Decorating Diruthenium Compounds with Frechet 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-Cl2Ph)F)(4-m)(DMBA-4-C2H)(m)Cl with m = 1 and 2, and D(3,5-Cl2Ph)F and DMBA-4-C2H as N,N'-bis(3,5-didiloro-phenyl)formamidinate and N,N'-dimethyl-4-ethynylbenzarnidinate, respectively. The resultant Ru-2(D(3,5-Cl2Ph)F)(4-m)(DMBA-D-n)(m)Cl compounds were further functionalized by the axial ligand displacement of Cl by -C2Ph to yield new compounds Ru-2(D(3,5-Cl2Ph)F)(4-m)(DMBA-D-n)(m)(C2Ph)(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. Densityfunctional 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.