Methoxy and Methyl Group Rotation: Solid-State NMR (1) H Spin-Lattice Relaxation, Electronic Structure Calculations, X-ray Diffractometry, and Scanning Electron Microscopy.

We report solid-state (1) H nuclear magnetic resonance (NMR) spin-lattice relaxation experiments, X-ray diffractometry, field-emission scanning electron microscopy, and both single-molecule and cluster ab initio electronic structure calculations on 1-methoxyphenanthrene (1) and 3-methoxyphenanthrene (2) to investigate the rotation of the methoxy groups and their constituent methyl groups. The electronic structure calculations and the (1) H NMR relaxation measurements can be used together to determine barriers for the rotation of a methoxy group and its constituent methyl group and to develop models for the two coupled motions.