title: New equation for calculating total interaction energy in one noncyclic ABC triad and new insights into cooperativity of noncovalent bonds.
abstract: In this work, a new equation consist of A⋅⋅⋅B, B⋅⋅⋅C, A⋅⋅⋅BC, and AB⋅⋅⋅C interactions is proposed for calculating the total interaction energy of noncyclic ABC triads. New equations are also proposed for calculating the changes in values of A⋅⋅⋅B and B⋅⋅⋅C interactions on the formation of triad from the corresponding dyads. The advantages of equations proposed here in comparison with many-body interaction energy approach are discussed. All proposed equations were tested in F3MLi⋅⋅⋅NCH⋅⋅⋅HLH and F3MLi⋅⋅⋅HLH⋅⋅⋅HCN (M = C, Si; L = Be, Mg) as well as H3N⋅⋅⋅XY⋅⋅⋅HF (X, Y = F, Cl, Br) noncyclic A⋅⋅⋅B⋅⋅⋅C triads. The data show that the total cooperativity of triad correlates well with the sum of the changes in values of A⋅⋅⋅B and B⋅⋅⋅C interactions calculated through new equations proposed here. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Chemistry, Bu-Ali Sina University, Hamedan, Iran.
authors.forename: Sadegh
authors.initials: S
authors.lastname: Salehzadeh
authors.affiliation: Department of Chemistry, Bu-Ali Sina University, Hamedan, Iran.
authors.forename: Farahnaz
authors.initials: F
authors.lastname: Maleki
keywords: cooperativity; interaction energy; many-body interaction energy; noncovalent interaction; noncyclic triad; stabilization energy