High binding yet accelerated guest rotation within a cucurbit[7]uril complex. Toward paramagnetic gyroscopes and rolling nanomachines †

G Casano (1) , F Poulhès (1) , T K Tran (1) , Mehmet Menaf Ayhan (1, 2) , H Karoui (1) , D Siri (1) , A Gaudel-Siri (1) , A Rockenbauer (3) , G Jeschke (4) , D Bardelang (1) , P Tordo (1) , O Ouari (1)

1 ICR - Institut de Chimie Radicalaire
2 Department of chemistry - Gebze Technical University
3 Department of Physics [Budapest]
4 Laboratory of Physical Chemistry

The (15-oxo-3,7,11-triazadispiro[5.1.5.3]hexadec-7-yl)oxidanyl, a bis-spiropiperidinium nitroxide derived from TEMPONE, can be included in cucurbit[7]uril to form a strong (K a ∼ 2 × 10 5 M −1) CB[7]@bPTO complex. EPR and MS spectra, DFT calculations, and unparalleled increased resistance (a factor of ∼10 3) toward ascorbic acid reduction show evidence of deep inclusion of bPTO inside CB[7]. The unusual shape of the CB[7]@bPTO EPR spectrum can be explained by an anisotropic Brownian rotational diffusion, the global tumbling of the complex being slower than rotation of bPTO around its " long molecular axis " inside CB[7]. The CB[7] (stator) with the encapsulated bPTO (rotator) behaves as a supramolecular para-magnetic rotor with increased rotational speed of the rotator that has great potential for advanced nano-scale machines requiring wheels such as cucurbiturils with virtually no friction between the wheel and the axle for optimum wheel rotation (i.e. nanopulleys and nanocars).

Mots clés: gyroscope; oxidanyl

Domaines: Chimie

G Casano, F Poulhès, T K Tran, Mehmet Menaf Ayhan, H Karoui, et al.. High binding yet accelerated guest rotation within a cucurbit[7]uril complex. Toward paramagnetic gyroscopes and rolling nanomachines †. Nanoscale, 2015, 7 (28), pp.12143-12150. ⟨10.1039/c5nr03288a⟩. ⟨hal-01259347⟩