Coordinative helix–helix association of heteroleptic metallosupramolecular helicates†
Abstract
The effective incorporation of well-defined coordination spheres, multiple types of ligands (heteroleptic), and specific assembly modes in a given structure enables the fabrication of simplified coordinative supramolecular bio-mimics. Herein, we report the fabrication of a unique racemic macrocycle via association of metallosupramolecular helicates. A nickel ({Ni4}) cluster-based supramolecular helicate, [Ni8(PDA)6(CDBA)3(DMF)2(H2O)4] (1) (PDA = 2,6-pyridinedicarboxylate, CDBA = 4,4′-carbonyldibenzoate, DMF = dimethylformamide), is successfully synthesized and fully characterized. Dimerization of right (P-) and left (M-) handed helicates of 1via the coordination of metalloligands, [Ni(PDA2)]2− affords {[Ni8(PDA)6(CDBA)3(DMF)4–Ni(PDA)2]2} (2), which can be a representative model of the coordinative helix–helix association of heteroleptic helicates. The solid-state structures of 1 and 2 show high and selective CO2 uptake properties.