Crystal and Molecular Structure of the Laterally Branched Nematogenic Compound 2-n-Nonyl-1,4-phenylene Bis (4-n-octyloxybenzoate)

Abstract

The crystal and molecular structure of the nematogenic compound 2-n-nonyl-1,4-phenylene bis(4-n-octyloxybenzoate) (NPOB) has been determined at – 100°C and at room temperature by X-ray analysis. NPOB crystallizes in space group P1 with two molecules in a unit cell of dimensions (values of the room temperature investigation are given in brackets) a = 9.878(2) [10.165(4)], b = 12.700(3) [12.863(5)], c = 17.830(4) [17.940(6)] Å, α = 71.83(2) [69.65(2)], β = 84.58(2) [85.23(2)], γ = 76.11(2) [75.43(2)]°. The structure was solved by direct methods and refined to an R value of 0.056 [0.108]. The most striking features of the molecular structure are the all-trans-conformation of the laterally branched nonyl group and the nearly parallel alignment of all three alkyl substituents. The crystal structure is characterized by a parallel arrangement and an interlocked packing of the molecules.

Key Words:

• Crystalline mesogens
• X-ray analysis
• molecular structure
• crystal structure
• laterally branched mesogens
• phenylene bis (benzoates)