Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (3): 671-682.doi: 10.3866/PKU.WHXB201512293

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Topological Analyses of Electron Density on π-hole Pnicogen Bonds in PO2X…PX3/PH2X (X = F, Cl, Br, CH3, NH2) Complexes

Yue-Hong WANG,Xiao-Yan LI,Yan-Li ZENG,Ling-Peng MENG,Xue-Ying ZHANG*()   

  • Received:2015-09-30 Published:2016-03-04
  • Contact: Xue-Ying ZHANG
  • Supported by:
    the National Natural Science Foundation of China(21371045, 21372062);Natural Science Foundation of Hebei Province, China(B2014205109);State Key Program from Ministry of Education of Hebei Province, China(ZD20131037, ZD20131053)


Acting as a molecular linker, the pnicogen bond plays an important role in crystal engineering and supramolecular synthesis. The structures and properties of π-hole pnicogen-bonded complexes PO2X…PX3 and PO2X…PH2X (X = F, Cl, Br, CH3, NH2) were investigated by ab initio MP2/aug-cc-pVTZ calculations and topological analyses of electron density. Two sets of π-hole pnicogen-bonded complexes were found on the potential surfaces. Type-A complexes have P…P and type-B ones have P…X pnicogen bonds. The atoms-inmolecules (AIM) theory, electron localization function (ELF) theory, noncovalent interaction (NCI) index method as well as the adaptⅣe natural density partitioning (AdNDP) approach were used to expand the nature of the interactions considered. The substituent groups strongly affect the properties of pnicogen bond interactions. Pnicogen bonds were covalent interactions for the electron-donating substituents (CH3, NH2), while they were noncovalent, partly covalent and covalent interactions when the substituents were electron-withdrawing groups. Natural bond orbital (NBO) analyses indicated that the larger the Wiberg bond order of the pnicogen-bonded interaction, the more covalent the bond and the greater its strength will be. In type-B conformations, charge transfer mainly occurs from an X lone pair of the PX3/PH2X molecule to the π*(P=O) orbital of PO2X.

Key words: Intermolecular interaction, Pnicogen bond, π-hole interaction, NCI analysis, Topological analysis of electron density, ELF analysis


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