CONFORMATION AND PACKING ANALYSIS OF POLYSACCHARIDES AND DERIVATIVES .6. DETAILED REFINEMENT OF TRI-O-ETHYLAMYLOSE-SOLVENT COMPLEXES TEA-CL AND TEAL-DCML

The crystal structures of two tri-O-ethylamylose polymorphs, with chloroform (TEA1-C1) and with dichloromethane (TEA1-DCM1) inside the crystal lattice, have been investigated. Both polymorphs are very similar: they crystallize in an orthorhombic unit cell, space group P212121. The chain conformations are 43 helices with a 4.005 Å rise per residue. The X-ray diffraction diagrams can be indexed with a = 16.76 ± 0.02 A ̊, b = 14.28 ± 0.03 A ̊, c = 16.02 ± 0.03 A ̊ (fibre repeat) for TEA-C1 and a = 16.52 ± 0.02 A ̊, b = 13.95 ± 0.02 A ̊, c = 16.02 ± 0.02 A ̊ (fibre repeat) for TEA1-DCM1. Two chains pass through the unit cell, and four solvent molecules are located in the interstitial spaces of the unit cell with close Cl ... O interatomic contact distances. © 1979.