Substitution, cooperative, and solvent effects on π pnicogen bonds in the FH2P and FH2As complexes

Ab initio calculations have been carried out to study the substitution effect on the pi pnicogen bond in ZH(2)P-C2HM (Z = H, H3C, NC, F; M = H, CH3, Li) dimer, cooperative effect of the pi pnicogen bond and hydrogen bond in XH-FH2Y-C2H4 (X = HO, NC, F; Y = P and As) trimer, and solvent effect on the pi pnicogen bond in FH2P-C2H2, FH2P-C2H4, FH2As-C2H2, and FH2As-C2H4 dimers. The interaction energy of pi pnicogen bond increases in magnitude from -1.51 kcal mol(-1) in H3P-C2H2 dimer to -7.53 kcal mol(-1) in FH2P-C2HLi dimer at the MP2/aug-cc-pVTZ level. The pi pnicogen bond is enhanced by 12-30 % due to the presence of hydrogen bond in the trimer. The pi pnicogen bond is also enhanced in solvents. The natural bond orbital analysis and symmetry adapted perturbation theory (SAPT) were used to unveil the source of substitution, cooperative, and solvent effects.