Rhenium(I) and (V) complexes of aroylhydrazone derivatives: Synthesis, spectroscopic and crystallographic studies

Abstract

The coordination mode of aroylhydrazones-based ligands to the fac-[ReCO)3]+, [ReO]3+ and [Re2O3]4+ cores is reported. The reaction of di-2-pyridylketone-2-aminobenzoylhydrazone (Hdpa) with [ReCO5Cl] in ethanol led to the complex [Re(CO)3Cl(Hdpa)] (1). Similar reaction using N′((pyridin-2-yl)methylene)benzohydrazide (Hhpmb) and [ReCO5Br] led to the complex [Re(CO)3Br(Hhpmb)] (2). The reaction of 2-hydroxy-N′-((thiophen-3-yl)methylene)benzohydrazide (H2htmb) with trans-[ReOCl3(PPh3)2] in acetonitrile gave the complex cis-[ReOCl2(Hhtmb)(PPh3)] (3). The complexes cis-[ReOBr2(Hhpb)(PPh3)] (4) and (μ-O)[ReO(pbz)2]2 (5) were isolated from the reaction of [ReOBr3(PPh3)2] with salicylhydrazide (Hshz) and trans-[ReO2(py)4]Cl with benzohydrazide (Hbhz) in acetone respectively. The chelating ligands 2-hydroxy-N′-(propan-2-ylidene)benzohydrazide (H2hpb) and N′-(propan-2-ylidene)benzohydrazide (Hpbz) were formed from the condensation of acetone with Hshz and Hbhz respectively upon the reaction of [ReOBr3(PPh3)2] with Hshz in acetone and [ReO2(py)4]Cl with Hbhz in acetone respectively. In addition to the X-ray crystal structures, conductivity, infra-red, 1H NMR and electronic properties are reported.