Ab Initio Study of Ternary Complexes X:(HCNH)+:Z with X, Z = NCH, CNH, FH, ClH, and FCl: Diminutive Cooperative Effects on Structures, Binding Energies, and Spin–Spin Coupling Constants Across Hydrogen Bonds

2011 ◽  
Vol 115 (45) ◽  
pp. 12677-12687 ◽  
Author(s):  
Janet E. Del Bene ◽  
Ibon Alkorta ◽  
José Elguero
Keyword(s):  
Hydrogen Bonds ◽  
Ab Initio ◽  
Ternary Complexes ◽  
Binding Energies ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Ab Initio Study ◽  
Cooperative Effects ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

1,2-Dihydro-1,3,2-diazaborinine tautomer as an electron-pair donor in hydrogen-bonded complexes

2021 ◽  
Author(s):  
Ibon Alkorta ◽  
Jose Elguero ◽  
Janet E Del Bene
Keyword(s):  
Hydrogen Bonds ◽  
Ab Initio ◽  
Electron Pair ◽  
Binding Energies ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Ab initio MP2/aug’-cc-pVTZ calculations have been carried out to investigate 1,2-dihydro-1,3,2-diazaborinine:HX complexes for HX = H+, HF, HCl, H2O, HCN, NH3, HCP, and HCCH. Most complexes are stabilized by linear, traditional hydrogen bonds except for those with H2O and NH3 which have bridging structures and nonlinear hydrogen bonds. H-atom transfer from N to B can occur in complexes with HF and HCl, with formation of a traditional F-H…N and a proton-shared Cl…H…N bond. The binding energies of the uncharged complexes range from 25 to 88 kJ.mol–1. Spin-spin coupling constants have been used to characterize these hydrogen-bonded complexes. Des calculs ab initio MP2/aug'-cc-pVTZ ont été effectués pour étudier les complexes 1,2-dihydro-1,3,2-diazaborinine:HX pour HX = H+, HF, HCl, H2O, HCN, NH3, HCP et HCCH. La plupart des complexes sont stabilisés par des liaisons hydrogène traditionnelles, linéaires, à l'exception de celles avec H2O et NH3 qui ont des structures pont et des liaisons hydrogène non linéaires. Le transfert de l'atome d'hydrogène de N à B peut se produire dans des complexes avec HF et HCl, avec formation d'une liaison F-H···N traditionnelle et d'une liaison Cl···H···N avec un proton comparti. Les énergies de liaison des complexes non chargés vont de 25 à 88 kJ·mol–1. Des constantes de couplage spin-spin ont été utilisées pour caractériser ces complexes à liaison l'hydrogène.

Using one halogen bond to change the nature of a second bond in ternary complexes with P⋯Cl and F⋯Cl halogen bonds

2017 ◽  
Vol 203 ◽  
pp. 29-45 ◽  
Author(s):  
Janet E. Del Bene ◽  
Ibon Alkorta ◽  
José Elguero
Keyword(s):  
Halogen Bond ◽  
Synergistic Effects ◽  
Ternary Complexes ◽  
Binding Energies ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Halogen Bonds ◽  
Binary Complexes ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Ab initio MP2/aug’-cc-pVTZ calculations have been carried out to determine the effect of the presence of one halogen bond on the nature of the other in ternary complexes H2XP:ClF:ClH and H2XP:ClF:ClF, for X = F, Cl, H, NC, and CN. The P⋯Cl bonds remain chlorine-shared halogen bonds in the ternary complexes H2XP:ClF:ClH, although the degree of chlorine sharing increases relative to the corresponding binary complexes. The F⋯Cl bonds in the ternary complexes remain traditional halogen bonds. The binding energies of the complexes H2XP:ClF:ClH increase relative to the corresponding binary complexes, and nonadditivities of binding energies are synergistic. In contrast, the presence of two halogen bonds in the ternary complexes H2XP:ClF:ClF has a dramatic effect on the nature of these bonds in the four most strongly bound complexes. In these, chlorine transfer occurs across the P⋯Cl halogen bond to produce complexes represented as (H2XP–Cl)+:−(F:ClF). In the ion-pair, the cation is also halogen bonded to the anion by a Cl⋯F− halogen bond, while the anion is stabilized by an −F⋯Cl halogen bond. The central ClF molecule no longer exists as a molecule. The binding energies of the ternary H2XP:ClF:ClF complexes are significantly greater than the binding energies of the H2XP:ClF:ClH complexes, and nonadditivities exhibit large synergistic effects. The Wiberg bond indexes for the complexes H2XP:ClF, H2XP:ClF:ClH, and H2XP:ClF:ClF, and the cations (H2XP–Cl)+ reflect the changes in the P–Cl and Cl–F bonds. Similarly, EOM-CCSD spin–spin coupling constants are also consistent with the changes in these same bonds. In particular, 1xJ(P–Cl) in H2XP:ClF complexes becomes 1J(P–Cl) in the ternary complexes with chlorine-transferred halogen bonds. A plot of these coupling constants shows a change in the curvature of the trendline as chlorine-shared halogen bonds in H2XP:ClF:ClH become chlorine-transferred halogen bonds in H2XP:ClF:ClF. 1xJ(F–Cl) coupling constants also reflect changes in the nature of F⋯Cl halogen bonds.

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