First crystal structures of oxo-bridged [CrIIITaV] dinuclear complexes: spectroscopic, magnetic and theoretical investigations of the Cr–O–Ta core

摘要: Heterodinuclear complexes [Cr(bpy)2(H2O)(μ-O)Ta(C2O4)3]2·3.5H2O (1) and [H2(terpy)][Cr(terpy)(C2O4)(μ-O)Ta(C2O4)3]·0.5H2C2O4·2.5H2O (2) (bpy = 2,2′-bipyridine; terpy 2,2′:6′,2′′-terpyridine) have been synthesised through a reaction of tris(oxalate)oxotantalate(V) anion complex chromium(III) cation with corresponding aromatic N-donor ligands. These are the first examples Cr–O–Ta bridge in molecular compounds, report heterodinuclear prepared from as building block. Structural analysis both compounds revealed that TaV pentagonal bipyramid geometry is connected slightly bent μ-O to CrIII having distorted octahedral environment. The optimization performed density functional theory (DFT) calculations gave very good agreement experimentally obtained structure 1. Room temperature solid state UV-Vis spectra were recorded for compared those starting reagents, order test possible new electronic transitions attributed metal-to-metal charge transfer between oxo-bridge. Infrared (IR) spectroscopy supported DFT was used assign vibrational modes all spectral features, especially coming μ-oxo bridge. Temperature dependence magnetic properties 1 2 probed susceptibility measurements on SQUID magnetometer. Additionally, zero-field splitting parameters determined electron paramagnetic resonance (EPR) compound values confirmed by calculations.