Bioinspired Diiron Complex with Proton Shuttling and Redox-Active Ligand for Electrocatalytic Hydrogen Evolution.

A μ-oxo diiron complex, featuring the pyridine-2,6-dicarboxamide-based thiazoline-derived redox-active ligand, HL (HL = N,N-bis(4,5-dihydrothiazol-2-yl)pyridine-2,6-dicarboxamide), was synthesized and thoroughly characterized. showed electrocatalytic hydrogen evolution reaction activity in the presence of different organic acids of varying p values in dimethylformamide. Through electrochemical analysis, we found that is a precatalyst that undergoes concerted two-electron reduction to generate an active catalyst.

Phenoxazinyl Zn(II) diradical complex formed redox-driven cyclization of a 2-aminophenol-based NO ligand. Isolation of the modified N ligand radical and its Ni(II) complex.

Aerobic reaction between the pyridine-2-carboxamide-2-aminophenol NO ligand (HL) and Zn(ClO)·6HO in CHCN affords an N phenoxazinylate coordinated Zn(II) complex; its diradical electronic structure [Zn{(L*)˙}] has been elucidated from redox, spectroscopic (UV-VIS and EPR), and magnetic measurements and DFT calculations. Isolation and characterization of the metal-assisted redox-driven modified N ligand as a radical cation (HL*)˙ and its Ni(II)-diradical complex [Ni{(L*)˙}] have also been achieved.

Carbonylative Transformations Using a DMAP-Based Pd-Catalyst through Ex Situ CO Generation.

A phosphine-free, efficient protocol for aminocarbonylation and carbonylative Suzuki-Miyaura coupling has been developed using a novel palladium complex, [Pd(DMAP)(OAc)]. The complex was successfully synthesized using a stoichiometric reaction between Pd(OAc) and DMAP in acetone at room temperature and characterized using single-crystal X-ray analysis. Only 5 mol % catalyst loading was sufficient for effective carbonylative transformations.

CuF/DMAP-Catalyzed N-Vinylation: Scope and Mechanistic Study.

CuF/DMAP has been established as an excellent catalytic system for vinylsilane-promoted N-vinylation of amides and azoles at room temperature without an external fluoride source. A mechanism has been proposed on the basis of the isolation of reactive intermediate [Cu(DMAP)Cl], fluoride ion-assisted transmetalation, and ultraviolet-visible spectroscopic studies. The catalytic efficiency of the synthesized and structurally characterized [Cu(DMAP)Cl] complex has been demonstrated.

Exploiting Coordination Behavior of 7-Azaindole for Mechanistic Investigation of Chan-Lam Coupling and Application to 7-Azaindole Based Pharmacophores.

Multiple spectroscopic techniques, along with single-crystal X-ray analysis, have been used to reveal the detailed structural and electronic information on reaction intermediates of a new copper(II)-DBU catalytic system for the N-arylation of 7-Azaindole. The reaction mixture of Chan-Lam cross-coupling yields two dimeric copper(II)-7-azaindole complexes, including one attached with DBU, prior to adding arylboronic acid and are confirmed structurally and spectroscopically. A suitable mechanism has been proposed using the dimeric copper(II) complex as a catalyst for the coupling reactions.

Ni(II) complexes of a new tetradentate NN'N''O picolinoyl-1,2-phenylenediamide-phenolate redox-active ligand at different redox levels.

Three square planar nickel(II) complexes of a new asymmetric tetradentate redox-active ligand HL in its deprotonated form, at three redox levels, open-shell semiquinonate(1-) radical, quinone(0) and closed-shell dianion of its 2-aminophenolate part, have been synthesized. The coordinated ligand provides N (pyridine) and N' and N'' (carboxamide and 1,2-phenylenediamide, respectively) and O (phenolate) donor sites. Cyclic voltammetry on the parent complex [Ni(L)] 1 in CHCl established a three-membered electron-transfer series (oxidative response at = 0.

Iron(III) Complexes of a Hexadentate Thioether-Appended 2-Aminophenol Ligand: Redox-Driven Spin State Switchover.

A green complex [Fe(L)] (), supported by the deprotonated form of a hexadentate noninnocent redox-active thioether-appended 2-aminophenolate ligand (HL = ,'-bis(2-hydroxy-3,5-di--butylphenyl)-2,2'-diamino(diphenyldithio)ethane), has been synthesized and structurally characterized at 100(2) K and 298(2) K. In CHCl, displays two oxidative and a reductive one-electron redox processes at values of -0.52 and 0.

Assisted π-stacking: a strong synergy between weak interactions.

Synergy between a pair of weak non-covalent interactions can predispose a molecular self-assembly towards a specific pathway. We report assisted π-stacking, a synergy between aromatic π-stacking and n →π* interactions that exhibits an unprecedented strength and thermal stability. Natural bond orbital analysis reveals the non-additive nature of the interaction.