The structure of 3,5-dimethylpyrazole/carboxylic acids co-crystals

2005 ARKIVOC  
Mixtures prepared either by mechanical grinding or by evaporation of equimolar amounts of 3,5dimethylpyrazole (1) and five carboxylic acids, four benzoic acids (2-5) and a pyrazole-4carboxylic acid (6), were studied by 13 C and 15 N CPMAS NMR spectroscopy. In the cases corresponding to 1 and 2,4,6-trimethylbenzoic acid (2) or 1 and 2,6-dimethylbenzoic acid (3) the spectrum of the mixture is different from those of its components and we interpret them in terms of co-crystals formation through
more » ... or-acceptor hydrogen bonds. The remaining pairs behave as physical mixtures of both components, the spectrum of the mixture being the sum of the individual spectra. The origin of the differences is the much higher acidity of o,o-disubstituted benzoic acids. Issue in Honor of Prof. Vladimir I. Minkin ARKIVOC 2005 (vii) 91-101 Issue in Honor of Prof. Vladimir I. Minkin ARKIVOC 2005 (vii) 91-101 Issue in Honor of Prof. Vladimir I. Minkin ARKIVOC 2005 (vii) 91-101 Issue in Honor of Prof. Vladimir I. Minkin ARKIVOC 2005 (vii) 91-101
doi:10.3998/ark.5550190.0006.711 fatcat:2jp3lbbelvbjhfsogrmjggg474