Quantum chemical exploration of the intramolecular hydrogen bond interaction in 2-thiazol-2-yl-phenol and 2-benzothiazol-2-yl-phenol in the context of excited-state intramolecular proton transfer: A focus on the covalency in hydrogen bond

Author(s):  
Bijan Kumar Paul ◽  
Aniruddha Ganguly ◽  
Nikhil Guchhait
2015 ◽  
Vol 14 (6) ◽  
pp. 1147-1162
Author(s):  
Bijan K. Paul ◽  
Narayani Ghosh ◽  
Ramakanta Mondal ◽  
Saptarshi Mukherjee

The photophysics and partial covalency in the intramolecular H-bond of3,5-DISAare addressed from spectroscopic and advanced quantum chemical computational approaches.


2019 ◽  
Vol 17 (38) ◽  
pp. 8690-8694 ◽  
Author(s):  
Minglei Yuan ◽  
Ifenna I. Mbaezue ◽  
Zhi Zhou ◽  
Filip Topic ◽  
Youla S. Tsantrizos

An intramolecular H-bond in the Brønsted acid OttoPhosa I accelerates the reaction and increases enantioselectivity for the transfer hydrogenation of quinolines.


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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