Synthesis, structure, and magnetic properties of (n-Bu4N)(2)[{Ni(MeoH)(2)}(2){Mo(NO)}(2)(mu(3)-OH)(2)(mu-OMe)(4){Mo5O13(OMe)(4)(NO)}(2)], a new type of polyoxometalate incorporating a rhomb-like cluster

The oxo-nitrosyl compound (n-Bu4N)(2)[{Na(MeOH)}Mo5O13(OMe)(4)(NO)]. 3MeOH reacts with various nickel(II) salts in methanol to give (n-Bu4N)(2)[{Ni(Me OH)(2)}(2){Mo(NO)}(2)(mu(3)-OH)(2)(mu-OMe)(4){Mo5O13(OMe4(NO)}(2)] which ha s been characterized by single-crystal X-ray diffraction analysis and magne tic susceptibility measurements. This reaction shows the dual behavior of t he defect Lindqvist-type species [Mo5O13(OMe)(4)(NO)](3-), which can act bo th as a ligand and as a source of the {Mo(NO)}(3+) unit. Furthermore, the r eaction is reminiscent of the dissolution-precipitation of oxide supports i n the preparation of supported catalysts and provides a novel illustration of the potential of polyoxometalates for probing the reactivity of oxides. The new polyoxomolybdate is made of a central rhomb-like (Ni2Mo2) cluster l inked to two terminal [Mo5O13(OMe)(4)(NO)](3-) units, each terminal cluster being linked to a molybdenum center of the central unit through two oxo li gands. The two Ni(II) ions are coupled in a ferromagnetic way (J = 13.1 cm( -1)).