Treatment of the bimetallic complexes Fp(ER2)nFp (1), (ER2)" = Si2Me4 (la), Si5Mei0 (lb), GeMe2 (lc), and SnMe2 (Id), with 1 equiv of lithium diisopropylamide, LDA, followed by quenching with Mel produced single-migration products Fp(EMe2)n(?y5-C5H4)Fe(CO)2Me, (2a,c,d from la,c,d, respectively), and a mixture of single-, 2b, and double-, [Me(CO)2Fe(j75-C5H4)]2(ER2)n (3b), migration products from lb. Treatment of Id with of LDA, added slowly, also produced a novel dimeric complex [(?/5-C5H4)Fe(CO)2-SnMe2]2 (4) containing both Fe-Sn and (?/5-C5H4)-Sn bonds. A single-crystal structure of this latter complex was determined. Treatment of the starting materials (la-d) with 2 equiv of LDA followed by quenching with Mel yielded double-migration products, 3a-d, in moderate yields, 30%-60%. Quenching the reaction between la and either 1 or 2 equiv of LDA with MesSnCl yielded the analogous tin single-and double-migrated derivatives, 5 and 6. Treatment of the analogous Mo and W tin complexes [(?75-C5H5)M(CO)3]2SnMe2, M = Mo, W, with LDA resulted in double-migration products, 7a,b. However, similar treatment of the related tungsten germanium derivative resulted in cleavage of the W-Ge bond. After the reaction was quenched with Mel, (i?5-CsH5)W(CO)3Me was obtained.
