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Title: Crystallographic studies of some cycloamylose complexes
Author: MacLennan, John M.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1978
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Cycloheptaamylose (CHA) and p-nitroacetanilide (PNA) were co-crystallised to form the 1:1 complex (CHAPNA). Crystals of this complex were examined using X-ray diffraction. The cell dimensions are a = 15.20 A b = 15.67 A, c = 15.70 A, alpha = 87.69, beta = 98.115, gamma = 103.18 with Z = 2 and the space group is P1. 5500 unique reflections were measured from Weissenberg photographs. The structure was solved by the trial and error rotation and translation of a model of the structure in the position and orientation that had been indicated by the Patterson map. Inspection of the difference Fourier map after initial refinement located both PNA molecules. The structure was further refined using blocked matrix refinement to an R-factor of 0.132 for all the data. The PNA molecule is included in the cavity. The CHA molecules are hydrogen bonded together to form a dimer which has approximately twofold symmetry. Attempts were made to solve both the CHA complex with water using trial and error methods and the CHA iodine complex using Patterson maps to locate the iodine and then conventional heavy atom techniques. Preliminary crystallographic investigations of the CHA complexes with p-bromoacetanilide, which was isomorphous with CHAPNA, and m-nitroacetanilide are reported. Structural data for CHA complexes were reviewed, and a new classification scheme for these complexes was proposed. The binding between the guest and the host molecule was examined, and a modified torsion angle index (MTAI) was defined to simplify the analysis of the distortion of the CHA molecule.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available