Structure and Reactivity of 1-Isothiocyanatosilatrane: The First Silatrane with a Direct Si−NCS Bond

Some unique features of 1-isothiocyanatosilatrane, 1, include concomitant NMR couplings of quadrupolar 14N(NCS) nucleus with adjacent heteroatoms [J(13C−14N) = 26.17 Hz; J(29Si−14N) = 28.47 Hz] and the crystallographically determined shortest N→Si bond, 2.007(3) Å, as well as a nearly linear structure of the heteroatoms N(1)−Si−N(2)−C(7)−S(1). Contrary to the known reactivity of tetracoordinate isothiocyanatosilanes, 1 invariably shows retention of the Si−N(CS) bond under normal nucleophilic/electrophilic reaction conditions. These novel features also get support from semiemperical MO calculations on the compound.