N,N′-ethylenebis(salicylideniminato)oxovanadium(IV): A new ligand coordinating sodium cation in a chain-layered structure. Synthesis and crystal structure

Article abstract of DOI:10.1021/ic50207a017

Sodium cation is complexed by N,N′-ethylenebis(salicylideniminato)oxovanadium(IV), VO(salen), when a tetrahydrofuran or acetonitrile solution of NaBPh₄ is treated with VO(salen), This reaction affords [(VO(salen))₂Na]BPh₄, as a light green crystalline solid, which contains Na⁺ trapped in a coordination cage provided by six oxygen atoms. The X-ray analysis performed on [(VO(salen))₂Na]BPh₄ shows that all the oxygens of VO(salen) are involved in coordination to the sodium cation, giving a cationic polymeric structure. The coordination geometry around Na⁺ is pseudooctahedral, where the six oxygens are provided by four different VO(salen) units. Vanadium is five-coordinate in an approximate square-pyramidal environment. The vanadium atom is displaced by 0.606 ? above the least-squares plane of the four coordinating atoms of the salen unit, and the mean value of the V=O bond distance is 1.584 (2) ?. Crystallographic details for [(VO-(salen))₂Na]BPh₄: space group P1 (triclinic), a = 16.053 (4) ?, b = 17.199 (4) ?, c = 11.221 (1) ?, α = 87.01 (2)°, β = 101.01 (2)°, γ = 124.29 (2)°, V = 2506.6 ?³, Z = 2. The final R factor was 4.4% for 3161 observed reflections. It was found that the complexation of potassium cation by the same ligand occurs only in the presence of a catalytic amount of Na⁺.