Synthesis and characterization of copper(II) complex with 2,6-diacetylpyridine-bis(phenylhydrazone)

Abstract

The syntheses, physicochemical and structural properties of the novel Cu(II) complex with 2,6-diacetylpyridine bis(phenylhydrazone) (L), of the formula [CuL2]Br2 are presented. In the reaction of warm MeOH solutions of the ligand, 2,6-diacetylpyridine bis(phenylhydrazone) and CuBr2 in molar ratio 2:1 resulted in formation of black single crystals of the bis(ligand) complex. This is the first Cu(II) complex with this ligand that is characterized by SC-XRD. Two ligand molecules are coordinated in the usual tridentate mode, via nitrogen atoms of the pyridine ring, and two azomethine nitrogen atoms, forming distorted octahedral environments of the metal ion.

Complexes of adamantane-derived Schiff bases

“…The ligand, in its neutral form, is coordinated to the central Co(II) as O 2 N 3 pentadentate, resulting in the formation of four five-membered metallocycles. Cobalt(II) is placed in pentagonal bipyramidal environment with the ligand's donor atoms at the base of this polyhedron and acetonitrile nitrogen in apical positions [32].…”

Reactions of copper(II) bromide with 2,6-diacetylpyridine bis(phenyl-hydrazone) (L)-molecular and crystal structure of L and its mixed-valence complex [CuIIL2][CuI2Br4]

“…The structure of the complex cation [CuL 2 ] 2+ was already described in a structurally characterized compound, [CuL 2 ]Br 2 . 16 While the complex cation in [CuL 2 ]Br 2 has crystallographic two-fold symmetry, in 1 this symmetry is only approximate (two-fold pseudosymmetry axis bisects N2A-Cu1-N4B angle). Allowing for a large tolerance margin, the cation has D 2 point group symmetry, with additional two-fold axes passing through the N1A--Cu1-N1B bonds and cutting across the N2A-Cu1-N2B angle, respectively.…”

“…[11][12][13][14] Some time ago, synthesis, spectroscopic and magnetic characterization of mono-and bis(ligand) complexes of Fe(II), Co(II), Ni(II) and Cu(II) with the tridentate N 3 ligand, 2,6-diacetylpyridine bis(phenylhydrazone) of general formulae [M(L)Cl 2 ] and [ML 2 ](ClO 4 ) 2 were described. 11 Recently, complexes with the title ligand, i.e., [CoL 2 ]I 2 15 and [CuL 2 ]Br 2 , 16 have been synthesized and structurally characterized, which represent the only metal complexes with this ligand to be characterized by SC-XRD so far. As a continuation of research on the coordinating properties of 2,6-diacetylpyridine bis(phenylhydrazone), in this paper, its new reactions with CuBr 2 in different solvents are described, which led to the synthesis, structure, and characterization of a mixed Cu(II)-Cu(I) complex with the formula [Cu II L 2 ][Cu I 2 Br 4 ].…”