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

Author(s):  
Ibon Alkorta ◽  
Jose Elguero ◽  
Janet E Del Bene

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.

2010 ◽  
Vol 88 (8) ◽  
pp. 694-699 ◽  
Author(s):  
Janet E. Del Bene ◽  
Ibon Alkorta ◽  
José Elguero

Ab initio equation-of-motion coupled cluster singles and doubles (EOM–CCSD) calculations have been carried out to evaluate spin–spin coupling constants in six pairs of homo- and hetero-chiral dimers: (HOOH)2, (H2NNH2)2, (FOOH)2, (FHNNH2)2, (HOOOH)2, and (FOOOH)2. Corresponding spin–spin coupling constants in these isomeric pairs of C2 and Ci symmetry may differ, but these differences are small and may not be detectable experimentally. For the complexes with O1–H···O and O1–H···F hydrogen bonds, 1J(O1–H) has a larger absolute value in the C2 isomer. For the same set of complexes, 1J(O1–O2) has a larger absolute value in the Ci isomer. No distinguishable patterns could be discerned in the remaining spin–spin coupling constants in the C2 and Ci isomers of these complexes, nor in complexes with N–H···N hydrogen bonds.


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