2-Aminobenzoic acid hydrogen bonds

For additional rules and a full discussion the reader is referred to the papers of Etter [Acc. Chem. Res. 23, 120-6 (1990) J. Phys. Chem. 95,4601-10 (1991)]. Figure 20.2.1 shows a hydrogen-bonded polar sheet where 3,5-dinitrobenzoic acid and 4-aminobenzoic acid are co-crystallized. 

The 1 1 cocrystal of 2-amino-5-nitrothiazole with 4-aminobenzoic acid comprises two constituent molecules associated by a hydrogen-bonded graph set dimer through the carboxylic group across the N/N site of the thiazole [0-H...N, 2.614(3)A N-H...O, 2.991(3)A] [144], 2-Bromo-5-nitrothiazole [145], tetrakis (mefa-acetato)bis[2-(2-thionyl)-amino-5-nitrothiazole]-dirhodium-II-dihydrate [146], and /V-(4-melhoxyben/yl (-/WS-nilro-1,3-thia/ol-2-yl) urea [147] have been studied by X-ray analysis. 

Sometimes, the existence of a few possibilities of different hydrogen bond networks results in polymorph structures. It occurs, for example, in ortho-aminobenzoic acid where three crystal structures corresponding to the P2 cn, Pbca and P2 /a space groups are formed31 32 56-58. 

Gong has recently described a class of oligoamides that employ quadruple hydrogen bonding to form solid-state homodimers (Fig. 7).18 The monomers were derived from 3-aminobenzoic acid, 1,3-benzenedicarboxylic acid, and 1,3-diamino-benzene and, similar to Meijer s group, formed via DADA and DDAA sequences. In contrast to Meijer and colleagues, however, the donor and acceptor units were separated within the monomers such that secondary interactions were less prevalent... 

Further prominent examples for face selective reactivity (but for different reasons) are encountered with sulfanilic acid monohydrate 16 and 4-aminobenzoic acid 7. They do not diazotize on their (010) face with N02 or on the (001) face with NOC1, respectively, where molecules cannot exit due to infinite hydrogen-bonded strings. Conversely, at slopes on (010) of 16 or on (100) of 7, where the hydrogen-bonded amino groups of the strings are freely available, reaction occurs [18, 32, 33]. 

Amphoteric property a-amino acid 1.0, aminobenzoic acid 0.5, pyridinecarboxylic acid 0.5 Dummy variable for the presence of p-lactam Summation of numbers of carbon and halogen atoms weighted by C, 1.0 F", 0.5 Cl, I.O Br, 1.5 and 1, 2.0 Dummy variable for the presence of intramolecular hydrogen bonds as ortho-OH and —CO—R, —OH and NH,... 

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