Zum Koordinationsverhalten von Alkinylphosphanen RnP(CC–R')3–n

Abstract

Coordination Ability of Alkynylphosphines RnP(CC – R')3 – nAlkynylphosphines RP(CC–R')2 (2) react with one equivalent of octacarbonyldicobalt to yield selectively the η2‐μ side‐on‐coordinated alkyne complexes (R)(R' – CC)P[(η2‐CC–R')Co2(CO)6] (6); with another equivalent of Co2(CO)8 the dicoordinated compounds (R)P[(η2‐CC–R')Co2(CO)6]2 (7) are obtained. 7 may also be synthesized directly by the reaction of 2 with two equivalents of Co2(CO)8. However, P(CC–Ph)3 yields with two equivalents of Co2(CO)8 the cyclic Co2P2C2 system {(Ph–CC)(R')P[(η2‐CC–Ph)Co2(CO)5]} 2 (4) [R' = (η2‐CC–Ph)Co2(CO)6]. Decarbonylation of 6a gives the six‐membered cyclic compound {(Ph)(Ph – C  C)P[(η2‐C  C – Ph)Co2(CO)5]}2 (8), while 6b yields the cluster Co3(CO)9(μ3‐PtBu) (9). The structure of (tBu)P[(η2‐C  C – H)Co2)CO)6]2 (7b) is elucidated by an X‐ray analysis.