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HgCl 2 (Caf): Co‐crystallization of Mercuric Chloride and Caffeine
Author(s) -
Meyer Gerd,
Nolte Matthias,
Mudring AnjaVerena
Publication year - 2006
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200500346
Subject(s) - monoclinic crystal system , chemistry , molecule , caffeine , chloride , crystallization , crystallography , crystal structure , crystal (programming language) , stereochemistry , organic chemistry , medicine , computer science , programming language , endocrinology
Colourless single crystals of the co‐crystallizate of mercuric chloride and caffeine, HgCl 2 (Caf), were obtained from an ethanolic solution of mercuric chloride, HgCl 2 , and caffeine (Caf) and recrystallized from hot water. The crystal structure (monoclinic, P2 1 , Z = 2, a = 398.36(8), b = 1964.5(4), c = 809.6(2) pm, β = 99.24(3)°, Z = 2, R 1 = 0.0584 for 1430 F o > 4σ(F o )) contains helical chains (parallel to the 2 1 screw axis) of almost unaffected HgCl 2 molecules and caffeine molecules which are very weakly bound to one keto‐oxygen atom (O4) of one and N9 of a second caffeine molecule at distances of 282 and 281 pm, respectively. To the contrary, theoretical calculations show that the molecule HgCl 2 (Caf) 2 is stable (in the gas phase at T = 0 K) with surprisingly strong bonding as indicated by the “tetrahedrization” of the molecule.