Primoz Segedin

COMPLEXES OF COPPER(II) ACETATE WITH NICOTINAMIDE : PREPARATION, CHARACTERIZATION AND FUNGICIDAL ACTIVITY; CRYSTAL STRUCTURES OF CU2(O2CCH3)4(NIA) AND CU2(O2CCH3)4(NIA)2

Abstract Three new copper (II) acetate complexes with nicotinamide (nia) were synthesized analyzed and characterized by standard chemical and physical methods and tested for fungicidal activity The crystal and molecular structures of the compounds [Cu2 (O2CCH3)4 (nia)] (1B) and [Cu2 (O2CCH3)4 (nia)2] (2) were determined by X-ray diffraction Both consist of binuclear units of bridging tetracarboxylate type however they differ in the bonding mode of nicotinamide molecules They are bonded at the apical positions of the dimers and connect them in an infinite chain in 1B On the other hand the dimers remain isolated in the structure of the compound 2 It seems that compound 1B is the first example where a nicotinamide molecule acts as a bidentate bridging ligand The results of EPR spectra agree with the dimeric nature of the complexes Dissolved in water or DMSO the compounds completely stop mycelial growth at a concentration of 50×10−3 mol l−1 Less concentrated solutions (up to 10×10−3 mol l−1) show weaker fungicidal activity.

Copper(II) carboxylates with 4-aminopyridine: neutral mononuclear structures, isomerism of aceto compounds and a novel tetranuclear structure

Reactions of copper(II) carboxylates with 4-aminopyridine (4-apy) were investigated and their products structurally characterized by single crystal X-ray diffraction. Reaction of copper(II) acetate resulted in two isomers of a monomeric complex of composition Cu(ac)2(4-apy)2 with markedly different stabilities: the violet form, 1, unstable in air and the blue, stable form, 2. In both isomers the ligands are arranged around the copper atom in a trans geometry. The 4-apy ligands lie almost in the plane in 1, while they are twisted with respect to each other in 2. Variations were observed also in the coordination of the acetate groups to the copper ion. The energy difference between the two isomers was obtained on the basis of ab initio MO calculations. The result agrees well with the observed relative stabilities in the solid state. Monomeric complexes of the same stoichiometry were obtained also by the reaction of Cu(II) hexanoate and heptanoate with 4-apy. The violet Cu(hex)2(4-apy)2, 3, and Cu(hep)2(4-apy)2, 4, are isostructural and possess trans geometry of the ligands around the copper centre. Reaction of 4-apy with Cu(II) octanoate lead to formation of a novel, unprecedented basic centrosymmetric tetranuclear compound of composition Cu4(oct)6(OH)2(4-apy)2, 5. Complex 5 contains bidentate bridging and monoatomic bridging carboxylate groups, triply bridging hydroxyl groups and 4-aminopyridine as a terminal ligand. In all five compounds 4-apy is coordinated through the endocyclic nitrogen atom only.

Di-μ-formato-1κ2O:2κ2O'-di-μ-pyridin-2-olato-1κO:2κN;1κN:2κO-bis[(2-pyridone-κO)copper(II) ] acetonitrile 1.02-solvate

In the title compound, [Cu2(CHO 2 ) 2 (C 6 H 4 NO)2(C 5 H 5 NO) 2 ]-1.02CH 3 CN, the dimeric unit is centrosymmetric, with two bidentate pyridin-2-olate and two bidentate formate syn-syn bridges, and two apical 2-pyridone ligands coordinated through the O atoms. The N atom from the apical 2-pyridone ligand is a donor of a hydrogen bond to the O atom of the bridging pyridinolate ligand of the same complex. The coordination polyhedron of the Cu atom is a distorted square pyramid.

Tetrakis(μ-benzoato-O:O')bis(urea)-1κO,2κO-dicopper(II)

The adduct of tetra-μ-benzoato-dicopper(II) with urea, [Cu(C 7 H 5 O 2 ) 2 (CH 4 N 2 O)]2 ° , is dinuclear. Each Cu atom is displaced by 0.195 (3) A from the plane of the four benzoato O atoms to which it is bonded. The Cu...Cu distance is 2.633(2)A. The average Cu-O(benzoate) distance is 1.964 (3) A and the Cu-O(urea) bond length is 2.156 (6) A.