1 Pharmaceutical Technology and Engineering, Department of Pharmacy, Faculty of Health and Medical Sciences, Københavns Universitet2 Univeristy of Cambridge3 Pharmaceutical Technology and Engineering, Department of Pharmacy, Faculty of Health and Medical Sciences, Københavns Universitet
A manual in situ crystallization technique is described, for application on a κ-geometry area-detector instrument. The technique has been applied to grow crystals of some linear alkynes: 1-heptyne, 1-octyne, 1-nonyne and 1-decyne, Cn H2n–2 (n=7, 8, 9, 10). The structures with odd n (1-heptyne and 1-nonyne) crystallize in space group Pca21. The structures with even n (1-octyne and 1-decyne) crystallize in space group P21/c, with two molecules in the asymmetric unit (Z′=2) and an approximately orthorhombic metric. All of the structures contain layers of molecules with a square unit mesh of dimensions 5.7×7.2 Å, identical to the layers present in the previously published structures of 1,7-octadiyne and 1,9-decadiyne. The structures differ where the methyl groups meet, giving systematically greater packing efficiency for 1-heptyne and 1-nonyne, compared to 1-octyne and 1-decyne. This systematic alternation in crystal density is correlated with an alternation in melting points.
Zeitschrift Fuer Kristallographie, 2014, Vol 229, Issue 9, p. 661-666