Structures of vanadium(III)-ethylenediamine-N,N'-diacetato-N,N'-di-3-propionato complexes. Critical role of pπ-dπ donation in determining the coordination number.

Li[V(eddadp)]·3H(2)O (1a) and Cs[V(eddadp)]·2H(2)O (1b) were characterized by X-ray crystallography. 1a crystallizes in the monoclinic space group Cc with a = 11.467(7) Å, b = 13.398(8) Å, c = 12.529(8) Å, ß = 114.85(4)°; V = 1746.7(2) Å(3), and Z = 4; 1b crystallizes in the monoclinic space group P2(1)/n with a = 10.265(5) Å, b = 11.673(6) Å, c = 15.507(8) Å, ß = 104.29(2)°, V = 1800.6(2) Å(3), and Z = 4. The solution structure of 1 has been ascertained to be predominantly six-coordinated with a hexadentate eddadp which is based on a comparison of the electronic and Raman spectra of aqueous solutions of 1 with those in the solid state.