Square planar complexes of Cu(II) and Ni(II) with N2O donor set of two Schiff base ligands: synthesis and structural aspects

Abstract

Two new square planar Cu(II) and Ni(II) complexes, [CuL 1 (NCO)] (1) and [NiL 2 (N 3 )] (2) have been synthesized with two different tridentate N 2 O donor Schiff base ligands L 1 H (1:1 condensation product of benzoylacetone and 2-diethylaminoethylamine) and L 2 H (1:1 condensation product of benzoylacetone and 2-dimethylaminoethylamine), respectively. Both the complexes 1 and 2 have been characterized by elemental analysis, IR, UVVis spectroscopy, room temperature magnetic susceptibility measurement, electrochemical, thermal, and single crystal X-ray diffraction studies. Structural studies reveal that in both the complexes metal centers have square planar environment with N 2 O donor set of Schiff base ligands and terminal pseudohalide anions (isocyanate for 1 and azide for 2) at four coordination sites of square plane.

Syntheses, characterization and crystal structures of two square-planar Ni(II) complexes with unsymmetrical tridentate Schiff base ligands and monodentate pseudohalides

“…In compound 2, C(31)-H(31a)ÁÁÁC (11)(12)(13)(14)(15)(16) contacts link molecules by translation along the a axis, and the methylene C(71)-H(71b) bond makes close contact with a neighbouring chelate ring and thus forms chains along a 2 1 symmetry axis parallel to the b axis. A comparison of 1 and 2 with our previously reported Cu(II) and Ni(II) complexes [24] indicates that the differences in bond distances, bond angles, and in the deviations of the metal ions from the mean square-planes between 1 and 2 arise not only from the presence of more bulky ethyl substituents in 2 compared to the less-steric methyl substituents in 1, but also from electronic effects of the Schiff base ligands and metal ion; the alignment and mode of bonding of the pseudohalogens, also play important roles.…”

“…We have previously reported work on L 1 H in one mononuclear Ni(II) complex [24] and in di-and polynuclear Cu(II) complexes [25], with L 2 H in three mononuclear Cu(II) complexes [24,26], and also with various other tridentate Schiff base ligands in the presence of coordinating NNN -, SCN -and OCN -anions in mononuclear Ni(II) complexes [19]. Here we discuss the coordination behavior of two unsymmetrical tridentate N 2 O donor ligands from the Schiff bases L 1 H and L 2 H (Scheme 1) in combination with pseudohalides (thiocyanate and azide) towards Ni(II) centers.…”

Tetradentate N2O2 Chelated Palladium(II) Complexes: Synthesis, Characterization, and Catalytic Activity towards Mizoroki‐Heck Reaction of Aryl Bromides

“…N 2 O 2 -tetradentate ligands possess many advantages such as facile approach, readily adjusted ancillary ligand, and electronic environments on the metal centre [19]. Active and well-de�ned Schiff base metals complexes have been widely studied due to the versatility of their steric and electronic properties, which can be �ne-tuned by choosing the amine precursors and ring substituents [20,21]. Due to these properties, N 2 O 2 -tetradentate ligands and their transition metal complexes oen act as catalyst.…”

Refinement of crystal structure of bis[4-chloro-2-((phenylimino)- methyl)phenol]copper(II), Cu(C13H9NOCl)2

“…Its complexes with Schiff base ligand, have proved to be of significant interest in the areas of magnetism, antioxidative activities and potential probes of DNA structure [1][2][3]. In the past years, we have prepared aseries of complexes of transition metals with Schiff base ligands, and investigated their structure and some relative properties [4,5].…”