Living ring-opening metathesis polymerisation of amino ester functionalised norbornenes

The living ring-opening metathesis polymerisation of norbornene monomers bearing amino ester- residues, using the molybdenum initiators Mo(=CHCMe2Ph)(=N¿2,6-i-Pr2C6H3)(OR)2, {R = CMe3, IA, CMe2CF3, IB, CMe(CF3)2, IC}, is reported. The monomers are derived from reactions of exo- and endo- himic anhydrides with the amino ester hydrochlorides of glycine (1), alanine (2) and isoleucine (3). The optically pure monomers derived from 2 and 3 afford optically active polymers whose optical activities are independent of cis content and molecular weight, indicating the absence of a cooperative effect between chiral centres along the chain. The polymers derived from the exo monomers show a cis-trans vinylene dependence upon the ancillary alkoxide ligands of the initiator with IA giving high trans contents and IC giving high cis. The cis/trans content for the endo polymers show relatively little or no dependence upon the initiator. Poly(exo-1) is exceptional in its ability to incorporate various hydrocarbons in the solid state, including hexane and methane.