Synthesis, structure and properties of a new unsymmetric tetranuclear mixed-valence vanadium(IV/V) complex containing distinct V2O33+ cores

The synthesis, X-ray crystal structure, spectroscopic, and electrochemical properties of a new tetranuclear vanadium(IV,V,IV,V) complex [(VO)4(btppnol)2(μ-O)2](ClO4)2·2DMF·2H2O (1) utilizing the previously described unsymmetrical dinucleating ligand N-(2-hydroxybenzyl)-N,N′,N′-tris(2-pyridylmethyl)-1,3-diaminopropan-2-ol (H2btppnol) are reported. The complex comprises two different [V2O3]3+ core structures: one [V2O3]3+ core in a syn-dioxo-μ-O(alkoxo) configurarion and another [V2O3]3+ core in an anti-dioxo-μ-oxo configuration, as well as being composed of non-equivalent vanadium centers as a consequence of the use of an unsymmetrical ligand. This complex represents the first example in the literature of a vanadium complex with this particular structure and its interesting electrochemical and spectroscopic properties were investigated.