CB[7]- and CB[8]-Based [2]-(Pseudo)rotaxanes with Triphenylphosphonium-Capped Threads: Serendipitous Discovery of a New High-Affinity Binding Motif

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG [Abstract] The synthesis of new triphenylphosphonium-capped cucurbit[7]uril (CB[7])- and cucurbit[8]uril (CB[8])-based [2]rotaxanes was achieved by a simultaneous threading-capping strategy. While the use of CB[7] produced the designed [2]rotaxane, attempts to obtain the CB[8] analogue were unsuccessful due to the unexpected strong interaction found between the host and the phosphonium caps leading to pseudo-heteroternary host–guest complexes. This unusual binding motif has been extensively studied experimentally, with results in good agreement with those obtained by dispersion-corrected DFT methods. This research was supported by the Agencia Estatal de Investigación (PID2019-105272GB-I00) and Xunta de Galicia (ED431C 2018/39). I.N. thanks the MECD (FPU program). The authors are indebted to Centro de Supercomputación de Galicia (CESGA) for providing the computer facilities Xunta de Galicia; ED431C 2018/39