A gyroscope-inspired tribenzylamine hemicryptophane provides a vehicle for exploring the structure and properties of multiple p-phenylene rotators within one molecule. The hemicryptophane was synthesized in three steps in good overall yield using mild conditions. Three rotator-forming linkers were cyclized to form a rigid cyclotriveratrylene (CTV) stator framework, which was then closed with an amine. The gyroscope-like molecule was characterized by (1)H NMR and (13)C NMR spectroscopy, and the structure was solved by X-ray crystallography. The rigidity of the two-component CTV-trismethylamine stator was investigated by (1)H variable-temperature (VT) NMR experiments and molecular dynamics simulations. These techniques identified gyration of the three p-phenylene rotators on the millisecond time scale at -93 °C, with more dynamic but still hindered motion at room temperature (27 °C). The activation energy for the p-phenylene rotation was determined to be ~10 kcal mol(-1). Due to the propeller arrangement of the p-phenylenes, their rotation is hindered but not strongly correlated. The compact size, simple synthetic route, and molecular motions of this gyroscope-inspired tribenzylamine hemicryptophane make it an attractive starting point for controlling the direction and coupling of rotators within molecular systems.
A gyroscope-inspired n class="Chemical">tribenzylamine hemicryptophane provides a vehicle for exploring the structure and properties of multiple p-phenylene rotators within one molecule. The hemicryptophane was synthesized in three steps in good overall yield using mild conditions. Three rotator-forming linkers were cyclized to form a rigid cyclotriveratrylene (CTV) stator framework, which was then closed with an amine. The gyroscope-like molecule was characterized by (1)H NMR and (13)C NMR spectroscopy, and the structure was solved by X-ray crystallography. The rigidity of the two-component CTV-trismethylamine stator was investigated by (1)H variable-temperature (VT) NMR experiments and molecular dynamics simulations. These techniques identified gyration of the three p-phenylene rotators on the millisecond time scale at -93 °C, with more dynamic but still hindered motion at room temperature (27 °C). The activation energy for the p-phenylene rotation was determined to be ~10 kcal mol(-1). Due to the propeller arrangement of the p-phenylenes, their rotation is hindered but not strongly correlated. The compact size, simple synthetic route, and molecular motions of this gyroscope-inspired tribenzylamine hemicryptophane make it an attractive starting point for controlling the direction and coupling of rotators within molecular systems.
Authors: S Rice; A W Lin; D Safer; C L Hart; N Naber; B O Carragher; S M Cain; E Pechatnikova; E M Wilson-Kubalek; M Whittaker; E Pate; R Cooke; E W Taylor; R A Milligan; R D Vale Journal: Nature Date: 1999-12-16 Impact factor: 49.962
Authors: M M Spence; S M Rubin; I E Dimitrov; E J Ruiz; D E Wemmer; A Pines; S Q Yao; F Tian; P G Schultz Journal: Proc Natl Acad Sci U S A Date: 2001-09-04 Impact factor: 11.205