Remarkable reactions of cationic carbyne complexes of manganese and rhenium with diiron anions [Fe-2(mu-CO)(mu-SeR)(CO)(6)](-). A route to RSe-bridged dimetal bridging carbene complexes

The reactions of cationic carbyne complexes of manganese and rhenium, [eta -C5H5(CO)(2)M drop CC6 H-5]BBr4 (1, M = Mn; 2, M = Re), with diiron anionic compounds [Et3NH] Fe-2(mu -CO)(mu -SeR)(CO)(6)] (3, R = C6H5; 4, R = p-CH3 C6H4) in THF at low temperature gave the dimetal bridging carbene complexes [MFe{mu -C(SeR)C6H5}(CO)(5)(eta -C5H5)] (10, M = Mn, R = C6H5; 11, M = Mn, R p-CH3C6H4; 13, M: = Re, R = C6H5; 14, M = Re, R = p-CH3C6H4), [eta -C5H5 M(CO)(3)] (7, M = Mn; 12, M = Re), and [Fe-2(mu -SeR)(2)(CO)(6)] (8, R = C6 H5; 9, R = P-CH3C6H4) Complexes 1 and 2 also react with [MgBr] [Fe-2(mu -CO )(mu -SeC2H5)(CO)(6)] (5) to produce [Fe-2(mu -SeC2H5)(2)(Co)(6)] (15) and dimetal bridging carbene complexes [MnFe{mu -C(SeC2H5)C6H5}(CO)(5)(eta -C5H 5)] (17) and [ReFe{mu -C(SeC2H5)C6H5}(CO)(5)(eta -C5H5)] (18), respectively . 2 reacts similarly with [MgBr] [Fe-2(mu -CO)(mu -SeC4H9-n)(CO)(6)] (6) to give [Fe-2(mu -SeC4H9-n)(2)(CO)(6)] (16) and a Re-Fe bridging carbene comp lex [ReFe{mu -C(SeC4H9-n)C6H5}(CO)(5)(eta -C5H5)] (19), while the analogous reaction of 1 with S produced an unexpected trimetal bridging carbyne comp lex [MnFe2(mu -H)(mu -CO)(2)(mu (3)-CC6H5)CO)(6)(eta -C5H5)] (20) The struc tures of complexes 9, 10, 13, 18, and 20 have been established by X-ray dif fraction studies.