文摘
Anionic Fischer-type aminocarbene complexes, [(CO)5MC(NMe2)CH2]Li (M=Cr or W) react with Ph2PCl and [Me2(MeS)S][BF4] aaa a source of SMe+ aaa to afford acyclic complexes (CO)5MC(NMe2)CH2X (X=PPh2, SMe2) and (CO)5MC(NMe2)CHX2 X=SMe), the chelates and, and the bridged compounds (CO)5MC(NMe2)CH2XM(CO)5 (X=PPh2, SMe). Cyclisation occurs much faster for Cr than for W. Crystal structures illustrate the bonding behaviour in the new complexes and especially characterise carbeneaaaphosphine and carbeneaaathioether four-membered chelates for the first time. The sulfur-donor in the tetracarbonyl complexes, and shows an exceptionally weak trans influence.