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THE INFLUENCE OF SMECTIC PHASES OF PERFLUORODECYL DECANE ON THE PHOTOREACTIONS OF PERFLUOROHEPTYL OCTYL KETONE. AN EXAMPLE OF MICROSCOPIC DISORDER IN HIGHLY ORDERED LAYERED PHASES *
Author(s) -
Vilalta Patricia M.,
Hammond George S.,
Weiss Richard G.
Publication year - 1991
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1991.tb02057.x
Subject(s) - decane , differential scanning calorimetry , methylene , solvent , chemistry , hexane , ketone , molecule , deuterium , crystallography , photochemistry , organic chemistry , thermodynamics , physics , quantum mechanics
The consequences of solvent order, imposed by the two smectic phases of 1,1,1,2,2,3,3,4, 4,5,5,6,6,7,7,8,8,9,9,10,10‐heneicosylfluoroeicosane (F10H10, a “diblock” molecule) on the photochemistry of 1,1,1,2,2,3,3,4,4,5,5.6,6,7,7‐pentadecylfluoro‐8‐hexadecanone (F7COH8) were investigated. Results from irradiations of F7COH8 in smectic F10H10 are compared to those obtained in hexane, perfluorohexane, and the isotropic phase of F10H10. They are complemented by 2 H‐NMR experiments on F10H10 solutions of F7COH8 deuterated at the methylene alpha to the carbonyl, and differential scanning calorimetry thermograms. More than 85% of the photoproducts are derived from carbonyl reduction and Norrish II processes. Based upon the 2 H‐NMR spectra and Norrish II photoproduct ratios, the microscopic environment experienced by the locus of reaction of F7COH8 in smectic F10H10 is not very restrictive towards the solute shape changes that must occur. This conclusion was not anticipated because the macroscopic order of the smectic phases of F10H10 is high.