Unfolding of the [Cu₂(1,3-bis(9-methyl-1,10-phenanthrolin-2-yl)propane)₂]²⁺Helicate. Coupling of the Chlorocarbon Dehalogenation to the Unfolding Process

Abstract

A new helical dimeric copper(I) complex [Cu(2)(mphenpr)(2)](ClO(4))(2) where mphenpr is 1,3-bis(9-methyl-1,10-phenanthrolin-2-yl)propane has been prepared and characterized by X-ray crystallography and NMR. In the solid state, the metal centers are 6.42 A apart, and the electronic structure has been investigated with use of density functional theory (DFT) calculations. In solution the dimer equilibrates with a monomeric form [Cu(mphenpr)](ClO(4)), and the mechanism of unfolding of the dimer into monomer has been studied. In the presence of CCl(4), formation of the monomer is coupled to the reductive dehalogenation of the halocarbon. The mechanism of this process has been probed by the study of short-lived potential reaction intermediates using fast kinetic pulse radiolysis techniques and comparisons with DFT calculations. The copper(II) product [Cu(mphenpr)Cl](ClO(4)) and an analogue [Cu(mphenpr)](ClO(4))(2) have been isolated and characterized by X-ray crystallography.

Hydroxyl Radical Generation and DNA Nuclease Activity: A Mechanistic Study Based on a Surface‐Immobilized Copper Thioether Clip‐Phen Derivative

“…In fact, the 1 H NMR spectrum in deareated C 2 D 2 Cl 4 presented in Figure S6 of the Supporting Information shows a complex pattern of signals, in addition to paramagnetic residues due to the fast oxidation of the cuprous complex in solution, likely by traces of oxygen. The aliphatic (3.3–3.7 ppm) and some aromatic (7.6–7.8 ppm) protons show a diastereotopic behavior in solution because of the formation of a helical bimetallic complex, which coexists with the monometallic complex in a dynamic equilibrium, as reported for several copper(I) compounds containing rigid bidentate ligands …”

Steric and Electronic Factors Affecting the Conformation of Bimetallic CuI Complexes: Effect of the Aliphatic Spacer of Tetracoordinating Schiff‐Base Ligands

“…Previously,w eh ave reportedt he effect of an odd aliphatic spacer on the stability of ab imetallic copper(I) helicate, [Cu I (mphenpr)] 2 2 + ,i nw hich the ligand mphenpr consists of two phenanthroline units linked by ap ropylb ridge. [33,34] According to the odd-even rule, the propyl spacer should promote the formation of am esocate. However,a so bserved in solid and solution phases,t he helical conformationi sf avored by stabilization involving p-p-interactionsb etween adjacent phenanthroline groups (closest interplanar distance 3.37 ).…”

“…Previously, we have reported the effect of an odd aliphatic spacer on the stability of a bimetallic copper(I) helicate, [Cu I (mphenpr)] 2 2+ , in which the ligand mphenpr consists of two phenanthroline units linked by a propyl bridge . According to the odd–even rule, the propyl spacer should promote the formation of a mesocate.…”

Reduction of N2 to NH3 catalyzed by a Keggin-type polyoxometalate-supported dual-atom catalyst

“…68–70 The standard 6-31G(d) basis set was used for the main group elements and the pseudopotential basis set LANL2DZ was selected for all metal atoms. 71,72 Frequency calculations were made to determine the characteristics of all stationary points as energy minima or transition states on the corresponding potential energy surfaces by the correct number of imaginary frequencies. The geometry optimization was full and without any symmetry constraints.…”