An unprecedented photodimerization of an anthraceno[2.2]paracyclophane

Abstract

Dedicated to our friend and colleague, Jim Coxon, on the occasion of his 65 th birthday Abstract Octafluoro[2.2](1,4)anthraceno-paracyclophane slowly undergoes a clean photodimerization upon being exposed, in solution, to fluorescent light. X-ray crystal analysis of this photodimer indicated that the aromaticity of the anthracene ring directly involved in the paracyclophane system was observed to be destroyed by forming a cyclobutane ring, with the two molecules linked to each other in a head to tail fashion.

Synthesis and modification of octafluoro[2.2]paracyclophane (parylene AF4)

“…The structure is unusual in that the anthracene ring directly involved in the cyclophane system breaks aromaticity to form a cyclobutane ring. 38 Scheme 16 The preparation of substituted AF4 analogues by an S RN 1 pathway.…”

Unsymmetrical Photodimerization of a 9-Aminomethylanthracene in the Crystalline Salt

“…Upon irradiation, anthracenes generally yield symmetric head-to-tail or head-to-head dimers, that is, 9,10:10‘,9‘ or 9,10:9‘,10‘ [4+4] cycloadducts, respectively. , In addition, they sometimes undergo unsymmerical photodimerization to give 9,10:4‘,1‘ or 9,10:1‘,4‘ [4+4] cycloadducts 9,10 and 9,10:1‘,2‘ [4+2] cycloadducts. 4a,b Very recently, formation of a novel 1,2:2‘,1‘ [2+2] cycloadduct has been reported . In the solid state, however, only the symmetric [4+4] dimerization reactions have been reported to date .…”