Acta Crystallographica Section C

Crystal Structure Communications

Volume 69, Part 10 (October 2013)

organic compounds

Acta Cryst. (2013). C69, 1164-1169    [ doi:10.1107/S0108270113023573 ]

Solvent-mediated pseudo-quadruple hydrogen-bond motifs in three lamotrigine-carb­oxy­lic acid complexes

B. Sridhar, J. B. Nanubolu and K. Ravikumar

Abstract: Lamotrigine, an anti­epileptic drug, has been complexed with three aromatic carb­oxy­lic acids. All three compounds crystallize with the inclusion of N,N-di­methyl­formamide (DMF) solvent, viz. lamotriginium [3,5-di­amino-6-(2,3-di­chloro­phenyl)-1,2,4-tri­az­in-2-ium] 4-iodo­benzoate N,N-di­methyl­form­amide monosolvate, C9H8Cl2N5+·C7H4IO2-·C3H7NO, (I), lamotriginium 4-methyl­benzoate N,N-di­methyl­formamide mono­solvate, C9H7Cl2N5+·C8H8O2-·C3H7NO, (II), and lamotriginium 3,5-di­nitro-2-hy­droxy­benzoate N,N-di­methyl­form­amide monosolvate, C9H8Cl2N5+·C7H3N2O7-·C3H7NO, (III). In all three structures, proton transfer takes place from the acid to the lamotrigine mol­ecule. However, in (I) and (II), the acidic H atom is disordered over two sites and there is only partial transfer of the H atom from O to N. In (III), the corresponding H atom is ordered and complete proton transfer has occurred. Lamotrigine-lamotrigine, lamotrigine-acid and lamotrigine-solvent inter­actions are observed in all three structures and they thereby exhibit isostructurality. The DMF solvent extends the lamotrigine-lamotrigine dimers into a pseudo-quadruple hydrogen-bonding motif.

Formula: C9H7.54Cl2N5+·C7H4.46IO2-·C3H7NO, C9H7Cl2N5+·C8H8O2-·C3H7NO and C9H8Cl2N5+·C7H3N2O7-·C3H7NO

Keywords: crystal structure; solvated lamotrigine salts; hydrogen bonding; anticonvulsants; antiepilepsy drugs; active pharmaceutical ingredients; isostructurality.

hkldisplay filedownload file

Structure factor file (CIF format) (273.8 kbytes)
[ doi:10.1107/S0108270113023573/lg3120Isup2.hkl ]
Contains datablock I

hkldisplay filedownload file

Structure factor file (CIF format) (263.9 kbytes)
[ doi:10.1107/S0108270113023573/lg3120IIsup3.hkl ]
Contains datablock II

hkldisplay filedownload file

Structure factor file (CIF format) (269.9 kbytes)
[ doi:10.1107/S0108270113023573/lg3120IIIsup4.hkl ]
Contains datablock III


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