I. The Crystal Structure of Cyclohex-1-enylcyclobutenedione. II. The Crystal Structure of 3,6-dimethylpiperazine-2,5-dione. III. Programs for the Burroughs Model 205 Computer

Citation

Schoomer, Bertrand Alva (1960) I. The Crystal Structure of Cyclohex-1-enylcyclobutenedione. II. The Crystal Structure of 3,6-dimethylpiperazine-2,5-dione. III. Programs for the Burroughs Model 205 Computer. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/W46M-W507. https://resolver.caltech.edu/CaltechETD:etd-07142006-084404

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The crystal structure of cyclohex-l-enylcyclobutenedione has been determined by x-ray diffraction techniques. Complete three-dimensional intensity data were collected about each of two axes using [...] radiation. A trial structure was evolved which proved to be correct. This structure was refined both in projection and in three dimensions by conventional Fourier and least-squares methods. During the last several cycles of refinement six thermal parameters and three positional parameters for each of the twelve heavy atoms were optimized. An unusually long carbon-carbon bond distance [...] has been found; this result is not inconsistent with purely chemical properties of the compound. The crystal structure of 3,6-dimethylpiperazine-2,5-dione has been investigated by means of x-ray diffraction methods. Three-dimensional intensity data have been collected and a trial structure has been evolved. This trial structure seems to be the only structure which affords a suitable hydrogen-bonding scheme and molecular packing. Moreover, it is in agreement with the very distinctive crystalline habit and cleavage of the compound. Apparently because of difficulties in scaling the data, however, the very large number of refinements which were attempted all failed to converge. Consequently, work on this compound has been stopped temporarily until sufficient additional information has been collected to allow all of the intensity data to be put onto a common scale. A number of programs of general crystallographic interest have been coded for the Burroughs electronic digital computer, model 205. A brief description of these programs is given.

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