Structural Relationships in High‐Nuclearity Heterobimetallic Bismuth‐Oxo Clusters

The novel heterobimetallic sodium‐bismuth‐oxo clusters [Bi 2 Na 4 O(OSiMe 3 ) 8 ] ( 1 ), [Bi 10 Na 5 O 7 (OH) 6 (OSiMe 3 ) 15 ] · 1.5C 7 H 8 ( 2· 1.5C 7 H 8 ), [Bi 15 Na 3 O 18 (OSiMe 3 ) 12 ] · C 7 H 8 ( 3· C 7 H 8 ) and [Bi 14 Na 8 O 18 (OSiMe 3 ) 14 (THF) 4 ] · C 6 H 6 ( 4· C 6 H 6 ) were prepared starting from BiCl 3 and NaOSiMe 3 . Compound 1 crystallises in the trigonal space group R $\bar {3}$ c with the lattice constants a = 12.8844(3) Å and c = 54.6565(3) Å, compound 2· 1.5C 7 H 8 crystallises in the triclinic space group P $\bar {1}$ with the lattice constants a = 15.0377(2) Å, b = 16.0373(2) Å, c = 27.8967(5) Å, α = 87.1321(6)°, β = 86.6530(7)° and γ = 63.6617(6)°, compound 3· C 7 H 8 crystallises in the monoclinic space group C 2/ c with the lattice constants a = 54.311(11), b = 19.846(4), c = 22.885(5) Å and β = 112.32(3)°, and compound 4· C 6 H 6 crystallises in the trigonal space group R $\bar {3}$ with the lattice constants a = 15.9786(4) Å and c = 46.8329(17) Å. The formation of M–O–M bonds results from both partial hydrolysis followed by condensation as well as from elimination of Me 3 SiOSiMe 3 from M–OSiMe 3 groups. The hexanuclear metal‐oxo silanolate 1 is more conveniently synthesised by the addition of NaOSiMe 3 to a toluene solution of in situ‐prepared [Bi(OSiMe 3 ) 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. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)