Ab Initio Studies of Hydrogen Bonding

Scheiner, Steve

doi:10.1007/978-3-642-58177-9_6

Cited by 41 publications

(50 citation statements)

References 203 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The hydrogen bonds involving N−H are classified as red-shifted hydrogen bonds4748, thus the red- and blue-shift of ν (N−H) in the two binary systems indicate the strengthening and weakening of the hydrogen bonds. To reveal the different relative energy relationships of self-associating amides and amide-DMSO complexes in the two systems, we turned to quantum chemical calculations.…”

Section: Resultsmentioning

confidence: 99%

Evidences for Cooperative Resonance-Assisted Hydrogen Bonds in Protein Secondary Structure Analogs

Zhou

Deng

Zheng

et al. 2016

Sci Rep

View full text Add to dashboard Cite

Cooperative behaviors of the hydrogen bonding networks in proteins have been discovered for a long time. The structural origin of this cooperativity, however, is still under debate. Here we report a new investigation combining excess infrared spectroscopy and density functional theory calculation on peptide analogs, represented by N-methylformamide (NMF) and N-methylacetamide (NMA). Interestingly, addition of the strong hydrogen bond acceptor, dimethyl sulfoxide, to the pure analogs caused opposite effects, namely red- and blue-shift of the N−H stretching infrared absorption in NMF and NMA, respectively. The contradiction can be reconciled by the marked lowering of the energy levels of the self-associates between NMA molecules due to a cooperative effect of the hydrogen bonds. On the contrary, NMF molecules cannot form long-chain cooperative hydrogen bonds because they tend to form dimers. Even more interestingly, we found excellent linear relationships between changes on bond orders of N−H/N−C/C = O and the hydrogen bond energy gains upon the formation of hydrogen bonding multimers in NMA, suggesting strongly that the cooperativity originates from resonance-assisted hydrogen bonds. Our findings provide insights on the structures of proteins and may also shed lights on the rational design of novel molecular recognition systems.

show abstract

Section: Resultsmentioning

confidence: 99%

Evidences for Cooperative Resonance-Assisted Hydrogen Bonds in Protein Secondary Structure Analogs

Zhou

Deng

Zheng

et al. 2016

Sci Rep

View full text Add to dashboard Cite

show abstract

“…A careful structural analysis of both donor and acceptors lead us to include route B, in which the active donor species was oxocarbenium ion II. The incipient acceptor could form hydrogen bonding 39,40 with the nitrile 41 functional group III). Preceding any direct glycosylation, the acceptor would be driven to target the anomeric carbocation from an axial trajectory to generate the 1,2-cis product.…”

Section: Discussionmentioning

confidence: 99%

The intriguing dual-directing effect of 2-cyanobenzyl ether for a highly stereospecific glycosylation reaction

Hoang

Liu

2014

Nat Commun

View full text Add to dashboard Cite

The diverse presence as well as their very specific bio-responses of glycoconjugates found in all living species requires scientists to synthesize the precise structure of these complex oligosaccharides for various studies on glycoscience. Very few approaches were able to offer the sole a-or b-glycosylated products, even at the cost of complicating the preparative route or usage of exotic chiral auxiliaries to drive the stereoselectivity. In this report, the unification of solvent assistance and neighbouring group participation concepts have led us to the use of 2-cyanobenzyl ether as the dual-directing auxiliary for stereospecific construction of a-and b-glycosidic bonds from a single starting material, and both isomers can be obtained in exclusive stereoselectivity. This work demonstrates the difference in reactivities of glycosyl acceptors can be employed to completely drive the stereoselectivity, drawing the parallel comparison with the arming/disarming concept, which has been exclusively confined to glycosyl donors.

show abstract

“…In this work, we reveal a quantitative relationship between the calculated components of the 1 H magnetic shielding tensor and the degree of covalency of HBs in liquid water 19 20 . The covalent component of intermolecular bonds is commonly defined as the strength of donor–acceptor orbital interactions between molecules 21 .…”

mentioning

confidence: 83%

Covalency of hydrogen bonds in liquid water can be probed by proton nuclear magnetic resonance experiments

2015

View full text Add to dashboard Cite

The concept of covalency is widely used to describe the nature of intermolecular bonds, to explain their spectroscopic features and to rationalize their chemical behaviour. Unfortunately, the degree of covalency of an intermolecular bond cannot be directly measured in an experiment. Here we established a simple quantitative relationship between the calculated covalency of hydrogen bonds in liquid water and the anisotropy of the proton magnetic shielding tensor that can be measured experimentally. This relationship enabled us to quantify the degree of covalency of hydrogen bonds in liquid water using the experimentally measured anisotropy. We estimated that the amount of electron density transferred between molecules is on the order of 10 m while the stabilization energy due to this charge transfer is ∼15 kJ mol−1. The physical insight into the fundamental nature of hydrogen bonding provided in this work will facilitate new studies of intermolecular bonding in a variety of molecular systems.

show abstract

Ab Initio Studies of Hydrogen Bonding

Cited by 41 publications

References 203 publications

Evidences for Cooperative Resonance-Assisted Hydrogen Bonds in Protein Secondary Structure Analogs

Evidences for Cooperative Resonance-Assisted Hydrogen Bonds in Protein Secondary Structure Analogs

The intriguing dual-directing effect of 2-cyanobenzyl ether for a highly stereospecific glycosylation reaction

Covalency of hydrogen bonds in liquid water can be probed by proton nuclear magnetic resonance experiments

Contact Info

Product

Resources

About