Molecular self-assembly: diastereoselective synthesis and structural characterisation of a novel binuclear copper(i) double helicate

Abstract

The reaction of copper(I) trifluoromethane sulfonate, CuCF₃SO₃·0.5C₆H₆ with 2,6-bis[(4S)-4-i-propyl-1,3-oxazoline-2-yl]pyridine S,S-L⁵ in acetonitrile gives the binuclear bis[{2,6-bis[(4S)-4-i-propyl-1,3-oxazoline-2-yl]pyridyl}copper(I)] trifluoromethane sulfonate 1, at room temperature. X-Ray crystallographic analysis shows that the unit cell consists of two distinct chiral binuclear structures, the cations of which represent a double-helical right-handed diastereomer (P), with the helical axis passing through the two copper centres. Spectroscopic data suggest the existence of the double helicate also in solution.