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

Abstract

Ab initio calculations have been carried out to study the substitution effect on the π pnicogen bond in ZH(2)P-C(2)HM (Z = H, H(3)C, NC, F; M = H, CH(3), Li) dimer, cooperative effect of the π pnicogen bond and hydrogen bond in XH-FH(2)Y-C(2)H(4) (X = HO, NC, F; Y = P and As) trimer, and solvent effect on the π pnicogen bond in FH(2)P-C(2)H(2), FH(2)P-C(2)H(4), FH(2)As-C(2)H(2), and FH(2)As-C(2)H(4) dimers. The interaction energy of π pnicogen bond increases in magnitude from -1.51 kcal mol(-1) in H(3)P-C(2)H(2) dimer to -7.53 kcal mol(-1) in FH(2)P-C(2)HLi dimer at the MP2/aug-cc-pVTZ level. The π pnicogen bond is enhanced by 12-30 % due to the presence of hydrogen bond in the trimer. The π 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.

Non-additivity between substitution and cooperative effects in enhancing hydrogen bonds

“…In FH:(PH 2 F:NH 2 F) triads, where both ZB and HB coexist, ZB displays a synergistic effect with HB when the F-H···F HB forms at the P-F end and the influence is antagonistic when the HB occurs at the N-F end. 50 The similar cooperative effect was found in H 2 FY:C 2 H 4 :XH (Y = P and As; X = HO, NC, and F) 13 and FH:(PH 2 F) 2 . 51 ZB also shows cooperative effects with other kinds of interactions such as dihydrogen bond, 52 halogen bond, 53 and cation-π interaction.…”

“…Clearly, HB and ZB become stronger in the triads with respect to the respective dyads, and this result confirms the conclusion that there is positive cooperativity between ZB and HB. 13,50,51 The increase of the HB interaction energy is close to that of the ZB interaction energy in most triads, but the increased percentage of interaction energy is greater for HB. That is, the stronger ZB has a greater effect on the weaker HB, and the stronger ZB is, the greater is the HB enhancement, and vice versa.…”

“…[5][6][7] Pnicogen bond (ZB) 8 is another important intermolecular interaction, in which a covalently bound pnicogen atom serves as the role of a Lewis acid paralleling to the proton in HBs. In spite of a newly proposed interaction, a detailed study has been performed for ZBs in complexes involving PH 3 and its derivatives, [9][10][11][12][13][14][15][16] and the electron donors in ZBs vary from lone pair electrons, π-electrons, 13,14 single electrons, 15 to sigma electrons. 16 Molecular electrostatic potentials (MEPs) of PH 3 and its derivatives indicate that there are the most negative and positive MEPs on the P atomic surface, corresponding to the lone pair and the σ-hole of P atom, respectively.…”

Theoretical estimation of pnicogen bonds and hydrogen bonds in small heterocyclic complexes: Red-shifts and blue-shifts ruled by polarization effects

“…Very recently, the intense search for such an intermolecular model seems to have become even more impracticable with the proposal of another intermolecular innovation named the pnicogen bond (PN-Bond) [26][27]. The discovery of the PN-Bond can be accredited to several research groups, but not exclusively, those headed by Scheiner [28], and Hey-Hawkins et al [29].…”

A comprehensive analysis of P···π pnicogen bonds: substitution effects and comparison with Br···π halogen bonds

“…Scheiner studied the effects of substituents on the P···N noncovalent bond in the complexes of mono-substituted [37,38] and the multisubstituted PH 3 molecule [39] with the NH 3 molecule. Del Bene et al investigated P···P and P···N pnicogen bonds in complexes (PH 2 X) 2 [40], H 2 XP:NXH 2 [41], and (PHFX) 2 [42], with a variety of substituents X. Li et al [43] investigated substitution, cooperative, and solvent effects on π pnicogen bonds in FH 2 P and FH 2 As complexes.…”