Linked Life Data

19458842

Source:http://linkedlifedata.com/resource/pubmed/id/19458842

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2009-5-21
pubmed:abstractText
In the present work, the excited-state double proton transfer (ESDPT) in 2-aminopyridine (2AP)/acid systems has been reconsidered using the combined experimental and theoretical methods. The steady-state absorption and fluorescence spectra of 2AP in different acids, such as formic acid, acetic acid, propionic acid, etc. have been measured. We demonstrated for the first time that the ESDPT reaction can take place between 2AP and all of these acids due to the formation of the intermolecular double hydrogen bonds. Furthermore, the vitally important role of the intermolecular double hydrogen bonds between 2AP and acids for ESDPT reaction has also been confirmed by the disappearance of ESDPT when we add the polar acetonitrile to the 2AP/acids systems. This may be due to that the respective polar solvation of 2AP and acids by the acetonitrile solvent disrupts the formation of intermolecular double hydrogen bonds between 2AP and acids. Moreover, the intermolecular double hydrogen bonds are demonstrated to be significantly strengthened in the electronic excited state of 2AP/acid systems using the time-dependent density functional theory (TDDFT) method. The ESDPT reaction is facilitated by the electronic excited-state hydrogen bond strengthening. In addition, potential energy curves of the electronic excited state along the proton transfer coordinate are also calculated by the TDDFT method. The stepwise mechanism of the ESDPT reaction in the 2AP/acid systems is theoretically reconfirmed, and the concerted mechanism is theoretically excluded. At the same time, the sequence of the double proton transfers is theoretically clarified for the first time using the potential energy curves calculated by TDDFT method.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jun
pubmed:issn
1463-9076
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
11
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4385-90
pubmed:year
2009
pubmed:articleTitle
Reconsideration of the excited-state double proton transfer (ESDPT) in 2-aminopyridine/acid systems: role of the intermolecular hydrogen bonding in excited states.
pubmed:affiliation
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, 116023, China.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't