Syntheses, Characterization, and Properties of Vanadium(III) Complexes Containing Tripodal Tetradentate Ligands with Single Pyridyl Groups

Article abstract of DOI:10.1246/bcsj.68.2581

The syntheses, characterization, and properties of (1a), (1b), (2), and Br2 (3) are described, where pda (N-(2-pyridylmethyl)iminodiacetate), bpg (N,N-bis(2-pyridylmethyl)glycinate), and tpa (tris(2-pyridylmethyl)amine) are tripodal tetradentate ligands with single pyridyl groups.Complexes 1a, 1b, and 2 were characterized on the basis of their electronic and Raman spectra.The structure of 3 was determined by X-ray crystallography.Complex 3 crystallizes in the P<*> space group with the following unit cell dimensions: a=11.505(5), b=11.509(5), c=16.348(7) Angstroem, α=103.73(2) deg, β=103.71(2) deg, γ=93.26(3) deg, and Z=2.The V-O-V angle is 175.3(2) deg and the V-μ-O distances are 1.783(2) and 1.784(2) Angstroem.In complex 3, the four unpaired electrons are ferromagnetically coupled.It was found that there is a positive correlation between 2 * ν_as(V-O-V) and the energy of the oxo-to- V(III) charge-transfer transition for single oxo-bridged dinuclear vanadium(III) complexes including the present complexes.This correlation is discussed in terms of the ? character of the V(III)-μ-O bond that is affected by the remaining donor groups.