Co-Crystals of Caffeine and Hydroxy-2-naphthoic Acids:  Unusual Formation of the Carboxylic Acid Dimer in the Presence of a Heterosynthon

2007 ◽  
Vol 4 (3) ◽  
pp. 339-346 ◽  
Author(s):  
Dejan-Krešimir Bučar ◽  
Rodger F. Henry ◽  
Xiaochun Lou ◽  
Richard W. Duerst ◽  
Thomas B. Borchardt ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acid Dimer ◽  
Unusual Formation

Supramolecular architectures in two 1:1 cocrystals of 5-fluorouracil with 5-bromothiophene-2-carboxylic acid and thiophene-2-carboxylic acid

2017 ◽  
Vol 73 (6) ◽  
pp. 481-485 ◽  
Author(s):  
Marimuthu Mohana ◽  
Packianathan Thomas Muthiah ◽  
Colin D. McMillen
Keyword(s):  
Solid State ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Base Pairs ◽  
X Ray ◽  
Supramolecular Architectures ◽  
Acid Acid ◽  
Carboxylic Acid Dimer

In solid-state engineering, cocrystallization is a strategy actively pursued for pharmaceuticals. Two 1:1 cocrystals of 5-fluorouracil (5FU; systematic name: 5-fluoro-1,3-dihydropyrimidine-2,4-dione), namely 5-fluorouracil–5-bromothiophene-2-carboxylic acid (1/1), C5H3BrO2S·C4H3FN2O2, (I), and 5-fluorouracil–thiophene-2-carboxylic acid (1/1), C4H3FN2O2·C5H4O2S, (II), have been synthesized and characterized by single-crystal X-ray diffraction studies. In both cocrystals, carboxylic acid molecules are linked through an acid–acid R 2 2(8) homosynthon (O—H...O) to form a carboxylic acid dimer and 5FU molecules are connected through two types of base pairs [homosynthon, R 2 2(8) motif] via a pair of N—H...O hydrogen bonds. The crystal structures are further stabilized by C—H...O interactions in (II) and C—Br...O interactions in (I). In both crystal structures, π–π stacking and C—F...π interactions are also observed.

scholarly journals Conformational Panorama and Chirality Controlled Structure–Energy Relationship in a Chiral Carboxylic Acid Dimer

2020 ◽  
Vol 132 (36) ◽  
pp. 15833-15840
Author(s):  
Fan Xie ◽  
Nathan A. Seifert ◽  
Wolfgang Jäger ◽  
Yunjie Xu
Keyword(s):  
Carboxylic Acid ◽  
Controlled Structure ◽  
Carboxylic Acid Dimer

N-Tosyl-L-proline benzene hemisolvate: a rare example of a hydrogen-bonded carboxylic acid dimer with symmetrically disordered H atoms

2019 ◽  
Vol 75 (9) ◽  
pp. 1228-1233
Author(s):  
Joanna Wojnarska ◽  
Katarzyna Ostrowska ◽  
Marlena Gryl ◽  
Katarzyna Marta Stadnicka
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Self Assembly ◽  
Acid Group ◽  
Benzene Molecule ◽  
Noncovalent Interaction ◽  
Hydrogen Bond Donor ◽  
Donor And Acceptor ◽  
Carboxylic Acid Dimer ◽  
Hydrogen Bonded

The carboxylic acid group is an example of a functional group which possess a good hydrogen-bond donor (–OH) and acceptor (C=O). For this reason, carboxylic acids have a tendency to self-assembly by the formation of hydrogen bonds between the donor and acceptor sites. We present here the crystal structure of N-tosyl-L-proline (TPOH) benzene hemisolvate {systematic name: (2S)-1-[(4-methylbenzene)sulfonyl]pyrrolidine-2-carboxylic acid benzene hemisolvate}, C12H15NO4S·0.5C6H6, (I), in which a cyclic R 2 2(8) hydrogen-bonded carboxylic acid dimer with a strong O—(1 \over 2H)...(1 \over 2H)—O hydrogen bond is observed. The compound was characterized by single-crystal X-ray diffraction and NMR spectroscopy, and crystallizes in the space group I2 with half a benzene molecule and one TPOH molecule in the asymmetric unit. The H atom of the carboxyl OH group is disordered over a twofold axis. An analysis of the intermolecular interactions using the noncovalent interaction (NCI) index showed that the TPOH molecules form dimers due to the strong O—(1 \over 2H)...(1 \over 2H)—O hydrogen bond, while the packing of the benzene solvent molecules is governed by weak dispersive interactions. A search of the Cambridge Structural Database revealed that the disordered dimeric motif observed in (I) was found previously only in six crystal structures.

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