ChemInform Abstract: The Role of Double Hydrogen Bonds in Asymmetric Direct Aldol Reactions Catalyzed by Amino Amide Derivatives.

ChemInform ◽  
2010 ◽  
Vol 42 (4) ◽  
pp. no-no
Author(s):  
Xiao-Hua Chen ◽  
Jie Yu ◽  
Liu-Zhu Gong
Keyword(s):  
Hydrogen Bonds ◽  
Aldol Reactions ◽  
Amide Derivatives ◽  
Amino Amide ◽  
Double Hydrogen

scholarly journals Coupled High Spin CoIIIons Linked by Symmetrical Double Hydrogen Bonds: Role of a Slowly Relaxing CuIIImpurity in Interrupting the CoII-CoIIExchange Interaction

2018 ◽  
Vol 2018 (42) ◽  
pp. 4604-4613
Author(s):  
Ana L. Pérez ◽  
Axel Kemmerer ◽  
Marilin A. Rey ◽  
Sergio D. Dalosto ◽  
Carlos A. Ramos ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
High Spin ◽  
Double Hydrogen

Insight into structure, stability and hydrogen bond in complexes of guanine and thymine at the molecular level using computational chemical method

2021 ◽  
Vol 11 (1) ◽  
pp. 127-134
Author(s):  
Nhung Ngo Thi Hong ◽  
Huong Dau Thi Thu ◽  
Trung Nguyen Tien
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Energy Surface ◽  
Covalent Bond ◽  
Electrostatic Energy ◽  
Substantial Contribution ◽  
Structure Stability ◽  
Dispersion Terms ◽  
Insight Into

Nine stable structures of complexes formed by interaction of guanine with thymine were located on potential energy surface at B3LYP/6-311++G(2d,2p). The complexes are quite stable with interaction energy from -5,8 to -17,7 kcal.mol-1. Strength of complexes are contributed by hydrogen bonds, in which a pivotal role of N−H×××O/N overcoming C−H×××O/N hydrogen bond, up to to 3.5 times, determines stabilization of complexes investigated. It is found that polarity of N/C−H covalent bond over proton affinity of N/O site governs stability of hydrogen bond in the complexes. The obtained results show that the N/C−H×××O/N red-shifting hydrogen bonds occur in all complexes, and a larger magnitude of an elongation of N−H compared C-H bond length accompanied by a decrease of its stretching frequency is detected in the N/C−H×××O/N hydrogen bond upon complexation. The SAPT2+ analysis indicates the substantial contribution of attractive electrostatic energy versus the induction and dispersion terms in stabilizing the complexes.

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