Multinuclear Ag Clusters Sandwiched by Pt Complex Units: Fluxional Behavior and Chiral‐at‐Cluster Photoluminescence
Shinnosuke Horiuchi, Sangjoon Moon, Akitaka Ito, Jacopo Tessarolo, Eri Sakuda, Yasuhiro Arikawa, Guido H. Clever, Keisuke Umakoshi
Angewandte Chemie International Edition
Multinuclear Ag clusters sandwiched by Pt complex units were synthesized and characterized by single crystal X‐ray diffraction and NMR studies. The sandwich‐shaped multinuclear Ag complexes showed two different types of fluxional behavior in solution: rapid slippage of Pt complex units on the Ag3 core and a reversible demetalation–metalation reaction by the treatment with Cl anion and Ag ion, respectively. The Ag2 complex obtained by demetalation reaction from the Ag3 complex displayed U to Z isomerization. These multinuclear Ag complexes showed strong photoluminescence whose properties depended on the existence of Pt→Ag dative bonds. The Ag3 complex, identified to be “chiral‐at‐cluster”, was optically resolved by the formation of a diastereomeric salt with a chiral anion. The enantiomers show circular dichroism (CD) and circularly polarized luminescence (CPL) properties which is unprecedented for compounds based on a chiral sandwich structure. Theoretical calculations allow to understand their structural features and photophysical properties.
sandwich complex, Ag cluster, photoluminescence, fluxional behavior, Pt complex, CPL, circularly polarized luminescence, circular dichroism