Anion interactions with (polypyridyl)ruthenium complexes, and their importance in the cation-exchange chromatographic separation of stereoisomers of dinuclear species †

Probing the Transition between the Localised (Class II) and Localised‐to‐Delocalised (Class II–III) Regimes by Using Intervalence Charge‐Transfer Solvatochromism in a Series of Mixed‐Valence Dinuclear Ruthenium Complexes

“…[17][18][19][20] The diastereoisomers exhibit several attractive features over dinuclear complexes that have been employed to date for IVCT studies: 1) the complexes are structurally rigid and 2) the dimensions of the clefts may be systematically modified through stereochemical variation, bridging ligand modification, or the judicious positioning of substituents on the terminal polypyridyl ligands, while maintaining the identity and coordination environments of the component metal centres. A further important feature is the extensive tuning of the ground-state electronic properties of the mixed-valence complexes […”

“…[19,20] Each product was dissolved in a minimum volume of acetone and loaded onto a short column of silica gel (dimensions 3 2.5 cm), washed with acetone, water and acetone and eluted with acetone containing 5 % NH 4 PF 6 . Addition of water and removal of the acetone under reduced pressure afforded dark green solids, which were collected by filtration through Celite and washed with diethyl ether (3 5 cm1 H NMR numbering scheme is shown in Figure S1 (in the Supporting Information).…”

The Effective Electron‐Transfer Distance in Dinuclear Ruthenium Complexes Containing the Unsymmetrical Bridging Ligand 3,5‐Bis(2‐pyridyl)‐1,2,4‐triazolate

“…Such difficulties have previously been noted for dinuclear complexes of ruthenium(). [46] The 1 H numbering schemes for the ligands in [{Ru-(bpy) 2 } 2 (µ-bpt -)] 4+ are shown in Figure S1 (Supporting Information; see footnote on the first page of this article) and the assignments of the spectra were performed with the assistance of 1 H COSY spectra. [47] The coordinated bpy ligands exhibited the expected coupling constant values [48] (J 3,4 = 8, J 3,5 = 1.5, J 4,5 = 8, J 4,6 = 1.5 Hz and J 5,6 = 5 Hz) and coupling patterns based on the symmetry requirements of the complexes.…”

Diastereoisomeric dinuclear ruthenium complexes of 2,5-di(2-pyridyl)thiazolo[5,4-d]thiazole

“…15 Separation relies on differential interaction of the toluene-4-sulfonate anion with the two diastereoisomeric cations thereby leading to different effective charges for the complexes. 16 In this case the major isomer, which was subsequently shown by X-ray crystallography to be the rac isomer (7rac), eluted first. For analogous complexes it is generally found that the meso isomer elutes first, but we have recently found that with bridging ligands such as 5, that laterally displace ("stepped parallel" 14b ) the metal centres relative to the bridging plane, the reverse is sometimes the case.…”

“…Cyclic voltammetry of each of the isomers shows two closely spaced reversible one-electron oxidations. The small difference in oxidation potentials (∆E ox = 70-90mV) for each isomer indicates relatively weak metal-metal interactions, as measured by the comproportionation constants (K c = [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] . Thus, ligand 5, with its N,S-mixed heteroatom five-membered ring system, does not facilitate the strong inter-metal interactions observed for ligands 3 and 4.…”