Multicomponent Solids of DL-2-Hydroxy-2-phenylacetic Acid and Pyridinecarboxamides

We prepared cocrystals of DL-2-Hydroxy-2-phenylacetic acid (D, L-H2ma) with the pyridinecarboxamide isomers, picolinamide (pic) and isonicotinamide (inam). They were characterized by elemental analysis, single crystal powder X-ray, IR spectroscopy 1H 13C NMR. The molecular structures (pic)-(D-H2ma) (1), (nam)-(L-H2ma) (2) (inam)-(L-H2ma) (3) studied. packing is stabilized primarily hydrogen bonding in some cases through π-π stacking interactions. analysis reveals existence characteristic heterosynthons binding motif R22(8) (primary amide–carboxilic acid) between molecules acid. Other synthons involve bonds such as O-H(carboxyl)···N(pyridine) O-H(hydroxyl)···N(pyridine) depending on isomer. 1 3 formed tetramers, for whose formation a crystallization mechanism based two stages proposed, involving an amide–acid (1) or amide–amide recognition first stage others, interdimeric interactions second. thermal stability was studied differential scanning calorimetry thermogravimetry. Further studies conducted to evaluate other physicochemical properties comparison pure coformers. Density-functional theory (DFT) calculations (including NCIplot QTAIM analyses) performed further characterize rationalize noncovalent