Synthesis, characterization and dioxygen reactivity of copper(i) complexes with glycoligands

Article abstract of DOI:10.1039/b801109e

A new family of copper(i) complexes with glycoligands containing a central saccharide scaffold, with 2-picolyl ether groups or 2-picolylamine or N-imidazolylamine groups, has been prepared and characterized. For this purpose, the following tetradentate ligands have been synthesized: methyl 2,3-di-O-(2-picolyl)-α-d-lyxofuranoside (L1), 1,5-anhydro-2-deoxy- 3,4-di-O-(2-picolyl)-d-galactitol (L2), 5-(amino-N-(2-salicyl))-5-deoxy-1,2-O- isopropylidene-3-O-(2-picolyl)-α-d-xylofuranose (L3), and 5-(amino-N-(2-salicyl))-5-deoxy-1,2-O-isopropylidene-3-O-(methylimidazol-2-yl) -α-d-xylofuranose (L4). The ligands and the complexes were characterized by elemental analysis, IR, ¹H and ¹³C NMR spectroscopies, ESI mass spectrometry, and cyclic voltammetry. Collaterally with the experimental work, HF-DFT(B3LYP/6-31G*) computations were performed to obtain additional structural information. The Cu(i) complexes are found to be pentacoordinated. The redox properties and the O₂-reactivity of the Cu^ILn complexes have been studied. Reactions of Cu(i) complexes with dioxygen in ethanol yield stable Cu(ii) complexes as confirmed by UV-visible spectrophotometry and EPR spectroscopy. The Royal Society of Chemistry 2008.