η1- und η2-Komplexe von Cp*-substituierten Diphosphenen und Arsaphosphenen: Synthese, Struktur und Umlagerung unter Cp*-Wanderung

Article abstract of DOI:10.1016/0022-328X(92)85093-C

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-η¹-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-η¹-complexes (13,14,15 and 16).The diphosphene 2 reacts with (Ph3P)Ni(C2H4)2 to yield the labile η¹-complex Cp^*(NiPPh3)P=PAr (24).The η²-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 η²-complex (ⁿBu3P)2Ni*2 (22) is formed as an intermediate; reaction with Ni(C2H4)3/TMEDA yields the labile η²-complex (TMEDA)Ni*2 (23).The η²-complex 22 and the η¹-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 1H, 13C, and 31P NMR data.The complex 11 has been investigated also by X-ray crystallography.