Preparation and characterization of tricobalt methylidyne clusters: X‐ray crystal structures of [Co3(CO)9(µ3‐CR)] (R = CH2CH3, CH2C(O)NH2, CH2C(O)CH3) and [Co3(CO)7(µ‐P,P‐PPh2CH2PPh2) (µ3‐CCH2C6H4NH2)

Abstract

AbstractA small quantity of the tricobalt methylidyne cluster [Co3(CO)9(µ3‐CCH2CH3)] (2) was obtained, along with the major product, [{[Co2(CO)6(µ‐HCC)]CH2NH}2CO] (1), from the reaction of HCCCH2NH2 with Co2(CO)8 in tetrahydrofuran at 45 °C for 5 h. The crystal structure of 2 showed that the amino group was unexpectedly detached from the propargylamine. The reactions of two related amines, HCCC6H4NH2 and HCCC(O)NH2, with Co2(CO)8 gave two tricobalt methylidyne clusters, [Co3(CO)9(µ3‐CCH2C6H4NH2)] (5) and [Co3(CO)9(µ3‐CCH2C(O)NH2)] (7), respectively. Further reaction of 5 with bis(diphenylphosphino)methane (DPPM) resulted in the formation of the DPPM‐bridged tricobalt methylidyne cluster [Co3(CO)7(µ‐P,P‐PPh2CH2PPh2)(µ3‐CCH2C6H4NH2)] (6). Similar procedures were followed for the reaction of HCCC(O)CH3 with Co2(CO)8; two compounds, [Co3(CO)9(µ3‐CCH2C(O)CH3)] (8) and [Co2(CO)6(µ2‐η2‐HCCC(O)CH3)] (9), were obtained. All these compounds were characterized by spectroscopic means; the crystal structures of 2, 5, 6, and 7 were also determined. Copyright © 2003 John Wiley & Sons, Ltd.