title: The effect of intermolecular hydrogen bonding on the fluorescence of a bimetallic platinum complex.
abstract: The bimetallic platinum complexes are known as unique building blocks and arewidely utilized in the coordination-driven self-assembly of functionalized supramolecular metallacycles. Hence, photophysical study of the bimetallic platinum complexes will be very helpful for the understanding on the optical properties and further applications of coordination-driven self-assembled supramolecular metallacycles. Herein, we report steady-state and time-resolved spectroscopic experiments as well as quantum chemistry calculations to investigate the significant intermolecular hydrogen bonding effects on the intramolecular charge transfer (ICT) fluorescence of a bimetallic platinum compound 4,4'-bis(trans-Pt(PEt(3))(2)OTf)benzophenone 3 in solution. We demonstrated that the fluorescent state of compound 3 can be assigned as a metal-to-ligand charge transfer (MLCT) state. Moreover, it was observed that the formation of intermolecular hydrogen bonds can effectively lengthen the fluorescence lifetime of 3 in alcoholic solvents compared with that in hexane solvent. At the same time, the electronically excited states of 3 in solution are definitely changed by intermolecular hydrogen bonding interactions. As a consequence, we propose a new fluorescence modulation mechanism by hydrogen bonding to explain different fluorescence emissions of 3 in hydrogen-bonding solvents and nonhydrogen-bonding solvents.
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
authors.forename: Guang-Jiu
authors.initials: GJ
authors.lastname: Zhao
authors.forename: Brian H
authors.initials: BH
authors.lastname: Northrop
authors.forename: Ke-Li
authors.initials: KL
authors.lastname: Han
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Stang
mesh_terms: D001577:Benzophenones / Q000737:chemistry; D006860:Hydrogen Bonding; D009942:Organometallic Compounds / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics
chemical_list: D001577:Benzophenones; D009942:Organometallic Compounds; D012997:Solvents; D010984:Platinum; C047723:benzophenone