η 1-und η 2-Komplexe von Cp★-substituierten Diphosphenen und Arsaphosphenen: Synthese, Struktur und Umlagerung unter Cp★-Wanderung

Abstract

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-η 1-complexes 6– 12 are formed (Cp★(Mo(CO) 5)PPAr ( 6), Cp★(W(CO)i)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-η 1-complexes ( 13, 14, 15 and 16). The diphosphene 2 reacts with (Ph 3P)Ni(C 2H 4) 2 to yield the labile η 1-complex Cp★(NiPPh 3)PPAr ( 24). The η 2-complexes 17– 21 are formed in the reaction of the corresponding diphosphenes or arsaphosphenes with (Ph 3P) 2Pt(C 2H 4) ((Ph 3P) 2Pt· 1 ( 17), (Ph 3P) 2Pt· 2 ( 18), (Ph 3P) 2Pt· 3 ( 19), (Ph 3P 2Pt· 4 ( 20), (Ph 3P) 2Pt· 5 ( 21)). In the reaction of 2 with ( nBu 3P) Ni(C 2H 4) 2 the η 2-complex ( nBu 3P) 2Ni· 2 ( 22) is formed as an intermediate; reaction with Ni(C 2H 4) 3/TMEDA yields the labile η 2-complex (TMEDA)Ni· 2 ( 23). The η 2-complex 22 and the η 2-complex 24 rearrange easily to the corresponding nickela-diphosphenes 25 and 26 (Ph 3P(Cp★)NiPAr ( 25), nBu 3P(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 31 P NMR data. The complex 11 has been investigated also by X-ray crystallography.