title: Halogen Bonding to Amplify Luminescence: A Case Study Using a Platinum Cyclometalated Complex.
abstract: The cocrystallization of a weakly luminescent platinum complex [Pt(btpy)(PPh3)Cl](1) (Hbtpy=2-(2benzothienyl)pyridine; emission quantum yield Φem=0.03) with fluorinated bromo- and iodoarenes C6F6-nXn (X=Br, I; n=1, 2) results in the formation of efficient halogen-bonding (XB) interactions Pt-Cl⋅⋅⋅X-R. An up to 22-fold enhancement (Φem =0.65) in the luminescence intensity of the cocrystallized compound is detected, without a substantial change of the emission energy. Based on crystallographic, photophysical, and theoretical investigations, the contribution of the XB donors C6F6-n Xn to the amplification of luminescence intensity is attributed to the enhancement of spin-orbit coupling through the heavy-atom effect, and simultaneously to the suppression of the nonradiative relaxation pathways by increasing the rigidity of the chromophore center.
authors.affiliation: Department of Chemistry, University of Eastern Finland, 80101 Joensuu (Finland).
authors.forename: Vasily V
authors.initials: VV
authors.lastname: Sivchik
authors.affiliation: Department of Chemistry, St. Petersburg State University, Universitetskii pr. 26, 198504 St. Petersburg (Russia).
authors.forename: Anastasia I
authors.initials: AI
authors.lastname: Solomatina
authors.affiliation: Department of Chemistry, National Taiwan University, Taipei 106 (Taiwan).
authors.forename: Yi-Ting
authors.initials: YT
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Aalto University, 00076 Aalto (Finland).
authors.forename: Antti J
authors.initials: AJ
authors.lastname: Karttunen
authors.affiliation: Department of Chemistry, St. Petersburg State University, Universitetskii pr. 26, 198504 St. Petersburg (Russia).
authors.forename: Sergey P
authors.initials: SP
authors.lastname: Tunik
authors.affiliation: Department of Chemistry, National Taiwan University, Taipei 106 (Taiwan). chop@ntu.edu.tw.
authors.forename: Pi-Tai
authors.initials: PT
authors.lastname: Chou
authors.affiliation: Department of Chemistry, University of Eastern Finland, 80101 Joensuu (Finland). igor.koshevoy@uef.fi.
authors.forename: Igor O
authors.initials: IO
authors.lastname: Koshevoy
keywords: crystal engineering; halogen bonding; luminescence; noncovalent interactions; platinum complexes