Neutral Pentacoordinate Silicon(IV) Complexes with Silicon–Chalcogen (S, Se, Te) Bonds

The neutral pentacoordinate silicon(IV) complexes 1 (SiS 2 ONC skeleton), 2 (SiSeSONC), 3 (SiTeSONC), 6/9 (SiSe 2 O 2 C), 7 (SiSe 2 S 2 C), and 8/10 (SiSe 4 C) were synthesized and structurally characterized by using single-crystal X-ray diffraction and multinuclear solid-state and solution-state (except for 6―9) NMR spectroscopy. With the synthesis of compounds 1―3 and 6―10, it has been demonstrated that pentacoordinate silicon compounds with soft chalcogen ligand atoms (S, Se, Te) can be stable in the solid state and in solution.