Remarkable Effect of Fluorine and Chlorine Atoms on the Stability of 1H‐Phosphirene

Abstract

Ab initio MO calculations at the MP4/6–31G** level show that both fluorine and chlorine atoms exert a strong stabilizing effect on the three‐membered ring 1H‐phosphirene relative to its isomers. While unsubstituted 1H‐phosphirene (12H) is the least stable C2H3P isomer, 1‐fluoro‐1H‐phosphirene (12F) is calculated to be the global minimum of the C2H2FP potential energy surface; 1‐chloro‐1H‐phosphirene (12Cl) is the third most stable of the six C2H2ClP isomers calculated. The remarkable stability of 12F is attributable to the particular strength of the P—F bond.