Controlled light and temperature induced valence tautomerism in a cobalt-o-dioxolene complex

DOI: 10.1021/acs.inorgchem.1c00638

Authors: Ludmila Leroy (Universidade Federal de Minas Gerais) , Thiago M. Francisco (Universidade Federal de Minas Gerais) , Helena J. Shepherd (University of Kent) , Mark R. Warren (Diamond Light Source) , Lucy K. Saunders (Diamond Light Source) , David A. Shultz (North Carolina State University) , Paul R. Raithby (University of Bath) , Carlos B. Pinheiro (Universidade Federal de Minas Gerais)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Inorganic Chemistry

State: Published (Approved)
Published: June 2021
Diamond Proposal Number(s): 22161 , 18816

Abstract: The mononuclear cobalt complex of 3,5-di-tert-butylcathecolate and cyan-pyridine (Co(diox)2(4-CN-py)2) is a very versatile compound that displays valence tautomerism (VT) in the solid state, which is induced by temperature, light, and hard X-rays, and modulated by solvent in the crystal lattice. In our work, we used single crystal X-ray diffraction as a probe for the light-induced VT in solid state and demonstrate the controlled use of hard X-rays via attenuation to avoid X-ray-induced VT interconversion. We report photoinduced VT in benzene solvated crystals of Co(diox)2(4-CN-py)2 illuminated with blue 450 nm light at 30 K with a very high yield (80%) of metastable hs-CoII states, and we also show evidence of the de-excitation of these photoinduced metastable states using red 660 nm light. Such high-yield light-induced VT had never been experimentally observed in molecular crystals of cobalt tautomers, proving that the 450 nm light illumination is triggering a chain of events that leads to the ls-CoIII to hs-CoII interconversion.

Journal Keywords: Crystals; X-rays; Ligands; Light; Irradiation

Subject Areas: Chemistry, Materials


Instruments: I19-Small Molecule Single Crystal Diffraction

Discipline Tags:

Inorganic Chemistry Molecular Complexes Physical Chemistry Material Sciences Chemistry

Technical Tags:

Diffraction Single Crystal X-ray Diffraction (SXRD)