Reduction of Ethylene by Ni^I(cyclam)⁺in Aqueous Solutions

Abstract

Ni(I)(1,4,8,11-tetraazacyclotetradecane)(+) reduces ethylene quantitatively to ethane plus butane (and hexane traces) in neutral aqueous solutions. A radical mechanism is proposed.

On the mechanism of reduction of maleate and fumarate by NiI(1,4,8,11-tetraazacyclotetradecane)+ in aqueous solutions

“…It should be pointed out that [Ni(I)L] + is reproduced in both reactions(20) and(21), and thus returned to the reaction mechanism. It should also be noted that the intermediate [Ni(II)L-CH(CO 2 -)CH 2 (CO 2 -)]is created in reaction (18) at 50% yield of the initial [Ni(I)L] + concentration.…”

“…The disappearance of Ni(I)L + in the presence of maleate is much faster than in the presence of ethylene, the kinetics in the latter system were too slow to be studied in the linear accelerator. 20 At the observation wavelength of 340 nm three distinct timeresolved reactions are observed (Fig. 1 and 2).…”

“…In a previous paper it was reported that Ni I (1,4,8,11tetraazacyclotetradecane) + , Ni(I)L + , reduces ethylene quantitatively to ethane plus butane (and hexane traces) in neutral aqueous solutions. 20 The following radical mechanism of reduction of ethylene was proposed. The first step probably involves the formation of a d→p* complex between the low valent Ni(I)L + complex and the ethylene:…”

On the mechanism of reduction of maleate by a Co(I) complex with a macrocylic ligand in aqueous solutions

“…* complexes with low valent transition metal ions. In a previous paper, it was reported that Ni I (1,4,8,11-tetraazacyclotetradecane) þ , NiðIÞL þ 1 , reduces ethylene quantitatively to ethane plus butane (and hexane traces) in neutral aqueous solutions [33]. A radical mechanism of reduction of ethylene was proposed.…”