Linked Life Data

18402440

Source:http://linkedlifedata.com/resource/pubmed/id/18402440

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2008-4-29
pubmed:abstractText
The structural effect on the metal-to-ligand charge transfer (MLCT) excited-state lifetime has been investigated in bis-tridentate Ru(II)-polypyridyl complexes based on the terpyridine-like ligands [6-(2,2'-bipyridyl)](2-pyridyl)methane ( 1) and 2-[6-(2,2'-bipyridyl)]-2-(2-pyridyl)propane ( 2). A homoleptic ([Ru( 2) 2] (2+)) and a heteroleptic complex ([Ru(ttpy)( 2)] (2+)) based on the new ligand 2 have been prepared and their photophysical and structural properties studied experimentally and theoretically and compared to the results for the previously reported [Ru( 1) 2] (2+). The excited-state lifetime of the homoleptic Ru (II) complex with the isopropylene-bridged ligand 2 was found to be 50 times shorter than that of the corresponding homoleptic Ru (II) complex of ligand 1, containing a methylene bridge. A comparison of the ground-state geometries of the two homoleptic complexes shows that steric interactions involving the isopropylene bridges make the coordination to the central Ru (II) ion less octahedral in [Ru( 2) 2] (2+) than in [Ru( 1) 2] (2+). Calculations indicate that the structural differences in these complexes influence their ligand field splittings as well as the relative stabilities of the triplet metal-to-ligand charge transfer ( (3)MLCT) and metal-centered ( (3)MC) excited states. The large difference in measured excited-state lifetimes for the two homoleptic Ru (II) complexes is attributed to a strong influence of steric interactions on the ligand field strength, which in turn affects the activation barriers for thermal conversion from (3)MLCT states to short-lived (3)MC states.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0020-1669
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3540-8
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Steric influence on the excited-state lifetimes of ruthenium complexes with bipyridyl-alkanylene-pyridyl ligands.
pubmed:affiliation
Department of Photochemistry and Molecular Science, Uppsala University, Uppsala, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't