Wires Based on Metal Complexes

Influence of Multiple Protonation on the Initial Excitation in a Black Dye

“…By incorporation of Ru centers in supramolecular assemblies, devices capable of vectorial electron and energy transfer can be designed. The interest in such assemblies is twofold: (i) They play an important role in investigating the nature of electron- and energy-transfer processes − and (ii) they are valuable candidates for a wide variety of light-harvesting applications as, e.g., in photocatalysis − and as sensitizers in dye-sensitized solar cells (DSSCs). − Furthermore, Ru(II) polypyridine complexes can be employed as sensors − and in molecular wires. − In these applications the environmental conditions have to be monitored closely because the pH value of the solvent may influence the electronic and optical properties of the complexes by protonation/deprotonation of basic/acidic positions in the ligand sphere. This dependence can be exploited for pH sensing or switching, as environmental properties have a strong impact on the functionality by influencing, e.g., electron and energy transfer rates and redox potentials. ,− For example, in Ru complexes containing imidazole ligands the pH-dependent properties were studied: in imidazo[4,5- f ][1,10]phenanthroline coordinating complexes, the protonation state of the imidazole ring has been shown to modify the luminescence behavior, and solvent pH modulates the electron transfer in imidazo4,5- f ][1,10]phenanthroline-bridged supramolecular assemblies and across an electrode interface. ,,,− Another group of complexes with pH-dependent properties coordinates benzimidazole ligands: ,− ,,, in binuclear benzimidazole-bridged complexes metal–metal interactions can be switched o...…”

Preparation of Dinuclear Vinylidene Complexes and Their New Deprotonation Reactions

“…Therefore the synthesis and reactivity of these unsaturated ligands, particularly the ruthenium vinylidene system, are nevertheless under active investigation . While the reactivity of mononuclear vinylidene complexes finds their applications, studies on dinuclear metal complexes with highly unsaturated carbon-rich ligands such as acetylide, vinylidene, and allenylidene have focused more or less on the electron-transfer phenomena mediated by a conjugated bridging ligand polyaromatics, polyynes, − polyenes, or polypyridyl complexes 17 have been used for prospective applications such as molecular wires, dyes, unusual magnetic 20 or nonlinear optical 21 properties, and quantum cell automata .…”

“…While the reactivity of mononuclear vinylidene complexes finds their applications, studies on dinuclear metal complexes with highly unsaturated carbon-rich ligands such as acetylide, vinylidene, and allenylidene have focused more or less on the electron-transfer phenomena mediated by a conjugated bridging ligand polyaromatics, polyynes, − polyenes, or polypyridyl complexes 17 have been used for prospective applications such as molecular wires, dyes, unusual magnetic 20 or nonlinear optical 21 properties, and quantum cell automata . We previously reported the synthesis of a number of mononuclear ruthenium cyclopropenyl complexes 23 by a deprotonation reaction of readily accessible ruthenium vinylidene complexes containing a −CH 2 R group bound to C β of the vinylidene ligand.…”

Deprotonation of Iron Vinylidene Complexes Containing a dppe Ligand

“…The formation of metal vinylidene intermediates has been used to promote new carbon−carbon bond forming reactions by the addition of carbon centers to the electrophilic vinylidene carbon atom. The reactivity of ruthenium vinylidene complexes finds their applications broadly in synthetic chemistry; however, studies on iron complexes with highly unsaturated carbon-rich ligands such as acetylide, vinylidene, and allenylidene are relatively scarce …”