Binary co-crystals of the active pharmaceutical ingredient 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene and camphoric acid.
Co-crystals comprising the active pharmaceutical ingredient 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene, C12H10N4, and the chiral co-formers (+)-, (-)- and (rac)-camphoric acid (cam), C10H16O4, have been synthesized. Two different stoichiometries of the API and co-former are obtained, namely 1:1 and 3:2. Crystallization experiments suggest that the 3:2 co-crystal is kinetically favoured over the 1:1 co-crystal. Single-crystal X-ray diffraction analysis of the co-crystals reveals N-H...O hydrogen bonding as the primary driving force for crystallization of the supramolecular structures. The 1:1 co-crystal contains undulating hydrogen-bonded ribbons, in which the chiral cam molecules impart a helical twist. The 3:2 co-crystal contains discrete Z-shaped motifs comprising three molecules of the API and two molecules of cam. The 3:2 co-crystals with (+)-cam, (-)-cam (space group P21) and (rac)-cam (space group P21/n) are isostructural. The enantiomeric co-crystals contain pseudo-symmetry consistent with space group P21/n, and the co-crystal with (rac)-cam represents a solid solution between the co-crystals containing (+)-cam and (-)-cam.
Analytical Discipline and Centralized Instrument Facility, CSIR - Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research, G. B. Marg, Bhavnagar 364 002, Gujarat, India.
Kamal Kumar
KK
Bisht
Analytical Discipline and Centralized Instrument Facility, CSIR - Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research, G. B. Marg, Bhavnagar 364 002, Gujarat, India.
Priyank
P
Patel
Analytical Discipline and Centralized Instrument Facility, CSIR - Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research, G. B. Marg, Bhavnagar 364 002, Gujarat, India.
Yadagiri
Y
Rachuri
Analytical Discipline and Centralized Instrument Facility, CSIR - Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research, G. B. Marg, Bhavnagar 364 002, Gujarat, India.
Suresh
S
Eringathodi
D002942:Circular Dichroism; D003460:Crystallization; D018360:Crystallography, X-Ray; D003517:Cyclopentanes / Q000737:chemistry*; D003998:Dicarboxylic Acids / Q000737:chemistry*; D006834:Hydrazines / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D033362:Powder Diffraction; D011725:Pyridines / Q000737:chemistry*; D012545:Schiff Bases / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
D003517:Cyclopentanes; D003998:Dicarboxylic Acids; D006834:Hydrazines; D011725:Pyridines; D012545:Schiff Bases
active pharmaceutical ingredient; camphoric acid; co-crystal; crystal engineering; molecular adduct