Monitoring reaction centers and molecules during an enantioselective photoreaction in a crystal

Monitoring Structural Transformations in Crystals. Part 15. Structural Changes in Crystals Caused by UV Radiation Despite the Lack of a Photochemical Reaction

“…Such compounds can potentially undergo the Yang photocyclization. Scheme 1b shows the formula of a similar compound (2), undergoing this photochemical reaction and studied by us in the past [9]. The Yang photocyclization is the second step of the Norrish-Yang reaction and involves formation of a cyclobutane ring from a 1,4-hydroxybiradical, see Scheme 1c [26].…”

“…In the case of intra-and intermolecular chemical processes, a cell volume can change by several percent [4,[7][8][9][10][11]. It is interesting that even for one type of a chemical reaction, cell constants and a cell volume for different compounds can change in a different manner [34,35].…”

“…Although, the changes are small, they are statistically significant at the 3r level. For chemical reactions the changes in orientation of molecular fragments are usually much bigger, namely even ca 20° [5][6][7][9][10][11].…”

“…In the recent decade the papers on monitoring photochemical reactions in crystals by means of X-ray structure analysis have started to appear in the scientific literature [1][2][3][4][5][6][7][8][9][10][11][12]. Those papers have provided the knowledge on structural changes brought about by photochemical reactions, in particular in a reaction center and positions of molecules in crystals.…”

Structural, analytical and DSC references to resolution of 2-methoxy-2-phenylacetic acid with chiral 1-cyclohexylethylamines through gas-antisolvent precipitation

“…The enantiopure 1-cyclohexylethylamines are also used as resolving agents in formation of diastereomeric ester derivatives of various acids. An abundant need for chiral 1-cyclohexylethylamines can be demonstrated with their capability to form chiral salts with certain achiral acids, as well [18][19][20][21]. The achiral acid, antracene-2-carboxylic acid, is found to induce a spontaneous resolution of racemic 1-cylcohexylethylamine through formation of salt conglomerate [22].…”