Proton‐Coupled Redox Chemistry, Oxidative Reactivity, and Electronic Characterization of Aqua‐, Hydroxo‐, and Oxo‐Triruthenium Clusters

Abstract

The pH-dependent electronic and electrochemical properties of a series of triangular μ 3 -oxo-centered trinuclear clusters of the type [Ru 3 O(Ac) 6 (py) 2 (OH x )] n (Ac = acetate; py = pyridine; x = 0, 1, or 2; where the formal oxidation states on the metal ions range from +II to +IV) have been investigated with emphasis on the elucidation of the successive proton-coupled redox processes spanning the interconvertible aqua-(x = 2), hydroxo-(x = 1), and oxo-(x = 0) forms, from which the complete Pourbaix diagram has been proposed. From the spontaneous slow coupling reaction of the monomeric cluster in its

A Convergent Approach for the Generation of Dendrimers Containing the ­[Ru3O(CH3COO)6] Electroactive Core

“…This behaviour and the well-known [15,16] dependence of the [Ru 3 O] properties on ligands parameters such as pK a and E L can provide the basis to plan, by the appropriate choice of ligands, dendrimeric structures having a gradient of electrochemical potential. This is particularly relevant for catalytic pur-poses [20,21] or for mimicking biologic systems such as the mitochondrial or photosynthetic electron-transport chain. [1][2][3][4][5] …”

Spectroscopic and electrochemical behavior of a supramolecular tetrapyridylporphyrin encompassing four terpyridine(oxalate)chloridoruthenium(II) complexes and its use in nitrite sensors

“…S3), the tetraruthenated porphyrin exhibits two irreversible processes at E 0 = À0.81 V versus NHE and À1.04 V versus NHE, that can be assigned to the first and second reduction of porphyrin (porphyrin 0/À1 and porphyrin 1/À2 ). The redox process observed at E 0 = À1.34 V versus NHE can be assigned to the first reduction process of the terpy ligand (Cl-terpy 0/À1 ) [31,34]. The electrochemical data were summarized in Table 2, for comparison purposes.…”

Electrocatalytic oxidation of methanol by the [Ru3O(OAc)6(py)2(CH3OH)]3+cluster: improving the metal-ligand electron transfer by accessing the higher oxidation states of a multicentered system

“…[2][3][4][5] A typical case of efficient transition metal electrocatalysis has been reported for the oxidation of 4-substituted-1,2-dimethoxybenzenes, in the presence of iron(II)polyimine catalysts. 6 In this regard, we have investigated the catalytic properties of ruthenium carboxylate clusters of the type [Ru 3 O(OAc) 6 (py) 2 L] n+ in the oxidation of organic compounds 7,8 (OAc = CH 3 CO 2 -, py = pyridine). These clusters exhibit a triangular structure strongly held by a central µ-oxo bridge, as well as by three double carboxylate bridges 9,10 as shown in Figure 1.…”

“…The catalysis was carried out at 65 o C under 40 psi of O 2, during 12-24 h. Recently, we have shown 7,8 that a particularly efficient catalyst in oxygen transfer reactions under mild conditions is the oxo-bridged ruthenium carboxylate cluster [Ru 3 O(OAc) 6 (py) 2 =O], and is rather special, since it exhibits two Ru IV centers for activating the Ru=O bond in oxygen transfer reactions. As a matter of fact, it exhibits excellent catalytic activity in the oxidation of benzyl alcohol to benzyl aldehyde, and even in the catalytic oxidation of hydrocarbons.…”