TY - JOUR
T1 - Organic crystal engineering with 1,4-piperazine-2,5-diones. 8. Synthesis, crystal packing, and thermochemistry of piperazinediones derived from 2-amino-4,7-dialkoxyindan-2-carboxylic acids
AU - Wells, Kirk E.
AU - Weatherhead, Robin A.
AU - Murigi, Francis N.
AU - Nichol, Gary S.
AU - Carducci, Michael D.
AU - Selby, Hugh D.
AU - Mash, Eugene A.
PY - 2012/10/3
Y1 - 2012/10/3
N2 - 1,4-Piperazine-2,5-diones possessing C 2hmolecular symmetry and bearing four methoxy, ethoxy, butoxy, hexyloxy, octyloxy, nonyloxy, dodecyloxy, or octadecyloxy groups weresynthesized from 2-amino-4,7-dialkoxyindan-2- carboxylic acids. Where possible, the piperazinediones were crystallized from appropriate solvents and the supramolecular organizations were determined by X-ray crystallography. In each case so studied, crystal assembly via three mutually orthogonal interactions, namely, R22(8) hydrogen bonding, arene perpendicular edge-to-center interactions, and alkyl chain interdigitation, was observed. The thermochemical properties of these compounds were studied by modulated differential scanning calorimetry. In most cases, one or more reversible thermal events were observed between room temperature and melting to an isotropic liquid. In the cooling cycle, freezing point temperatures were observed to decrease with increasing hydrocarbon chain length. This may be due to greater entropic penalties for hydrogen-bond association of molecules with longer hydrocarbon chains.
AB - 1,4-Piperazine-2,5-diones possessing C 2hmolecular symmetry and bearing four methoxy, ethoxy, butoxy, hexyloxy, octyloxy, nonyloxy, dodecyloxy, or octadecyloxy groups weresynthesized from 2-amino-4,7-dialkoxyindan-2- carboxylic acids. Where possible, the piperazinediones were crystallized from appropriate solvents and the supramolecular organizations were determined by X-ray crystallography. In each case so studied, crystal assembly via three mutually orthogonal interactions, namely, R22(8) hydrogen bonding, arene perpendicular edge-to-center interactions, and alkyl chain interdigitation, was observed. The thermochemical properties of these compounds were studied by modulated differential scanning calorimetry. In most cases, one or more reversible thermal events were observed between room temperature and melting to an isotropic liquid. In the cooling cycle, freezing point temperatures were observed to decrease with increasing hydrocarbon chain length. This may be due to greater entropic penalties for hydrogen-bond association of molecules with longer hydrocarbon chains.
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U2 - 10.1021/cg301003p
DO - 10.1021/cg301003p
M3 - Article
AN - SCOPUS:84867025829
VL - 12
SP - 5056
EP - 5068
JO - Crystal Growth and Design
JF - Crystal Growth and Design
SN - 1528-7483
IS - 10
ER -