Coordination chemistry of P-rich phosphanes and silylphosphanes. XXV [1] Formation and structure of [{cyclo-P-3((PBu2)-Bu-t)(3)}{Ni(CO)(2)}{Ni(CO)(3)}]

(Bu2P)-Bu-1-P=P(P(R)Bu-t(2) (R=Br, Me) reacts with [Ni(CO)(4)] yielding [(c yclo-P-3((PBu2)-Bu-t)(3))(Ni(CO)(2))(Ni(Co)(3))]. The two cis-(Bu2P)-Bu-t s ubstituents of the cyclotriphosphane. which results from the trimerization of the phosphinophosphinidene (Bu2P)-Bu-t-P, are coordinating to a Ni(CO)(2 ) unit forming a five-membered P4Ni chelate ring. The trans-(Bu2P)-Bu-t gro up is linked to a Ni(CO)(3) unit. The compound crystallizes in the orthorho mbic space group Pbca (No.61) with a = 933.30(5), b = 2353.2(1) and c = 337 4.7(3) pm.