NMR Spectroscopy of Tetra(propyn- 1-yl)silane in the Solid State and in Solution

The crystal structure of tetra(propyn-1-yl)silane, Si(C≡CMe)4 1, has revealed a completely asymmetric molecule (point group C1). Since this finding concerns a single crystal, the bulk material of 1 was studied by solid-state 29Si and 13C MAS NMR. This confirmed the result of the X-ray analysis, and by comparison with previous NMR measurements of the tin analogue 1(Sn) it is concluded that 1 and 1(Sn) must have very similar solid-state structures which are in contrast to those known for other tetra(alkyn-1-yl)silicon and -tin compounds. The NMR data set of 1 in solution was completed by determination of the magnitude of coupling constants 1J(13C,13C).