Trapping tetramethoxyzincate and -cobaltate(II) between Mo24+ units

Two compounds of a new type, [Mo(2)](CH(3)O)(2)M(CH(3)O)(2)[Mo(2)] where [Mo(2)] is an abbreviation for Mo(2)[(p-MeOC(6)H(4))NCHN(p-MeOC(6)H(4))](3) and M = Zn (1) and Co (2), are reported. Discrete [M(OR)(4)](2-) ions, either as such or in the mu(2),eta(4) role, have not heretofore been described. In these compounds they have distorted tetrahedral structures and bridge two [Mo(2)] groups in much the same way as did SO(4)(2-), MoO(4)(2-), and WO(4)(2-) ions in other recently reported compounds (Cotton, F. A.; Donahue, J. P.; Murillo, C. A. Inorg. Chem. 2001, 40, 2229). The (1)H NMR spectrum of 1 and the visible spectrum and magnetic properties of 2 are consistent with these structures. The M(OCH(3))(4) bridges are moderately effective in coupling the two [Mo(2)] redox centers. Compounds 1 and 2 may also be viewed as having Zn(II) and Co(II) centers tetrahedrally coordinated by the bidentate ligand [Mo(2)[(p-MeOC(6)H(4))NCHN(p-MeOC(6)H(4))](3)(OMe)(2)](-). From that point of view they may be compared with Zn(DPM)(2) and Co(DPM)(2) (3), where DPM is the anion of dipivaloylmethane. For purposes of comparison, 3 has been fully characterized structurally, spectroscopically, and magnetically. Close analogies between 2 and 3 are shown to exist.