Synthesis and characterization of binary and heterobimetallic complexes of dithiofuroate with 3d-metal ions

New complexes [M(dtf)2] (M=MnII or CuII), Cr(dtf)3 and V(dtf)4 (dtf=dithiofuroate) and heterobimetallic complexes M[Cd(dtf)4] (M=VO2+, MnII, FeII, CoII, NiII or ZnII) have been prepared in H2O−EtOH and characterized by elemental analyses, magnetic susceptibility measurements and spectroscopic studies. The known complexes Fe(dtf)3, Co(dtf)3, Ni(dtf)2, and Zn(dtf)2 have been screened towards the bacteria Pseudomonas spergillus and Bacillus spergillus. In vitro results of the binary complexes on P-815 (murine mastocytoma) indicate that these complexes show significant inhibition of [3H]thymidine and [3H]uridine incorporation in DNA and RNA in the tumour cells. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis and structural characterization of 3d-metal complexes of pyridine-4-carboxaldehyde thionicotinoyl hydrazone

Summary Pyridine-4-carboxaldehyde thionicotinoyl hydrazone (4-PTNH) forms 1:1 adducts with metal(II) halides and 1:2 complexes (metal to ligand) with metal(II) thiocyanates. Magnetic and spectral studies indicate polymeric octahedral geometry for M(4-PTNH)X₂ (M=Co^II or Cu^II, X=Cl; M=Ni^II, X=Cl, Br or I), five coordinate geometry for Co(4-PTNH)X₂ (X=Br or I) and octahederal geometry for [M(4-PTNH)₂(NCS)₂] (M=Co^II or Ni^II). I.r. spectral studies show that 4-PTNH acts as a neutral bidentate ligand in all the complexes, the bonding sites being the thione sulphur and azomethine nitrogen.     

Synthesis and characterization of cobalt(III) tetraaza macrocyclic complexes containing chloro and azido ligands

The complexes [Co(L)Cl₂]Cl · 4H₂O (1) and [Co(L)(N₃)₂]N₃ · 2H₂O (2) (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo [14,4,0^1.18,0^7.12]docosane) have been synthesized, and structurally characterized by X-ray crystallography, spectroscopy and cyclic voltammetry. The crystal structure of (1) is centrosymmetric and the cobalt(III) atom has an axially elongated octahedral geometry with four nitrogen atoms of the macrocycle and two chloride ligands. The cobalt(III) ion in (2) is coordinated to four nitrogen atoms from the macrocycle, and two azide ligands in an octahedral environment, which forms the 1D polymer through hydrogen bonding contacts involving the cation, azide anion and solvent water molecules. Electronic spectra of the complexes also exhibit a low-spin octahedral environment. Cyclic voltammetry of the complexes undergoes a one-electron wave corresponding to Co(III)/Co(II) processes. The electronic spectra and electrochemical behaviors of the complexes are significantly affected by the nature of the axial ligands.     

Synthesis, crystal structures and DNA-binding properties of dinuclear complexes with macrocyclic ligands

Two symmetrical macrocyclic dinuclear complexes, [Cu₂L¹(ClO₄)₂(H₂O)₂][Cu₂L¹(H₂O)₂] (ClO₄)₂ (1) and [Cu₂L²(ClO₄)₂] (2), (where H₂L¹ and H₂L² are the [2?+?2] condensation products of 1,3-diaminopropane with 2,6-diformyl-4-methylphenol and 2,6-diformyl-4-flurophenol, respectively), have been synthesized and characterized. The electronic and magnetic properties of the complexes were studied by cyclic voltammetry and magnetic susceptibility. There are strong antiferromagnetic couplings between the two copper(II) centers in both complexes. The strongly electron-withdrawing fluorine groups in H₂L² weaken the antiferromagnetic exchange, but make the metal centers more easily reduced than its analog H₂L¹. The interactions of the complexes with calf thymus DNA were studied by UV?CVis and CD spectroscopic techniques.     

Binuclear and polynuclear transition metal complexes with macrocyclic ligands 7. Directed step-by-step synthesis of novel unsymmetric macrocyclic ligands

Novel asymmetric macrocyclic Schiff bases were synthesized by the condensation of N,N′-bis(2-aminophenyl)-3,4-diphenylthiophene-2,5-dicarboxamide (1) with diformyl derivatives of phenol, furan, difurans, pyridine, pyrrole, and dipyrroles. The reaction proceeds in high yields and without by-products in methanol in the presence of inorganic and organic acids (proton-template condensation). In the case of monocyclic diformyl derivatives and di(5-formylfuran-2-yl) sulfide, the reaction occurs in 1,4-dioxane (templateless synthesis). The synthesized macrocycles were characterized by elemental analysis data and NMR and mass spectra. For Part 6, see Ref. 1. Dedicated to Academician N. S. Zefirov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2152–2156, September, 2005.     

Synthesis,characterization, and biological activities of macrocyclic polyamine complexes

Two new dinuclear macrocyclic complexes, [Ni₂L¹(OAc)]·ClO₄ (1) and [Co₂L²(OAc)]·1.5(ClO₄)·0.5Na·2(CH₃OH) (2) (where H₂L¹ and H₂L² are the condensation products of N,N-bis(3-aminopropyl)-4-methoxybenzylamine with 2,6-diformyl-4-brominephenol and 2,6-diformyl-4-methylphenol in the presence of metal ions, respectively) have been synthesized and characterized by infrared spectra, elemental analysis, electrospray mass spectra, and X-ray single crystal diffraction. The interactions of the complexes with CT-DNA have been measured by UV-absorption titrations and fluorescence quenching experiments.     

Binuclear and polynuclear transition metal complexes with macrocyclic ligands. 3. New polydentate macrocyclic ligands in reactions of 4-alkyl-2,6-diformylphenols with 1,2-diaminobenzenes

The mechanism of abnormal condensation of 2,6-diformyl-4-R-phenols with 1,2-diaminobenzenes accompanied by the reduction of two of four double C=N bonds in macrocyclic Schiff"s bases formed was studied by DFT (gradient-corrected PBE functional, TZ2p basis set). In the first step, [1+1] Schiff"s base is formed and disproportionates further to afford amine and benzoimidazolylphenols. Two new macrocyclic polydentate ligands containing two CH₂—NH moieties in the rings were synthesized. The reduction of one of these ligands with sodium borohydride gave the new macrocyclic ligand, whose structure and conformations were studied by the DFT method.     

Versatile chemical transformations of benzoxazole based ligands on complexation with 3d-metal ions

Two benzoxazoles derivative ligands were synthesized from the condensation of 3,5-di-tert-butyl-o-benzoquinone (DTBBQ) with ethanolamine or 1,3-diamino-2-hydroxypropane in methanol. Condensation of DTBBQ with ethanolamine gives the expected 5,7-di-tert-butyl-2-methylenhydroxylbenzoxazole (HL1) while with 1,3-diamino-2-hydroxypropane it gives (2-hydroxyethyl-2-{2,4-bis(1,1-dimethylethyl)-1-phenol-6 amino}-2{5,7-di-tert-butyl-benzoxazole}) (H(2)L2) with only one benzoxazole ring instead of the symmetric bis-benzoxazole derivative. The structure of HL1 and H(2)L2 were confirmed by NMR-spectroscopy and X-ray diffraction on a single crystal for HL1. The reaction of HL1 with CuCl(2) gives a mononuclear [Cu(II)(HL1)(2)Cl(2)] (1) complex for which the crystal structure shows that HL1 is preserved. In contrast, upon reaction with nickel(II), cobalt(II), and manganese(II) H(2)L2 is further oxidized and transformed in new ligands HL3 in mononuclear complexes [M(II)(L3)(2)] (M = Ni(II) (2); M = Co(II) (3)) and H(2)L4 in tetranuclear complex [Mn(II)(4)(HL4)(4)Cl(4)] (4) as found from the crystal structures of complexes 2-4. Electrochemical studies for complexes 2 and 3 evidence complicated redox properties. [Mn(II)(4)(HL4)(4)Cl(4)] (4) has a cubane-like structure with a "4 + 2" fashion The magnetic susceptibility of 4 is well fitted considering one Mn---Mn interaction J(a)(Mn(II)-Mn(II)) = -0.50(1) cm(-1) with g = 2.00(7).     

三联苯基配体稳定的锇-锗配合物合成及表征

研究了锇-锗单键双金属配合物[OsGe(ArTrip)(PPh₃)(H) Cl₂] (1)的反应性, 其中 ArTrip=C₆H₃-2-(η⁶-Trip)-6-Trip, Trip=2, 4,6-ⁱPr₃-C₆H₃。通过与不同试剂反应, 成功合成并表征了 3个新型锇-锗双金属配合物。通过配合物 1与 EtMgBr反应合成了锗原子上氯原子被溴原子取代的产物[OsGe(ArTrip)(PPh₃)(H)Br₂] (2); 1 与 LiHBEt₃反应合成了锗原子上氯原子被乙基取代的产物[OsGe(ArTrip)(PPh₃)(H) Et₂] (3); 1 与 HBF₄ 作用合成了加成产物[OsGe(ArTrip)(PPh₃)(H)₂Cl₂]BF₄ (4)。配合物 4 不稳定, 在 H₂O(n_H2O/n₄=1)作用下能转化为配合物 1。     

Synthesis and characterization of divalent metal complexes with bipyridylamide ligands

Reaction of N-(4-pyridyl)picolinamide (4-ppa), N-(4-pyridyl)nicotinamide (4-pna), N-(4-pyridyl)isonicotinamide (4-pina), and N-(2-pyridyl)isonicotinamide (2-pina) with divalent metal salts led to the formation of six new coordination complexes. The X-ray structure of [Zn(4-ppa)₂Cl₂] (1) shows a mononuclear structure with interesting intermolecular hydrogen bonding interactions. [Zn(4-pna)(OAc)₂]_n (2), Cu(4-pna)(OTf)₂(DMF)₂]_n (3), {[Zn(4-pina)(DMF)₄](OTf)₂}_n (4), {[Fe(4-pina)(DMF)₄](OTf)₂}_n (5), and [Cu(2-pina)(OTf)₂(DMF)₂]_n (6) are one-dimensional coordination polymers with conformational differences caused by the coordination donor disposition, which demonstrates the flexibility of the pyridylamide ligands in polymeric structures. Reflectance UV-visible spectra and thermal properties of the coordination polymers are also reported.     

三联苯基配体稳定的锇-锗配合物合成及表征

研究了锇-锗单键双金属配合物[OsGe(ArTrip)(PPh₃)(H)Cl₂] (1)的反应性,其中ArTrip=C₆H₃-2-(η⁶-Trip)-6-Trip,Trip=2,4, 6-ⁱPr₃-C₆H₃。通过与不同试剂反应,成功合成并表征了3个新型锇-锗双金属配合物。通过配合物1与EtMgBr反应合成了锗原子上氯原子被溴原子取代的产物[OsGe(ArTrip)(PPh₃)(H)Br₂] (2);1与LiHBEt₃反应合成了锗原子上氯原子被乙基取代的产物[OsGe(ArTrip)(PPh₃)(H)Et₂] (3);1与HBF₄作用合成了加成产物[OsGe(ArTrip)(PPh₃)(H)₂Cl₂]BF₄ (4)。配合物4不稳定,在H₂O (n_H2O/n₄=1)作用下能转化为配合物1。     

Binuclear and polynuclear transition metal complexes with macrocyclic ligands. 5. Novel complexes of asymmetric polydentate macrocyclic Schiff bases. Step-by-step synthesis

Reactions of 2,6-bis(3-aminopropylaminocarbonyl)pyridine (1) with 4-tert-butyl-2,6-diformylphenol and 2,5-diformylpyrrole in the presence of Ba(ClO₄)₂ in EtOH afford barium complexes with asymmetric macrocyclic Schiff bases as soft and hard ligands. The reaction of compound 1 with Cu(OCOCMe₃)₂ involves closure of a tetrahydropyrimidine ring to give a mononuclear complex, which was structurally characterized by X-ray diffraction analysis.     

Synthesis and structural characterization of ruthenium(II) complexes bearing phosphine-pyrazolyl based tripod ligands

Phosphine-pyrazolyl based tripod ligands ROCH₂C(CH₂Pz)₂(CH₂PPh₂) (R = H, Me, allyl; Pz = pyrazol-1-yl) were efficiently synthesized and characterized. Reactions of these ligands with [Ru(η⁶-p-cymene)Cl₂]₂ afforded complexes of the type [Ru(η⁶-p-cymene)Cl₂](L) (6-8) in which the ligands exhibit κ¹-P-coordination to the metal center. Complex [Ru(η⁶-p-cymene)Cl₂{Ph₂PCH₂C(CH₂OH)(CH₂Pz)₂}] (6) underwent chloride-dissociation in CH₂Cl₂/MeCN to give complex [RuCl(η⁶-p-cymene){κ²(P,N)-Ph₂PCH₂C(CH₂OH)(CH₂Pz)₂}][Cl] (9). Complexes 6-9 demonstrated poor to moderate catalytic activity in the transfer hydrogenation of acetophenone. All these complexes were fully characterized by analytical and spectroscopic methods and their molecular structures were determined by X-ray crystallographic study.     

Synthesis and characterization of new macrocyclic diimine complexes of nickel(II)

Summary The reaction of 3,4-thiophenedicarboxaldehyde and 1,3-diaminopropane in EtOH gives a tetraazamacrocylic ligand (L). Two Ni^II complexes of L were prepared by a simple addition reaction, while other macrocyclic Ni^II complexes were prepared by metal-controlled condensation reactions between 3,4-thiophenedicarboxaldehyde and aliphatic diamines. On the basis of various physical properties, the complexes can be described as six co-ordinate pseudo-octahedral structures. Simple reactions led to the isolation of isothiocyanate and percholorate derivatives.     

Ferrocenyl-nitrogen donor ligands. Synthesis and characterization of rhodium(I) complexes of ferrocenylpyridine and related ligands

The preparation of a series of complexes of the types [RhCl(CO)₂(L)], [RhCl(cod)(L)] and [Rh(cod)(L)₂]ClO₄, where L is a ligand incorporating a ferrocenyl group and a pyridine ring is described. Complexes were characterized using NMR, IR and electronic spectroscopy. The electrochemical behaviour of the complexes was examined using cyclic voltammetry. The X-ray structures of three of the complexes, [RhCl(CO)₂{NC₅H₄CNC₆H₄(η⁵-C₅H₄)Fe(η⁵-C₅H₅)}], [RhCl(cod)(3-Fcpy)] and [RhCl(cod){3-Fc(C₆H₄)py}], were determined.     

Syntheses and structures of two NiIICoIINiII complexes of macrocyclic ligands

Two new linear trinuclear complexes, [Co(NiL¹)₂(SCN)₂] (1) and [Co(NiL²)₂(H₂O)₂](ClO₄)₂?·?2C₂H₅OH (2), have been prepared by using Co(ClO₄)₂?·?6H₂O and two macrocyclic complex ligands NiL¹ and NiL². L¹ and L² are the doubly deprotonated forms of dimethyl 5,6,7,8,15,16-hexahydro-6,7-dioxodibenzo[1,4,8,11]tetraazabicyclo[12.4.0^15,16]13,18-dicarboxylate and dimethyl 5,6,7,8,15,16-hexahydro-15-methyl-6,7-dioxodibenzo[1,4,8,11]tetraazacyclotetradecine-13,18-dicarboxylate, respectively. X-ray single crystal analyses reveal the coordination geometries around Ni(II) in both 1 and 2 are identical and slightly distorted square planar with N₄ donors; all Ni–N bonds in the two complexes are very short. The Co(II) ions are at the centers of the trinuclear complexes and have distorted octahedral coordination geometries of O₄N₂ donors in 1 and an O₆ in 2. π?···?π interactions involving aromatic and non-aromatic π-systems join the trinuclear entities to form 2-D layers in the crystals of 1 and 2.