Bond strengths in ChCl3- and ChOCl3- (Ch = S, Se, Te): Experiment and theory

The strengths of the SeCl2−Cl-, SeOCl2−Cl-, SeBr2−Br-, and TeCl2−Cl- bonds have been measured to be 133 ± 9, 150 ± 10, 110 ± 6, and 170 ± 7 kJ mol-1, respectively, by determining thresholds for collision-induced dissociation in a flowing afterglow-tandem mass spectrometer. These values are stronger than the previously measured D(SCl2−Cl-) and D(SOCl2−Cl-), both 85 ± 8 kJ mol-1. Bond energies and other properties for these molecules and TeOCl3- have also been computed by several high-level computational techniques, including B3LYP/aug-cc-pVTZ. There is excellent agreement between the experimental and computational energetics for SeCl3-, SeOCl3-, and TeCl3-. The bond strengths increase in the order S < Se < Te.