A phenoxyl radical complex of copper(ii)

Abstract

A new N,O-bidentate pro-ligand (HL), [ML2] (M = Cu, Zn) and [CuL2][BF4] have been synthesised; [CuL2].4DMF and [CuL2][BF4].2CH2Cl2 have been crystallographically and spectroscopically characterised; these data indicate that [CuL2]+ cations are constituted as [Cu2+(L.)(L-)]+ and involve the phenoxyl radical L..

The Geometric and Electronic Structure of a One‐Electron‐Oxidized Nickel(II) Bis(salicylidene)diamine Complex

“…[9] On average, the Ni À O and Ni À N bond lengths both decrease by approximately 0.02 in the oxidized complex, which is opposite to that reported for other structurally characterized metal-phenoxyl radical complexes. [15][16][17] In these complexes, the metal-phenoxyl radical bond lengthens, which is consistent with a decrease of the electron-donating ability of the phenoxyl ligand relative to that of phenolate.…”

“…[11] The improved stability of 1 + under the oxidation conditions reported herein allows the isolation of single crystals of 1 + -SbF 6 À suitable for X-ray structural analysis (Figure 1). [14] Limited structural data exists for phenoxyl radical complexes (Cr III , [15] Cu II , [16] and Zn II [17] ), and this is the first structural characterization of a Ni II -phenoxyl complex. The structures of both 1 and 1 + possess a slightly distorted square-planar geometry about the nickel center with an angle between the N(1)-Ni(1)-O(1) and N(2)-Ni(1)-O(2) planes of 7.68 and 8.68, respectively.…”

Unique Ligand‐Based Oxidative DNA Cleavage by Zinc(II) Complexes of Hpyramol and Hpyrimol

“…www.chemeurj.org likely due to the formation of phenoxyl radical species, and is assigned to the p-p* transition of the phenoxyl radical, as MLCT bands are not occurring for zinc(II) systems. [46,47] Cyclic voltammetry studies: Electrochemical investigations have been performed in order to appraise the role of the non-redox zinc(II) ions on the dehydrogenation of the ligand Hpyramol, and in the formation of the reactive phenoxyl radicals upon coordination. Therefore, the redox behaviour of the free ligands Hpyramol and Hpyrimol, and of the zinc complexes 1-3 and 5 have been investigated by using cyclic voltammetry at room temperature, under argon, in DMF with tetrabutylammonium hexafluorophosphate as the supporting electrolyte and with Ag/AgCl as the reference electrode.…”

Spectroelectrochemical studies of nuclease-active zinc(II) coordination compounds from the ligands Hpyramol and Hpyrimol

“…The intensity of the band observed at 369 nm decreases, and three new shoulders appear at 309, 327 and 438 nm (very slight), while the band at 286 nm progressively shifts to 276 nm during the electrolysis. Similar absorption bands have previously been observed for phenoxyl radicals, and have been attributed to -* transitions [29][30][31][32][33]. It is well known that the formation of a phenoxyl radical is triggered by the attack of the phenoxyl ring by a hydroxyl • OH radical [35][36][37][38], which may take place through at least two different types of oxidation reactions with • OH.…”