Mixed‐Ligand Complexes of Copper(II) with α‐Hydroxycarboxylic Acids and 1,10‐Phenanthroline

Eight new two‐ligand complexes of copper(II) with 1,10‐phenanthroline and one of four different α‐hydroxy‐carboxylic acids (glycolic, lactic, mandelic and benzylic) were prepared. The complexes of general formula [Cu(HL)₂(phen)] · nH₂O (HL = monodeprotonated acid) ( 1 – 4 ) were characterized by elemental analysis, IR, electronic and EPR spectroscopy, magnetic measurements and thermo‐gravimetric analysis. The complexes of general formulae [Cu(HL)(phen)₂](HL) · H₂L · nSolv [ 1 a (HL = HGLYO^–, n = 1, Solv = MeCN) and 3 a (HL = HMANO^–, n = 0)] and [Cu(L)(phen)(OH₂)] · nH₂O [ 2 a (L = LACO^2–, n = 4) and 4 a (L = BENO^2–, n = 2)] were characterized by X‐ray diffractometry. In all these latter a pentacoordinated copper atom has a basically square pyramidal coordination polyhedron, the distortion of which towards a trigonal bipyramidal configuration has been evaluated in terms of the parameter τ. In 1 a and 3 a there are three forms of α‐hydroxycarboxylic acid: a monodentate monoanion, a monoanionic counterion, and a neutral molecule lying in the outer coordination sphere; in 2 a and 4 a the α‐hydroxycarboxylic acid is a bidentate dianion coordinating through carboxyl and hydroxyl oxygens.     

Syntheses,Structures, and Catalytic Properties of Three Copper(II) Coordination Polymers Based on 2,3,5,6‐Tetrafluoro‐1,4‐bis(triazole‐ylmethyl)benzene and Benzene Carboxylate Ligands

Three new mixed‐ligand coordination polymers of Cu^II, namely, [Cu(Fbtx)(L1)(H₂O)]_n ( 1 ), [Cu(Fbtx)_0.5(HL2)(H₂O)₂]_n ( 2 ), and {[Cu(Fbtx)_1.5(HL3)(H₂O)] · H₂O}_n ( 3 ) [Fbtx = 2,3,5,6‐tetrafluoro‐1,4‐bis(1,2,4‐triazole‐1‐ylmethyl)benenze, H₂L1 = terephthalic acid, H₃L2 = trimesic acid, NaH₂L3 = 5‐sulfoisophthalic acid monosodium salt], were hydrothermally synthesized and structurally characterized by elemental analysis, IR spectra, and single‐crystal and powder X‐ray diffraction techniques. All the complexes have a two‐dimensional (2D) coordination layer structure. Of these, 1 displays a planar 4⁴‐ sql structure whereas both 2 and 3 are highly undulated 6³‐ hcb nets. Moreover, their thermal stability and catalytic behaviors in the aerobic oxidation of 4‐methoxybenzyl alcohol were also investigated as well. The results indicate that the benzene dicarboxylate ligands have an effective influence on the structures and catalytic properties of the resulting coordination polymers.     

Synthesis and spectroscopic studies of 2,5-hexanedione bis(isonicotinylhydrazone) and its first raw transition metal complexes

New VO²⁺, Mn²⁺, Co²⁺, Ni²⁺ Cu²⁺ and Zn²⁺ complexes of 2,5-hexanedione bis(isonicotinylhydrazone) [H₂L] have been synthesized and characterized. The analyses confirmed the formulae: [VO(L)]·H₂O, [Mn₂(H₂L)Cl₂(H₂O)₆]Cl₂, [Co(L)(H₂O)₂]·2H₂O, [Ni(HL)(OAc)]·H₂O, [Cu(L)(H₂O)₂]·2H₂O, [Cu(L)]·2H₂O and [Zn(L)(H₂O)₂]. The formulae of [Ni(HL)(OAc)]·H₂O, [Zn(L)(H₂O)₂] and [Mn₂(H₂L)Cl₂(H₂O)₆]Cl₂, are supported by mass spectra. The molecular modeling of H₂L is drawn and showed intramolecular hydrogen bonding. The ligand releases two protons during reaction from the two amide groups (NHCO) and behaves as a binegative tetradentate (N₂O₂); good evidence comes from the ¹H NMR spectrum of [Zn(L)(H₂O)₂]. The ligand has a buffering range 10–12 and pK's of 4.62, 7.78 and 9.45. The magnetic moments and electronic spectra of all complexes provide a square-planar for [Cu(L)]·2H₂O, square-pyramidal for [VO(L)]·H₂O and octahedral for the rest. The ESR spectra support the mononuclear geometry for [VO(L)]·H₂O and [Cu(L)(H₂O)₂]·2H₂O. The thermal decomposition of the complexes revealed the outer and inner solvents where the end product in most cases is metal oxide.     

Syntheses, Supramolecular Structures and Antibacterial Activities of Five Helical Transition Complexes with 5-Chloro-1-phenyl-1H-pyrazole-3,4-dicarboxylic Acid

Five new transition metal complexes [Cu(HL)₂(H₂O)₂] ( 1 ), [Cu(HL)₂(phen)] ( 2 ), [Cu(HL)₂(H₂O)]₂(4,4′‐bipy) ( 3 ), [Zn(HL)₂(H₂O)₂]·(4,4′‐bipy) ( 4 ), [Ag(HL)(4,4′‐bipy)]_n ( 5 ), (H₂L=5‐chloro‐1‐phenyl‐1H‐pyrazole‐3,4‐dicarboxylic acid, phen=1,10‐phenanthroline; 4,4′‐bipy=4,4′‐bipyridine) have been synthesized and characterized. Complexes 1 , 2 and 4 exhibit monomeric structures, 3 shows a dinuclear structure, 5 displays 1D chain structure, and all extend to 3D supramolecular network via rich hydrogen bonds. Complexes 1 , 2 , 3 , 5 comprise single helical chains, while complex 4 generates quadruple‐stranded helical chains. Furthermore, the antibacterial activities of the titled complexes against bacterial species, three Gram positive bacteria (Staphylococcus aureus, Bacillus subtilis and Candida albicans) and two Gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were studied and compared to the activities of free ligands by using the microdilution method.     

Potentiometric study of the formation of hydroxo complexes of [Cu(terpy)]2+. Synthesis and crystal structure of [Cu(terpy) (H2O)](CF3SO3)2

Two complexes of formula [Cu(terpy)(H₂O)](CF₃SO₃)₂ (1) and [Cu(terpy)(OH)]BPh₄ (2) (terpy=2,2′∶6′,2″-terpyridine and BPh₄=tetraphenylborate anion) have been synthesized and characterized by spectroscopic techniques. The x-ray crystal structure of (1) has been determined by x-ray diffraction. The structure is made up of [Cu(terpy)(H₂O)]²⁺ mononuclear cations plus semi-coordinated CF₃SO₃ ⁻ anions. The coordination geometry around the copper atom is approximately elongated tetragonal octahedral. The oxygen atom of water and the three nitrogen atoms of terpy occupy the equatorial sites whereas the apical ones are filled by trifluoromethanesulphonate oxygen atoms. The formation of hydroxo complexes of [Cu(terpy)(H₂O)]²⁺ has been investigated by potentiometry in aqueous solutions and the constants of the Equilibria (1) and (2)      

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).     

Solvent‐Vapor‐Induced Reversible Single‐Crystal‐to‐Single‐Crystal Transformation of a Triphosphaazatriangulene‐Based Metal–Organic Framework

A triphosphaazatriangulene (H₃L) was synthesized through an intramolecular triple phospha‐Friedel–Crafts reaction. The H₃L triangulene contains three phosphinate groups and an extended π‐conjugated framework, which enables the stimuli‐responsive reversible transformation of [Cu(HL)(DMSO)?(MeOH)]_n, a 3D‐MOF that exhibits reversible sorption characteristics, into (H₃L?0.5 [Cu₂(OH)₄?6 H₂O] ?4 H₂O), a 1D‐columnar assembled proton‐conducting material. The hydrophilic nature of the latter resulted in a proton conductivity of 5.5×10^?3 S cm^?1 at 95 % relative humidity and 60 °C.     

Synthesis,characterization and antitumour studies of metal chelates of acetoacetanilide thiosemicarbazone

Summary Complexes of transition metals with acetoacetanilide thiosemicarbazone, AatH₂, have been prepared and characterized. The complexes were found to have the following stoichiometries: [Mn(Aat)(H₂O)₂]_n; [Zn(Aat)(H₂O)₂]; [M(Aat)(H₂O)], where M = Cd^II or Hg^II; [Cu(Aat)]_n; [Ag(AatH)]; [M(AatH)₂], where M = Co^II or Ni^II, and [Fe(Aat)Cl(H₂O)]_n. The compounds have been studied for their possible antitumour activity against Ehrlich Ascites tumour cells in vitro.     

Synthesis,crystallographic and spectroscopic characterization and magnetic properties of dimer and monomer ternary copper(II) complexes with sulfonamide derivatives and 1,10-phenanthroline. Nuclease activity by the oxidative mechanism

Three dinuclear and one mononuclear copper(II)-1,10-phenanthroline ternary complexes, [Cu(L1)(phen)(OH)]₂ (1), [Cu(L2)(phen)(OH)]₂·3H₂O (2), [Cu(L3)(phen)(OH)]₂ (3) and [Cu(L4)₂(phen)(H₂O)] (4), with thiadiazole sulfonamide derivative ligands: HL1 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)naphthalene-1-sulfonamide), HL2 (N-(5-ethylthio)-1,3,4-thiadiazol-2-yl)-4-methylbenzenesulfonamide), HL3 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide) and HL4 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)-4-methylbenzenesulfonamide) have been synthesized and characterized. In the four complexes each copper atom is five-coordinated. The structure of complexes 1, 2 and 3 consists of a dimeric unit with a C2 symmetry axis, where both coppers are bridged by two hydroxo anions. Magnetic measurements show that the dimer complexes are ferromagnetic according to the Cu–O–Cu angles. Cleavage experiments using pUC18 plasmid DNA in the presence of H₂O₂/ascorbic acid as an activating agent show that the title complexes are potent artificial chemical nucleases, the order of efficiency being 3 > 2 ∼ 1 > 4. Control cleavage experiments indicated that the dimer complexes are stronger artificial nucleases than the [Cu(phen)₂]²⁺ complex under the same experimental conditions, while the monomer 4 has a lower nuclease activity than the [Cu(phen)₂]²⁺ complex. The inhibition of the cleavage process in the presence of reactive oxygen intermediate scavengers suggests that the hydroxyl radical and the superoxide anion are reactive species for the breakage of the DNA strands.     

Synthesis,Structures, and Luminescent Properties of Three Coordination Polymers Constructed from Tricarboxylate and Bisbenzoimidazole Ligand

The hydrothermal reaction of the tricarboxylate ligand 5‐(carboxymethoxy)isophthalic acid (H₃L) with Zn^II, Cd^II, and Sn^II salts in the presence of the bisbenzoimidazole coligand 1, 3‐bis(benzimidazol‐2‐yl)‐2‐oxapropane (bbop) afforded the coordination polymers, [Zn(HL)(bbop)]_n ( 1 ), [Cd(HL)(bbop)]_n ( 2 ), and {[H₂(bbop)][Sn₂L₂]}_n ( 3 ). The complexes were characterized by elemental analyses, IR spectroscopy, single‐crystal X‐ray diffraction analyses, thermogravimetric analyses, and fluorescence properties. The structures of complexes 1 and 2 are constructed by 1D chains and show strong blue luminescence emission. The structure of complex 3 is a 2D anionic dilayer, and shows a vase‐like porous structure occupied by the bulky [H₂(bbop)]²⁺ cation, which is an uncommon structural feature in transition metal coordination polymers. The three complexes are further connected by hydrogen bonds to form 3D supramolecular architectures.     

Synthesis and structure of new copper(II) coordination compounds with 8-quinoline aldehyde semicarbazones and thiosemicarbazones

Copper(II) salts were reacted with various quinoline aldehyde chalcogensemicarbazones to yield compounds formulated as Cu(HL)X₂ · nH₂O (I: HL = quinoline aldehyde thiosemicarbazone (HL¹), X = ClO₄, n = 2; II: HL = quinoline aldehyde 4-C₂H₅-thiosemicarbazone (HL^1a), X = NO₃, n = 0; III: HL = quinoline aldehyde semicarbazone (HL²), X = ClO₄, n = 3 and IV: HL = quinoline aldehyde 4-Ph-semicarbazone (HL^2a), X = NO₃, n = 1). Regardless of the reagent ratio, the products were compounds having the metal: ligand ratio of 1: 1, where the organic ligand was coordinated tridentate in a molecular form. Single-crystal X-ray diffraction showed that, depending on the chalcogen atom in the organic ligand (S or O), the substituent in the 4th position (at the terminal nitrogen atom), and the specifics of the acido ligand, complexes I–IV had appreciably differing molecular structure organizations. The structures of I and III are formed by a 1D charged coordination polymer, ClO ₄ ^? anions, and water molecules and may be described by the formula [Cu(HL)(H₂O)(ClO₄)] _n (ClO₄) _n · nH₂O. Copper(II) coordination polyhedra in I and II are (4 + 2) and (4 + 1 + 1) tetragonal bipyramids, respectively. In II and IV, the structures are monomeric and can be described as [Cu(HL^1a)(NO₃)₂] with the metal coordination polyhedron shaped as a (4 + 1) tetragonal pyramid in II and as [Cu(HL^2a)(H₂O)(NO₃)](NO₃) with the metal coordination polyhedron shaped as a (3 + 2) trigonal bipyramid in IV. The structure of II is built of molecular complexes, each comprising, apart from ligand HL^1a, two monodentate coordinated NO ₃ ^? groups. The oxygen atom of one anion together with the NNS donor atom set of ligand HL^1a form the base, and the oxygen atom of the other anion is in the apex of the coordination polyhedron. In IV, the structure is ionic and built of NO ₃ ^? anions and [Cu(HL^2a)(H₂O)(NO₃)]⁺ complex cations, where a cationic coordination polyhedron has a trigonal-bipyramidal configuration with organic ligand HL^2a positioned along the long edge. The bipyramidal base is made up by the oxygen atoms of the coordinated water molecule and monodentate nitrato group and the nitrogen atom N2 of the azomethyne group.     

Dipyridylamide Donor Disposition and Isophthalate Substituent Steric Effect on the Dimensionality and Topology of Divalent Copper Coordination Polymers

Divalent copper coordination polymers containing an isophthalate ligand and a dipyridylamide ligand show different dimensionalities and topologies depending on pyridyl nitrogen donor disposition and the steric bulk of the substituent on the dicarboxylate aromatic ring. According to single‐crystal X‐ray diffraction, [Cu(ip)(3‐pna)]_n ( 1 , ip = isophthalate, 3‐pna = 3‐pyridylnicotinamide) shows a (4, 4) layered grid structure based on {Cu₂(OCO)₂} dimeric units. {[Cu(ip)(3‐pina)]·H₂O}_n ( 2 , 3‐pina = 3‐pyridylisonicotinamide) exhibits similar dimeric units, but in contrast to 1 these are connected into a non‐interpenetrated 3D 6⁵8 cds network. Both [Cu(mip)(3‐pina)]_n ( 3 , mip = 5‐methylisophthalate) and [Cu(meoip)(3‐pina)]_n ( 4 , mip = 5‐methoxyisophthalate) display dimer‐based 4¹²6³ pcu networks in contrast to 2 . Use of 5‐hydroxyisophthalate (H₂hip) as a precursor afforded a mixture of {[Cu₂(hip)₂(3‐pina)₄]·9.5H₂O}_n ( 5 ) and [Cu(hip)(3‐pina)]_n ( 6 ). Compound 5 shows a 2D interdigitated structure with [Cu(hip)]_n coordination polymer layers featuring {Cu₂(OCO)₂} dimeric units and pendant 3‐pina ligands, while 6 also showed a dimer‐based 4¹²6³ pcu network. Use of the very sterically bulky 5‐tert‐butylisophthalate (tbip) ligand afforded the 1D chain coordination polymer {[Cu(tbip)(3‐pina)₂(H₂O)]·H₂O}_n ( 7 ), which contains isolated copper ions in contrast to 1 – 6 , and has a curious “butterfly“ resemblance. Very weak antiferromagnetic coupling is seen within the {Cu₂(OCO)₂} dimeric units in 1 . Thermal decomposition behavior is also discussed.     

Transition metal complexes with thiosemicarbazide-based ligands,Part II,Synthesis and characterisation of nickel(II), cobalt(II), manganese(II) and zinc(II) complexes with the pentadentate ligand, 2,6-diacetylpyridine bis(S-methylisothiosemicarbazone)

Summary The reaction of warm alcoholic solutions of acetates of Co^II, Mn^II, Zn^II and Ni^II with 2, 6-diacetylpyridine andS-methylisothiosemicarbazide hydrogen iodide yielded the complexes: [Co(H₂L)I₂]·H₂O, [Mn(H₂L)(MeOH)₂]I₂, [Zn(H₂L)(MeOH)I]I and [Ni(HL)]I, (H₂L=the pentadentate pentaaza-ligand 2, 6-diacetylpyridine bis(S-methylisothiosemicarbazone)). The reaction of methanolic solutions of [Ni(HL)]I and NH₄NCS or LiOAc.2H₂O, give [Ni(HL)]NCS and NiL, respectively. For the complexes of Co^II, Mn^II and Zn^II, a pentagonal bipyramidal configuration is proposed, with H₂L in the equatorial plane and two unidentate ligands (I and/or MeOH) in the axial positions. The complexes [Ni(HL)]X (X=I or NCS) and NiL probably have monomeric five- and dimeric six-coordinate structures, respectively, in which only the chelate ligand is involved in coordination.     

Bivalent metal complexes ofp-methyl- andp-methoxybenzoylhydrazone oximes

Summary Bivalent metal complexes ofp-chloro-,p-methyl- andp-methoxybenzoylhydrazone oximes (H₂BMCB, H₂BMMB or H₂BMTB=H₂L), [M(H₂L)Cl₂]. nH₂O (M=Zn^II, Cd^II or Hg^II, n=0 or 1; [M(H₂L)Cl₂] (M=Zn^II or Cd^II); [M(HL)₂(H₂O)_n]. YH₂O (M=Co^II, Cu^II, Zn^II or U^VIO₂, n=0–2); [Ni(H₂BMCB)(H₂O)₃]Cl₂, [Ni(BMMB)(H₂O)]₂ and [Ni(BMTB)(H₂O)]₂, were synthesized by conventional physical and chemical measurements. I.r. spectra show that the ligands are bidentate or tridentate. Spectral, magnetic and molecular weight measurements suggest that cobalt(II) and nickel(II) have monomeric octahedral geometry when derived from H₂BMCB, a dimeric square planar geometry for nickel(II) and monomeric square planar geometry for cobalt(II) for those isolated from H₂BMMB or H₂BMTB. Also, a monomeric distorted octahedral structure is proposed for copper(II) complexes derived from the ligands under investigation.     

Synthesis,Characterization and SOD Activities of IP-copper（Ⅱ）-L-amino Acid Complexes

Four new ternary complexes： [Cu（IP）（L-Val）（H2O）]ClO4·1.5H2O（1）, [Cu（IP）（L-Leu）（H2O）]ClO4（2）, [Cu（IP）（L-Tyr）（H2O）]ClO4·H2O（3） and [Cu（IP）（L-Trp）（H2O）]ClO4·1.5H2O（4） have been synthesized and character/zed by elementa/analysis, molar conductivity, infrared absorption spectroscopy, electronic absorption spectroscopy and cyclic voltammetry, where IP=imidazo[4,5-f][1,10] phenanthroline, L-Val=L-valinate, L-Leu=L-leucinate, L-Tyr=L-tyrosinate and L-Trp=L-tryptophanate. Complex 3 was structurally characterized by X-ray diffraction method, which crystallizes in orthorhornbic space group P21212 in a unit cell of dimensions a=3.0567（4） nm, b=0.74079（9） nm, c= 1.06198（13） nm, V=2.4047（5） nm^3, Z=4,μ=0.1084 cm^-1. The SOD-like activities of catalytic disrnutation of superoxide anions （O2^-· ） by the complexes were determined by means of modified nitroblue tetrazolium （NBT） photoreduction. The IC50 values of complexes 1, 2, 3 and 4 are 0.072, 0.147, 0.429 and 0.264 μmol·L^-1, respectively     

Solvent-Vapor-Induced Reversible Single-Crystal-to-Single-Crystal Transformation of a Triphosphaazatriangulene-Based Metal–Organic Framework

A triphosphaazatriangulene (H₃L) was synthesized through an intramolecular triple phospha-Friedel–Crafts reaction. The H₃L triangulene contains three phosphinate groups and an extended π-conjugated framework, which enables the stimuli-responsive reversible transformation of [Cu(HL)(DMSO)⋅(MeOH)]_n, a 3D-MOF that exhibits reversible sorption characteristics, into (H₃L⋅0.5 [Cu₂(OH)₄⋅6 H₂O] ⋅4 H₂O), a 1D-columnar assembled proton-conducting material. The hydrophilic nature of the latter resulted in a proton conductivity of 5.5×10⁻³ S cm⁻¹ at 95 % relative humidity and 60 °C.     

Syntheses,Crystal Structures,and Magnetic Properties of Three 1D Chain Metal–Nitroxide Complexes Bridged by ­Flexible Dicarboxylate Anions

Three new one‐dimensional (1D) chain metal–nitroxide complexes {[Cu(NIT4Py)₂(suc)(H₂O)] · 3H₂O}_n ( 1 ), {[Cd(NIT4Py)₂(suc)(H₂O)] · [Cd(NIT4Py)₂(suc)(H₂O)₂] · 3H₂O}_n ( 2 ), and {[Zn(NIT4Py)(glu)(H₂O)] · H₂O}_n ( 3 ) [NIT4Py = 2‐(4′‐pyridyl)‐4, 4, 5, 5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide, suc = succinate anion and glu = glutarate anion] were synthesized and structurally characterized. Single‐crystal X‐ray analyses indicate that the three complexes crystallize in neutral 1D chains in which the metal‐nitroxide units are linked by flexible dicarboxylate anions. The succinate anions only adopt trans configuration in complexes 1 and 2 , whereas the glutarate anion has gauche/anti conformation in complex 3 . Magnetic measurements show that complex 1 exhibits weak antiferromagnetic interactions between the copper ions and the nitroxides.     

Cobalt(II), nickel(II) and copper(II) complexes of 5-(2-carboxyphenylazo)-2-thiohydantoin

A new series of hexacoordinate cobalt(II), nickel(II) and copper(II) complexes of 5-(2-carboxyphenylazo)-2-thiohydantoin HL having formulae [LM(OAc)(H₂O)₂] · nH₂O (M = Co^II, Cu^II and Ni^II), [LMCl(H₂O)₂] · nH₂O (M = Co^II and Ni^II), [LCuCl(H₂O)]₂ · 2H₂O, [LCu(H₂O)₃](ClO₄) and [LCu(HSO₄)(H₂O)₂] were isolated and characterized by elemental analyses, molar conductivities and magnetic susceptibilities, and by i.r., electronic and e.s.r. spectral measurements, as well as by thermal (t.g. and d.t.g.) analyses. The i.r. spectra indicate that the ligand HL behaves as a monobasic tridentate towards the three divalent metal ions via an azo-N, carboxylate-O and thiohydantoin-O atom. The magnetic moments and electronic spectral data suggest an octahedral geometry for Co^II complexes, distorted octahedral geometry for both Ni^II and Cu^II complexes with a dimeric structure for [LCuCl(H₂O)]₂ · 2H₂O through bridged chloro ligands. The X-band e.s.r. spectra reveal an axial symmetry for the copper(II) complexes with unsymmetrical M_s = ± 1 signal and G-parameter less than four for the dimeric [LCuCl(H₂O)]₂ · 2H₂O. The thermogravimetry (t.g. and d.t.g.) of some complexes were studied; the order and kinetic parameters of their thermal degradation were determined by applying Coats–Redfern method and discussed.     

Coordination compounds of nickel with trithiocyanuric acid. Part IV. Structure of [Ni(pmdien)(ttcH)] (pmdien = N,N,N′,N′,N′′-pentamethyldiethylenetriamine,ttcH3 = trithiocyanuric acid)

Ni^II mixed-ligand complexes of compositions [Ni(pmdien)(ttcH)] (1), [Ni(baphen)₂(ttcH)] · 4H₂O (2), [Ni-(dpa)(ttcH)(H₂O)] (3), [Ni(cyclam)(ttcH)] · 2H₂O (4), [Ni(hexaa)](ttcH) (5) and [Ni(hexab)(ttcH)] · 2H₂O (6), (baphen = 4,7-diphenyl-1,10-phenanthroline, dpa = 2,2-dipyridylamine, cyclam = 1,4,8,11-tetraazacyclotetradecane, hexaa = 1,3,6,9,11,14-hexaazatricyclo[12.2.1.1^6,9]-octadecane, hexab = 1,8-dimethyl-1,3,6,8,10,13-hexaazacyclotetradecane) have been prepared and characterized by means of i.r., u.v.–vis. spectroscopies and magnetochemical measurements. The redox properties of the complexes were studied by cyclic voltammetry. The crystal and molecular structure of [Ni(pmdien)(ttcH)] was determined. The nickel atom is penta-coordinated by three N atoms of pmdien, and by S and N atoms of trithiocyanurate(2–) anion.     

Spectroscopic studies and biological evaluation of some transition metal complexes of Schiff-base ligands derived from 5-arylazo-salicylaldehyde and thiosemicarbazide

Synthesis and spectroscopic characterization of Schiff-base complexes of Cu(II), Ni(II), and Mn(II) resulting from condensation of salicylaldehyde derivatives with thiosemicarbazide [PHBT = 1-(5-(2-phenyldiazenyl)-2-hydroxybenzylidene)thiosemicarbazide, CHBT = 1-(5-(2-(2-chlorophenyl)diazenyl)-2-hydroxybenzylidene)thiosemicarbazide, and MHBT = 1-(5-(2-p-tolyldiazenyl)-2-hydroxybenzylidene)thiosemicarbazide] are discussed. The solid complexes were confirmed by elemental analysis (CHN), molar conductance, and mass spectra. Important infrared (IR) spectral bands corresponding to the active groups in the three ligands, ¹H-NMR and UV-Vis spectra and thermogravimetric analysis were performed. The dehydration and decomposition of [Cu(PHBT)(H₂O)], [Ni(PHBT)(H₂O)] · 2H₂O, [Mn(PHBT)(H₂O)] · H₂O, [Cu(CHBT)(H₂O)], [Ni(CHBT)(H₂O)] · H₂O, [Mn(CHBT)(H₂O)] · H₂O, [Cu(MHBT)(H₂O)], [Ni(MHBT)(H₂O)] · 2H₂O, and [Mn(MHBT)(H₂O)] · 2H₂O complexes were studied. The ligands are tridentate forming chelates with 1 : 1 (metal : ligand) stoichiometry. The molar conductance measurements of the complexes in DMSO indicate non-electrolytes. The biological activities of the metal complexes have been studied against different gram positive and gram negative bacteria.