Exploiting exciton coupling of ligand radical intervalence charge transfer transitions to tune NIR absorption.

ABSTRACT: We detail the rational design of a series of bimetallic bis-ligand radical Ni salen complexes in which the relative orientation of the ligand radical chromophores provides a mechanism to tune the energy of intense intervalence charge transfer (IVCT) bands in the near infrared (NIR) region. Through a suite of experimental (electrochemistry, electron paramagnetic resonance spectroscopy, UV-vis-NIR spectroscopy) and theoretical (density functional theory) techniques, we demonstrate that bimetallic Ni salen complexes form bis-ligand radicals upon two-electron oxidation, whose NIR absorption energies depend on the geometry imposed in the bis-ligand radical complex. Relative to the oxidized monomer [1˙]+ (E = 4500 cm-1, ε = 27 700 M-1 cm-1), oxidation of the cofacially constrained analogue 2 to

SUBMITTER: Clarke RM 

PROVIDER: S-EPMC5887452 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature