Arylthiazylamides: Syntheses, structures, and bonding properties

Air-sensitive, thermally unstable tris(dimethylamino)sulfonium (TAS) salts (3) of the title anions [ArNSN](-) have been prepared from corresponding su lfurdiimides Ar-N=S=N-SiMe3 (2) by Si-N bond cleavage with [(Me2N)(3)S](+)[ Me3SiF2](-)(TASF). They are characterized by low-temperature X-ray crystall ography as Z isomers. Because of the very short terminal S-NI distance (144 .2 (3h) - 147.9 (3i) pm) and the relatively long internal S-N distance (158 .3 (3i) - 160.3 (3c) pm) the [ArNSN](-) ions should be regarded as thiazyla mides 1b, rare species containing a SN triple bond. A bonding model is deve loped and the experimental results are compared with those of restricted Ha rtree-Fock (R drop HF), density functional theory (DFT), and Moller-Plesset second-order (MP2) calculations.