Molecular and crystal structure analysis of some oxalamide and carbazol derivatives

Molecular and crystal structure of `N-(1,3-dioxo?1,3,3a,4,7,7a-hexahydro-2H?4,7 methanoisoindol?2-yl)-2,2-dimethylpropanamide' and `2-(Carbazol?9-yl)acetic acid' have been determined by single crystal X-ray diffraction study.The first compound, which is an oxalamide derivative, crystallized in the orthorombic system and its space group is Pca21. The structure was solved by direct methods and 344 parameters were refined to a final R = 0.066 for 5227 reflections with I>2sigma(I). The compound, which has two molecules in asymmetric unit, is a chiral compound. With C1, C2, C7, C8 and C15, C16, C21, C22, it has 8 stereogenic center. The configuration of C2, C3, C6, C7 atoms are S, R, S, R. Similarly C16, C17, C20, C21 atoms are in S, R, S, R configuration. Compound occures non-centrosymmetric dimeric structure with N ? H?O type H bond. The crystal structure of the compound is stabilized by intermolecular N ? H?O type and intramolecular C ? H?O, N ? H?O type H-bonds, also C? O?pi weak interactions. Bond angles and distances of atoms in the dicarboximide and norbornane rings are compatible with the literature.The second compound is a derivative of carbazol. It is crystallized in the monoclinic system, its space group is C2/c. The structure was solved by direct methods and 190 parameters were refined to a final R = 0.046 for 1975 reflections with I>2sigma(I). In the compound, the tricyclic aromatic ring system is almost planar. (Maximum deviation = 0.036 (2) Å with C3 atom.) The dihedral angle between the two benzene rings is 2.41 (2)°, while the carboxyl group forms a dihedral angle of 87.7 (2)° with the pyrrole ring. Besides O ? H?O intermolecular hydrogen bond, there are two C ? H?pi weak interactions effectthe stabilizied of the crystal.