Decorating diruthenium compounds with Fréchet dendrons via the click reaction.

A series of dendronized-Ru(2) compounds were prepared using the Cu(I)-catalyzed 1,3-dipolar cycloaddition (click reaction) between the terminal azides of azidopoly(benzyl ether) dendrons ([D(n)]-N(3), n = 0-3) and Ru(2) units bearing one or two terminal ethynes, Ru(2)(D(3,5-Cl(2)Ph)F)(4-m)(DMBA-4-C(2)H)(m)Cl with m = 1 and 2, and D(3,5-Cl(2)Ph)F and DMBA-4-C(2)H as N,N'-bis(3,5-dichloro-phenyl)formamidinate and N,N'-dimethyl-4-ethynylbenzamidinate, respectively. The resultant Ru(2)(D(3,5-Cl(2)Ph)F)(4-m)(DMBA-D(n))(m)Cl compounds were further functionalized by the axial ligand displacement of Cl by -C(2)Ph to yield new compounds Ru(2)(D(3,5-Cl(2)Ph)F)(4-m)(DMBA-D(n))(m)(C(2)Ph)(2) (where m = 1 and 2; n = 0 and 1). All Ru(2) compounds reported herein were analyzed via mass spectrometry, voltammetry, and UV-visible and fluorescence spectroscopy. Density-functional theory (DFT) calculations were performed on a model compound to gain more insight into the molecular orbital energy levels possibly associated with the photophysical data obtained and presented herein.