Coordination Polymer-Mediated Molecular Surgery for Precise Interconversion of Dicyclobutane Compounds.

A Cd(II)-based coordination polymer {[Cd(5-F-1,3-bpeb)(FBA)]·HO} () was obtained from Cd(II) salt, 5-fluoro-1,3-bis[2-(4-pyridyl)ethenyl]benzene (5-F-1,3-bpeb), and -fluorobenzoic acid (HFBA). Within the one-dimensional chain structure of , a pair of 5-F-1,3-bpeb was arranged in a face-to-face style. Upon UV irradiation and heat treatment, multiple cyclobutane isomers, including specific monocyclobutanes ( with an -cyclobutane ring in and with an -cyclobutane ring in ) and dicyclobutanes (,-dicyclobutane in , ,-dicyclobutane in , and ,-dicyclobutane in ) were stereoselectively produced. These isomers could be interconverted inside the via cutting/coupling specific bonds, which may be regarded as a type of molecular surgery. The precision of cutting/coupling relied on the thermal stability of the cyclobutanes and the alignment of the reactive alkene centers. The conversion processes were tracked through nuclear magnetic resonance, in situ powder X-ray diffraction, and IR spectroscopy. This approach can be considered as skeletal editing to construct complex organic compounds directly from one precursor.