Linked Life Data

18588270

Source:http://linkedlifedata.com/resource/pubmed/id/18588270

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
29
pubmed:dateCreated
2008-7-17
pubmed:abstractText
Two-photon absorption (TPA) phenomena of a series of single-strand as well as supramolecular self-assembled ladders and prisms of highly conjugated ethyne bridged multiporphyrin dimer, trimer, and star shaped pentamer have been investigated. The ligand mediated self-assembled supramolecular structures were characterized by UV-visible spectroscopy and small- and wide-angle X-ray scattering (SAXS/WAXS) analysis. The TPA cross section values of multiporphyrins increase nonlinearly from approximately 100 to approximately 18000 GM with an increased number of porphyrin units and elongated pi-conjugation length by virtue of charge transfer and excited-state cumulenic configurations. The observed opposite TPA behavior between their supramolecular ladder and prism configurations necessitates the importance of interstrand interactions between the multiporphyrinic units and the overall shape of the assembly. Furthermore, the diminished TPA cross section of the pentamer, despite the increased pi-conjugation resulting from duplex formation suggests that destabilizing the essential functional configurations at the cost of elongation of pi-delocalization pathway must cause unfavorable effects. We have also shown that one- and two-photon allowed energy-levels of linear multiporphyrins are nearly isoenergetic and the latter transition originates exclusively from the extent of pi-delocalization within the molecule. The identical TPA maximum position of the trimer and pentamer indicates that the TPA of the pentamer arises only from its basic trimer unit in spite of its extended two-dimensional pi-conjugation pathway involving five porphyrinic units.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jul
pubmed:issn
1520-5215
pubmed:author
pubmed:issnType
Electronic
pubmed:day
24
pubmed:volume
112
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6563-70
pubmed:year
2008
pubmed:articleTitle
Structure-property relationship for two-photon absorbing multiporphyrins: supramolecular assembly of highly-conjugated multiporphyrinic ladders and prisms.
pubmed:affiliation
Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
pubmed:publicationType
Journal Article