In control of switching, motion, and organization

Abstract

Nature’s solutions to control organization, switching, and linear and rotary motion are not only extremely elegant, but fascinating if one considers the design and synthesis of artificial molecular systems with such functions in order to add components to the nanotoolbox. The synthesis of chiroptical molecular switches and their application in the control of the organization of liquid crystalline materials is outlined. The first light-driven unidirectional molecular motor is described, and the second-generation motor as well as approaches to control the speed of the rotary motion are discussed.

Serendipitous discovery of a pH-dependant atropisomer bond rotation: Toward a write-protectable chiral molecular switch?☆

“…[19,20] We previously reported the use of immobilized amide atropisomers as imprintable media for carrying out chromatographic separations. [21] In this approach, deracemization of the stationary phase is accomplished by prolonged exposure to a single enantiomer of a guest analyte that is bound with high affinity and high enantioselectivity.…”

A New Tool in Peptide Engineering: A Photoswitchable Stilbene‐type β‐Hairpin Mimetic

“…The combined organic phases were filtered through Celite and MgSO 4 and were then concentrated under reduced pressure, yielding a yellowish oil, containing 1.5 % debrominated byproduct (1.09 g, 4.47 mmol, 68 %). 1 2 Cl 2 ] (52.6 mg, 75.0 mmol), tributylvinyltin (1.1 cm 3 , 3.75 mmol), and LiCl (264.9 mg, 6.30 mmol) in DMF (1.5 cm 3 ) were stirred in a Smith Process Vial at 130 8C for 25 min in the microwave cavity. This procedure was repeated four times, and the combined reaction mixture was then filtered through Celite and extracted with concentrated aqueous NaHCO 3 .…”

“…The organic phase was filtered through CaCO 3 and concentrated under reduced pressure, yielding a yellowish oil (1.15 g, 7.81 mmol, 78 %). 1 [2-(3-Vinylphenyl)ethyl]carbamic acid tert-butyl ester (10): 2-(3-Vinylphenyl)ethylamine (950.0 mg, 6.50 mmol) and di-tert-butyl dicarbonate (1.55 g, 7.10 mmol) were dissolved in CH 2 Cl 2 (20 cm 3 ) and mixed with aqueous potassium carbonate (20 cm 3 , 2.68 g, 19.4 mmol K 2 CO 3 ). The heterogeneous mixture was rigorously stirred for 24 h, and the organic phase was then separated, filtered through MgSO 4 , and concentrated.…”

“…Molecular switches are compounds capable of existing in two or more interconvertible conformational states. [1] External switching between these isomers may be driven by pH change, chemical reactions, complexation, electron transfer, heat, or magnetic or electric fields, or it may be triggered by irradiation at a selected wavelength. [2] The development of such photoresponsive systems is of outstanding interest because they have considerable potential for application as new tools in biomedical engineering.…”

Molecular Rotors as Switches

“…In general, however, a molecular machine should be capable of performing an action leading to a desired function following the input of a signal with a supply of energy. Recent demonstrations of wholly synthetic molecular machines include rotary motors [38,39], a rotary motor displaying net unidirectional motion [40], and linear motors [41,42]. There are reports on the use of rotaxane for crossbar memory in which the linear motion is introduced by redox in solution and in solid support [42].…”