Catalytic-Type Excited-State N-H Proton-Transfer Reaction in 7-Aminoquinoline and Its Derivatives.

Autor: Chang KH; Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan) (R.O.C., Liu YH; Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan) (R.O.C., Liu JC; Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan) (R.O.C., Peng YC; Department of Medical Applied Chemistry, Chung Shan Medical University and, Department of Medical Education, Chung Shan Medical University Hospital, Taichung, 40201, Taiwan) (R.O.C., Yang YH; Department of Medical Applied Chemistry, Chung Shan Medical University and, Department of Medical Education, Chung Shan Medical University Hospital, Taichung, 40201, Taiwan) (R.O.C., Li ZB; Department of Medical Applied Chemistry, Chung Shan Medical University and, Department of Medical Education, Chung Shan Medical University Hospital, Taichung, 40201, Taiwan) (R.O.C., Jheng RH; Department of Medical Applied Chemistry, Chung Shan Medical University and, Department of Medical Education, Chung Shan Medical University Hospital, Taichung, 40201, Taiwan) (R.O.C., Chao CM; Department of Medical Applied Chemistry, Chung Shan Medical University and, Department of Medical Education, Chung Shan Medical University Hospital, Taichung, 40201, Taiwan) (R.O.C., Liu KM; Department of Medical Applied Chemistry, Chung Shan Medical University and, Department of Medical Education, Chung Shan Medical University Hospital, Taichung, 40201, Taiwan) (R.O.C., Chou PT; Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan) (R.O.C.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2019 Nov 22; Vol. 25 (65), pp. 14972-14982. Date of Electronic Publication: 2019 Oct 25.
DOI: 10.1002/chem.201904027
Abstrakt: 7-Aminoquinoline (7AQ) and various amino derivatives thereof (-NHR) have been strategically designed and synthesized to study their excited-state proton-transfer (ESPT) properties. Due to the large separation between the proton donor -NHR and the acceptor -N- site, ESPT in 7AQ derivatives, if available, should proceed under protic solvent catalysis. ESPT is found to be influenced by the acidity of -NHR and the basicity of the proton-acceptor -N- in the quinoline moiety. The latter is varied by the resonance effect at the quinoline -N- site induced by the -NHR substituent. For those 7AQ derivatives undergoing ESPT, increased quinoline basicity results in a faster rate of ESPT, implying that proton donation from methanol to the quinoline moiety may serve as a key step in the process. Our studies also indicate the existence of an equilibrium between cis and trans arrangements of -NHR in terms of its hydrogen-bond (H-bond) configuration with methanol, whereby only the cis-H-bonded form undergoes methanol-assisted ESPT. With one exception, the interconversion between cis and trans configurations is much faster than the rate of ESPT, yielding amino-type (normal form) and imine-type (proton-transfer tautomer) emissions with distinct relaxation dynamics.
(© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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