The Crystal and Molecular Structure of N-(4-n octyloxybenzylidene)-4'-butylaniline (80.4) and the Crystal-Smectic G Transition

Abstract

The crystal and molecular structure of N-(4-n octyloxybenzylidene)-4'-butylaniline (80.4), C₂₅H₃₅NO, has been determined at room temperature partially by direct methods and completed by subsequent Fourier synthesis. The crystals belong to the triclinic system with space group P1, a=5.452(3), b=7.948(4), c=27.356(4) Å, α=90.83(2), β=86.43(2) and γ=108.14(2)[ddot] with two molecules per unit cell. The structure consists of interdigitated sheets of molecules with alternate sheets in an head-to-tail configuration and displaced in the direction of the long molecular axes so as to give interdigitation of alkyl tails and of cores plus alkoxy tails. It is shown that the superficially very different structure of the homologue 40.8 may be described in a similar way. In neither case is there a close relation with the structure of the liquid crystal phase found in melting.