The Gas-Phase Molecular Structure of 1-Fluorosilatrane from Electron Diffraction

The molecular geometry of 1-fluorosilatrane has been determined by gas-phase electron diffraction. The distance between the nitrogen and silicon atoms is much longer in the gas phase, viz., 2.324 +/- 0.014 angstrom, than in the crystal, 2.042 (1) angstrom [5]. This indicates a weakened donor-acceptor interaction possibly as a consequence of the absence of intermolecular interactions in the gas phase. The five-membered rings take envelope conformations with the carbon atoms adjacent to nitrogen at the envelope tips. The following bond distances (r(g), angstrom) and bond angles (degrees) were obtained with their estimated total errors: N-C, 1.481 +/- 0.008; C-C, 1.514 +/- 0.011; O-C, 1.392 +/- 0.004; Si-O, 1.652 +/- 0.003; Si-F, 1.568 +/- 0.006; C-H, 1.118 +/- 0.005; N-C-C, 104.5 +/- 0.6; C-C-O, 117.0 +/- 0.7; C-O-Si, 123.7 +/- 0.6; O-Si-F, 98.7 +/- 0.3; O-Si-O, 117.8 +/- 0.1; C-N-C, 115.0 +/- 0.3.