Novel Materials Comprised of Molecular Springs: Synthetic Approaches to Bridgehead-Substituted Bicyclo[n.n.n]alkane Monomers

Abstract

Materials and polymer chemistry are a huge part of our everyday world. From replacing hazardous glass materials with shatterproof plastic to wet and leaky diapers being upgraded with super-absorbent polyacrylate, scientists are constantly searching for novel materials and innovative applications. A new mode of action to manifest bulk elastic properties through the inherent flexibility of a monomer in the polymer main chain rather than through traditional chain entanglements has previously been proposed. A linear polymer containing saturated macrobicyclic monomers, termed molecular springs, has never been made in large enough quantities to be synthesized and studied. A scalable synthetic approach to produce mass quantities of out,out-dimethyl bicyclo[8.8.8]hexacosane-1,10-dicarboxylate has been accomplished. The synthesis features ring-closing metathesis to form monocyclic and bicyclic rings, and an atypical solvent for hydrogenation reactions, dichloromethane. The crystal structure of the bicycle revealed the interbridgehead distance to be 6.20 Å with 170º and 173º bridgehead angles exhibiting a colinear arrangement of bridgehead substituents.