Centrosymmetric structures of three substituted malonic acids
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Date
2010
Journal Title
Journal ISSN
Volume Title
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Journal of Chemical Crystallography 3(41): 306-311
Abstract
Crystal structures of 2-methylmalonic acid 2-ethlmalonic acid and 2-phenylmalonic acid, which are derivatives of malonic acid and have found usefulness in diagnostics and biochemical evaluations as markers and organic synthesis, are reported. 2-Methylmalonic acid and 2-ethylmalonic acid both crystallize in triclinic P-1 space group with cell parameters of a = 5.1033(7), b = 5.4231(7), c = 10.0887(14) , Ǎ = 88.074(4), = 89.999(5) and = 67.955()o for 2-methylmalonic acid, and a = 5.2073(4), b = 7.2258(6), c = 8.5655(6) Ǎ, a = 88.086(2), β = 75.307(2) and y = 85.904(3)o for 2-ethylmalonic acid, 2-phenylamlonic acid on the other hand crystallizes in monoclinic P21/c with cell parameters a = 8.6494(4), b = 5.48733(1(), c = 17.1706(6) Ǎ and β = 90.1068(17)o. The observed topology of the hydrogen bonding network is to a large extent dictated by the symmetrical substitution pattern with an open arrangement of hydrogen bonds. Each of the C=O double bonds in both 2-methylmalonic acid and 2-ethylmalonic acid in translationally offset, forming planarcentrosymmetric carboxy-dimmers. Molecules related by centre of inversion in spite of the constraints imposed by substituents are linked by O-H .. O hydrogen bonds. This results in the formation of paralled zig-zag chains running along the [101] direction. In 2-phenylmalonic acid, the zig-zag molecular residue is parallely stacked with successive catemers. These laterally displaced catemers are also coiled in a twofold twist on the screw axis (x, ½ + y, ½ - z) along the b-glide (x, ½ = y, ½ z) when viewed along the (101) plane.
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Keywords
2-Methylmalonic acid, 2-Ethylmalonic acid, 2-Phenylmalonic acid, Hydrogen bonding, Centrosymmetric dimmers, Biochemical markers, Catemer