Structures of eleven organic acid-base adducts from 2-aminobenzothiazole/2-aminothiazole and acidic compounds

Cocrystallization of 2-aminobenzothiazole/2-aminothiazole with a set of organic acids got a total of 11 crystalline adducts with the compositions: (2-aminobenzothiazole): (saccharin) [(HL1) + • (sac) − , sac = saccharinate] (1) , (2-aminobenzothiazole): (dichloroacetic acid) [(HL1) + • (dca) − , dca = dichloroacetate] (2) , (2-aminobenzothiazole): (trichloroacetic acid) [(HL1) + • (tca) − , tca = trichloroacetate] (3) , (2-aminothiazole): (glycolic acid) [(HL2) + • (gla) − , gla = glycolate] (4) , (2-aminothiazole): (2-methyl-2-phenoxypropanoic acid) [(HL2) • (mppa), mppa = 2-methyl-2-phenoxypropanoiate] (5) , (2-aminothiazole): ((2,4-dichlorophenoxy)-acetic acid) [(HL2) • (dcpa), dcpa = (2,4-dichlorophenoxy)-acetate] (6) , (2-aminobenzothiazole) 2 : (2,3-dibromo-butanedioic acid) 2 [(HL1) 2 + • (dba) 2- • (H 2 dba), dba = 2,3-dibromo-butanedioate] (7) , (2-aminothiazole): (1,4-cyclohexanedicarboxylic acid) [(L2) 2 • (1,4-H 2 cha), 1,4-H 2 cha = 1,4-cyclohexanedicarboxylic acid] (8) , (2-aminothiazole): (4-nitrophthalic acid) [(HL2 + ) • (4-Hnpa − ), Hnpa −  = 4-nitro hydrogenphthalate] (9) , (2-aminothiazole): (5-hydroxyisophthalic acid) [(HL2 + ) • (5-Hipta − ), 5-Hipta −  = 5-hydroxy hydrogenisophthalate] (10) and (2-aminobenzothiazole): (3-nitrophthalic acid): CH 3 CH 2 OH [(HL1) • (3-Hnpa − ) • CH 3 CH 2 OH, 3-Hnpa −  = hydrogen 3-nitrophthalate] (11) . These adducts have been examined by XRD, IR and elemental analysis and the melting points were also gauged. Their structural and supramolecular aspects are fully analyzed. The result unveils that among the investigated crystalline solids 1 - 7 and 9 - 11 the aryl N in thiazole moieties are protonated when the organic acids are deprotonated, the crystal packing is ruled by the strong charge-assisted N-H⋯O H-bond from the NH + and the deprotonated acids. 8 is a cocrystal sustained by the neutral N-H⋯O/O-H⋯N H-bonds. Except the N-H⋯O H-bonds, the O-H•••O H-bonds were also found at 4, 7 and 9 - 11. 1 has the additional N-H•••S/N-H•••N H-bonds. The N-H•••Cl H-bond was appeared in 3 . Further analysis of the crystal packing told that a different set of additional CH 2 -C, CH-O/CH 2 -O, CH-S, CH-CH, CH-Cl, Cl-Cl, Cl-S, Br-S, Br-π, CH-π/CH 2 -π/CH 3 -π, N-π, C-S, O-C π , O-N, O-O, O-S, π-π and O-π contacts contribute to the stabilization and expansion of the total structures. For the interplay of the various weak nonbonding interactions these structures adopted homo or hetero supramolecular synthons or both. The recognition of the base-acid created the classical R 2 2 (8) synthon in all compounds except 7 . For the cooperation of these weak bonds, 1D-3D structures were made.