Unexpected White Phosphorus (P4 ) Activation Modes with Silylene-Substituted o-Carboranes and Access to an Isolable 1,3-Diphospha-2,4-disilabutadiene.

Abstract

New types of metal‐free white phosphorus (P4) activation are reported. While the phosphine‐silylene‐substituted dicarborane 1, 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 species 2, the analogous bis(silylene)‐substituted compound 3, CB‐Si2 , reacts with P4 in the molar ratio of 2 : 1 to furnish the first isolable 1,3‐diphospha‐2,4‐disilabutadiene (Si=P−Si=P‐containing) compound 4. For the latter reaction, two intermediates having a CB‐Si2P4 and CB‐Si2P2 core could be observed by multinuclear NMR spectroscopy. The compounds 2 and 4 were characterized including single‐crystal X‐ray diffraction analyses. Their electronic structures and mechanisms were investigated by density functional theory calculations.