(L)2C2P2: Dicarbondiphosphide Stabilized by N-Heterocyclic Carbenes or Cyclic Diamido Carbenes

Angewandte Chemie - International Edition

5 years ago

(L)2C2P2: Dicarbondiphosphide Stabilized by N-Heterocyclic Carbenes or Cyclic Diamido Carbenes

Diego M. Andrada, Gernot Frenking, Cheng-Yong Su, Zoltán Benkö, Jeffrey R. Harmer, Zhongshu Li, Yaqi Li, Xiaodan Chen, Hansjörg Grützmacher

Carbon phosphides, CnPm, may have highly promising electronic, optical, and mechanical properties, but they are experimentally almost unexplored materials. Phosphaheteroallenes stabilized by N-heterocyclic carbenes undergo a one-electron reduction to yield compounds of the type (L)2C2P2 with diverse structures. The use of imidazolylidenes as ligands L give complexes with a central four-membered ring C2P2, while more electrophilic cyclic diamidocarbenes (DAC) give a compound with an acyclic π-conjugated CP−PC unit. Cyclic C2P2 compounds are best described as non-Kekulé molecules that are stabilized by coordination to the NHC ligands NHC(C2P2)NHC. These species can be easily oxidized to give stable radical cations [(NHC)2C2P2]+.. The remarkably stable molecules with an acylic C2P2 core are best described with electron-sharing bonds (DAC)=C=P−P=C=(DAC). Hope for CP? Carbonphosphides, CnPm, are scarcely known but are predicted to have interesting properties. The non-Kekulé molecule NHCC2P2NHC and the classical DAC=C=P−P=C=DAC could now be synthesized and may allow the development of CnPm chemistry (NHC=N-heterocyclic carbene, DAC=diamidocarbene).

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/anie.201612247