The influence of steric effects of proton-transfer equilibrium in intramolecular hydrogen bonds

1990 ◽  
Vol 221 ◽  
pp. 109-114 ◽  
Author(s):  
Maria Rospenk
2019 ◽  
Vol 58 (2) ◽  
pp. 154-162
Author(s):  
Rita S. Elias ◽  
Bahjat A. Saeed ◽  
Fadhil S. Kamounah ◽  
Fritz Duus ◽  
Poul Erik Hansen

RSC Advances ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 5134-5140 ◽  
Author(s):  
Chaozheng Li ◽  
Yonggang Yang ◽  
Chi Ma ◽  
Yufang Liu

The electronic density redistributes and it migrates in opposite directions for HBO when compared to those of 5A-HBO and 6A-HBO. The amino group in the HBO framework can change the behavior of the intramolecular hydrogen bonds.


1988 ◽  
Vol 53 (3) ◽  
pp. 633-637 ◽  
Author(s):  
Stanislav Sámek ◽  
Tomáš Trnka ◽  
Miloslav Černý

Relative rate constants for reaction of 1,6 : 2,3- and 1,6 : 3,4-dianhydro-β-D-hexapyranoses with iodomethane in acetonitrile in the presence of silver oxide were measured. Their values, ranging from 1 to 8.6 were interpreted on the basis of polar and steric effects and intramolecular hydrogen bonds.


2018 ◽  
Vol 96 (3) ◽  
pp. 351-357 ◽  
Author(s):  
Dapeng Yang ◽  
Min Jia ◽  
Xiaoyan Song ◽  
Qiaoli Zhang

In this work, the excited state dynamical behavior of a novel π-conjugated dye 2,2′-((5-(2-(4-methoxyphenyl)ethenyl)-benzene-1,1-diyl)-bis-(nitrilomethylylidene)-diphenol) (C1) has been investigated. Two intramolecular hydrogen bonds of C1 are tested to pre-existing in the ground state via AIM and reduced density gradient. Using a time-dependent density functional theory (TDDFT) method, it has been substantiated that the intramolecular hydrogen bonds of C1 should be strengthened in the S1 state via analyzing fundamental bond length, bond angles, and corresponding infrared vibrational modes. The most obvious variation of these two hydrogen bonds is the O4–H5···N6 bond, which might play important roles in excited state behavior for the C1 system. Furthermore, based on electronic excitation, charge transfer could occur. Just due to this kind of charge re-distribution, two hydrogen bonds should be tighter in the first excited state, which is consistent with the variation of hydrogen bond lengths. Thus, the phenomenon of charge transfer is reasonable evidence for confirming the occurrence of the excited state proton transfer (ESPT) process in the S1 state. Our theoretically constructed potential energy surfaces of C1 show that excited state single proton transfer should occur along with the O4–H5···N6 hydrogen bond rather than the O1–H2···N3 bond. We not only clarify the ESIPT mechanism for C1 but put forward new affiliation and explain a previous experiment successfully.


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