Silicon-29 NMR investigation of silyl derivatives of the iron-group transition metals

Abstract

The 29Si NMR spectra of M(CO),(SiMe,-,CI,)(H) (M = Fe, n = 0-3; M = Ru, Os, n = 3), M(C0)4(SiMe3-,C1,)2 (M = Fe, Ru, Os, n = 0-3 (cis and trans isomers)), (C5H5)Fe(C0)2(SiMe3_.C1,) ( n = 1-3), [M(CO),(SiMe,..,CI,)], (M = Ru, n = 0-3; M = Os, n = 2, 3), (C1nMe3.nSi)Os3(CO)12(SiMe3-,C1,) ( n = 2, 3), M3(~-H)3(C0)9(SiC1,)3 (M = Ru, Os), and (arene)Ru(CO)(SiCl,), (arene = C6HSC1, C6H6, C6H,Me3, C6Me6, C6H4-t-Bu2) have been recorded. Several empirical relationships were found: (1) for a series of M(SiMe,-,CI,) ( n = 0-3) compounds, the SiMeCI, derivative usually gave the 29Si NMR resonance to lowest field; (2) for M(SiMe,-,CI,) complexes the 29Si NMR resonance shifted upfield on going to the transition metal (M) lower in the periodic table; (3) for M(C0)4(SiMe3-,C1,)2 the resonance of the trans isomer came to lower field than that of the cis isomer; (4) for (arene)Ru(CO)(SiCI& there was a linear correlation between the 29Si chemical shift and the CO stretching frequency of the compounds. The 29Si NMR spectra of M'(CO),(SICl,) (M' = Mn, Re, m = 5; M' = Co, m = 4) were also obtained.