Affiliation:
1. Organisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
2. Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
Abstract
AbstractThe solvent and catalyst free thermolysis of biphenylenes at 350 °C furnishes [n]cyclo‐ortho‐phenylenes ([n]COPs, n=4–10) in one step and in high yields. At 400 °C biphenylene dimerizes into tetraphenylene, but lower reaction temperatures produce cyclooligomers. If suitably substituted, the oligomers are soluble and can be isolated and characterized. The products are exclusively cyclic. In the crystalline state, [6]COP displays an alternating crown‐shaped conformation.