Molecular Devices: Brakes, Rotors, Sensors, and Balances and the Non-Covalent Interactions That Power Them

In 1959, Richard Feynman's famous lecture 'There's Plenty of Room at the Bottom' predicted the advent of nano- and molecular-scale machines. Only recently has Feynman's vision begun to be realized with the syntheses of molecular devices that convert chemical or kinetic energy into controlled mechanical molecular motions. In this thesis, several types of molecular devices will be presented that can function as molecular switches, rotors, sensors, and measurement devices. Each device is based on an N-arylimide rotor framework. Restricted rotation around the single bond 'axle' of the N-arylimide groups leads to the formation of distinct rotamers. The devices are designed to control the ratios and the rates of interconversion of the rotamers using external stimuli such as guest molecules, protons, solvent, and non-covalent interactions. The molecular device systems highlighted in this thesis include: 1) two guest-accelerated molecular rotors, 2) a colorimetric charge transfer molecular sensor, and 3) the application of these molecular devices to measure weak non-covalent interactions. Specifically, highlighted will be the versatile design and syntheses, the ability to interface and control molecular-scale motion, and the application of these devices to important problems.