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Banerjee, Anuradha (1985) The determination of the crystal structure of four compounds of industrial importance. Doctoral thesis, City of London Polytechnic.
This thesis describes the determination of the crystal structures of one organo-metallic and three organic compounds. Originally the research programme had envisaged working on substances which were obtained by the corrosive action of hydrocarbon oils on metallic lead, but after some considerable time had been spent on attempting to crystallise these rather intractable materials, the research was switched to deal with other compounds of industrial importance which were more readily available in the Polytechnic. Of the four crystalline compounds investigated, two were connected with the inhibition of the corrosion of steel, one was an additive used in the polymer industry, and one was a molecular complex which had exhibited some unusual physico-chemical properties.
X-ray intensity data were collected in several different ways. One crystal structure was solved from visually estimated photographic data, two sets of data were collected on our. Stoe Stadi-2 diffractometer which uses Weissenberg geometry, and one set which comprised over 7000 intensities, the largest data-set ever worked on in this Department, was recorded on the CAD-4 diffractometer at Queen Mary College, University of London, by arrangement with Dr M Hursthouse.
A variety of techniques were used in working out the crystal structures. One was solved by the MULTAN direct methods computer program, two by the use of the NRC direct methods program using 12 relationships, and one by "trial-and-error" because none of the other methods produced any meaningful results. Refinement of all four structures was carried out using the NRC suite of programs implemented on our Polytechnic computers (DEC-IO, DEC-20, and VAX 11/750). Anisotropic thermal vibrations were allowed for, and hydrogen atom positions were calculated resulting in the conventional R-factors of 6.7, 6.1, 6.6 and 6.1% for the four structures.
No abnormalities were encountered in the results for three of the structures, but the picric acid - naphthalene complex turned out to be disordered with some of.the picric acid molecules occupying an alternative orientation in the unit cell which resulted in displacement of the naphthalene molecules also, and the possibility of proton transfer within the picric acid molecule which was confirmed by differences in bond lengths and anisotropic temperature parameters.
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