title: Photophysical Enhancement of Triplet Emitters by Coordination-Driven Self-Assembly.
abstract: The quantum yields of organic fluorophores used as donors in coordination-driven self-assembly often suffer from the heavy atom effect of nearby metal sites. Here, the role of intersystem crossing from a deactivating process to one that delivers emissive triplet states was reversed. A phosphorescent trans bis-N-heterocyclic carbene platinum(II) compound, Pt(dhim)2(C≡C-4-py)2(D1; dhim=1,3-dihexyl-2-H-imidazol-2-ylidene), was used along with other linear donors 4,4'-bipyridine (D2) and 1,4-bis(4-pyridyl ethynyl)benzene (D3) in self-assembly reactions with Pt(dtbpy)X2acceptors (dtbpy=4,4'-di-tert-butyl-2,2'-bipyridine) to afford three metallacycles. Photophysical investigations revealed that, although the building blocks used to construct M1 have relatively low quantum yields (Φ=1.2 and <1 % for D1 and 2, respectively), the metallacycle has a quantum yield of 14 %. This increase reflects a change in radiative rate constant from 3.6×104s-1for D1 to 2.1×105s-1for M1.
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York, 14260, USA.
authors.forename: Yuzhen
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York, 14260, USA.
authors.forename: Cressa Ria P
authors.initials: CR
authors.lastname: Fulong
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York, 14260, USA.
authors.forename: Cory E
authors.initials: CE
authors.lastname: Hauke
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York, 14260, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Crawley
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York, 14260, USA.
authors.forename: Alan E
authors.initials: AE
authors.lastname: Friedman
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York, 14260, USA.
authors.forename: Timothy R
authors.identifier: http://orcid.org/0000-0002-7668-8089
authors.initials: TR
authors.lastname: Cook
keywords: coordination-driven self-assembly; metallacycle; phosphorescence; photophysics; platinum