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Updated: Sep 27, 2025
The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Low-energy optical switching of SO2 linkage isomerisation in single crystals of a ruthenium-based coordination
Jacqueline M Cole1,2,3,4, David J Gosztola4, Sven O Sylvester1
1Cavendish Laboratory, Department of Physics, University of Cambridge J. J. Thomson Avenue Cambridge CB3 0HE UK jmc61@cam.ac.uk.
Abstract:
Single crystals that behave as optical switches are desirable for a wide range of applications, from optical sensors to read-write memory media. A series of ruthenium-based complexes that exhibit optical switching in their single-crystal form via SO2 linkage photoisomerisation are of prospective interest for these technologies. This study explores the optical switching behaviour in one such complex, trans-[Ru(SO2)(NH3)4(H2O)]tosylate2 (1), in terms of its dark and photoinduced crystal structure, as well as its light and thermal decay characteristics, which are deduced by photocrystallography, single-crystal optical absorption spectroscopy and microscopy. Photocrystallography results reveal that a photoisomerisation level of 21.5(5)% is achievable in 1. Biphasic photochromic crystals of 1 were generated by applying green and then red light to switch on and off the η2-(OS)O photoisomer in different regions of a crystal. Heat is a known alternative to its thermal decay, whereby a method is demonstrated that employs optical absorption spectra to determine its activation energy of 30 kJ mol-1. This low-energy barrier to optical switching agrees well with computational studies on 1, as well as being comparable to activation energies in ruthenium-based nitrosyl linkage photoisomers that also display solid-state optical switching.
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