Synthesis, structure and reactivity of ferrio-chloro-phosphanes, -arsanes and -stibanes [(CO)2 [η-C5Me5)FePn(Cl)R] (Pn=P, As, Sb); (R= tetramethylcyclopentadienyl, 2,7-di-tert-butylfluorenyl, 2,7-di-tert-butyl-9-trimethylsilylfluorenyl) as precursor to novel metallo-phosphaalkenes, -arsaalkenes and -stilbaalkenes

Weber L, Pumpenmeier L, Stammler H-G, Neumann B. Synthesis, structure and reactivity of ferrio-chloro-phosphanes, -arsanes and -stibanes [(CO)2 [η-C5Me5)FePn(Cl)R] (Pn=P, As, Sb); (R= tetramethylcyclopentadienyl, 2,7-di-tert-butylfluorenyl, 2,7-di-tert-butyl-9-trimethylsilylfluorenyl) as precursor to novel metallo-phosphaalkenes, -arsaalkenes and -stilbaalkenes. Journal of the Chemical Society. Dalton Transactions. 2004;(4):659-667.Reaction of one equivalent of the complexes [FeCp*(CO)(2)PnCl(2)] (Pn=P, As, Sb) with tetramethylcyclopentadienyl-lithium afforded compounds [FeCp*(CO)(2){Pn(Cl)(C5Me4H)}]. Dehydrochlorination by means of tert-butyllithium led to decomposition. Only in the case of the phosphorus compound was evidence for the initial formation of a phosphaalkene given by P-31 NMR spectroscopy. Similarly treatment of equimolar amounts of [FeCp*(CO)(2)PnCl(2)] with 2,7-di-tert-butyl-9-H-fluorenyllithium or 2,7-di-tert-butyl-9-trimethylsilylfluorenyllithium yielded the asymmetrically substituted ferriopnicogenanes [FeCp*(CO)(2){Pn(Cl)-9-R-Fl*}] (Pn=P, As, Sb; R=H, Me3Si; Fl*=2,7-di-tert-butylfluorenylidene). Dehydrohalogenation of [FeCp*(CO)(2){Pn(Cl)-9-H-Fl*}] with lithium diisopropylamide resulted in the formation of the anticipated phosphaalkene [FeCp*(CO)(2){P=Fl*}], whereas in the case of the arsenic and antimony derivatives the novel ferriopnicogenanes [FeCp*(CO)(2){Pn(9-H-Fl*)(2)}] (Pn=As, Sb) were obtained as products. The new compounds were characterized by elemental analyses and spectra (IR, H-1, C-13, Si-29, P-31 NMR). The molecular structures of [FeCp*(CO)(2){Pn(Cl)(C5Me4H]}] (Pn=As, Sb), [FeCp*(CO)(2){As(Cl)-(9-Me3Si-Fl*)}] and [FeCp*(CO)(2){Sb(9-H-Fl*}(2)] were elucidated by single X-ray diffraction analyses