Synthesis, thermal, spectral and magnetic studies of complexes of Co(II), Ni(II), Cu(II), Ru(II), Pd(II) and Pt(II) with 2, 3-disubstituted quinazolin-(3H)-4-ones

A number of complexes of Co(II), Ni(II), Cu(II), Ru(II), Pd(II) and Pt(II) with 2-methyl-3-(carboxy methyl) quinazolin (3H)-4-one (MCMQ) and 2-phenyl-3-(carboxy methyl) quinazolin (3H)-4-one (PCMQ) have been synthesized and characterized by analytical, conductivity, thermal, magnetic, infrared, electronic, proton magnetic resonance and electron spin resonance spectral data. Based on analytical data, the stoichiometry and the association with other molecules of the complexes have been determined. Conductivity data show that all these complexes are nonelectrolytes. Infrared and PMR spectral data indicate that both the ligands are uninegative bidentate with all the metal ions. Based on electronic spectral data, the geometries of the complexes have been indicated. Electronic spectral parameters for Co(II) and Ni(II) and ESR parameters for Cu(II) complexes have been calculated and relevant conclusions have been drawn with respect to the nature of bonds present in them.     

Tetradentate bis(o-iminobenzosemiquinonate(1-)) pi radical ligands and their o-aminophenolate(1-) derivatives in complexes of nickel(II), palladium(II), and copper(II)

The coordination chemistries of the potential tetradentate ligands N,N'-bis(3,5-di-tert-butyl-2-hydroxyphenyl)ethylenediamine, H4[L1], the unsaturated analogue glyoxal-bis(2-hydroxy-3,5-di-tert-butylanil), H2[L2], and N,N'-bis(2-hydroxy-3,5-di-tert-butylphenyl)-2,2-dimethylpropylenediamine, H4[L3], have been investigated with nickel(II), palladium(II), and copper(II). The complexes prepared and characterized are [Ni(II)(H3L1)2] (1), [Ni(II)(HL2)2].5/8CH2Cl2 (2), [Ni(II)(L3**)] (3), [Pd(II)(L3**)][Pd(II)(H2L3) (4), and [Cu(II)(H2O)(L4)] (5), where (L4)2- is the oxidized diimine form of (L3)4- and (L3**)2- is the bis(o-iminosemiquinonate) diradical form of (L3)4-. The structures of compounds 1-5 have been determined by single crystal X-ray crystallography. In complexes 1 and 2, the ligands (H3L1)- and (HL2)- are tridentate and the nickel ions are in an octahedral ligand environment. The oxidation level of the ligands is that of an aromatic o-aminophenol. 1 and 2 are paramagnetic (mu(eff) approximately 3.2 mu(B) at 300 K), indicating an S = 1 ground state. The diamagnetic, square planar, four-coordinate complexes 3 and [Pd(II)(L3**)] in 4 each contain two antiferromagnetically coupled o-iminobenzosemiquinonate(1-) pi radicals. Diamagnetic [Pd(II)(H2L3)] in 4 forms an eclipsed dimer via four N-H.O hydrogen bonding contacts which yields a nonbonding Pd.Pd contact of 3.0846(4) A. Complex 5 contains a five-coordinate Cu(II) ion and two o-aminophenolate(1-) halves in (L4)2-. The electrochemistries of complexes 3 and 4a ([Pd(II)(L3**)] of 4) have been investigated, and the EPR spectra of the monocations and -anions are reported.     

Zinc(II), cadmium(II), mercury(II), and ethylmercury(II) complexes of phosphinothiol ligands

Neutral zinc, cadmium, mercury(II), and ethylmercury(II) complexes of a series of phosphinothiol ligands, PhnP(C6H3(SH-2)(R-3))3-n (n = 1, 2; R = H, SiMe3) have been synthesized and characterized by IR and NMR ((1)H, (13)C, and (31)P) spectroscopy, FAB mass spectrometry, and X-ray structural analysis. The compounds [Zn{PhP(C6H4S-2)2}] (1) and [Cd{Ph2PC6H4S-2}2] (2) have been synthesized by electrochemical oxidation of anodic metal (zinc or cadmium) in an acetonitrile solution of the appropriate ligand. The presence of pyridine in the electrolytic cell affords the mixed complexes [Zn{PhP(C6H4S-2)2}(py)] (3) and [Cd{PhP(C6H4S-2)2}(py)] (4). [Hg{Ph2PC6H4S-2}2] (5) and [Hg{Ph2PC6H3(S-2)(SiMe3-3)}2] (6) were obtained by the addition of the appropriate ligand to a solution of mercury(II) acetate in methanol in the presence of triethylamine. [EtHg{Ph2PC6H4S-2}] (7), [EtHg{Ph2P(O)C6H3(S-2)(SiMe3-3)}] (8), [{EtHg}2{PhP(C6H4S-2)2}] (9), and [{EtHg}2{PhP(C6H3(S-2)(SiMe3-3))2}] (10) were obtained by reaction of ethylmercury(II) chloride with the corresponding ligand in methanol. In addition, in the reactions of EtHgCl with Ph2PC6H4SH-2 and with the potentially tridentate ligand PhP(C6H3(SH-2)(SiMe3-3)) 2, cleavage of the Hg-C bond was observed with the formation of [Hg{Ph2PC6H4S-2}2] (5) and [Hg(EtHg) 2{PhP(O)(C6H3(S-2)(SiMe3-3))2}2] (11), respectively, and the corresponding hydrocarbon. The crystal structures of [Zn3{PhP(C6H4S-2)2}2{PhP(O)(C6H4S-2)2}] (1*), [Cd2{Ph2PC6H4S-2}3{Ph2P(O)C6H4S-2}] (2*), 3, 5, 6, [EtHg{Ph2P(O)C6H4S-2}] (7*), 8, 9, [{EtHg}2{PhP(O)(C6H3(S-2)(SiMe3-3))2}] (10*), and 11 are discussed. The molecular structures of 1, 2, 4, 7, and 10 have also been studied by means of density functional theory (DFT) calculations.     

Synthesis and Physicochemical Study of Iron(II), Cobalt(II), Nickel(II), and Copper(II) Complexes with 4-(2-Pyridyl)-1,2,4-Triazole

New complexes of iron(II), cobalt(II), and nickel(II) with 4-(2-pyridyl)-1,2,4-triazole (PyTrz), [Fe₃(PyTrz)₈(H₂O)₄]A₆ (A = NO₃ ^-, ClO₄ ^-, Br^-) and [M₃(PyTrz)₈(H₂O)₄](NO₃)₆ (M = Co, Ni), were synthesized and studied by X-ray diffraction, magnetochemical method, and electronic and IR spectroscopy. The complex [Fe₃(PyTrz)₈(H₂O)₄](NO₃)₆) was also studied by adiabatic calorimetry. The Fe(II), Co(II), and Ni(II) nitrate complexes were shown to be isostructural to the previously synthesized linear trinuclear [Cu₃(PyTrz)₈H₂O)₄](NO₃)₆ complex. In all compounds, antiferromagnetic exchange interactions between M²⁺ ions were detected. The complex [Fe₃(PyTrz)₈(H₂O)₄](NO₃)₆ undergoes the ¹ A ₁ ⁵ T ₂ spin transition.     

Synthesis and study of cobalt(II), nickel(II), and copper(II) complexes with 4-(4-hydroxyphenyl)-1,2,4-triazole

New complexes of Co(II), Ni(II), and Cu(II) nitrates, chlorides, and perchlorates with 4-(4-hydroxyphenyl)-1,2,4-triazole (L) were obtained and examined by single-crystal X-ray diffraction, X-ray powder diffraction, and electronic absorption and IR spectroscopy. The cations of all the complexes have linear trinuclear structures. Ligand L is coordinated to the metal ions in a bidentate bridging fashion through the N(1) and N(2) atoms of the heterocycle. The coordination polyhedron of the metal atoms is a distorted octahedron. The molecular and crystal structures of the complexes [Co₃L₆(H₂O)₆](ClO₄)₆ · 3C₂H₅OH · 3.75H₂O and [M₃L₆(H₂O)₆](ClO₄)₆ · 6H₂O (M = Cu²⁺ and Ni²⁺) were determined.     

Cobalt(II), nickel(II) and copper(II) complexes of 4-(sulfonylazido)phenylazopyrazolones

Transition metal complexes of Co^II, Ni^II and Cu^II with 4-(4-azidosulfophenylazo)-5-phenyl-3,4-dihydro-2H-pyrazol-3-oneHL¹, 4-(4-azidosulfophenylazo)-5-methyl-2-phenyl-3,4-dihydro-2H-pyrazol-3-one HL² and 4-(3-azidosulfo-6-methoxyphenylazo)-5-methyl-2-phenyl-3,4-dihydro-2H-pyrazol-3-one HL³ were prepared and characterized by elemental analyses, molar conductances and magnetic susceptibilities and by i.r., electronic and e.s.r. spectral measurements as well as thermal (d.t.a and t.g.a.) analysis. The i.r. spectra indicate that HL acts as a bidentate ligand coordinating via the azo and enolic-oxygen linkages. The electronic spectral data and magnetic moments suggest a tetragonally distorted octahedral geometry for the complexes having the formula ML₂·2H₂O, (M = Co^II, Ni^II and Cu^II), square pyramidal geometry for CuL ₂ ³ H₂O and tetrahedral geometry for CoL ₂ ³ . The X-band e.s.r. spectra of the copper(II) complexes reveal anaxial symmetry for both CuL ₂ ² 2H₂O and CuL ₂ ³ H₂O while CuL ₂ ¹ O is isotropic in the solid state at room temperature. The d.t.a. curves show two exothermic peaks for all three complexes CoL ₂ ³ ,NiL ₂ ³ 2H₂O and CuL ₂ ³ H₂O and one endothermic peak for the latter two aqua complexes.     

Studies of Mn(II), Co(II), Ni(II) and Cu(II) Chelates with 3-phenyl-4-(p-methoxy- phenylazo)-5-pyrazolone

Mn(II), Co(II), Ni(II) and Cu(II) chelates with3-phenyl-4-(p-methoxyphenylazo)-5-pyrazolone have been synthesized and were characterized by elemental and thermal analyses as well as by IR, UV-VIS, ¹HNMR, conductometric and magnetic measurements. The first stage in the thermal decomposition process of these complexes shows the presence of water of hydration, the second denotes the removal of the coordinated water molecules. The final decomposition products were found to be the respective metal oxides. The data of the investigated complexes suggest octahedral geometry with respect to Co(II) 1:1, tetrahedral for Ni(II) 1:1and 2:3; square planar for Cu(II) 1:1 and 2:3; the complexes with no coordinated water molecules (2:3) Co(II) and Mn(II) complexes are tetrahedral. This revised version was published online in August 2006 with corrections to the Cover Date.     

Preparation, characterization and biological activity of Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) complexes of new cyclodiphosph(V)azane of sulfaguanidine

Novel hexachlorocyclodiphosph(V)azane of sulfaguanidine, H(4)L, l,3-[N'-amidino-sulfanilamide]-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane was prepared and its coordination behaviour towards the transition metal ions Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV-vis, (1)H NMR, mass spectra, reflectance, magnetic susceptibility measurements and thermogravimetric analysis (TGA). The hyperfine interactions in the isolated complex compounds were studied using 14.4keV gamma-ray from radioactive (57)Co (M?ssbauer spectroscopy). The data show that the ligand are coordinated to the metal ions via the sulfonamide O and deprotonated NH atoms in an octahedral manner. The H(4)L ligand forms complexes of the general formulae [(MX(z))(2)(H(2)L)H(2)O)(n)] and [(FeSO(4))(2) (H(4)L) (H(2)O)(4)], where X=NO(3) in case of UO(2)(II) and Cl in case of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The molar conductance data show that the complexes are non-electrolytes. The thermal behaviour of the complexes was studied and different thermodynamic parameters were calculated using Coats-Redfern method. Most of the prepared complexes showed high bactericidal activity and some of the complexes show more activity compared with the ligand and standards.     

Synthesis and reactions of triphenylsilanethiolato complexes of manganese(II), iron(II), cobalt(II), and nickel(II)

Reactions of Fe[N(SiMe(3))(2)](2) with 1 and 2 equiv of Ph(3)SiSH in hexane afforded dinuclear silanethiolato complexes, [Fe(N(SiMe(3))(2))(mu-SSiPh(3))](2) (1) and [Fe(SSiPh(3))(mu-SSiPh(3))](2) (2), respectively. Various Lewis bases were readily added to 2, generating mononuclear adducts, Fe(SSiPh(3))(2)(L)(2) [L = CH(3)CN (3a), 4-(t)BuC(5)H(4)N (3b), PEt(3) (3c), (LL) = tmeda (3d)]. From the analogous reactions of M[N(SiMe(3))(2)](2) (M = Mn, Co) and [Ni(NPh(2))(2)](2) with Ph(3)SiSH in the presence of TMEDA, the corresponding silanethiolato complexes, M(SSiPh(3))(2)(tmeda) [M = Mn (4), Co (5), Ni (6)], were isolated. Treatment of 3a with (PPh(4))(2)[MoS(4)] or (NEt(4))(2)[FeCl(4)] resulted in formation of a linear trinuclear Fe-Mo-Fe cluster (PPh(4))(2)[MoS(4)(Fe(SSiPh(3))(2))(2)] (7) or a dinuclear complex (NEt(4))(2)[Fe(2)(SSiPh(3))(2)Cl(4)] (8). On the other hand, the reaction of 3a with [Cu(CH(3)CN)(4)](PF(6)) gave a cyclic tetranuclear copper cluster Cu(4)(SSiPh(3))(4) (9), where silanethiolato ligands were transferred from iron to copper. Silicon-sulfur bond cleavage was found to occur when the cobalt complex 5 was treated with (NBu(4))F in THF, and a cobalt-sulfido cluster Co(6)(mu(3)-S)(8)(PPh(3))(6) (10) was isolated upon addition of PPh(3) to the reaction system. The silanethiolato complexes reported here are expected to serve as convenient precursors for sulfido cluster synthesis.     

Complexes of Co(II), Ni(II), and Cu(II) with 4-(3,4-dichlorophenyl)-1,2,4-triazole

Novel oligonuclear complexes of Co(II), Ni(II), and Cu(II) with 4-(3,4-dichlorophenyl)-1,2,4-triazole (L) of the composition [M₃L₁₀(H₂O)₂](NO₃)₆ (M = Co(II), Ni(II)), [Ni₃L₆(H₂O)₆]Hal₆ (Hal = Cl^?, Br^?), and [Cu₅L₁₆(H₂O)₂](NO₃)₁₀ · 2H₂O were synthesized and studied by magnetic susceptibility, electronic and IR spectroscopy, and powder X-ray diffraction methods. All the above complexes are X-ray amorphous. Antifer-romagnetic exchange interactions between the M²⁺ ions were discovered in the [Co₃L₁₀(H₂O)₂](NO₃)₆ and [Ni₃L₁₀(H₂O)₂](NO₃)₆ complexes, whereas ferromagnetic exchange interactions were observed in the complexes [Ni₃L₆(H₂O)₆]Cl₆, [Ni₃L₆(H₂O)₆]Br₆, and [Cu₅L₁₆(H₂O)₂](NO₃)₁₀ · 2H₂O.     

Syntheses, crystal structures, and magnetic properties of one-dimensional oxalato-bridged Co(II), Ni(II), and Cu(II) complexes with n-aminopyridine (n = 2-4) as terminal ligand

The reaction of M(ox) x 2H(2)O (M = Co(II), Ni(II)) or K(2)(Cu(ox)(2)) x 2H(2)O (ox = oxalate dianion) with n-ampy (n = 2, 3, 4; n-ampy = n-aminopyridine) and potassium oxalate monohydrate yields one-dimensional oxalato-bridged metal(II) complexes which have been characterized by FT-IR spectroscopy, variable-temperature magnetic measurements, and X-ray diffraction methods. The complexes M(mu-ox)(2-ampy)(2) (M = Co (1), Ni (2), Cu (3)) are isomorphous and crystallize in the monoclinic space group C2/c (No. 15), Z = 4, with unit cell parameters for 1 of a = 13.885(2) A, b = 11.010(2) A, c = 8.755(1) A, and beta = 94.21(2) degrees. The compounds M(mu-ox)(3-ampy)(2).1.5H(2)O (M = Co (4), Ni (5), Cu (6)) are also isomorphous and crystallize in the orthorhombic space group Pcnn (No. 52), Z = 8, with unit cell parameters for 6 of a = 12.387(1), b = 12.935(3), and c = 18.632(2) A. Compound Co(mu-ox)(4-ampy)(2) (7) crystallizes in the space group C2/c (No. 15), Z = 4, with unit cell parameters of a = 16.478(3) A, b = 5.484(1) A, c = 16.592(2) A, and beta = 117.76(1) degrees. Complexes M(mu-ox)(4-ampy)(2) (M = Ni (8), Cu (9)) crystallize in the orthorhombic space group Fddd (No. 70), Z = 8, with unit cell parameters for 8 of a = 5.342(1), b = 17.078(3), and c = 29.469(4) A. All compounds are comprised of one-dimensional chains in which M(n-ampy)(2)(2+) units are sequentially bridged by bis-bidentate oxalato ligands with M.M intrachain distances in the range of 5.34-5.66 A. In all cases, the metal atoms are six-coordinated to four oxygen atoms, belonging to two bridging oxalato ligands, and the endo-cyclic nitrogen atoms, from two n-ampy ligands, building distorted octahedral surroundings. The aromatic bases are bound to the metal atom in cis (1-6) or trans (7-9) positions. Magnetic susceptibility measurements in the temperature range of 2-300 K show the occurrence of antiferromagnetic intrachain interactions except for the compound 3 in which a weak ferromagnetic coupling is observed. Compound 7 shows spontaneous magnetization below 8 K, which corresponds to the presence of spin canted antiferromagnetism.     

A photometric study of the complexation reaction between Alizarin complexan and zinc(II), nickel(II), lead(II), cobalt(II) and copper(II)

The complexation reaction between Alizarin complexan ([3-N,N-di(carboxymethyl)aminomethyl]-1,2-dihydroxyanthraquinone; H(4)L) and zinc(II), nickel(II), lead(II), cobalt(II) and copper(II) has been studied by a spectrophotometric method. All these metal ions form 1:1 complexes with HL; 2:1 metal:ligand complex were found only for Pb(II) and Cu(II). The stability constants are (ionic strength I = 0.1, 20 degrees C): Zn(2+) + HL(3-) right harpoon over left harpoon ZnHL(-) log K +/- 3sigma(log K) = 12.19 +/- 0.09 (I = 0.5) Ni(2+) + HL(3-) right harpoon over left harpoon NiHL(-) log K +/- 3sigma(log K) = 12.23 +/- 0.21 Pb(2+) + HL(3-) right harpoon over left harpoon PbHL(-) log K +/- 3sigma(log K) = 11.69 +/- 0.06 PbHL(-) + Pb(2+) right harpoon over left harpoon Pb(2)L + H(+) log K approximately -0.8 Co(2+) + HL(3-) right harpoon over left harpoon CoHL(-) log K 3sigma(log K) = 12.25 + 0.13 Cu(2+) + HL(3-) right harpoon over left harpoon CuHL(-) log K 3sigma(log K) = 14.75 +/- 0.07 Cu(2+) + CuHL(-) right harpoon over left harpoon Cu(2)L + H(+) log K approximately 3.5 The solubility and stability of both the reagent and the complexes and the closenes of the values of the stability constants make this reagent suitable for the photometric detection of several metal ions in the eluate from an ion-exchange column.     

Synthesis, characterization and thermal behavior of 1,1-dialkyl-3-(4-(3,3-dialkylthioureidocarbonyl)-benzoyl)thiourea and its Cu(II), Ni(II), and Co(II) complexes

We report the synthesis, characterization, and thermal behavior of 1,1-diethyl-3-(4-(3,3-diethylthioureidocarbonyl)benzoyl)thiourea, 1,1-di-n-propyl-3-(4-(3,3-di-n-propylthioureido carbonyl)benzoyl)thiourea and 1,1-di-n-butyl-3-(4-(3,3-di-n-butylthioureidocarbonyl)benzoyl)thiourea and their Ni(II), Cu(II), and Co(II) complexes. The structure of the prepared compounds was determined by elemental analysis, FT-IR, ¹H NMR spectroscopy and mass spectrometry. The ligands are coordinated to metal atoms in a bidentate manner yielding an essentially neutral complex of the type M₃L₃. Thermal decomposition of related compounds was investigated by DTA and TG techniques. The pyrolytic end product was identified by X-ray powder diffraction method. The text was submitted by the authors in English.     

Coordination chemistry of amine bis(phenolate) cobalt(II), nickel(II), and copper(II) complexes

Cobalt(II), nickel(II), and copper(II) (1, 2, and 3) complexes of the dianionic form of the bis(phenolate) ligand N,N-bis(3,4-dimethyl-2-hydroxybenzyl)-N',N'-dimethylethylenediamine (H2L) have been synthesized by electrochemical oxidation of the appropriate metal in an acetonitrile solution of the ligand. When copper is used as the anode, the addition of 1,10-phenanthroline to the electrolytic phase gave rise to a different compound [CuL]2.2CH3CN (4). The compounds [CoL]2.2CH3CN (1), [Ni2L2(H2O)].H2O (2), [CuL]2.3H2O (3), and [CuL]2.2CH3CN (4) were characterized by microanalysis, IR, electronic spectroscopy, FAB mass spectrometry, magnetic measurements and by single-crystal X-ray diffraction. The crystal structures show that the complexes have a dinuclear structure. In compounds 1, 3, and 4, two metal ions are coordinated by the two amine nitrogens and the two phenol oxygen atoms of a deprotonated pendant phenol ligand, with one phenolic oxygen atom from ligand acting as a bridge. In compounds 1 and 3, each metal center has a geometry that is closest to trigonal bipyramidal. Magnetic susceptibility data for both compounds show an antiferromagnetic coupling with 2J = -15 cm(-1) for the cobalt(II) complex and a strong antiferromagnetic coupling with 2J = -654 cm(-1) for the copper(II) complex. However, in 4 the geometry around the metal is closer to square pyramidal and the compound shows a lower antiferromagnetic coupling (2J = -90 cm(-1)) than in 3. The nickel atoms in the dimeric compound 2 are hexacoordinate. The NiN2O4 chromophore has a highly distorted octahedral geometry. In this structure, a dianionic ligand binds to one nickel through the two amine nitrogen atoms and the two oxygen atoms and to an adjacent nickel via one of these oxygen atoms. The nickel atoms are linked through a triple oxygen bridge involving two phenolic oxygens, each from a different ligand, and an oxygen atom from a water molecule. The two nickel ions in 2 are ferromagnetically coupled with 2J = 19.8 cm(-1).     

Synthesis and characterization of azo-linked Schiff bases and their nickel(II), copper(II), and zinc(II) complexes

Azo compounds were prepared by coupling of benzenediazonium chloride ions with 1-amino-2-hydroxy-4-naphthalene sulfonic acid under alkaline conditions, and Schiff bases, L_1–3 were then obtained by the condensation of 1-amino-2-hydroxy-3-(phenylazo)-4-naphthalene sulfonic acid, 1-amino-2-hydroxy-3-(4-ethylphenylazo)-4-naphthalene sulfonic acid, and 1-amino-2-hydroxy-3-(4-nitrophenylazo)-4-naphthalene sulfonic acid with salicylaldehyde. New copper(II), nickel(II), and zinc(II) complexes of the Schiff base ligands were also prepared and characterized by spectroscopic methods, magnetic measurements, elemental, and thermogravimetric analysis.     

Complexes of Co(II), Ni(II), and Cu(II) with (Z)-10-(2-(4-Amino-5-Thioxo-4,5-Dihydro-1H-1,2,4-Triazol-3-yl)hydrazono)-9-Phenanthrone: Synthesis,Spectral Studies,and Quantum Chemical Simulation of the Structures

Russian Journal of Coordination Chemistry - The complexes of (Z)-10-(2-(4-amino-5-thioxo-4,5-dihydro-1Н-1,2,4-triazol-3-yl)hydrazono)-9-phenanthrone (HL) with the Co(II), Ni(II), and Cu(II)...     

Convenient synthesis of 2-(2-pyridyl)-1, 3-diaminopropane,and its copper(II), nickel(II), and cobalt(III) complexes

Summary 2-(2-Pyridyl)-1, 3-propanediol was converted into the diacetate, which was then condensed with phthalimide. The product was hydrolyzed with hydrochloric acid to give 2-(2-pyridyl)-1, 3-diaminopropane. The free amine gave 12 complexes with copper(II), nickel(II), and cobalt(III), which were characterized spectroscopically and magnetically. Features of the amine as a ligand are discussed. A few related complexes were also studied.     

Electron transfer reactions of peroxydisulfate and fluoroxysulfate reactions with the cyanide complexes M(CN)n4- (M=Fe(II), Ru(II), Os(II), Mo(IV), and W(IV))

The stoichiometry and the kinetics of oxidation of the cyanide complexes M(CN)n4- (M = Fe(II), Ru(II), Os(II), Mo(IV), and W(IV)) by the peroxydisulfate ion, S2O8(2-), and by the much more strongly oxidizing fluoroxysulfate ion, SO4F-, were studied in aqueous solutions containing Li+. Reactions of S2O8(2-) with M(CN)n4- are known to be strongly catalyzed by Li+ and other alkali metal ions, and this applies also to the corresponding reactions of SO4F-. The primary reactions of S2O8(2-) and SO4F- have both been found to be one-electron processes in which the equally strong O-O and O-F bonds are broken. The primary reaction of S2O8(2-) consists of a single step yielding M(CN)n3-, SO4-, and SO42-, whereas the primary reaction of SO4F- comprises two parallel one-electron steps, one leading to M(CN)n3-, SO4-, and F- and the other yielding M(CN)n-1(2-), CN-, SO4- and F-. The relationship between the rate constants and the standard free energies of reaction for the Li+-catalyzed reactions of SO4F- and S2O8(2-) with M(CN)n(4-), and for the uncatalyzed reactions of S2O8(2-) with bipyridyl and phenanthroline complexes MLn2+ (M = Fe(II), Ru(II), and Os(II)) studied previously, suggests that the intrinsic barrier for all three sets of reactions is similar, i.e., unaffected by the Li+ catalysis, and that the electron transfer and the breakage of the O-O and O-F bonds are concerted processes.     

Heteropolytopic arsanylarylthiolato ligands: cis-trans isomerism of nickel(II), palladium(II), and platinum(II) complexes of 1-AsPh2-2-SHC6H4

Heteropolytopic arsanylthiolato ligands 1-AsPh(2)-2-SHC(6)H(4) (AsSH), PhAs(2-SHC(6)H(4))(2) (AsS(2)H(2)), and As(2-SHC(6)H(4))(3) (AsS(3)H(3)) have been prepared by lithiation-electrophilic substitution procedures. The 2:1 reaction of AsSH with NiCl(2)·6H(2)O, Na(2)[PdCl(4)], and [PtI(2)(cod)] (cod = 1,5-cyclooctadiene) in the presence of NEt(3) afforded the square-planar complexes trans-[Ni{(AsS)-κ(2)S,As}(2)] (1), cis-[Pd{(AsS)-κ(2)S,As}(2)] (2), trans-[Pd{(AsS)-κ(2)S,As}(2)] (3), and cis-[Pt{(AsS)-κ(2)S,As}(2)] (4). In the cases of nickel and platinum, only one isomer was isolated. With palladium, initially the cis isomer 2 is formed and undergoes slow isomerization to the trans isomer 3 in solution. Small amounts of the trinuclear complex [{PtI(1-AsPh(2)-μ-2-S-C(6)H(4)-κ(2)S,As)}(3)] (5) are also formed besides the mononuclear platinum bis-chelate complex 4. Density functional theory calculations support a dissociative mechanism for the isomerization of the palladium(II) complexes.     

Spectroscopic, thermal and biological studies of the coordination compounds of sulfasalazine drug: Mn(II), Hg(II), Cr(III), ZrO(II), VO(II) and Y(III) transition metal complexes

The complexations of sulfasalazine (H3Suz) with some of transition metals have been investigated. Three types of complexes, [Mn(HSuz)-2(H2O)4] x 2H2O, [M(HSuz)-2(H2O)2] x xH2O (M=Hg(II), ZrO(II) and VO(II), x=4, 8 and 6, respectively) and [M(HSuz)-2(Cl)(H2O)3] x xH2O (M=Cr(III) and Y(III), x=5 and 6, respectively) were obtained and characterized by physicochemical and spectroscopic methods. The IR spectra of the complexes suggest that the H3Suz behaves as a bidentate ligand. The thermal decomposition of the complexes as well as thermodynamic parameters (DeltaE*, DeltaH*, DeltaS* and DeltaG*) were estimated using Coats-Redfern and Horowitz-Metzger equations. In vitro antimicrobial activities of the H3Suz and the complexes were tested.