sal)₂dpt = 2,2′-[1,1′-(4-azapentane-1,7-diyldinitrilo)diethylidyne] diphenolate, have been investigated. These complexes have been characterized by elemental analyses, IR, UV–Vis, and ¹H-NMR spectroscopy. The crystal structures of these complexes have been determined by X-ray diffraction. Complex 1 crystallizes in the triclinic space group P 1, with a = 7.8443(4) Å, b = 11.0660(5) Å, c = 11.6216(6) Å, α = 73.360(1)°, β = 76.965(1)°, γ = 84.436(1)° and Z = 2. Complex 2 crystallizes in the monoclinic space group P2₁/n, with a = 12.1985(13) Å, b = 10.9332(12) Å, c = 15.2808(16) Å, β = 76.965(1)° and Z = 4. The coordination geometry around cobalt(III) in both complexes is a distorted octahedron. The electrochemical reduction of these complexes at a glassy carbon electrode in acetonitrile indicates that the first reduction corresponding to Co^III–Co^II is electrochemically irreversible, accompanied by dissociation of the axial Co–N(N₃) bond. The second reduction step of Co(II/I) leads to decomposition of the complex. These observations are rationalized based on the structure-function relations.     

Synthesis and physiochemical studies on binuclear Cu(II) complexes derived from 2,6-[(N-phenylpiperazin-1-yl)methyl]-4-substituted phenols

Preparation of the ligands HL¹ = 2,6-[(N-phenylpiperazin-1-yl)methyl]-p-ethylphenol; HL² = 2,6-[(N-phenylpiperazin-1-yl)methyl]-p-methoxyphenol and HL³ = 2,6-[(N-phenylpiperazin-1-yl)methyl]-p-nitrophenol are described together with their Cu(II) complexes with different bridging units. The exogenous bridges incorporated into the complexes are: hydroxo [Cu₂L(OH)(H₂O)₂](ClO₄)₂.H₂O (L¹=1a, L² =1b, L³ =1c), acetato [Cu₂L(OAc)₂]ClO₄.H₂O (L¹ =2a, L² =2b, L³ =2c) and nitrito [Cu₂L¹(NO₂)₂(H₂O)₂]ClO₄.H₂O (L¹=3a, L² =3b, L³ =3c). Complexes1a,1b,1c and2a,2b,2c contain bridging exogenous groups, while3a,3b,3c possess only open μ-phenolate structures. Both the ligands and complexes were characterized by spectral studies. Cyclic voltammetric investigation of these complexes revealed that the reaction process involves two successive quasireversible one-electron steps at different potentials. The first reduction potential is sensitive to electronic effects of the substituents at the aromatic ring of the ligand system, shifting to positive potentials when the substituents are replaced by more electrophilic groups. EPR studies indicate very weak interaction between the two copper atoms. Various covalency parameters have been calculated.     

Synthesis,crystal structures,and antibacterial activities of Schiff base nickel(II) and cadmium(II) complexes with tridentate Schiff bases

Reaction of tridentate Schiff bases with nickel and cadmium salts in methanol afforded two new mononuclear complexes, [Ni(L¹)₂] (I) and [Cd(L²)₂] (II), where L¹ and L² are the anions of 2-bromo-4-chloro-6-[(3-dimethylaminopropylimino)methyl]phenol (HL¹) and 2-bromo-4-chloro-6-[(3-morpholin-4-ylpropylimino)methyl]phenol (HL²), respectively. The complexes were characterized by singlecrystal X-ray diffraction (CIF files CCDC nos. 1428653 (I) and 1428654 for (II)), FT-IR, and elemental analysis. Complex I crystallizes in the monoclinic space group P2 ₁/c, with a = 8.8216(8), b = 14.0424(8), c = 11.8687(12) Å, β = 111.238(2)°, V = 1370.4(2) ų, Z = 2. Complex II crystallizes in the monoclinic space group P2 ₁/n, with a = 9.6774(4), b = 15.8970(6), c = 20.3144(7) Å, β = 90.408(2)°, V = 3125.1(2) ų, Z = 4. The metal atoms in the complexes are coordinated by two tridentate Schiff base ligands, forming octahedral coordination. The free Schiff bases and the complexes were assayed for antibacterial activities. Both complexes are more active against the bacteria than the free Schiff bases. Complex II has the MIC value of 0.39 μg mL^–1 against Bacillus subtilis.     

Transition Metal Complexes with the Thiosemicarbazide-based ligands. XII. Complexes of nickel(II) with benzoylacetone S-methylisothiosemicarbazone and N(1)-2-butylidene-4-oxo-4-phenyl-N(4)-salicylidene-S-methylisothiosemicarbazide

A template synthesis procedure yielded [Ni(HL¹)NH₃]I, where HL¹ is the monoanion of the terdentate ONN benzoylacetone S-methylisothiosemicarbazone ligand. The reaction of this complex with an excess of NH₄NCS, pyridine, or hydrazine resulted in the complexes [Ni(HL¹)(NH₃)NCS] and [Ni(L¹)A] (A = Py, N₂H₄). The monoanionic form of the ligand is obtained by deprotonation of the enolic form of the benzoylacetone moiety, whereas the dianion is formed by additional deprotonation of the terminal NH₂ group. Finally, the reaction of [Ni(HL¹)NH₃]I with salicyladehyde produced the NiL² complex in which L² stands for the dianion of the ONNO ligand N(1)-2-butylidene-4-oxo-4-phenyl-N(4)-salicylidene-S-methylisothiosemicarbazide. All complexes are diamagnetic and have a square-planar configuration, except for [Ni(HL¹)(NH₃)NCS], for which te data of i.r. spectra suggest a square-pyramidal structure. The electronic absorption spectra of the ethanolic solutions of all complexes are characteristic of typical square-planar coordination of nickel(II).     

Synthesis and Characterization of A Nickel(II) Complex With Bis(Benzimidazol-2-Ylmethyl) (2-Hydroxyethyl)Amine

This paper reports the synthesis, crystal structure and properties of two new mononuclear nickel(II) complexes, [NiL(phen)][ClO₄]₂(1) and [NiL(bpy)][ClO₄]₂(2), where L is bis(benzimidazol-2-ylmetheyl)(2-hydroxyethyl)amine and phen and bpy are 1,10-phenanthroline and 2,2'-bipyridine, respectively. The crystal structure of 1 ·2EtOH has been determined by single-crystal X-ray analysis. It crystallizes in the monoclinic system, space group C2/c, a= 24.279(2), b= 20.864(2), c= 17.635(1)Å, g = 121.730(2)°, Z= 8, R ₁= 0.064, wR ₂= 0.167. The Ni(II) ion in 1 ·2EtOH is coordinated to three nitrogen atoms and one oxygen atom of the ligand L and two nitrogen atoms of phen to form a distorted octahedron. Spectroscopic properties of 1 and 2 are reported.     

Synthesis and Characterization of N,N‐Di‐substituted Acylthiourea Copper(II) Complexes

A series of six N,N‐di‐substituted acylthiourea ArC(O)NHC(S)NRR′ ligands (denoted as HLⁿ) [Ar = 1‐Naph: NRR′ = NPh₂, HL¹ ( 1 ); N(iPr)Ph, HL² ( 2 ). Ar = Mes: NRR′ = NPh₂, HL⁴ ( 3 ); N(iPr)Ph, HL⁵ ( 4 ); NEt₂, HL⁶ ( 5 ). Ar = Ph: NRR′ = N(iPr)Ph, HL⁸ ( 6 )] were synthesized and characterized. These ligands were deprotonated to form Cu^II complexes through metathesis or combined redox reaction with copper halides. The structures of the complexes were investigated with single‐crystal X‐ray diffraction. The reaction of the 1‐naphthalene derivative HL¹ ( 1 ) with CuBr in the presence of sodium acetate produced cis‐CuL¹₂ ( 7 ), where the deprotonated ligand is bound to the Cu^II atom in a bidentate‐(O, S) coordination mode. Similarly treatment of HL² ( 2 ) with NaOAc and CuCl resulted in the formation of the cis‐arranged product [cis‐CuL²₂ ( 8 )]. The reaction of mesityl derivative HL⁴ ( 3 ) and CuBr with and without the addition of NaOAc gave the cis‐CuL⁴₂ ( 9 ) and cis‐(HL⁴)₂CuBr ( 10 ), respectively. In contrast, reaction of HL⁵ ( 4 ) and CuI in the presence of NaOAc resulted in trans‐CuL⁵₂ ( 11 ). Alternatively trans‐CuL⁶₂ ( 12 ) was obtained by the reaction of diethyl‐substituted HL⁶ ( 5 ) with CuCl₂ in the absence of a base.     

Structural and spectral studies of nickel(II) complexes with N(4),N(4)-(butane-1,4-diyl) thiosemicarbazones

Nickel(II) complexes of quinoline-2-carbaldehyde N(4),N(4)-(butane-1,4-diyl) thiosemicarbazone (HL¹) and 2-benzoylpyridine N(4),N(4)-(butane-1,4-diyl) thiosemicarbazone (HL²) have been synthesized and physico-chemically characterized by means of partial elemental analyses, molar conductance measurements, magnetic measurements, electronic and infrared spectral studies. Three complexes were given the formulae [Ni(HL¹)₂]Cl₂ (1), [Ni(HL²)L²]ClO₄ · 7H₂O (2) and [NiL²Cl] · 0.5H₂O (3). The structure of compound 1 has been solved by single crystal X-ray crystallography and is found to be distorted octahedral. Compound 2, when crystallized in DMSO solution, got deprotonated to form a new compound [Ni(L²)₂] (2a), with a distorted octahedral Ni(II) center. In compound 1, HL¹ coordinates to the metal in the thione form, while in compounds 2a and 3, HL² coordinates in its deprotonated thiolate form.     

Structural and Spectral Studies on the Ni(II) Complexes of 1,5‐Diazacyclooctane (DACO) Bearing Heterocyclic Pendants: Formation of a Two‐dimensional Network via Hydrogen Bonds and π‐π Stacking Interactions

A penta‐coordinated Ni(II) complex with a 1,5‐diazacyclooctane (DACO) ligand functionalized by two imidazole donor pendants, [NiL¹Cl] (ClO₄) H₂O (1) (where L¹ = 1,5‐bis (imidazol‐4‐ylmethyl)‐l,5‐diazacyclooctane) has been synthesized and characterized by X‐ray diffraction, infrared spectra, elemental analyses, conductance, thermal analyses and UV‐Vis techniques. Complex 1 crystallizes in triclinic crystal system, P‐l space group with a = 0.74782(7), b = 1.15082 (10), c = 1.23781(11) nm, α = 82.090(2), β = 73.011(2), γ = 83.462(2)°, V = 1.00603(16) nm³, M, = 486.00, Z = 2, D_c = 1.604 g/cm³, final R = 0.0435, and wR = 0.1244. The structures of 1 and its related complexes show that in all the three mononuclear complexes, each Ni(II) center is penta‐coordinated with a near regular square pyramid (RSP) to distorted square‐pyramidal (DSP) coordination environment due to the boat/chair configuration of DACO ring in these complexes, and the degree of distortion increases with the augment of the size of the heterocyclic pendants. In addition, the most striking feature of complex 1 resides in the formation of a two‐dimensional network structure through hydrogen bonds and stabilized by π‐π stacking. The solution behaviors of the Ni(II) complexes are also discussed in detail.     

Vanadium(IV) dimer complexes containing [V(o-C6H4OS)3]2− fragment and caged sodium ions

Tris[o-mercaptophenolato]vanadium(IV) dimer complexes (A)₂[V(mp)₃NaLL']₂ (A = Ph₄P₊, H₂mp = o-mercaptophenol, L = MeCN, L'=EtOH, (1); L' = MeOH, (2)) were prepared by the reaction of anhydrous VC1₃, and Na₂mp in the molar ratio 1:3. Complex (3) (A = Et₄N⁺, L=L' = MeOH) was prepared by the reaction of VC1₃, Na₂mp and Li₂S in the molar ratio 1:2:1. The complexes were characterized by X-ray diffraction crystallography, infrared spectra, magnetic susceptibility, and cyclic voltammetric measurements. Complex 2 crystallizes in the triclinic space group P1 with a=12.813(6), b = 14.199(4), c = 12.790(5) Å, α = 112.72(2), β = 104.24(4). γ = 88.68(4)°, V = 2073.6 ų, and Z=1. The structure was refined to R=0.058. Complex 3 crystallizes in the mono-clinic space group P2₁/n with a=12.359(3), b=17.452(6), c=14.829(13) Å, βequals;96.51(5)°, V=3177.8 ų, and Z=2. The final R factor is 0.067. Both of the anions of 2 and 3 contain two [V(mp)₃]^2? fragments linked by sodium ions through the μ₃-O bridges with a crystallographic center of symmetry. The V(IV) atom is in a coordination environment intermediate between a trigonal prism and an ideal octahedron.     

Synthesis,Characterization, and Crystal Structures of [Cu(ca2en)2]ClO4, and [Cu(ca2en)(PPh3)2]ClO4 Complexes

Synthesis, spectroscopy, and crystal structures of [Cu(ca₂en)₂]ClO₄ ( 1 ) and [Cu(ca₂en)(PPh₃)₂]ClO₄ ( 2 ) (ca₂en=N,N′‐bis(trans‐cinnamaldehyde)ethylenediimine) are reported. Compound 1 crystallizes in the orthorhombic space group Pbca, with a=12.5647(7), b=21.8203(11), c=27.992(2) Å, V=7674.3(7) ų, Z=8. Compound 2 crystallizes in the triclinic space group P , with a=13.0540(11), b=14.2935(13), c=14.9863(13) Å, α=84.130(2), β=69.761(2), γ=87.749(2)°, V=2609.8(4) ų, Z=2. The coordination polyhedron about the Cu^I center in the two complexes is best described as a distorted tetrahedron. The ¹H‐NMR and electronic spectra of these complexes are also reported and discussed. The cyclic voltammetry of the complexes indicate a quasireversible redox behavior for complex 1 (E_1/2=0.51 V). However, complex 2 displays an irreversible oxidation wave at 0.91 V. A weak emission is observed for complex 2 in CHCl₃ at room temperature.     

Diversity of Strontium Nitridogermanates(IV): Novel Sr4[GeN4], Sr8Ge2[GeN4], and Sr17Ge2[GeN3]2[GeN4]2

Single crystals of three new strontium nitridogermanates(IV) were grown in sealed niobium ampules from sodium flux. Dark red Sr₄[GeN₄] crystallizes in space group P2₁/c with a = 9.7923(2) Å, b = 6.3990(1) Å, c = 11.6924(3) Å and β = 115.966(1)°. Black Sr₈Ge₂[GeN₄] contains Ge^4– anions coexisting with [Ge^IVN₄]^8– tetrahedra and adopts space group Cc with a = 10.1117(4) Å, b = 17.1073(7) Å, c = 10.0473(4) Å and β = 115.966(1)°. Black Sr₁₇Ge₆N₁₄ features the same anions alongside trigonal planar [Ge^IVN₃]^5– units. It crystallizes in P1 with a = 7.5392(1) Å, b = 9.7502(2) Å, c = 11.6761(2) Å, α = 103.308(1)°, β = 94.651(1)° and γ = 110.248(1)°.     

Mono- and dinuclear Zn(II) complexes of Schiff-base ligands: syntheses,characterization and studies of photoluminescence

Six Schiff-bases HL¹-HL⁴, L⁵ and L⁶ [HL¹ = 2,6-bis[1-(2-aminoethyl)pyrolidine-iminomethyl]-4-methyl-phenol, HL² = 2,6-bis[1-(2-aminoethyl)piperidine-iminomethyl]-4-methyl-phenol, HL³ = N-{1-(2-aminoethyl)pyrolidine}salicylideneimine, HL⁴ = N-{1-(2-aminoethyl)piperidine}salicylideneimine, L⁵ = 2-benzoyl pyridine-N-{1-(2-aminoethyl)pyrolidine}, L⁶ = 2-benzoylpyridine-N-{1-(2-aminoethyl)piperidine}] have been synthesized and characterized. Zn(II) complexes of those ligands have been prepared by conventional sequential route as well as by template synthesis. The same complexes are obtained from the two routes as evident from routine physicochemical characterizations. All the Schiff-bases exhibit photoluminescence originating from intraligand (π–π*) transitions. Metal mediated fluorescence enhancement is observed on complexation of HL¹-HL⁴ with Zn(II), whereas metal mediated fluorescence quenching occurs in Zn(II) complexes of L⁵ and L⁶.     

Dinuclear and Mononuclear Platinum(II) and Palladium(II) Complexes with Modified 2,2′‐Dipyridylamine Ligands Featuring a Cisplatin Analogous Structure Motif

In modern cancer therapy the clinical application of platinum‐based drugs is more and more limited by the occurrence of intrinsic or acquired resistances. In this context the potential use of dinuclear platinum complexes in chemotherapy is increasingly relevant. The novel complexes Pd(Bzdpa)Cl₂, Pd₂(C₄H₈(dpa)₂)Cl₄, and Pt₂(C₄H₈(dpa)₂)Cl₄ allow a direct comparison of mono‐ and dinuclear palladium and platinum complexes respectively deriving from a 2,2′‐dipyridylamine (Hdpa) ligand system. They were characterized by single crystal X‐ray analysis as well as infrared spectroscopy and elemental analysis. The cisplatin analogous mononuclear palladium complex Pd(Bzdpa)Cl₂ ( 1 ) (Bzdpa: (2,2′‐dipyridylbenzyl)amine) belongs to a range of 2,2′‐dipyridylamine‐based compounds which were extensively studied in our laboratories. 1 crystallizes in the orthorhombic space group Pna2₁ with a = 13.722(3), b = 13.457(3), c = 9.483(2), V = 1751.1(6) ų, and Z = 4. The metal binding motif of 1 was expanded by a flexible butyl‐linker to form the tetradentate C₄H₈(dpa)₂ ligand. The resulting isotypic dinuclear complexes Pd₂(C₄H₈(dpa)₂)Cl₄·2CH₃CN ( 2 ) and Pt₂(C₄H₈(dpa)₂)Cl₄·2CH₃CN ( 3 ) crystallize in the triclinic space group with a = 7.8427(2), b = 8.7940(2), c = 11.7645 (3), α = 79.219(2)°, β = 84.033(2)°, γ = 87.744(2)°, V = 792.58(3) ų ( 2 ) and a = 7.831(5), b = 8.814(5), c = 11.817(5), α = 79.271(5)°, β = 83.571(5)°, γ = 88.063(5)°, V = 796.3(8) ų ( 3 ), both with one centrosymmetrical molecule in the unit cell.     

SYNTHESIS AND CHARACTERIZATION OF THE FORMAL Ni(III) AND Cu(III) COORDINATION COMPLEXES OF THE NEW 1,2-DITHIOLENE, 1,4-BUTANEDIYLDITHIOETHYLENE-1,2-DITHIOLATE

Abstract

The new 1,2-dithiolene, 1,4-butanediyldithioethylene-1,2-dithiolate, has been isolated. In addition, new monoanionic bis-complexes with nickel and copper have been prepared and isolated. The formal Ni(III) complex crystallizes in the orthorombic space group, P_bca, with a = 9.762(9), b = 12.53(2), and c = 23.166(3) Å, with 4 molecules in the unit cell. The structure was refined to an R = 9.01% (R_w = 8.95%). The formal Cu(III) complex crystallizes in the monoclinic space group, C_2/c, with a = 25.567(6), b = 8.011(3), c = 14.504(3) Å, and β = 106.17(2)° with 4 molecules in the unit cell. The structure refined to R = 4.2% with R _w = 4.3%. Comparisons to similar 1,2-dithiolenes suggest this ligand produces only modest structural and electronic differences when compared to the 1,3-propanediyldithioethylene-1,2-dithiolate complexes. The oxidation (to a neutral complex) and reduction (to a dianion) for the Ni(III) and Cu(III) complexes show large differences from those of maleonitriledithiolate. Other physical data are presented as well.     

Synthesis,crystal structures,antimicrobial activities,and DFT calculations of two new azido nickel(II) complexes

Two new complexes, [Ni(HL¹)(N₃)(μ_1,1N₃)]₂ (1) [HL¹: NC₅H₄CH₃C=NNH (C=O) NH₂] and [Ni(L²)N₃] (2) [HL²: NC₅H₄HC=N NH(C=S)NH₂], have been synthesized by reaction of Ni(OAC)₂·4H₂O and sodium azide with HL¹ and HL² and characterized by elemental analysis, FT-IR, and UV–vis spectral studies. Single-crystal X-ray diffraction reveals that 1 is dinuclear with nickel(II) in an octahedral environment of NNO donors of HL¹, two nitrogens of azide bridges and one nitrogen of terminal azide; 2 is mononuclear containing nickel(II) in a distorted square-planar environment of NNS donors of HL² and one terminal azide. The structures of 1 and 2 have been optimized by density functional theory. The results of antimicrobial activities of ligands, 1 and 2 demonstrated that HL² and 2 have good antimicrobial activity in contrast with HL¹ and 1, related to the presence of sulfur donor in HL².     

Synthesis,crystal structures,and antimicrobial activities of hydrazone complexes of vanadium(V)

Two hydrazone ligands, (E)-N′-(3-bromo-2-hydroxybenzylidene)-2-methoxybenzohydrazide (HL^a) and (E)-N′-(2-hydroxy-3-methylbenzylidene)-2-methoxybenzohydrazide (HL^b), were prepared and characterized by IR, UV–vis, and ¹H NMR spectroscopy. The corresponding vanadium(V) complexes, 2[VOL^aL]·CH₃OH (1) and [VOL^bL] (2), where L is the monoanionic form of benzohydroxamic acid (HL), were prepared and characterized by IR and UV–vis spectroscopy, and single-crystal X-ray diffraction. Complex 1 crystallizes as the monoclinic space group P2₁/c, with unit cell dimensions a = 14.4161(16) Å, b = 14.0745(16) Å, c = 24.069(2) Å, β = 96.247(2), V = 4854.5(9) Å³, Z = 4, R₁ = 0.0541, wR₂ = 0.1423, Goof = 1.032. Complex 2 crystallizes in the orthorhombic space group Pbca, with unit cell dimensions a = 13.5906(6) Å, b = 18.1865(11) Å, c = 18.4068(11) Å, V = 4549.5(4) Å³, Z = 8, R₁ = 0.0549, wR₂ = 0.1397, Goof = 1.054. X-ray analysis indicates that the complexes are mononuclear octahedral vanadium(V) complexes. The thermal behavior of the complexes was investigated. The hydrazone ligands and their complexes were also evaluated for their antibacterial (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence) and antifungal (Candida albicans and Aspergillus niger) activities using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The two complexes have moderate to good activities against B. subtilis and S. aureus, and 1 has moderate activity against E. coli.