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Control of Hydrogen Bond Strengths through Push–Pull Effects Triggered by a Remote Reaction Center: A Theoretical Study
Author(s) -
Hwang TsongSong,
Juan Ning,
Chen HsingYin,
Chen ChengChung,
Lo ShihJung,
Chao Ito
Publication year - 2004
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200305514
Subject(s) - hydrogen bond , intramolecular force , chemistry , conjugated system , protonation , hydrogen , acceptor , photochemistry , molecule , stereochemistry , physics , ion , organic chemistry , polymer , condensed matter physics
In an effort to manipulate the bond strengths of hydrogen bonds, we have studied a three‐component chemical system consisting of a reaction center, a conjugated bridge, and a hydrogen‐bonding site. Protonation of the reaction center triggers intramolecular charge transfer from the hydrogen‐bonding site, altering its affinity to bind to an acceptor. Previously, we had found that this communication (signal transduction) between the reaction center and the hydrogen‐bonding site does not necessarily die out with increasing length of the conjugated bridge. In certain cases, this signal transduction is maintained—and even amplified—over long distances (I. Chao, T.‐S. Hwang, Angew. Chem. 2001 , 113 , 2775–2777; Angew. Chem. Int. Ed. 2001 , 40 , 2703–2705). In this study we report the results of an extensive theoretical investigation of this problem to provide insights into this intriguing phenomenon. In the systems we investigated it was found that the push–pull process between the hydrogen‐bonding site and the protonatable reaction center was mediated with the greatest facility by conjugated bridges with low‐lying π and π* orbitals.