01056nas a2200181   4500008004100000245011300041210006900154260000800223300001600231490000700247520038800254100001800642700002400660700002200684700001800706700002200724856012800746       2016                        eng d00aElectrocatalytic water oxidation by a molecular cobalt complex through a high valent cobalt oxo intermediate0 aElectrocatalytic water oxidation by a molecular cobalt complex t  cAUG  a11787-117900 v523 aBiuret-modified tetraamidomacrocyclic cobalt complex [Co-III-bTAML]- is shown to catalyze electrochemical water oxidation at basic pH leading to the formation of O-2. Electrochemical and spectroscopic studies indicate a high valent cobalt oxo intermediate isoelectronic to Co-V(O) as the active oxidant. The kinetic isotope effect of 8.63 indicates an atom proton transfer mechanism.1 aDas, Debasree1 aPattanayak, Santanu1 aSingh, Kundan, K.1 aGarai, Bikash1 aGupta, Sayam, Sen  uhttps://library.ncl.res.in/content/electrocatalytic-water-oxidation-molecular-cobalt-complex-through-high-valent-cobalt-oxo01993nas a2200205   4500008004100000022001400041245006700055210006700122260000800189300001000197490000800207520135400215100002101569700001801590700001801608700002301626700001901649700002201668856009701690       2022                        eng d  a1359-664000aElectrocatalytic alcohol oxidation by a molecular iron complex0 aElectrocatalytic alcohol oxidation by a molecular iron complex  cMAY  a42-570 v2343 a<p>
	An efficient electrochemical method for the selective oxidation of alcohols to their corresponding aldehydes/ketones using a biomimetic iron complex, [(bTAML)Fe-III-OH2](-), as the redox mediator in an undivided electrochemical cell with inexpensive carbon and nickel electrodes using water as an oxygen source is reported. The substrate scope also includes alcohols that contain O and N heteroatoms in the scaffold, which are well tolerated under these reaction conditions. Mechanistic studies show the involvement of a high-valent Fe-V(O) species, [(bTAML)Fe-V(O)](-), formed via PCET (overall 2H(+)/2e(-)) from [(bTAML)Fe-III-OH2](-) at 0.77 V (vs. Fc(+)/Fc). Moreover, electrokinetic studies of the oxidation of C-H bonds indicate a second-order reaction, with the C-H abstraction by Fe-V(O) being the rate-determining step. The overall mechanism, studied using linear free energy relationships and radical clocks, indicates a ``net hydride'' transfer, leading to the oxidation of the alcohol to the corresponding aldehyde or ketone. When the reaction was carried out at pH &gt; 11, the reaction could be carried out at a similar to 500 mV lower potential than that at pH 8, albeit with reduced reaction rates. The reactive intermediate involved at pH &gt; 11 is the corresponding one-electron oxidized [(bTAML)Fe-IV(O)](2-) species.</p>
1 aKuiry, Himangshu1 aDas, Debasree1 aDas, Soumadip1 aChakraborty, Soham1 aChandra, Bittu1 aGupta, Sayam, Sen  uhttps://library.ncl.res.in/content/electrocatalytic-alcohol-oxidation-molecular-iron-complex