To cooperate or not: the role of central functionality in bisthiourea [6]polynorbornane hosts

© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Using fused [n]polynorbornane scaffolds functionalised at each end with a thiourea recognition unit a series of anion hosts of increasing length were constructed. The three longest [6]polynorbornyl hosts possessed central functionality to influence the binding cleft. The functional groups comprised (i) two methyl esters (ii) an unfunctionalised imide to introduce an additional N–H hydrogen-bond donor and (iii) a large p-anisole group to provide negative steric interactions. The family of bisthiourea hosts were evaluated for their ability to bind five aromatic dicarboxylate guests of varying shapes and lengths.