The competition of Y⋯o and X⋯n halogen bonds to enhance the group V σ‐hole interaction in the NCY⋯o  PH 3 ⋯ NCX and O  PH 3 ⋯ NCX⋯NCY ( X, Y  F, Cl , and Br ) complexes

The positive electrostatic potentials (ESP) outside the σ‐hole along the extension of OP bond in OPH 3 and the negative ESP outside the nitrogen atom along the extension of the CN bond in NCX could form the Group V σ‐hole interaction OPH 3 ⋯NCX. In this work, the complexes NCY⋯OPH 3 ⋯NCX and OPH 3 ⋯NCX⋯NCY (X, YF, Cl, Br) were designed to investigate the enhancing effects of Y⋯O and X⋯N halogen bonds on the P⋯N Group V σ‐hole interaction. With the addition of Y⋯O halogen bond, the V S, max values outside the σ‐hole region of OPH 3 becomes increasingly positive resulting in a stronger and more polarizable P⋯N interaction. With the addition of X⋯N halogen bond, the V S, min values outside the nitrogen atom of NCX becomes increasingly negative, also resulting in a stronger and more polarizable P⋯N interaction. The Y⋯O halogen bonds affect the σ‐hole region (decreased density region) outside the phosphorus atom more than the P⋯N internuclear region (increased density region outside the nitrogen atom), while it is contrary for the X⋯N halogen bonds. © 2015 Wiley Periodicals, Inc.