Transition metal-induced self-assembly of small molybdenum clusters.

The first-row transition metals (TMs) are applied to induce the assembly of small molybdenum clusters (SMCs) in the molybdenum/TM/phosphate system, and eight SMC-based compounds are synthesized: [(V(2)O(2))(H(2)PMo(8)V(4)O(40))]·2(en)·12H(2)O (1), [CrMo(6)O(18)(OH)(6)]·1.5(H(2)en)·5H(2)O (2), [MnMo(12)O(24)(OH)(6)(HPO(4))(2)(PO(4))(6)]·7(H(2)en)·6H(2)O (3), {[Co(H(2)O)](2)[CoMo(12)O(24)(OH)(6)(H(2)PO(4))(2)(PO(4))(6)]}·4(H(2)en)·4H(2)O (4), [Ni(5)(H(2)O)(22)(Mo(2)O(4))(8)(HPO(4))(20)(PO(4))(6)]·32H(2)O (5), Cu(2)(en)(4)(Mo(8)O(26)) (6), [Cu(en)(2)Mo(5)O(15)(HPO(4))(2)]·(H(2)en)·2H(2)O (7) and {Zn(2)[Na(H(2)O)(2)][NaMo(12)O(24)(OH)(6)(H(2)PO(4))(6)(PO(4))(2)]}·5(en)·11H(2)O (8) (en = ethylenediamine). Six kinds of SMCs as molecular building blocks have been observed within these eight compounds, namely, Mo(2)V, Mo(4), Mo(5), Mo(6)(1), Mo(6)(2) and Mo(8). In present reaction system, these TMs not only induce the assembly of SMCs, but also regulate the dimensionality of these compounds, ranging from discrete 0D to infinite 1D, 2D and 3D frameworks. Moreover, the electrochemical properties of compounds 1-8 are also investigated.