Organometallic selenolates .4. Reactions of MSeW(CO)(3)cp (M=Li, Na) with organodi- and -tetrahalides - X-ray crystal structures of C6H5CH2W(CO)(3)(eta(5)-C5H5), mu-[m-C6H4{CH2SeW(CO)(3)(eta(5)-C5H5)}(2)], mu-[p-C6H4{CH2SeW(CO)(3)-(eta(5)-C5H5)}(2)], and C6H5CH[SeW(CO)(3)(eta(5)-C5H5)](2)

Organotungsten-selenolato complexes were prepared in moderate yields by insertion of selenium into the alkali metal-tungsten bonds of MSeW(CO)(3)cp (M = Li, Na) and subsequent reactions with the organohalides o-, m-, and p-C6H4(CH2Br)(2), C6H5CHBr2, m-C6H4(CHBr2)(2) and C6H5CCl3. The Se-77-NMR data of the new complexes are discussed and compared with those of related complexes derived from organomonohalides. Moreover, the X-ray crystal structures of C6H5CH2W(CO)(3)cp (1), mu-[m-C6H4{CH2SeW(CO)(3)cp}(2)] (3), mu-[p-C6H4{CH2SeW(CO)(3)cp}(2)] (4), and C6H5CH[SeW(CO)(3)cp](2) (5) were determined. In complex (1), the W-CH, bond length is 2.374 Angstrom; the W-Se bond lengths in the complexes 3, 4, and 5 are all in the range 2.625-2.655 Angstrom, corresponding to W-Se single bonds.