Cooperative effects between halogen bonds and pnicogen bonds in XBr∙∙∙OFH2P∙∙∙NH3 (X = F, Cl, CN, NC, OH, and NO2) complexes.

Quantum chemical calculations were carried out to investigate interplay between halogen bonds and pnicogen bonds in XBr∙∙∙OFH2P∙∙∙NH3 (X = F, Cl, CN, NC, OH, and NO2) complexes at the M06-2X/aug-cc-pVDZ level. Cooperative effects are observed when halogen bonds and pnicogen bonds coexist in the same complex. These effects are analyzed in terms of geometric and energetic properties of the complexes. The mechanism of cooperative effects is analyzed in view with molecular electrostatic potential, natural bond orbital, and density difference of molecule formation analyses.