THE FORMATION OF DIMETALLOCYCLES FROM REACTIONS OF ALKYNES WITH (η-C5Me5)2Rh2(CO)2; X-RAY STRUCTURE OF 2, η2-C(O)C2(CF3)2>>

Article abstract of DOI:10.1016/S0022-328X(00)87086-2

The complexes (η-C5Me5)2Rh2(Rh2(μ-CO) <μ-η²,η²-C(O)CRCR> are obtained from reactions between (η-C5Me5)2Rh2(CO)2 and the alkynes RC<*>CR (R=CF3, CO2Me, or Ph) at 25 deg C.The molecular geometry of the complex with R=CF3 has been established by X-ray diffraction; the bridging 'ene-one' unit adopts a μ-η²,η² conformation.Other complexes isolated from these reactions include (η-C5Me5)Rh(C6R6) (R=CF3, CO2Me), (η-C5Me5)2Rh2(C4R4) (R=CO2Me) and (η-C5Me5)Rh2(CO2C2R2) (R=Ph).The reaction between (η-C5Me5)2Rh2(CO)2 and C6F5C<*>CC6F5 gives (η-C5Me5)2Rh2(CO)2(C6F5C2C6F5).Mononuclear complexes such as (η-C5Me5)Co(C4R4CO) are the major products isolated from reactions between (η-C5Me5)2Co2(CO)2 and alkynes at 25 deg C.