Reaction of 3,3,5,5‐Tetraphenyl‐1,2,4‐trithiolane with Pt 0 (bisphosphane)(η 2 ‐nbe) Complexes Bearing Bridged Bisphosphane Ligands with Various Bite Angles

A series of Pt 0 (η 2 ‐nbe) complexes [nbe = norbornene (bicyclo[2.2.1]hept‐2‐ene)] bearing bridged bisphosphane ligands with various bite angles ( 5a – c ) was treated with 3,3,5,5‐tetraphenyl‐1,2,4‐trithiolane ( 1 ) at 50 °C in a toluene solution. These reactions resulted in the formation of the appropriate dithiolato complexes 6a – c as well as the η 2 ‐thioketone complexes 7a – c with respect to the 31 P{ 1 H} NMR spectroscopic data. All isolated complexes were fully characterized. Kinetic investigations using 31 P{ 1 H} NMR spectroscopy revealed first‐order kinetics in 1 , pointing to the known cycloreversion of 1 as the initial and rate‐determining step for these reactions. The formation of dithiolato complexes 6a – c suggests 1,3‐dipolar electrocyclization of diphenylthiosulfine ( 3 ) to diphenyldithiirane ( 4 ) in solution. On the basis of these results a plausible mechanism for the overall reaction is developed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)