New disiloxane based on N-acetylvaline: synthesis and structure

Synthesis and structure of (O → Si)-chelate fluorosilane, a novel complex of pentacoordinate silicon with N-acetylvaline

“…The NMR 29 Si spectrum of fluoride 2 shows a singlet at -12.7 ppm, which confirms the pentacoordinate state of silicon in solution. 3,4 The correlation between the O→Si bond length and δ( 29 Si) observed for N'-(dimethylfluorosilylmethyl)-N'-methyl-N-(organosulfonyl)prolinamides 9 with a similar coordination environment of silicon suggests that the coordination bond in fluoride 2 in solution has a similar length to that in crystal (2.28 Å), which is somewhat longer than typical O→Si distances in monofluorides of pentacoordinate silicon. The same conclusion can be drawn from the correlational analysis of structurally similar bromides and triflates.…”

“…The synthesis and X-ray diffraction study of disiloxane 1 have been reported by us recently. 8 As a continuation of this work, we now report the synthesis and structure of a novel pentacoordinate silicon complex, fluoride 2.…”

“…The Si1-O1 bond length is 2.2792(19) Å, which is slightly longer than the coordination bonds in similar organosilicon derivatives of aminoacid amides. 9 The reason for that could be the formation of a hydrogen bond between the O1 atom and the carboxyl group (Fig. 2).…”