Non-covalent interactions of the hydroperoxo group in crystalline adducts of organic hydroperoxides and their potassium salts†
ab
Alexander G.
Medvedev,
a
Alexey A.
Mikhaylov,
a
Andrei V.
Churakov,
a
Ovadia
Lev
*c
and
Petr V.
Prikhodchenko
*a
Abstract
The present study demonstrates the similarity of hydrogen bonding of hydroperoxo functionality in organic hydroperoxide crystalline adducts (HPCA) and the much larger group of crystalline peroxosolvates. Based on a systematic analysis of the reported HPCA in the crystal database, the following common features, similar to those previously observed for crystalline peroxosolvates, could be derived: i) the hydroperoxo groups play a dominant structure-directing role in the crystal structure of HPCA; ii) organic hydroperoxides always form one hydrogen bond (per OOH group) as a proton donor (HB-D) in cocrystals; iii) a basic or amphoteric nature of the coformers is a requirement to obtain HPCA. Three new cocrystals of potassium salts of organic hydroperoxides with molecular hydroperoxides were synthesized. Single crystal X-ray diffraction revealed strong charge-assisted ROO−⋯HOOR hydrogen bonds (H-bonds). The energies/enthalpies of charge-assisted and ordinary H-bonds and K⋯O interactions in HPCA were estimated for the first time using solid-state DFT computations and periodic electron density analysis. The calculated energy values of the ordinary intermolecular HB-D are lower than those of the charge-assisted bonds and are close to those found for hydrogen peroxide in peroxosolvates. The H-bond energy values of hydroperoxo groups exceed those of the hydroxo groups in adducts with Cy3P![[double bond, length as m-dash]](https://www.rsc.org/images/entities/char_e001.gif)
O. Moreover, considering only the unique interactions, the total value of H-bond energies is almost twice as high as the total value of K⋯O coordination bond energies in one of the synthesized HPCA.
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