title: Brightly luminescent Pt(II) pincer complexes with a sterically demanding carboranyl-phenylpyridine ligand: a new material class for diverse optoelectronic applications.
abstract: A series of three Pt(II) complexes with a doubly cyclometalating terdentate ligand L1, L1H2 = 3,6-bis(p-anizolyl)-2-carboranyl-pyridine, and diethyl sulfide (1), triphenylphosphine (2), and t-butylisonitrile (3) as ancillary ligands were synthesized. X-ray diffraction studies of 1 and 2 show a coordination of the L1 ligand in a C-N-C mode in which the bulky and rigid o-carborane fragment is cyclometalated via a C atom. Importantly, no close intermolecular Pt-Pt contacts occur with this ligand type. The new Pt(II) pincer complexes display very high luminescence quantum yields at decay times of several tens of μs even in solution under ambient conditions. On the basis of the low-temperature (T = 1.3 K) emission decay behavior, the emission is assigned to a ligand centered triplet excited state (3)LC with small (1,3)MLCT admixtures. Because the phosphorescence is effectively quenched by molecular oxygen, optical sensors operating in a wide range of oxygen pressure can be developed. Owing to the very high luminescence quantum yields, the new materials might also become attractive as emitter materials for diverse optoelectronic applications.
authors.affiliation: Ural Federal University , Department of Organic Chemistry, Mira-st. 28, 620002 Ekaterinburg, Russian Federation.
authors.forename: Anton M
authors.initials: AM
authors.lastname: Prokhorov
authors.forename: Thomas
authors.initials: T
authors.lastname: Hofbeck
authors.forename: Rafal
authors.initials: R
authors.lastname: Czerwieniec
authors.forename: Alfiya F
authors.initials: AF
authors.lastname: Suleymanova
authors.forename: Dmitry N
authors.initials: DN
authors.lastname: Kozhevnikov
authors.forename: Hartmut
authors.initials: H
authors.lastname: Yersin
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D008163:Luminescent Measurements; D015394:Molecular Structure; D009944:Organoplatinum Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D055668:Photochemical Processes; D011725:Pyridines / Q000737:chemistry*; D011789:Quantum Theory; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001896:Boron Compounds; D008024:Ligands; D009944:Organoplatinum Compounds; D011725:Pyridines