title: Circular dichroism spectroscopy study of crystalline-to-amorphous transformation in chiral platinum(II) complexes.
abstract: Two couples of enantiomeric platinum(II) complexes: Pt(L1a )Cl (1a), Pt(L1b )Cl (1b) and Pt(L1a )(C ≡ C - Ph) (2a), Pt(L1b )(C ≡ C - Ph) (2b) (L1a  = (+)-1,3-di-(2-(4,5-pinene)pyridyl)benzene, L1b  = (-)-1,3-di-(2-(4,5-pinene)pyridyl)benzene) were synthesized and characterized. Their absolute configurations were determined by single crystal X-ray diffraction and further verified by circular dichroism (CD) spectra (including electronic circular dichroism [ECD] and vibrational circular dichroism [VCD]). These complexes show interesting mechanoluminescence and/or vapoluminescence due to crystalline-to-amorphous transformation. The crystalline solids, grinding-induced amorphous powders, and vapor-induced amorphous powders of complexes 2a and 2b were comparatively investigated by solid-state ECD and VCD spectra. The transformation from crystalline solids to amorphous powders was accompanied by significant variances of the spectral feature in both ECD and VCD spectra.
authors.affiliation: State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, 210093, Nanjing, People's Republic of China.
authors.forename: Xiao-Peng
authors.initials: XP
authors.lastname: Zhang
authors.forename: Tao
authors.initials: T
authors.lastname: Wu
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Jin-Cheng
authors.initials: JC
authors.lastname: Zhao
authors.forename: Cheng-Hui
authors.initials: CH
authors.lastname: Li
authors.forename: Xiao-Zeng
authors.initials: XZ
authors.lastname: You
keywords: chiral platinum(II) complexes; crystalline-to-amorphous transformation; electronic circular dichroism; vibrational circular dichroism