Syntheses and structures of nickel(II) and copper(II) complexes with biacetyl bis(benzoylhydrazone): one-dimensional self-assembly via π–π interaction and hydrogen bonding

Abstract

Reactions of Ni(O 2 CCH 3 ) 2 Á4H 2 O and Cu(O 2 CCH 3 ) 2 ÁH 2 O with biacetyl bis(benzoylhydrazone) (H 2 babh) in alcoholic media afford mononuclear nickel(II) and copper(II) complexes of general formula [M(babh)]. The complexes have been characterized by microanalysis (C, H, N), magnetic susceptibility, and various spectroscopic measurements. X-ray structures of both complexes have been determined. The metal centre in [Ni(babh)] is in squareplanar N 2 O 2 environment provided by the tetradentate babh 2-. On the other hand, [Cu(babh)] crystallizes as distorted square-pyramidal [Cu(babh)(CH 3 OH)] from methanol. Here the tetradentate babh 2-constitutes the N 2 O 2 square-base and the O-coordinating methanol occupies the apical site. In the crystal lattice, the molecules of [Ni(babh)] form a one-dimensional p-stacked structure. The [Cu(babh)-(CH 3 OH)] molecules also form a one-dimensional structure with alternating long and short CuÁÁÁCu distances via intermolecular O-HÁÁÁN hydrogen bonding and p-p interaction.

Anion and solvent effects on the coordination behavior of N-(2-pyridinylmethylene)benzoylhydrazone with copper(II): synthesis and structural characterization

“…The coordination chemistry of transition metals with ligands from the hydrazine family has been studied extensively due to their structural diversities, versatile properties and their use in analytical procedures [1][2][3][4][5]. These complexes can also exhibit biological activity as anticancer, antibacterial and antimicrobial agents [6][7][8][9].…”

Synthesis and Structural Characterization of a Double Helical Dinuclear Copper(II) Complex With Tetradentate Biacetyl Bis(benzoylhydrazone)

“…2,13,14,25,33 The average of Cu-O bond lengths in the dinuclear complex (1.978 Å) is very similar to the corresponding distances in previously reported mononuclear copper(II) complex (1.978 Å). 22 However, the average of Cu-N bond lengths in the dinuclear complex (1.992 Å) is longer than the corresponding bonds in mononuclear copper(II) complex (1.918 Å). 22 The differences are perhaps due to the difference in the coordination modes and the twisting of ligand babh 2-along the -C=N-N=C-single bond for the coordination of the ligand to the copper(II) ions in the formation of [Cu 2 (μ 1,3 -babh) 2 …”

“…Also, the structure of the complex is compared with mono-and dinuclear copper(II) complexes that have been previously reported with the H 2 babh ligand. 21,22 2. Experimental…”

Synthesis and characterization of dodecahedral cerium(IV) and gadolinium(III) complexes with a tetradentate Schiff Base

“…Recently, we have reported two mononuclear complexes of nickel(II) and copper(II) and a double helical dicopper(II) complex with the tetradentate Schiff base biacetyl bis(benzoylhydrazone) (H 2 babh, 2 H's represent the two dissociable amide protons). 23,24 In the mononuclear complexes, the dianionic ligand (babh 2− ) provides the expected N 2 O 2 square-plane around the metal centre and forms 5,5,5-membered fused chelate rings. 23 On the other hand, each bridging ligand in [Cu 2 (μ-babh) 2 ] is twisted along the single bond of its =(CH 3 )C−C(CH 3 )= fragment to accommodate the two metal centres.…”