First Structural Study of a Thiophosphorane Containing a Six-Membered Ring. Phosphorus-Sulfur vs Phosphorus-Oxygen Ligand Preferences

Abstract

Oxidative addition of phenanthrenequinone to the newly synthesized dithiaphosphorinane, (Xylyl-O)P-S(CH2)3 S(1), results in a new thiophosphorane containing a sulfur-bonded six-membered ring. X-ray analysis on separate crystals reveals both a monoclinic and triclinic modification. This represents the first structural study of a six-membered ring containing thiophosphorane. The structure which is a trigonal biyramid has the ring sulfur atoms located in apical-equatorial sites instead of the expected diequatorial arrangement. As a consequence, the more electronegative xylyloxy oxygen atom is relegated to an equatorial position. A slightly twisted boat conformation exists for the dithiaphosphorinane ring. 1H NMR spectroscopy is consistent with the retention of the solid-state structure in solution which undergoes rapid intramolecular ligand exchange. © 1990, American Chemical Society. All rights reserved.