Polymers and oligomers with transverse aromatic groups and tightly controlled chain conformations

Abstract

Anionic ring-opening polymerisation of spiro[cyclopropane-1,9′-fluorene] with fluorenyl anion as initiator yields polymers 1 with chains which are essentially all-anti and have transversely-oriented fluorenyl groups, as shown by strong upfield shifts for the mid-chain methylene and 1,8-fluorenyl protons; synthetic routes to some specific oligomers are also reported.