Water splitting into hydrogen and oxygen by non-traditional redox inactive zinc selenolate electrocatalyst

The development of alternative energy sources is the utmost priority of the developing society. Unlike many prior homogenous electrocatalysts that rely on the change in an oxidation state of metal center and or electrochemically active ligand, the synthesized novel bimetallic zinc selenolate complex consisting of redox inactive zinc metal ion and catalytically inactive ligand catalyzes the electrochemical oxygen evolution from the water with rate constant 7.28 s-1 at onset potential 1.028 V vs. NHE. On the other hand, the hydrogen evolution reaction proceeds with 47.32 s-1 observed rate constant and -0.256 V onset potential vs. NHE. DFT computations and control experiments suggest that the redox chemistry at selenium center, Lewis acidity, and cooperativity effect of two zinc atoms facilitate the electrochemical oxidation and reduction of water into oxygen and hydrogen, respectively.

Coordination of tridentate ligands to SmI2: cooperativity and incremental effect on reduction potential and on reactivity

The effect of coordination of a series of tridentate ligands (TDLs) on various features of SmI2 was determined. The TDLs used in this study were diethylene glycol (OOO), diethanolamine (ONO), 2-(2-Aminoethoxy) ethanol (OON), N-(2-Hydroxyethyl) ethylene diamine (ONN) and glycerol (GLY). Of special interest is the effect of these additives on the reduction potential of SmI2. The cyclic voltammograms of the TDLs with nitrogen at the binding sites display simultaneously several peaks, each corresponding to a different coordination level of SmI2, enabling determination of three equilibrium constants. The results are in concert with electronic spectra of SmI2 complexes with these ligands. The second and third equilibrium constants were found to be larger than the first, demonstrating the cooperativity effect. Moreover, the incremental effect of each moiety on the reduction potential of SmI2 was determined. Regarding reactivity of SmI2, excessive coordination of some ligands is shown to have an adverse effect.

Cooperativity effect of the π⋯π interaction between drug and DNA on intercalative binding induced by H-bonds: a QM/QTAIM investigation of the curcumin⋯adenine⋯H2O model system

Anti-cooperative effect of π⋯π interactions is the main driving force for the intercalative binding of drug to DNA bases.