PUB - Publikationen an der Universität Bielefeld

Metal complexes of the pentamethylcyclopentadienyl (Cp*)-substituted diphosphenes and arsaphosphenes 1-5 are described (Cp*P=PCp* (1), Cp*P=PAr (2), Cp*As=PAr (3), Cp*P=AsAr (4), Cp*P=AsCp* (5), Ar = 2,4,6-Tri-t-butylphenyl). In the reaction with metal carbonyls the trans-eta1-complexes 6-12 are formed (CP*(MO(CO)5)P=PAr (6), Cp*(W(CO)5)P=PAr (7), Cp*(Cr(CO)5)P=PAr (8), Cp*(Cr(CO)5)As = PAr) (9), Cp*(Fe(CO)4)P=PAr (10), Cp*(Ni(CO)3)P=PAr (11), Cp*(Ni(CO)3)As=PAr (12)). The complexes 8, 6, 7 and 9 are converted photochemically to the cis-eta1-complexes (13, 14, 15 and 16). The diphosphene 2 reacts with (Ph3P)Ni(C2H4)2 to yield the labile eta1-complex Cp*(NiPPh3)P=PAr (24). The eta2-complexes 17-21 are formed in the reaction of the corresponding diphosphenes or arsaphosphenes with (Ph3P)2Pt(C2H4) ((Ph3P)2Pt.1 (17), (Ph3p)2Pt.2 (18), (Ph3P)2Pt.3 (19), (Ph3P)2Pt.4 (20), (Ph3P)2Pt.5 (21)). In the reaction of 2 with (nBu3P)Ni(C2H4)2 the eta2-complex (nBu3P)2Ni.2 (22) is formed as an intermediate; reaction with Ni(C2H4)3/TMEDA yields the labile eta2-complex (TMEDA)Ni.2 (23). The eta2-complex 22 and the eta1-complex 24 rearrange easily to the corresponding nickela-diphosphenes 25 and 26 (Ph3P(Cp*)NiP=Ar (25), nBu3P(CP*)NiP=PAr (26)). These Cp* migration processes are discussed with respect to the underlying reaction sequences. The synthesis of the arsaphosphenes 4 and 5 is described. The structure of all new compounds is discussed on the basis of their H-1, C-13, and P-31 NMR data. The complex 11 has been investigated also by X-ray crystallography.