THE UTILITY OF 4-AMINOBENZOIC ACID IN PROMOTION OF HYDROGEN-BONDING IN CRYSTALLIZATION PROCESSES - THE STRUCTURES OF THE COCRYSTALS WITH HALO AND NITRO SUBSTITUTED AROMATIC-COMPOUNDS, AND THE CRYSTAL-STRUCTURES OF THE ADDUCTS WITH 4-NITROANILINE (1 1), 4-(4-NITROBENZYL)PYRIDINE (1/2), AND (4-NITROPHENYL)ACETIC ACID (1/1)/

A number of molecular adducts of 4-aminobenzoic acid (4-ABA) have been prepared and characterized using infrared spectroscopy and in three c ases by X-ray diffraction methods; These three compounds are with 4-ni troaniline [(4-ABA) (C6H6N2O2)], 4-(4-nitrobenzyl) pyridine, [(4-ABA)( 2) (C12H10N2O2)(4)], and (4-nitrophenyl)acetic acid, [(4-ABA) (C8H7NO4 )]. Other compounds described are with 4-chlorobenzoic acid, [(4-ABA) (C7H5ClO2)], 4-bromobenzoic acid, [(4-ABA) (C7H5BrO2)], 4-cyanobenzoic acid, [(4-ABA) (C7H6N2)], 2-nitrobenzoic acid, [(4-ABA) (C7H5NO4)], a nd 3-nitrobenzoic acid, [(4-ABA) (C7H5NO4)]. All compounds have 1:1 st oichiometry except that with 4-(4-nitrobenzyl)pyridine (1:2) which is unique in being retro-stoichiometric. A review of the systematics of t he 4-aminobenzoic acid adducts is also made, particularly with respect to the infrared characterization of the cocrystalline materials and p rediction of their NLO potential.