57Fe NMR Spectroscopy of Some Sila-[1]ferrocenophanes and a Phospha-[1]ferrocenophane

Z. Naturforsch. 57 b, 305–308 (2002); received Dezember 10, 2001 Ferrocene, [1]Ferrocenophanes, Fe NMR Fe NMR spectra (11.66 MHz) of the 1,1-diorganosila-[1]ferrocenophanes, [Fe(C5H4)2]SiRR 2 (1) (R = R = Me) and (2) (R = Me, R = Ph), the 1-chloro-1-organosila-[1]ferrocenophanes [Fe(C5H4)2]Si(Cl)R 3 (R =Me) and 4 (R = Ph), and of 1,1-dichlorosila-[1]ferrocenophane, [Fe(C5H4)2]SiCl2 5, were measured. All Fe resonance signals are shifted to lower frequencies with respect to ferrocene, the largest shift being observed for 5 (–147.7 ppm). The influence of chloro substituents at silicon in comparison to organo groups is much more pronounced in the ferrocenophanes than in non-cyclic 1-silylor 1,1’-di(silyl)-ferrocene derivatives. In the case of 2,2,6,6-tetramethylpiperidin-1-yl-phospha-[1]ferrocenophane, [Fe(C5H4)2]P(tmp) 6, the Fe nucleus is deshielded (129.8 ppm) with respect to ferrocene, and the coupling constant J(Fe,P) = 3.4 Hz was measured for the first time.