Source:http://linkedlifedata.com/resource/pubmed/id/17408265
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
9
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pubmed:dateCreated |
2007-4-23
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pubmed:abstractText |
Three new luminescent cyclometalated Pt(II) complexes, [Pt(L)Cl] (1), [Pt2(L-)2] (2), and [Pt(L)(PPh3)]ClO4 (3.ClO4) (where HL=2-phenyl-6-(1H-pyrazol-3-yl)-pyridine), were synthesized and characterized by X-ray crystallography. HL represents a new class of C,N,Npyrazolyl cyclometalating ligands containing a Cphenyl, a Npyridyl, and a Npyrazolyl donor moiety, as well as a 1-pyrazolyl-NH, that can also be available for metal coordination and other chemical interactions. Complex 1 possesses intense intraligand transitions at 275-375 nm and moderately intense metal-to-ligand charge transfer (1MLCT) (dpi(Pt)-->pi*(L)) transition at 380-410 nm. The room temperature solid-state emission lambdamax of 1 occurs at 580 nm and is attributable to the 3MMLCT (dsigma*(Pt)-->pi*(L)) transition. It also displays strong phosphorescence in acetonitrile solutions at room temperature with an emission lambdamax at 514 nm, which can be tentatively assigned to the 3MLCT (pi*(L)-->dpi(Pt)) transition. Complex 1 can be deprotonated in organic solvents to yield a cycloplatinated dimer 2, which shows a relatively high room-temperature luminescent quantum yield of 0.59 in DMF (lambdamax=509 nm). Substitution of the ancillary chloro-ligand in 1 by triphenylphosphine yields 3, which also possesses a good room-temperature luminescent quantum yield of 0.52 in DMF (lambdamax=504 nm) and a better solubility in water. Complex 3 is synthesized to demonstrate the pH dependence of luminescent properties of this C,N,Npyrazolyl cyclometalated Pt(II) system. Such a pH response is ascribable to the protonation/deprotonation of the 1-pyrazolyl-NH on the C,N,Npyrazolyl cyclometalating ligand. The pKa of the 1-pyrazolyl-NH in 3, measured in 1:2 (v/v) aqueous DMF solutions, is approximately 4.0.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Ligands,
http://linkedlifedata.com/resource/pubmed/chemical/Platinum Compounds,
http://linkedlifedata.com/resource/pubmed/chemical/Pyrazoles,
http://linkedlifedata.com/resource/pubmed/chemical/Pyridines,
http://linkedlifedata.com/resource/pubmed/chemical/Solutions
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pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
0020-1669
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
30
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pubmed:volume |
46
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
3603-12
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pubmed:meshHeading |
pubmed-meshheading:17408265-Crystallography, X-Ray,
pubmed-meshheading:17408265-Cyclization,
pubmed-meshheading:17408265-Ligands,
pubmed-meshheading:17408265-Models, Molecular,
pubmed-meshheading:17408265-Molecular Structure,
pubmed-meshheading:17408265-Platinum Compounds,
pubmed-meshheading:17408265-Pyrazoles,
pubmed-meshheading:17408265-Pyridines,
pubmed-meshheading:17408265-Solutions,
pubmed-meshheading:17408265-Spectrum Analysis,
pubmed-meshheading:17408265-Temperature
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pubmed:year |
2007
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pubmed:articleTitle |
Synthesis and spectroscopic studies of cyclometalated Pt(II) complexes containing a functionalized cyclometalating ligand, 2-phenyl-6-(1H-pyrazol-3-yl)-pyridine.
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pubmed:affiliation |
Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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