Enhanced kinetic inertness in the electrochemical interconversion of Cu(i) double helical to Cu(ii) monomeric complexes
- 3 April 2007
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in New Journal of Chemistry
- Vol. 31 (6) , 927-935
Abstract
Three new ligands made of two iminoquinoline halves separated by an (R,R)-trans-1,2-cyclohexenediyl spacer have been synthesized. These ligands feature –OR functions appended in the 8-positions of the quinoline rings (R = n-alkyl). The ligands display a behaviour similar to that of their analogues that contain unsubstituted quinolines, forming a bistable system with copper. [Cu2L2]2+ helicates are obtained with Cu+ and [CuL]2+ monomers with Cu2+, as shown by UV/Vis titrations, determination of complex formation constants, mass and NMR measurements, and X-ray crystallographic analysis. The OR groups are found to be non-coordinating, but the presence of such substituents on the quinoline rings slows the electrochemical interconversion of [Cu2L2]2+ into [CuL]2+. In particular, oxidation of [Cu2L2]2+ gives a reversible two-step profile in cyclic voltammetry experiments, due to the formation of the Cu2+ helicate [Cu2L2]4+, that does not evolve into [CuL]2+in the CV experiment time scale.Keywords
This publication has 25 references indexed in Scilit:
- Amide-based molecular shuttles (2001-2006)Pure and Applied Chemistry, 2007
- Photo-driven molecular devicesChemical Society Reviews, 2006
- Transition metal complexes as molecular machine prototypesChemical Society Reviews, 2006
- Artificial nanomachines based on interlocked molecular species: recent advancesChemical Society Reviews, 2006
- Cu(ii) and Ni(ii) complexes with dipyridine-containing macrocyclic polyamines with different binding unitsElectronic supplementary information (ESI) available: selected bond lengths [Å] and angles [°] for [CuL1](ClO4)2 (Table S1) and for [NiL1](ClO4)2 (Table S2); absorption spectra of L2 in the presence of Cu(ii) (1 ∶ 1 molar ratio) at different pH values (Fig. S1). See http://www.rsc.org/suppdata/dt/b2/b211904h/Dalton Transactions, 2003
- Monitoring the Redox-Driven Assembly/Disassembly of a Dicopper(I) Helicate with an Auxiliary Fluorescent ProbeInorganic Chemistry, 2003
- Electrochemical Assembling/Disassembling of Helicates with HysteresisInorganic Chemistry, 2001
- Controlling the assembling/disassembling process of metal-containing superstructuresCoordination Chemistry Reviews, 2001
- M and P Double Helical Complexes of Copper(I) with Bis-imino Bis-quinoline Enantiomerically Pure Chiral LigandsInorganic Chemistry, 2000
- Electrochemically Controlled Assembling/Disassembling Processes with a Bis-imine Bis-quinoline Ligand and the CuII/CuI CoupleChemistry – A European Journal, 1999