Synthesis, Electrochemistry, and Excited-State Properties of Three Ru(II) Quaterpyridine Complexes.

The complexes [Ru(qpy)LL'](2+) (qpy = 2,2':6',2″:6″,2‴-quaterpyridine), with 1: L = acetonitrile, L'= chloride; 2: L = L'= acetonitrile; and 3: L = L'= vinylpyridine, have been prepared from [Ru(qpy) (Cl)2]. Their absorption spectra in CH3CN exhibit broad metal-to-ligand charge transfer (MLCT) absorptions arising from overlapping (1)A1 → (1)MLCT transitions. Photoluminescence is not observed at room temperature, but all three are weakly emissive in 4:1 ethanol/methanol glasses at 77 K with broad, featureless emissions observed between 600 and 1000 nm consistent with MLCT phosphorescence.

Formation of iridium(IV) oxide (IrOX) films by electroflocculation.

Films of iridium(IV) oxide nanoparticles (IrOX NPs) become deposited on electrodes from nanoparticle solutions when potentials sufficient to initiate water oxidation are applied. Evidence is given that the film-forming mechanism is nanoparticle precipitation. Following an induction period during which a significant amount of charge is passed, the NPs begin to deposit as islands.