Characterization of the first hexacoordinate phosphorus compound with S→P←S bonds

The first example of a hexacoordinate phosphorus compound [S{6-t-Bu-4-Me-C6H2O}2]2P+(Cl−·C3H4N2) with two S→P bonds is reported. This compound can be construed as an oxophosphonium salt with double intramolecular coordination by sulfur atoms. X-ray structure reveals a facial arrangement of the ligands with two coordinating sulfur atoms cis to each other. The S→P distance of 2.334 (1) Å is one among very short coordinate bond distances between sulfur and phosphorus.