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Structure-reactivity correlations in solid state photochemistry : studies on some novel carbonyls, thiocarbolnyls and inclusion compounds

University of British Columbia

Four N-alkylsuccinimides were synthesized for solid state photochemical studies and all were found to undergo 7-hydrogen abstraction in the solid state. The crystal structures of N-(t-butyl)succinimide as well as its photoproduct were determined, and the structure-reactivity correlations were derived. The phase changes during the solid state photolysis of N-(t-butyl)succinimide were also studied by X-ray powder diffraction and were interpreted using a simplified phase diagram. Chiral crystals of salts of 4-[2,4,6-tris(1-methylethyl)benzoyl]benzoic acid (21) and different optically active amines were prepared for solid state asymmetric induction studies. The solid state photolyses of these complexes afford photoproducts in enantioenriched form. The crystal structure of one complex (21 S-proline) was determined. The low ee obtained in its solid state photolysis was correlated with its crystal structure. [scientific models (21) (14)] Crystals of 2,4,6-triisopropylthiobenzophenone (14) and its 4'-methoxy derivative (15) were synthesized for solid state photochemical studies of their 7- hydrogen abstraction reactions. The X-ray crystal structures of these two compounds reveal information about the hydrogen abstraction geometry for thiones. These results are discussed and compared with the well-established preferred hydrogen abstraction geometry for n,n* excited carbonyl compounds. A/-Phenyi-A/-(phenylthioxomethyl)benzenepropanamide and some of Its derivatives were prepared. The original intention was to study their hydrogen abstraction reactions in the crystalline state. However, both solid state structurereactivity correlation studies and deuterium labeling experiments indicate that the photocleavage of these compounds does not involve initial 7-hydrogen abstraction as originally suggested in the' literature. Alternative mechanistic possibilities are presented and discussed. Several inclusion complexes of 9,10-dihydro-9,10-ethenoanthracene- 11,12-bis(diphenylmethanol) (22) were prepared and their photochemistry studied in both solution and the solid state. The X-ray crystal structures of three different complexes of 22 were determined and correlated with their photochemical reactivities. The structures of three solvent inclusion complexes of 9,10-dihydro-9,10-ethenoanthracene-11,12-bis(diphenylphosphine) oxide were also determined by X-ray crystallography. Their photochemistry and structures are compared with those of diol 22. [scientific models]

Thesis/Dissertation

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2009-04-14

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http://hdl.handle.net/2429/7079

Chemistry

University of British Columbia

UBCV

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