Substituent effects on cooperativity of pnicogen bonds

Abstract

Substituent effects on cooperativity of P···N pnicogen bonds are studied in XH2P···NCH(2)P···NCY (X=F, Cl; Y=H, F, CN, OH, NH(2)) complexes using high-level ab initio calculations. An increased attraction or a positive cooperativity is observed on introduction of a third molecule to the XH(2)P···NCH(2)P and NCH(2)P···NCY dyads. The shortening of the each pnicogen bond distance in the triads is dependent on the strength of the P···N bond and is increased in the order Y = NH(2) > OH > H > F > CN. The energy decomposition analysis indicates that the polarization energy is the important element in the interaction energy of P···N bond and may be regarded as being responsible for the stabilization in these systems. Natural bond orbital theory is used to characterize the interactions and analyze their enhancement with varying orbital interactions.

Does Oxygen Feature Chalcogen Bonding?

“…Traditionally, the positive and negative signs of the local minimum and maximum of the electrostatic potential ( V S,min and V S,max , respectively) have been invoked to characterize the positive and negative sites on the molecular surfaces, respectively [33,41,42,43,44,45]. Note that the sign and magnitude of potential on the electrostatic surface of a main group atom M along the outer portion of the R–M bond extension is generally used to characterize the nature and quantify the strength and size of its σ-hole, respectively [42,43,44,45,46,47]. The larger the V S,max associated with a site on M, the stronger its interaction with the Lewis base might be [43,46,47].…”

“…Note that the sign and magnitude of potential on the electrostatic surface of a main group atom M along the outer portion of the R–M bond extension is generally used to characterize the nature and quantify the strength and size of its σ-hole, respectively [42,43,44,45,46,47]. The larger the V S,max associated with a site on M, the stronger its interaction with the Lewis base might be [43,46,47]. Whereas the choice of an isodensity envelope is arbitrary [33,48], we used the 0.001 au isodensity envelope on which to compute the electrostatic potential.…”

Very strong chalcogen bonding: Is oxygen in molecules capable of forming it? A First-Principles Perspective

“…The latter results unequivocally demonstrate that the local most VS,max values associated with O's s-hole in isolated monomers cannot be used as a universal descriptor of intermolecular interactions, or a measure of complex stability. This is arguably because the dependence between VS,max and DE has previously been demonstrated to be linear in some systems, 22,[84][85][86] but observed not to be so in the complexes reported in this study. This suggests that the Coulombic view of explaining the origin of intermolecular interactions in the complexes examined in this study is incomplete, and such a view is not applicable to all systems as is not universal.…”

The Key Role of Orbital Interaction in Cooperativity between B⋅⋅⋅N and Hydrogen/Lithium Bonding: An ab initio Study

“…Previous studies have shown that the QTAIM analysis is very helpful tool for studying the cooperative effects between noncovalent interactions . Considering the linear relationship between the strength of an interaction and electron density ( ρ BCP ) at the corresponding bond critical point (BCP), an increase in the ρ BCP values at the B⋅⋅⋅N and M⋅⋅⋅N BCPs of the ternary complexes with respect to the binary systems can provide another evidence for the strengthening of these interactions.…”