Low-energy optical switching of SO2 linkage isomerisation in single crystals of a ruthenium-based coordination complex.

Change log
Sylvester, Sven O 

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.

3402 Inorganic Chemistry, 34 Chemical Sciences, 7 Affordable and Clean Energy
Journal Title
Conference Name
Journal ISSN
Volume Title
Royal Society of Chemistry (RSC)
Royal Academy of Engineering (RAEng) (RCSRF1819\7\10)
STFC (Unknown)
BASF/Royal Academy of Engineering Research Chair in Data-Driven Molecular Engineering of Functional Materials (STFC); 1851 Royal Commission of the Great Exhibition (2014 Fellowship in Design); U.S. Department of Energy (DOE) Office of Science, Office of Basic Energy Sciences (contract no. DE-AC02-06CH11357); Cambridge Commonwealth Trust