Unexpected Photodegradation of a Phosphaketenyl‐Substituted Germyliumylidene Borate Complex

Abstract

Abstract The first zwitterionic borata‐bis(NHC)‐stabilized phosphaketenyl germyliumylidene [(L 2 (O=C=P)Ge:] 2 (L 2 =( p ‐tolyl) 2 B[1‐(1‐adamantyl)‐3‐yl‐2‐ylidene] 2 ) has been synthesized by salt‐metathesis reaction of [L 2 (Cl)Ge:] 1 with sodium phosphaethynolate [(dioxane) n NaOCP]. Unexpectedly, its exposure to UV light affords, after reductive elimination of the entire PCO group, the unprecedented [L 2 Ge‐GeL 2 ] complex 3 in 54 % yields bearing the Ge 2 2+ ion with Ge in the oxidation state +1. In addition, the 1,3‐digermylium‐2,4‐diphosphacyclobutadiene [L 2 Ge(μ‐P) 2 GeL 2 ] 4 and bis(germyliumylidenyl)‐substituted diphosphene [(L 2 Ge‐P=P‐GeL 2 )] 5 could also be obtained in moderate yields. The formation of 3 – 5 and their electronic structures have been elucidated with DFT calculations.