title: Potential switchable circularly polarized luminescence from chiral cyclometalated platinum(II) complexes.
abstract: A series of chiral cyclometalated platinum(II) complexes, [Pt((-)-L1)(Dmpi)]Cl ((-)-1), [Pt((+)-L1)(Dmpi)]Cl ((+)-1), [Pt((-)-L2)(Dmpi)]Cl ((-)-2), [Pt((+)-L2)(Dmpi)]Cl ((+)-2), [Pt3((-)-L2)2(Dmpi)4](ClO4)4 ((-)-3), and [Pt3((+)-L2)2(Dmpi)4](ClO4)4 ((+)-3) [(-)-L1 = (-)-4,5-pinene-6'-phenyl-2,2'-bipyridine, (+)-L1 = (+)-4,5-pinene-6'-phenyl-2,2'-bipyridine), (-)-L2 = (-)-1,3-bis(2-(4,5-pinene)pyridyl)benzene, (+)-L2 = (+)-1,3-bis(2-(4,5-pinene)pyridyl)benzene, Dmpi = 2,6-dimethylphenyl isocyanide], have been designed and synthesized. In aqueous solutions, (-)-1 and (+)-1 aggregate into one-dimensional helical chain structures through Pt···Pt, π-π, and hydrophobic-hydrophobic interactions. (-)-3 and (+)-3 represent a novel helical structure with Pt-Pt bonds. The formation of helical structures results in enhanced and distinct chiroptical properties as evidenced by circular dichroism spectra. Circularly polarized luminescence (CPL) was observed from the aggregates of (-)-1 and (+)-1 in water, as well as (-)-3 and (+)-3 in dichloromethane. The CPL activity can be switched reversibly (for (-)-1 and (+)-1) or irreversibly (for (-)-3 and (+)-3) by varying the temperature.
authors.affiliation: State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, People's Republic of China.
authors.forename: Xiao-Peng
authors.initials: XP
authors.lastname: Zhang
authors.forename: Victoria Y
authors.initials: VY
authors.lastname: Chang
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Xiao-Liang
authors.initials: XL
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Yizhi
authors.initials: Y
authors.lastname: Li
authors.forename: Cheng-Hui
authors.initials: CH
authors.lastname: Li
authors.forename: Gilles
authors.initials: G
authors.lastname: Muller
authors.forename: Xiao-Zeng
authors.initials: XZ
authors.lastname: You
mesh_terms: D001555:Benzene Derivatives / Q000737:chemistry*; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D049449:Luminescence; D008163:Luminescent Measurements; D000432:Methanol; D008752:Methylene Chloride; D008968:Molecular Conformation; D009944:Organoplatinum Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D012997:Solvents; D013237:Stereoisomerism; D013696:Temperature; D014867:Water
chemical_list: D001555:Benzene Derivatives; D056831:Coordination Complexes; D009944:Organoplatinum Compounds; D011725:Pyridines; D012997:Solvents; D014867:Water; D008752:Methylene Chloride; D000432:Methanol