Structure and stability of MCl4 carbene complexes (M = Si, Ge, Sn): Experiment and theory

• Structures of the toluene solvates of the complexes of MCl 4 ·I Dipp (M = Ge, Sn) and SnCl 4 ·2I Dipp were determined for the first time • Thermal decomposition of 1:1 complexes results in H/Cl exchange in NHC, while in the case of the 1:2 complex chlorination of the NHC occurs • Possible reaction pathways for the decomposition are proposed on the basis of experimental and computational data Toluene solvates of MCl 4 · n I Dipp ( n = 1, M = Ge, Sn; n = 2, M = Sn) complexes have been synthesized and structurally characterized. Mass spectrometry studies indicate that upon heating complexes of a 1:1 composition MCl 4 ·I Dipp undergo sublimation and dissociation into the components, while a complex of 1:2 composition SnCl 4 ·2I Dipp does not exist in the gas phase. Thermal decomposition of MCl 4 ·I Dipp is accompanied by H/Cl exchange by formation of C 27 H 34 Cl 2 N 2 molecules. In contrast, upon decomposition or prolonged storage of SnCl 4 ·2I Dipp a chlorination of I Dipp takes place by formation of C 27 H 36 Cl 2 N 2 . Experimental findings are in qualitative agreement with the results of DFT computations.