Unexpected White Phosphorus (P4) Activation Modes with Silylene‐Substitutedo‐Carboranes and Access to an Isolable 1,3‐Diphospha‐2,4‐disilabutadiene

AbstractNew types of metal‐free white phosphorus (P4) activation are reported. While the phosphine‐silylene‐substituted dicarborane1, CB‐SiP(CB=ortho‐C,C′‐C2B10H10,Si=PhC(tBuN)2Si,P=P[N(tBu)CH2]2), activates white phosphorus in a 2 : 1 molar ratio to yield the P5‐chain containing species2, the analogous bis(silylene)‐substituted compound3, CB‐Si2,reacts with P4in the molar ratio of 2 : 1 to furnish the first isolable 1,3‐diphospha‐2,4‐disilabutadiene (Si=P−Si=P‐containing) compound4. For the latter reaction, two intermediates having a CB‐Si2P4and CB‐Si2P2core could be observed by multinuclear NMR spectroscopy. The compounds2and4were characterized including single‐crystal X‐ray diffraction analyses. Their electronic structures and mechanisms were investigated by density functional theory calculations.