Synthesis, spectroscopic and electrochemical properties of mononuclear and dinuclear bis(bipy)ruthenium(ii) complexes containing dimethoxyphenyl(pyridin-2-yl)-1,2,4-triazole ligands

Abstract

and electrochemical properties of mononuclear and dinuclear bis(bipy)ruthenium(II) complexes containing dimethoxyphenyl(pyridin-2-yl)-1,2,4-triazole ligands.

Modulation of Internuclear Communication in Multinuclear Ruthenium(II) Polypyridyl Complexes

“…It would be expected that the binuclear complexes would exhibit twice the number of proton signals due to the presence of diastereoisomers as is the case for 1a 7d , however due to the large separation of the metal centres, no appreciable differences between the spectra of the diastereoisomers are observed. It is clear that the spectra of the mono and binuclear complexes are almost identical, confirming that the binuclear complexes are N2N2 bound, in agreement with related complexes 7,8,12,15 . For 4, 5 and 6b N2N2 coordination was confirmed by 1 H NMR spectroscopy in a similar manner.…”

“…In order to confirm the coordination mode of the complexes, 1 H NMR spectroscopy was employed 12 . Figure 4 shows the 1 H NMR spectra of 6a and its mononuclear analogue m6a.…”

A Recoverable Ruthenium Aqua Complex Supported on Silica Particles: An Efficient Epoxidation Catalyst

“…The complexes exhibit ligand-based p-p*b ands below 350 nm and relatively intense bands above 350 nm, mainly due to dp(Ru)p*(L) metal-to-ligand charge-transfer (MLCT) transitions. [12][13][14] The redoxproperties of complexes 2 and 3 were determined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) experiments (see Figures S5 and S6 in the Supporting Information). [12][13][14] The redoxproperties of complexes 2 and 3 were determined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) experiments (see Figures S5 and S6 in the Supporting Information).…”

“…[11] The MLCT bands of the Ru chlorido complex are shifted to longer wavelengths relative to the corresponding Ru aqua complex because of the destabilization of the dp(Ru) levels provoked by the anionic chlorido ligand. [12][13][14] The redoxproperties of complexes 2 and 3 were determined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) experiments (see Figures S5 and S6 in the Supporting Information). Chlorido complex 2 ( Figure S5a in the Supporting Information) exhibits aq uasireversible one-electronR u III/II redox wave at E 1/2 % 0.93 Vv ersus SCE;t he analogousc omplex [RuCl(trpy)(pypz-Me)] + [8] reaches the Ru III oxidation state at lower potential( 0.80 V), which evidencest he greatere lectronwithdrawing capacity of the trpy-P-Et ligand with regard to trpy,w hich destabilizes the Ru III oxidation state in complex 2.…”

Oxidative Electrochemical Switching in Dithienylcyclopentenes, Part 1: Effect of Electronic Perturbation on the Efficiency and Direction of Molecular Switching

“…[37] Localisation of the HOMO: methoxyphenyl versus thienyl, and the driving force for ring closure: The driving force for ring opening/closing in the dithienylcyclopentene compounds may be rationalised (at least to a first approximation) by consideration of the relative frontier orbital energies and the effect of varying the bridgehead (the cyclopentene unit) and the C5 substituents. [38] The oxidation potential for the methoxyphenyl unit is typically about 1.2-1.5 V versus SCE, [39] and hence for 2 H the low redox potentials (Table 1) of both the open and closed forms and the close similarity in behaviour of 2 H and 1 H suggest that the redox chemistry does not involve oxidation of the methoxyphenyl unit. It is clear from both electrochemical and spectroelectrochemical studies that for 1 H and 2 H the redox properties are dominated by the dithienylethene unit.…”