Preparation, Characterization, Redox Properties, and UV−Vis−NIR Spectra of Binuclear Ruthenium Complexes [{(Phtpy)(PPh3)2Ru}2{C⋮C−(CHCH)m−C⋮C}]n+ (Phtpy = 4‘-phenyl-2,2‘:6‘,2‘ ‘-terpyridine)