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This work outlines a strategy to combine the use of visible light and confined spaces to form a supramolecular photocatalyst system. Polypyridyl ruthenium(II) complexes [Ru(bpy)3]2+ (bpy = 2,2′-bip...

A series of imidazolinium salts, their six-, seven- and eight-membered homologues, and the related formamidinium salts were prepared, and their pKa values were determined in DMSO at 25 °C using the bracketing indicator method. The effect of each type of structural variation on the acidity of each salt was considered, particularly noting the importance of ring size and the effect of the steric and electronic nature of the N-aryl substituents. The effect of a cyclic structure was also probed through comparing the cyclic systems with the corresponding formamidinium salts, noting the importance of conformational flexibility in the latter cases. Along with allowing choice of appropriate bases for deprotonation of these species, it is anticipated that the data presented will aid in the understanding of the nucleophilicity, and potentially catalytic efficacy, of the corresponding carbenes.

Ruthenium(II) trisdiimine complexes, including polypyridine complexes, have found many applications in the past decade as photoredox catalysts for organic transformations. This review article highlights the ability of these types of complexes to undergo photo-induced ligand exchange reactions, especially by anions. This property has been well known for decades but is generally overlooked when exploring reaction conditions for photoredox reactions. The demonstrated ability of common ruthenium(II) complexes to undergo ligand exchange reactions is surveyed, the accepted means of predicting this stability, as well as possible future directions in photoredox catalysis, is discussed.

A family of five easily prepared tridentate monoanionic 2,5-dipyridyl-3-(R1)-4-(R2)-pyrrolide anions (dppR1,R2)−, varying in the nature of the R1 and R2 substituents [R1, R2 = CN, Ph; CO2Et, CO2Et; CO2Me, 4-Py; CO2Me, Me; Me, Me], has been used to generate the analogous family of neutral [CoII(dppR1,R2)2] complexes, two of which are structurally characterized at both 100 and 298 K. Both the oxidation and spin states of these complexes can be switched in response to appropriate external stimuli. All complexes, except [CoII(dppMe,Me)2], exhibit gradual spin crossover (SCO) in the solid state, and SCO activity is observed for three complexes in CDCl3 solution. The cobalt(II) centers in the low spin (LS) complexes are Jahn–Teller tetragonally compressed along the pyrrolide-Co-pyrrolide axis. The complexes in their high spin (HS) states are more distorted than in the LS states, as is also usually the case for SCO active iron(II) complexes. The reversible CoIII/II redox potentials are predictably tuned by choic...

The efficient and reliable microwave synthesis of [Ru(bpy)3](PF6)2, [Ru(phen)3](PF6)2, [Ru(bpy)2(phen)](PF6)2, and [Ru(phen)2(bpy)](PF6)2 are reported (where bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline). Solution NMR data are presented, including detailed 2D experiments.

We have designed linear metalloligands which contain a central photoactive [Ru(N∧N)3]2+ unit bordered by peripheral metal binding sites. The combination of these metalloligands with Zn(II) and Fe(II) ions leads to heterometallic tetrahedral cages, which were studied by NMR spectroscopy, mass spectrometry, and photophysical methods. Like the parent metalloligands, the cages remain emissive in solution. This approach allows direct incorporation of the favorable properties of ruthenium(II) polypyridyl complexes into larger self-assembled structures.

A series of enantiopure ruthenium(II) polypyridyl complexes are reported that feature pendant pyridyl groups suitable for building larger self-assembled structures. The complexes are characterized in detail in solution using NMR spectroscopy, cyclic voltammetry, and photophysical methods and in the solid state using single-crystal X-ray crystallography. The complexes are luminescent, displaying long excited-state lifetimes that are quenched when the pendant pyridyl groups are protonated. Reaction with cadmium(II) ions results in the formation of a mixed-metal one-dimensional coordination polymer, which was characterized by single-crystal X-ray crystallography.