Effects of the reaction cavity on metastable optical excitation in ruthenium-sulfur dioxide complexes

We report photoexcited-state crystal structures for two new members of the [Ru(SO(2))(NH(3))(4)X]Y family: 1:X=H(2)O, Y=(perpendicular to)-camphorsulfonate(2); 2:X=isonicotinamide, Y=tosylate(2). The excited states are metastable at 100 K, with a photoconversion fraction of 11.1(7)% achieved in 1, and 22.1(10)% and 26.9(10)% at the two distinct sites in 2. We further show using solid-state density-functional-theory calculations that the excited-state geometries achieved are strongly influenced by the local crystal environment. This result is relevant to attempts to rationally design related photoexcitation systems for optical data-storage applications.