Synthesis, Characterization, and Catalytic Activities of A Nickel(II) Monoamido-Tetradentate Complex: Evidence For Ni -Oxo and Ni -Oxo Species.

A new mononuclear nickel(II) complex, [Ni (dpaq)Cl] (1), containing a tetradentate monoamido ligand, dpaq (dpaq=2-[bis(pyridin-2-ylmethyl)amino]-N-(quinolin-8-yl)acetamide), has been synthesized and characterized by IR spectroscopy, elemental analysis, and UV/Vis spectroscopy. The structure of the nickel complex has been determined by X-ray crystallography. This nonheme Ni complex 1 catalyzed the epoxidation reaction of a wide range of olefins with meta-chloroperoxybenzoic acid (m-CPBA) under mild conditions.

A discrete {Co4(μ3-OH)4}(4+) cluster with an oxygen-rich coordination environment as a catalyst for the epoxidation of various olefins.

Using the sterically hindered terphenyl-based carboxylate, the tetrameric Co(ii) complex [Co4(μ3-OH)4(μ-O2CAr(4F-Ph))2(μ-OTf)2(Py)4] () with an asymmetric cubane-type core has been synthesized and fully characterized by X-ray diffraction, UV-vis spectroscopy, and electron paramagnetic resonance spectroscopy. Interestingly, the cubane-type cobalt cluster with 3-chloroperoxybenzoic acid as the oxidant was found to be very effective in the epoxidation of a variety of olefins, including terminal olefins which are more challenging targeting substrates. Moreover, this catalytic system showed a fast reaction rate and high epoxide yields under mild conditions.