Fixation of CO with Epoxides Catalyzed by Pincer-Type Azo-Aromatic Complexes of Cobalt as Catalysts.

Employing a series of azo-aromatic pincer-type cobalt(II) complexes, -, and an imine-based cobalt complex, , a highly efficient catalytic protocol for the cycloaddition of CO with epoxides at low pressure of CO is reported. The electron-withdrawing group-substituted ligands containing complexes and were most efficient. The catalytic protocol with involved a synergistic participation of an azo-aromatic catalyst (0.

Ligand redox controlled amine dehydrogenation and imine hemilability in singlet diradical azo-aromatic Ni(II) complexes: characterization of the electron transfer series of azo-imine complexes of Ni(II).

Herein, using azo-amine (H2L) and azo-imine (L) ligands, singlet diradical Ni(II) complexes [1] and [2] were synthesized from Ni(0)(COD) in THF. In separate reactions, homoleptic Ni complexes, [3a]2+-[3c]2+, were synthesized from [Ni(HO)](ClO) and L, respectively. All these complexes were characterized thoroughly.

Completely -Phenylene Bridged -Cyclophane: A Missing Link in the Phenylene Bridge -Cyclophane Family.

Unprecedented types of metal-free complete -phenylene bridged -cyclophanes ( and ) have been synthesized via sequential palladium-catalyzed Buchwald-Hartwig -arylation reactions. These cyclophanes may be considered as aromatic analogues of aliphatic group-spaced -macrocycles. These have been characterized fully using physicochemical characterization techniques and finally by single crystal X-ray structure determination.