Electrochemical and spectral properties of hexacoordinate polypyridyl silicon complexes

Recent advances in hexacoordinate silicon with pyridine-containing ligands: Chemistry and emerging applications

“…[50] The redox activity of polypyridylsilicon(IV) complexes were explored using cyclic voltammetry. [45] [Si(bpy)3](PF6)4 can be reduced electrochemically with up to 6 electrons ( Table 5). The first three one-electron reduction waves were reversible on the electrochemical time scale.…”

Exploring the structure and redox activity of hexacoordinate bis(bipyridyl)silicon(IV) complexes

“…For example, the potential for the first reduction of 5 is approximately 1.1 V less negative than that of Ru(bpy) 2 (cat) (E 1/2 (0/À1) = À2.16 V versus Fc/Fc + ) or Os(bpy) 2 (cat) (E 1/2 (0/À1) = À2.09 V) [12]. A similar anodic shift (approximately 1.2 V) was observed for the first bipyridine based reduction of Si(bpy) 3 +4 compared to Ru(bpy) 3 +2 [2].…”

“…Our lab has been exploring redox active polypyridylsilicon complexes for electronic and electrochromic applications, demonstrating for example that salts of Si(bpy) 3 +4 and Si(terpy) 2 +4 are well behaved electrochemically, undergoing multiple, reversible one-electron reductions at low reduction potentials [2]. Wieghardt employed DFT calculations and X-ray crystallography to explore the non-innocence of bipyridine ligands in group 14 complexes, and concluded that both of the neutral species Si(bpy) 3 and Si(bpy) 2 possess tetravalent silicon centers with ligand localized reductions [3].…”

Silylation of carbon surfaces through the electrochemical reduction of 2,2′-bipy·R 3 SiCl adducts

“…Later, Kummer and colleagues prepared similar complexes with polychloro silanes, disilanes and disiloxanes [12][13][14]; however, as was pointed out already in first works [11], such adducts could not be formed with monochloro silanes. In contrast to this statement, the electrochemical response of 2,2'-bipyridine in the presence of polyhalo (for SiI 4 , see [15]) and monochlorosilanes R 3 SiCl [16] is quite similar. When a monochlorosilane is added to the solution of bipy (own reversible one-electron reduction at -2.1 V vs. SCE), a new redox system appears at up to 1 V less cathodic potentials (for Et 3 SiCl, E p = -1.17 V) as shown in Figure 1.…”