Conformational behavior and electronic structure of silylketenes studied with quantum chemical calculations and photoelectron spectroscopy

The He(I) photoelectron spectra of silylketenes (Me 3 Si) 2 C=C=O (1), Me 5 Si 2 CH=C=O (2), Me 2 Si(CH=C=O) 2 (3), MeSi(CH=C=O) 3 (4), (SiMe 2 CH=C=O) 2 (5), and (CH 2 SiMe 2 CH=C=O) 2 (6) have been recorded and their structures and orbital energies have been calculated by ab initio methods. Orbital energies for disilanes 2 and 5 are strongly dependent on a Si-Si-C-C torsional angle due to σ–π orbital interaction. Comparisons between …