Two stable phosphorus-containing four-membered ring radical cations with inverse spin density distributions

Yuanting Su; Xin Zheng; Xingyong Wang; Xuan Zhang; Yunxia Sui; Xinping Wang

doi:10.1021/ja502675d

Two stable phosphorus-containing four-membered ring radical cations with inverse spin density distributions

J Am Chem Soc. 2014 Apr 30;136(17):6251-4. doi: 10.1021/ja502675d. Epub 2014 Apr 16.

Authors

Yuanting Su¹, Xin Zheng, Xingyong Wang, Xuan Zhang, Yunxia Sui, Xinping Wang

Affiliation

¹ State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, China.

PMID: 24731124
DOI: 10.1021/ja502675d

Abstract

Two phosphorus-containing four-membered ring radical cations 1(•+) and 2(•+) have been isolated and characterized by UV-vis absorption spectroscopy, electron paramagnetic resonance (EPR), and single-crystal X-ray diffraction. Compared with neutral molecules 1 and 2, radical 1(•+) has elongated P-P bonds and more pyramidalized phosphorus atoms, while shortened P-Nring distances and larger angles around phosphorus centers are observed for 2(•+). EPR studies indicate that for 1(•+) spin density mainly resides on the exocyclic nitrogen atoms with very minor contribution from endocyclic phosphorus atoms, while the situation is opposite for 2(•+). Such an inverse spin density distribution is controlled by the exocyclic substituents, which is supported by DFT calculations.