Cocrystals of 3,5-Dimethyl-1H-pyrazole and Salicylic Acid:  Controlled Formation of Trimers via O−H···N Hydrogen Bonds

Abstract

Solid-state reactions of 3,5-dimethyl-1H-pyrazole (dmpz) and salicylic acid (sa) in different stoichiometries afford two different trimers whose structures have been determined by X-ray diffraction and analyzed by 13C and 15N solid-state nuclear magnetic resonance spectroscopy. GIAO absolute shieldings at the B3LYP/6-311++G** level have been calculated and compared with the experimental chemical shifts. Hydrogen-bond interactions between dmpz and sa provide sufficient driving force to direct molecular recognition and crystal packing.

Pyrazole Complexes and Supramolecular Chemistry

“…Because of this common feature, supramolecular adducts of carboxylic acids with pyrazoles ( Figure 4) have been used as crystal engineering synthons. [13] N-H pyrazoles undergo tautomeric prototropy (Figure 5). [14] For many pyrazoles, this has been found to be a fast process in solution at room temperature.…”

Crystal structure of triethylammonium 3,5-dihydroxybenzoate, [C6H16N][C7H5O4] Crystal structure of triethylammonium 3,5-dihydroxybenzoate, [C6H16N][C7H5O4]

“…The crystal structure of triethylammonium benzoate salt is similar to that of its analogue salicylic salts [1,2]. Among the complex intermolecular interactions [3,4], the most important hydrogen bonding is N1-H1×××O2 (bond length 2.744 (2) .I na ddition, the hydrogen bonds O4-H4D×××O2 and O3-H3B×××O1 (bond lengths 2.58(2) Åa nd 2.68(2) Åand bond angles 163.25°and 162.4°, respectively) are another important force to stabilize the crystal structure [5].…”

“…The crystal structure of triethylammonium benzoate salt is similar to that of its analogue salicylic salts [1,2]. Among the complex intermolecular interactions [3,4], the most important hydrogen bonding is N1-H1×××O2 (bond length 2.744(2) Å; bond angle 174.4°), providing the main driving force for direct binding of carboxylate anion [3,5- …”

Computational NMR Spectroscopy

“…One can consider the solid state as a special case of solvation; only, instead of solvent there are other molecules in the unit cell. For comparing experimental CPMAS chemical shifts, we have reported calculations for dimers [10] and trimers [34]. d) Specific solute-solvent interactions: spin-spin coupling constants.…”