Ferrocenylethynyl-terminated azobenzenes: synthesis, electrochemical, and photoisomerization studies.

Ferrocenylethynyl-terminated derivatives 8-12 have been synthesized and characterized by electrochemistry and UV/Vis spectroscopy. The electrochemical and photophysical studies indicate that the electronic communication in ferrocenylethynyl-substituted derivatives is strongly influenced by the substituted position of the ferrocenylethynyl moiety. In situ electrochemical oxidation or chemical oxidation caused a characteristically weak ligand-to-metal charge-transfer (LMCT) band to appear at 700-1000 nm.

Ruthenium(II) bis(terpyridine) electron transfer complexes with alkynyl-ferrocenyl bridges: synthesis, structures, and electrochemical and spectroscopic studies.

Two novel alkynyl-bridged symmetric bis-tridentate ligands 1,2-bis(1'-[4'-(2,2':6',2''-terpyridinyl)]ferrocenyl)ethyne (3a; tpy-Fc-C[triple bond]C-Fc-tpy; Fc = ferrocenyl; tpy = terpyridyl) and 1,4-bis(1'-[4'-(2,2':6',2''-terpyridinyl)]ferrocenyl)-1,3-butadiyne (3b; tpy-Fc-C[triple bond]C-C[triple bond]C-Fc-tpy) and their Ru(2+) complexes 6a and 6b have been synthesized and characterized by cyclic voltammetry, UV-vis and luminescence spectroscopy, and in the case of 3b by single-crystal X-ray diffraction. Cyclic voltammograms of both compounds, 3a and 3b, display two severely overlapping ferrocene-based oxidative peaks with only one reductive peak. The redox behavior of 6a and 6b is dominated by the Ru(2+)/Ru(3+) redox couple (E(1/2) from 1.