Transition metal complexes with pyrazole-based ligands. XXII. Di-mu-thiocyanato-bis[(3,5-dimethyl-1H-pyrazole-1-carboxamidine-kappa N-2,N )(thiocyanato-kappa N)copper(II)] and a redetermination of bis(3,5-dimethyl-1H-pyrazole-1-carboxamidine-kappa N-2,N )bis(nitrato-kappa O)-copper(II)

The title Cu-II complex, [Cu-2(NCS)(4)(C6H10N4)(2)], represents the first crystal structure of a polynuclear transition metal complex with the 3,5-dimethyl-1H-pyrazole-1-carboxamidine ligand (HL). It is compared with previously reported crystal structures of metal complexes with the same HL ligand. The molecule contains an eight-membered binuclear Cu-2(NCS)(2) ring, which is centrosymmetric and in a chair conformation. The Cu atom has a distorted square-pyramidal geometry with a very elongated Cu-S bond of 2.993 (2) angstrom. The crystal structure redetermination of the bis(3,5-dimethyl-1H-pyrazole-1-carboxamidine-kappa(2)N,N) bis(nitrato-kappa O) copper(II) complex, [Cu(NO3)(2)(C6H10N4)(2)], and analysis of its hydrogen bonds confirm the significance of the NO3 groups in the formation of a three-dimensional hydrogen-bonding network. Both complexes are centrosymmetric, the inversion centre being located at the mid-point of the Cu center dot center dot center dot Cu line in (I) and the Cu atom being located at the inversion centre in (II)

Transition metal complexes with pyrazole-derived ligands. XI. [Zn(mu-L)(HL)(OAc)](2) (HL is 4-acetyl-3-amino-5-methylpyrazole)

The title compound, bis(mu-4-acetyl-3-amino-5-methylpyrazolato-N-1 :N-2)bis[(acetato-O)(4-acetyl-3-amino-5-methylpyrazole-N-2)zinc(II)], [Zn-2(C6H8N3O)(2)(C2H3O2)(2)(C6H9N3O)(2)], exists as a centrosymmetric binuclear molecule with two tetrahedrally coordinated Zn atoms bridged by two pyrazolate anions. The geometry of the terminal and bridging pyrazole ligands are slightly different as a consequence of their differing modes of coordination

Tris(3,5-dimethyl-1H-pyrazole-1-thiocarboxamidato-kappa N-2(2),N)cobalt(III)

In the crystal structure of the title complex, [Co(C6H8N3S)(3)], the Co-III atom is octahedrally coordinated by three monodeprotonated bidentate 3,5-dimethyl-1H-pyrazole-1-thiocarboxamide ligands with two thiocarboxamide N atoms in axial positions. The asymmetric unit contains two molecules (A and B) and these molecules are arranged in chains in an alternating fashion connected by N-H...S interactions

Transition metal complexes with pyrazole-derived ligands. X. [Zn(CH3COO)(2)L-2]center dot-2MeOH (L=3-amino-5-phenylpyrazole)

Monocrystals of the title complex, bis(acetato-O)bis(3-amino-5-phenylpyrazole-N-2)zinc(II) dimethanol solvate, [Zn(C2H3 O-2)(2)(C9H9N3)(2)] . 2CH(4)O, were obtained by crystallization from a methanolic solution of Zn(OAc)(2).-2H(2)O and 3-amino-5-phenylpyrazole (L) (1:2 molar ratio). The two pyridine-N atoms from the pyrazole derivative and two O atoms from the acetate groups are coordinated to the Zn atom in a distorted tetrahedral arrangement. The phenyl and aminopyrazole rings in both ligand molecules are planar within experimental accuracy. As a consequence of the arrangement of the molecules in the unit cell, the dihedral angles between the phenyl and aminopyrazole ring planes in the two ligand molecules are 5.6(2) and 27.4 (2)degrees

Le Grand écho du Nord de la France

06 décembre 18931893/12/06 (A75,N340).Appartient à l’ensemble documentaire : NordPdeC

Reaction of copper(II) with 1-carboxamide-3,5-dimethylpyrazole, 1-carboxamidine-3,5-dimethylpyrazole, 4-acetyl-3-amino-5-methylpyrazole and 5-amino-4-carboxamide-1-phenylpyrazole

Complex formation of copper(II) bromide and acetate with 1-carboxamide-3,5-dimethylpyrazole (HL3) and copper(II) bromide with 5-amino-4-carboxamide-1-phenylpyrazole (L-2), 4-acetyl-3-amino-5-methylpyrazole (HL4) and 1-carboxamidine-3,5-dimethylpyrazole (HL5), was studied. The obtained compounds, CuBr2(L-2)(2), Cu(L-3)(2), CuBr2(HL4)(2), CuBr2(HL5)(2) and [CuBr(HL1)(L-3)](2) (HL1 denotes the 3,5-dimethylpyrazole), are characterized by elemental analysis, FT-IR spectrometry, molar conductivity, TG-MS and DSC. The X-ray structure of [CuBr(HL1)(L-3)](2) and Cu(L-3)(2) is discussed. For [CuBr(HL1)(L-3)](2) a dimeric penta-co-ordinated structure has been found; the co-ordination around the metal in Cu(L-3)(2) is trans-square planar. To CuBr2(L-2)(2) and CuBr2(HL4)(2) a nearly tetrahedral, while for CuBr2(HL5)(2) an octahedral geometry may be assumed. It means that the geometry of the compounds in the first place depends on the ligand substituents. The course of the complex formation reaction is anion-dependent and may be explained on the basis of Pearsons theory, taking into account the steric factors. A low stability intermediate formation was observed in the thermal decomposition of Cu(L-3)(2). (C) 2003 Elsevier B.V. All rights reserved