SYNTHESIS AND CRYSTAL-STRUCTURE OF A NOVEL HEXANUCLEAR ZR(IV) COMPLEXWITH HYDROXO AND CARBOXYLATO BRIDGING

A novel hexanuclear eight-coordinate complex, [Zr-6(OH)(8)(OCH3)(4)(Ph 2CHCOO)(12)].2CH(3)CN (1), has been prepared and characterized on the basis of elemental analysis, infrared-spectroscopy measurements, and X -ray crystallography. The crystallographic data for complex 1 are:mono clinic, P2(1)/n, a = 18.09(1), b = 21.73(2), c = 20.349(8) Angstrom, b eta = 96.26(4)degrees, V = 7952(8) Angstrom(3), Z = 2, R = 0.055 and R -W = 0.058 for 5133 observed reflections [I > 3 sigma(l)]. Complex 1 r esides on a crystallographic inversion center, thus making only three of the six zirconium unique. The six zirconium ions are arranged in ap ices of an octahedron. Two axial Zr(IV) metal ions (Zr1, Zr1) are joi ned with four equatorial Zr(IV) metal ions (Zr2, Zr2, Zr3, Zr3*) by e ight syn-syn bridging carboxylate groups, and both axial Zr(IV) ions h ave four triangle mu(3)-OH bridges through equatorial Zr(IV) metal ion s. On the other hand, each equatorial Zr(IV) metal ion is connected wi th axial Zr(IV) metal ions by two bridging carboxylates and four trian gle mu(3)-OH bridges. Besides these, each equatorial Zr(IV) metal ion is coordinated by one monodentate carboxylate and one methoxy group.