Systematic Elucidation of Crystal Structure of Fluorinated Gemini-Type Diamide Derivatives Having Different Lengths with Thixotropic Induced-Ability to Solvents

Abstract Molecular packing structures for Gemini-type diamide derivatives with different linker and fluoroalkyl chain lengths were systematically determined using reciprocal lattice analysis. Diamide derivatives with two fluorocarbons, in which the linker was replaced with one hexamethylene chain and one pentamethylene chain, exhibited hydrogen bonding and crystallinity. Powder X-ray diffraction profiles displayed extremely sharp diffraction peaks like inorganic materials. Small-angle X-ray scattering analysis indicated extended chain crystals (ECCs) in these molecular groups. Reciprocal lattice analysis and high crystallinity allowed for the development of packing models for all compounds used in this study. Fifteen compounds were assigned to nearly orthorhombic and/or slightly distorted monoclinic systems, with one exception. All fluorinated Gemini-type diamides are characterized by a developed c-axis and have an ab-plane area that can accommodate a fluorocarbon chain. These fluorinated Gemini-type diamide derivatives are candidates for additive molecules to induce solvent thixotropy and form crystalline nanofibers through intermolecular hydrogen bonding. A correlation was found between molecular chain packing and crystal growth; a helical growth mode that permits gel formation by incorporating solvent molecules was also confirmed.