title: A Platinum-Dithiolene Monoanionic Salt Exhibiting Multiproperties, Including Room-Temperature Proton-Dependent Solution Luminescence.
abstract: The platinum salt C[PtL2], where C = [(R)-Ph(Me)HC*-NMe3](+) and [PtL2](-) = radical monoanion based on [4', 5': 5, 6][1, 4]dithiino[2,3-b]quinoxaline-1',3'dithiolato, shows a variety of properties both in solution and in the solid state thanks to the electronic and/or structural features of the ligand. The complex crystallizes in the chiral space group P1 due to the presence of the enantiopure cation (R)-Ph(Me)HC*-NMe3(+), and it shows paramagnetic behavior relatable to the [PtL2](-) radical monoanion. This anionic complex is redox active and shows a strong near-infrared absorbance peak at 1085 nm tunable with the oxidation state of the complex. This complex exhibits a proton-dependent emission at 572 nm in solution at room temperature. The excitation band corresponds to the HOMO-1 (π-orbitals of the S2C2S2 system) → LUMO (π-orbitals of the quinoxaline and benzene-like moieties) transition suggesting that emission is mainly ligand centered in character. The luminescent properties are highly unusual, since the emission falls well above the energy of the lowest energy absorption (anti-Kasha behavior). Joint experimental and density functional theory (DFT) and time-dependent DFT studies are discussed to provide a satisfactory structure/property relationship.
authors.forename: Salahuddin
authors.initials: S
authors.lastname: Attar
authors.forename: Davide
authors.initials: D
authors.lastname: Espa
authors.forename: Flavia
authors.initials: F
authors.lastname: Artizzu
authors.forename: M Laura
authors.initials: ML
authors.lastname: Mercuri
authors.forename: Angela
authors.initials: A
authors.lastname: Serpe
authors.forename: Elisa
authors.initials: E
authors.lastname: Sessini
authors.forename: Giorgio
authors.initials: G
authors.lastname: Concas
authors.forename: Francesco
authors.initials: F
authors.lastname: Congiu
authors.affiliation: Dipartimento di Chimica, Università di Parma , Parco Area delle Scienze 17A, I43124 Parma, Italy.
authors.forename: Luciano
authors.initials: L
authors.lastname: Marchiò
authors.forename: Paola
authors.initials: P
authors.lastname: Deplano