Tetranuclear heterodimetallic metallamacrocyles with M–Sn(IV) (M=Mo or W) bonds. Crystal structures of {p-[(CO)3MoC5H4C(O)]2C6H4}{(Ph2Sn)2S} and {p-[(CO)3MoC5H4C(O)]2C6H4}{(Ph2Sn)2CH2}

The dianions {[p-(CO)3MC5H4C(O)]2C6H4}2− reacted with Ph2SnBr2 in a 1:2 or 1:1 ratio to give tetranuclear heterodimetallic complexes p-[(Ph2BrSn)(CO)3MC5H4C(O)]2C6H4 (M=Mo (1) or W (2), respectively), and with CH2(SnPhBr2)2 to yield tetranuclear heterodimetallic metallamacrocycles {p-[(CO)3MC5H4C(O)]2C6H4}{(Ph2−nBrnSn)2CH2} (n=1, M=Mo (5) and W (6); n=0, M=Mo (7) and W (8), respectively). Only one bromide on the tin atom was replaced by the metallic anions owing to the electron-withdrawing groups on the cyclopentadienyl rings greatly decreasing the nucleophilicity of the metallic anions. Treatment of complexes 1 and 2 with Na2S·9H2O yielded the novel metallamacrocyclic complexes {p-[(CO)3MC5H4C(O)]2C6H4}{(Ph2Sn)2S} (M=Mo (3) and W (4), respectively). All compounds have been characterized by elemental analyses, IR and 1H-NMR spectra. The crystal structures of complexes 3 and 7 determined by X-ray crystallography indicate a novel 14-membered organometallic metallamacrocyclic ring system in which two Mo–Sn units are linked by the bridging cyclopentadienyl ligand and the sulfur or carbon atom. In addition, the carbonyl group π-system is coplanar with the adjacent cyclopentadienyl ring system, but markedly deviates from the bridging phenyl plane.