2134/25415 Edwin C. Constable Edwin C. Constable Catherine E. Housecroft Catherine E. Housecroft Peter Kopecky Peter Kopecky Colin J. Martin Colin J. Martin Iain Wright Iain Wright Jennifer A. Zampese Jennifer A. Zampese Investigating the effects of supramolecularly caging ligands in [Ru(bpy)2L]2+ complexes Loughborough University 2017 Ruthenium(II) Bipyridine Crystal structure Electrochemistry Photophysics Absorption spectroscopy Chemical Sciences not elsewhere classified Inorganic Chemistry 2017-06-16 08:24:29 Journal contribution https://repository.lboro.ac.uk/articles/journal_contribution/Investigating_the_effects_of_supramolecularly_caging_ligands_in_Ru_bpy_2L_2_complexes/9395705 Five ruthenium(II) complexes [Ru(bpy)2(L)][PF6] 2 in which L is a 6-substituted 2,2′-bipyridine ligand (ligands 1-3), 5-(2-picoloyl) (4), or an N,O-donor (5) have been prepared and characterized to investigate the role of the intramolecular caging effect of pendant aryl-substituents on the electronic and photophysical properties. The single crystal structures of three of the complexes are reported; in [Ru(bpy)2(L)][PF6]2 where L = 6-(selenophen-2-yl)-2,2′-bipyridine, intra-cation face-to-face π-stacking of the selenophenyl unit and one pyridine ring of an adjacent ligand is observed. In comparison to [Ru(bpy)3]2+, the energy of the MLCT band in [Ru(bpy)2(L)]2+ for L = 1, 2, 3 or 4 is little affected, but a red-shift of 35 nm is observed for [Ru(bpy) 2(5)]2+. The new complexes are emissive at room temperature in degassed MeCN solution; values of λmaxem range from 613 to 689 nm for [Ru(bpy)2(L)]2+ (L = 1 to 5). The electrochemical behaviour of [Ru(bpy)2(L)][PF 6]2 for L = 1, 2 and 3 is similar; in contrast, [Ru(bpy)2(4)][PF6]2 exhibits more complicated ligand-based redox behaviour, and for [Ru(bpy)2(5)][PF 6]2, the presence of the N,O-donor shifts the metal-based oxidation to lower potential. © 2013 Elsevier Ltd. All rights reserved.