Die starke elektronische Delokalisierung in der Titelverbindung (Ru rot, C grün, N blau, O violett), die durch voltammetrische, spektroskopische und magnetische Daten belegt wird, macht sie zu einem molekularen Draht.

Conjugated organometallic compounds diruthenium(6+) bis(alkynyl)s exhibit an unusual structure that is severely distorted from a typical D(4) paddlewheel geometry. Density functional theory calculations suggest that the distortion is driven by both the need for an enlarged highest occupied molecular orbital-lowest unoccupied molecular orbital gap and stronger Ru-Ru bonding through the formation of partial sigma and pi bonds.

The reaction between Ru2(ap)4Cl (ap = 2-anilinopyridinate) and lithiated 1,1′-diethynylferrocene resulted in the expected product 1,1′-[Ru2(ap)4(CC)]2Fc (1) and 1-(Me3SiCC),1′-[Ru2(ap)4(CC)]Fc (2) as a byproduct. X-ray diffraction study of compound 1 revealed an anti arrangement of two Ru2(ap)4(σ-CC) fragments around the Fc unit. Cyclic and differential pulse volatmmetric (CV and DPV) measurements indicated that two Ru2 termini in 1 are weakly coupled in the reduced form. Also reported is the MO analysis of coupling mechanism based on the extended Hückel calculation of 1.

The neutral, monocationic, and dicationic linear trinuclear ruthenium compounds [Ru(3)(dpa)(4)(CN)(2)], [Ru(3)(dpa)(4)(CN)(2)][BF(4)], [Ru(3)(dpa)(4)Cl(2)][BF(4)], and [Ru(3)(dpa)(4)Cl(2)][BF(4)](2) (dpa=the anion of dipyridylamine) have been synthesized and characterized by various spectroscopic techniques. Cyclic voltammetric and spectroelectrochemical studies on the neutral and oxidized compounds are reported. These compounds undergo three successive metal-centered one-electron-transfer processes. X-ray structural studies reveal a symmetrical Ru(3) unit for these compounds. While the metal--metal bond lengths change only slightly, the metal--axial ligand lengths exhibit a significant decrease upon oxidation of the neutral complex. The electronic configuration of the Ru(3) unit changes as the axial chloride ligands are replaced by the stronger "pi-acid" cyanide axial ligands. Magnetic measurements and (1)H NMR spectra indicate that [Ru(3)(dpa)(4)Cl(2)] and [Ru(3)(dpa)(4)Cl(2)][BF(4)](2) are in a spin state of S=0 and [Ru(3)(dpa)(4)Cl(2)][BF(4)], [Ru(3)(dpa)(4)(CN)(2)], and [Ru(3)(dpa)(4)(CN)(2)][BF(4)] are in spin states of S=1/2, 1, and 3/2, respectively. These results are consistent with molecular orbital (MO) calculations.