中文摘要：

磷键作为一种新型的分子键合力,因在晶体工程和超分子合成等方面的重要作用而越来越多地引起科研工作者的广泛关注。本文采用量子化学从头算和电子密度拓扑分析等方法,在MP2/aug-cc-pVTZ理论水平上,对PO_2X…PX_3和PO_2X…PH_2X（X=F,Cl,Br,CH_3,NH_2）π型复合物的结构和磷键性质进行了理论研究。研究表明：π-hole磷键复合物存在A和B两种稳定构型,分别以P…P和P…X磷键作用为主。分子中原子（AIM）、非共价作用（NCI）、电子定域函数（ELF）及适应性自然密度划分（AdNDP）分析表明,不同取代基对该类磷键作用的性质产生很大影响：当取代基为给电子基（CH_3,NH_2）时,磷键具有明显的共价作用特征;当取代基为吸电子基（F,Cl,Br）时,构型和取代基不同的磷键分别表现为非共价、部分共价或共价作用特征。自然键轨道（NBO）分析指出,分子间磷键的Wiberg键级的数值越大,磷键的共价性越强,磷键的作用强度越大。构型B的电荷转移主要是PX_3/PH_2X中X原子上的孤对电子转移到PO_2X中π＊（P=O）反键空轨道。

英文摘要：

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 PO_2X…PX_3 and PO_2X…PH_2X（X = F, Cl, Br, CH_3, NH_2） 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（Ad NDP） 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（CH_3, NH_2）, 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 PX_3/PH_2 X molecule to the π＊（P=O） orbital of PO_2 X.