Structural diversity of homochiral cadmium-camphorates with 2,2′-bipyridine

Homochiral framework materials are of current interest due to their potential applications in asymmetric catalysis and enantioselective separation. Four new Cd(II) camphorates (1–4) with 2,2′-bipyridine ligand (= 2,2′-bipy) are successfully synthesized and show distinct structural features. Such rich Cd-cam-2,2′-bipy system is composed of four compounds, [Cd(d-cam)(2,2′-bipy)(DMF)]n (1), [Cd(d-cam)(2,2′-bipy)(H2O)]n (2), [Cd2(d-cam)2(2,2′-bipy)2]n (3) and [Cd2Cu2(d-cam)4(2,2′-bipy)2]n·4nH2O (4), which are obtained under different conditions. Both compounds 1 and 2 show infinite homochiral Cd-camphorate chain, while compounds 3 and 4 exhibit homochiral layered structures based on different dinuclear units. The results demonstrate the rich coordination chemistry of the enantiopure d-camphorate ligand and the structural diversity of metal-camphorate compounds.

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► New homochiral Cd(II)-camphorate coordination polymers with 2,2′-bipyridine ligand.
► Structural diversity of homochiral Cd(II)-camphorates determined by synthetic conditions.
► Rich Cd(II)-camphorates system with chain-like structures and layered structures.