Structural relationships in high-nuclearity heterobimetallic bismuth-oxo clusters

The novel heterobimetallic sodium-bismuth-oxo clusters [Bi2Na4O(OSiMe3)(8)] (1), [Bi10Na5O7(OH)(6)(OSiMe3)(15)]center dot 1.5C(7)H(8) (2 center dot 1.5C(7)H(8)), [Bi15Na3O18(OSiMe3)(12)]center dot C7H8 (3 center dot C7H8) and [Bi14Na8O18(OSiMe3)(14)(THF)(4)]center dot C6H6 (4 center dot C6H6) were prepared starting from BiCl3 and NaOSiMe3. Compound 1 crystallises in the trigonal space group R (3) over barc with the lattice constants a = 12.8844(3) angstrom and c = 54.6565(3) angstrom, compound 2 center dot 1.5C(7)H(8) crystallises in the triclinic space group P (1) over bar with the lattice constants a = 15.0377(2) angstrom, b = 16.0373(2) angstrom, c = 27.8967(5) angstrom, a = 87.1321(6)degrees, beta = 86.6530(7)degrees and gamma = 63.6617(6)degrees, compound 3 center dot C7H8 crystallises in the monoclinic space group C2/c with the lattice constants a = 54.311(11), b = 19.846(4), c = 22.885(5) angstrom and beta = 112.32(3)degrees, and compound 4 center dot C6H6 crystallises in the trigonal space group R (3) over bar with the lattice constants a = 15.9786(4) angstrom and c = 46.8329(17) angstrom. The formation of M-O-M bonds results from both partial hydrolysis followed by condensation as well as from elimination of Me3SiOSiMe3 from M-OSiMe3 groups. The hexanuclear metal-oxo silanolate I is more conveniently synthesised by the addition of NaOSiMe3 to a toluene solution of in situ-prepared [Bi(OSiMe3)(3)]. The metal-oxo(hydroxo) silanolates differ significantly in composition, but show similar building units. Thermal decomposition of the metal-oxo silanolates in the solid state gave heterogeneous decomposition products containing bismuth silicates.