Comparison between hydrogen and dihydrogen bonds among H[sub 3]BNH[sub 3], H[sub 2]BNH[sub 2], and NH[sub 3] (original) (raw)
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Comparison between hydrogen and dihydrogen bonds among H3BNH3, H2BNH2, and NH3
The Journal of Chemical Physics, 2003
Several possible binary complexes among ammonia-borane, aminoborane, and ammonia, via hydrogen and/or dihydrogen bonds, have been investigated to understand the effect of different hybridization. Møller-Plesset second-order perturbation theory with aug-cc-pVDZ basis set was used. The interaction energy is corrected for basis set superposition error, and the Morokuma-Kitaura method was employed to decompose the total interaction energy. Like H 3 BNH 3 , the sp 2 hybridized H 2 BNH 2 also participates in Hand dihydrogen bond formation. However, such bonds are weaker than their sp 3 analogs. The contractions of BN bonds are associated with blueshift in vibrational frequency and stretches of BH and NH bonds with redshift. The polarization, charge transfer, correlation, and higher-order energy components are larger in dihydrogen bonded complexes, compared to classical H-bonded ammonia dimers.
Comparative ab initio and semi-empirical study of hydrogen bonded complexes of NH3 and H2O
Journal of Molecular Structure: THEOCHEM, 1992
Recently developed semiempirical methods ( AMl, MNDO-PM3 and MNDO/M) are tested by comparison with ab initio Hartree-Fock and Meller-Plesset 4-31G and 6-311G (d,p) calculations on cuts of the potential energy hyperfaces of the hydrogen bonded diiers Hz0.H20, NH3.NH, and NH3 -HzO. AM1 gives a bifurcatedly hydrogen-bonded complex for the water dimer, as already published, whereas it gives trifurcated structures for the other two dimers. There is no indication of a quasi-linear hydrogen bonded dimer in these last two cases, in agreement with the ab initio calculations. Moreover, there is a secondary minimum in the ammonia dimer surface, with a cyclic structure, which closely resembles that obtained in the ab initio calculations. MNDO-PM3 gives the quasi-linear hydrogen bonded structure of the water dimer as the correct one. For NH3-NH3 the global minimum is no longer the trifurcated structure (which is, however, a secondary minimum) but a cyclic one. However, the ring is so closed that hydrogen atoms of both monomers are almost head-to-head. For NH,*HxO a further minimum appears, which is now the global one, corresponding to the linearly hydrogen-bonded structure of the dimer. The aspect of this attractor, as well as the aspect of the cut in the PES of the water dimer, suggests that undue importance has been given to linear hydrogen bonds in the parametrization of MNDO-PM3. MNDO/M behaves in a very similar way to MNDO-PM3 and, owing to its better definition, the latter should be preferred. In conclusion, none of these methods is truly reliable for calculations on weakly bound dimers. MNDO-PM3 is better than AM1 for the water and the ammonia-water dimers but not for the ammonia dimer; MNDO/M is no better than MNDO-PM3.
Physical Chemistry Chemical Physics, 2008
Theoretical calculations at the MP2/6-311++G(2d,2p) level are used to analyze the interaction between HNZ (Z = O, S) and H 2 XNH 2 (X = B, Al). In the most stable conformation, the complexes are cyclic, the molecules being held together by conventional NHÁ Á ÁZ hydrogen bonds and by XHÁ Á ÁHN dihydrogen bonds. Binding energies including ZPE-and BSSE-corrections lie in the range 6.2-6.9 kJ mol À1 and there is little sensitivity to the nature of the X and Z atoms. In the XHÁ Á ÁHN dihydrogen bonds, the NH stretching vibrations are blue-shifted in the HNO complexes and red-shifted in the H 2 AlNH 2 -HNS complex. In the conventional NHÁ Á ÁZ hydrogen bonds, the NH stretching vibrations are red-shifted. The topological parameters at the bond critical point are in the usual range for hydrogen or dihydrogen bonds. A natural bond orbital analysis including the calculation of the atomic charges, hybridization, occupation of the antibonding orbitals and hyperconjugation energies shows that the shifts of the NH stretching vibrations in the conventional and dihydrogen bonds are mainly determined by the changes in occupation of the s*(NH) antibonding orbitals. The mechanism of intramolecular coupling is discussed and appears to be different for the HNO and HNS complexes. The analysis of all the theoretical data reveals that the NHÁ Á ÁZ bonds are stronger in the H 2 BNH 2 than in the H 2 AlNH 2 systems and that the XHÁ Á ÁHN dihydrogen bonds are stronger in the H 2 AlNH 2 than in the H 2 BNH 2 complexes. w Electronic supplementary information (ESI) available: Cartesian coordinates and energies including ZPE correction of monomers and complexes at the MP2/6-311++G(2d,2p) level of theory. See
Defining the hydrogen bond: An account (IUPAC Technical Report)
Pure and Applied Chemistry, 2000
The term “hydrogen bond” has been used in the literature for nearly a century now. While its importance has been realized by physicists, chemists, biologists, and material scientists, there has been a continual debate about what this term means. This debate has intensified following some important experimental results, especially in the last decade, which questioned the basis of the traditional view on hydrogen bonding. Most important among them are the direct experimental evidence for a partial covalent nature and the observation of a blue-shift in stretching frequency following X
A Spectroscopic Overview of Intramolecular Hydrogen Bonds of NH…O,S,N Type
Molecules, 2021
Intramolecular NH . . . O,S,N interactions in non-tautomeric systems are reviewed in a broad range of compounds covering a variety of NH donors and hydrogen bond acceptors. 1 H chemical shifts of NH donors are good tools to study intramolecular hydrogen bonding. However in some cases they have to be corrected for ring current effects. Deuterium isotope effects on 13 C and 15 N chemical shifts and primary isotope effects are usually used to judge the strength of hydrogen bonds. Primary isotope effects are investigated in a new range of magnitudes. Isotope ratios of NH stretching frequencies, νNH/ND, are revisited. Hydrogen bond energies are reviewed and two-bond deuterium isotope effects on 13 C chemical shifts are investigated as a possible means of estimating hydrogen bond energies.
Physical Chemistry Chemical Physics, 2018
The solvation structures of two systems rich in hydrogen and dihydrogen bonding interactions have been studied in detail experimentally through neutron diffraction with hydrogen/deuterium isotopic substitution. The results were analysed by an atomistic Monte Carlo simulation employing refinement to the experimental scattering data. The systems studied were the hydrogen storage material ammonia borane (NH 3 BH 3 , AB) dissolved in tetrahydrofuran (THF), and liquid ammonia (NH 3), the latter in which AB shows unusually high solubility (260 g AB per 100 g NH 3) and potential regeneration properties. The full orientational and positional manner in which AB-AB, AB-THF and AB-NH 3 pairs interact with each other were successfully deciphered from the wide Q-range total neutron scattering data. This provided an unprecedented level of detail into such highly (di)hydrogen bonding solute-solvent interactions. In particular this allowed insight into the way in which H-B acts as a hydrogen bond acceptor. The (di)hydrogen bonding was naturally determined to dictate the intermolecular interactions, at times negating the otherwise expected tendency for polar molecules to align themselves with anti-parallel dipole moments. Several causes for the extreme solubility of AB in ammonia were determined, including the ability of ammonia to (di)hydrogen bond to both ends of the AB molecule and the small size of the ammonia molecule relative to AB and THF. The AB B-H to ammonia H dihydrogen bond was found to dominate the intermolecular interactions, occurring almost three times more often than any other hydrogen or dihydrogen bond in the system. The favourability of this interaction was seen on the bulk scale by a large decrease in AB clustering in ammonia compared to in the dihydrogen bond-less THF.
Factors Affecting the Strength of N-H.cntdot..cntdot..cntdot.H-Ir Hydrogen Bonds
Journal of the American Chemical Society, 1995
The strengths of intramolecular W *H and H. *Y hydrogen bonding between a ligating 2-aminopyridine NH group and a cis Ir-H bond or a cis halo group has been estimated (1.8-5.2 kcal/mol) in a series of compounds of general form [IrH2(Y)(2-C6H4NH2)(PPh3)*In+ (Y = H-, F-, C1-, Br-, I-, SCN-, and CN-, n = 0, and Y = CO and MeCN, n = 1) by a new method involving measuring the Ar-NH2 rotation barrier by 'H NMR. The H-bonding interaction is surprisingly strong; in cases where both are possible, N-W *H-Ir hydrogen bonding is preferred over N-H* C1-Ir H-bonding. The experimental barrier for C-N bond rotation in [IrH2(Y)(2-C6H4NH2)(PPh3>*]"+ was in the range 7.6-11.0 kcavmol, as determined by 'H NMR. From a simple geometrical study it appears that the two H-bonded hydrogens can approach appropriately close to each other. In contrast, the geometry of the situation is not as favorable for N-H..*Y-Ir H-bonding for Y = F-, C1-, Brand nd I-. From core potential ab initio studies, the H-bond strength was estimated to be in the range 5.7-7.1 kcdmol, assuming that the intrinsic C-N rotation barrier is the same in free and coordinated 2-C5H&H*. These unusual hydrogen bonds (A-H.. *B) are proposed to be strong for an element B having the electronegativity of hydrogen because of (i) a favorable geometry which allows NH and IrH to approach very close to one another and (ii) the facility with which Ir-H may be polarized in the sense @+-Hd-on the approach of the N-H bond. The calculations also suggest that the reason changing the nature of the ligand Y trans to the H-bonded Ir-H group alters the strength of the H-bond is that the 6charge on the Ir-H is affected. The higher the trans effect of Y, the higher the 6charge and the stronger the NW-eHIr bonding interaction.