Non-covalent molecular tweezer/guest complexation with Pt(ii)⋯Pt(ii) metal–metal interactions: toward intelligent photocatalytic materials

Abstract

A new organoplatinum(II) molecular tweezer with a stimuli-responsive 2,2′:6′,2′′-terpyridine spacer has been synthesized, which undergoes “U”- to “W”-shaped conformational transition upon adding Zn²⁺ ions. The molecular tweezer receptor displays a high binding affinity toward the complementary guests, with the implementation of Pt(II)⋯Pt(II) metal–metal interactions for the non-covalent tweezering systems. MMLCT absorbance simultaneously emerges in the visible-light region (470–620 nm), which can be sensitized by O₂ and thereby utilized for photo-catalyzed reactions in organic and aqueous media. Moreover, temporally “on-demand” photo-catalytic efficiency can be accomplished, via the successive addition of Zn(OTf)₂ and a competitive ligand to the supramolecular tweezering photosensitizers. Hence, the current study opens up new avenues toward intelligent photocatalytic materials via elaborate supramolecular engineering.