Chiral 3D coordination polymers consisting of achiral terpyridyl precursors: from spontaneous resolution to enantioenriched induction

A pair of enantiomers of three-dimensional (3D) chiral coordination polymers (CCPs) were successfully constructed by using achiral components 4,2':6',4''-terpyridyl precursors and Cu(2+) through spontaneous resolution (1 a). By utilising feeding controlled chiral-templated induction and chiral auxiliary behaviour of optically pure camphor sulfonate (CSA), the enantioenriched (1 b-P and 1 b-M) and CSA captured (1 c-P and 1 c-M) CCPs were successfully synthesised, respectively. The chiral information of the corresponding products was confirmed by X-ray single crystal diffraction and solid-state CD spectra. Meanwhile, the formation processes of 1 b-P and 1 b-M were monitored through solution CD spectra, UV/Vis spectra and ESI-TOF MS. Based on these results, a reasonable chiral-templated induction mechanism of forming 1 b-P and 1 b-M was proposed.