On Tuesday, March 14, 2000, at Cornell College, Mount Vernon, Iowa, two students who prepared the photochromic compound 2-(2,4-dinitrobenzyl)pyridine obtained their product as a single crystal, one weighing 864 mg and the other 891 mg. As far as we know, this has happened only once before, also at Cornell College in Iowa. The web version of this paper includes a time-lapse video of the photochromic conversion in which the original brown-sugar brown crystals turn into the blue-jeans blue form under the influence of the photographer's floodlight.
A revised procedure for carrying out this laboratory and the time-lapse video below
of the photochromic crystals prepared using this method are available.
The video requires QuickTime 4 or higher. QuickTime can be downloaded here.
The Division of Chemical Education (CHED) of the American Chemical Society (ACS), along with the Journal of Chemical Education is offering a new value called the "Chemistry Teacher Connection" (CTC). This product is created especially for high school chemistry teachers. It offers an online-only subscription to CLIC along with membership in the Division of Chemical Education. Normally, these two items would cost $65 per year, but are available as the CTC for only $40 a year. CTC subscribers will receive access to all articles and accompanying supplements shown on the CLIC website. This will include all published JCE items that have been designated in a print issue's table of contents as being of interest to high school teachers, from 1996 through the current issue.
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