Spectroelectrochemistry and electrocatalytical activity of the bis(2,6-diacetylfurfuryliminepyridine)iron(II) complex

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.…”

“…Drago et al 11,12 have reported on the catalytic oxidation of primary alcohols to aldehydes and of secondary alcohols to ketone by [Ru 3 O(O 2 CR) 6 L 3 ] n+ complexes (R = CH 3 , C 2 H 5 ; L = H 2 O, PPh 3 ). 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.…”

“…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.…”

“…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. A convenient way of obtaining this species is from the [Ru 3 O(OAc) 6 6 (py) 2 (X)] + species, where X = CH 3 OH or DMSO, using oxygen donors such as iodosylbenzene or terc-butilhydroperoxide. In the last case, it should be noticed that a high catalytic activity is only observed in the presence of ligands such as CH 3 OH or (CH 3 ) 2 SO which are easily oxidized, yielding, respectively, the weakly-coordinating formaldehyde or (CH 3 ) 2 SO 2 species.…”

“…In this work, we explored a different catalytic route for the [Ru 3 O(OAc) 6 (py) 2 L] n+ complexes, by focusing on the methanol derivative ( Figure 1c). In contrast to the preceding examples which require oxygen donor species, such as iodosyl benzene and peroxides to promote the catalysis, here we pursued the direct electrocatalytical oxidation of methanol by the cluster species.…”