Synthetic, Crystallographic, and Computational Studies of Extensively Hydrogen Bonded Bilayers in Thermally Stable Adamantane Hydroperoxides

Abstract

The use of moleculari odine as ah eterogeneous catalyst for the peroxidation of adamantan-2-one with 30 % H 2 O 2 resulted in an unexpected hydroperoxydiadamantyl peroxide and oxahomoadamantan-5-one,i na ddition to the expected adamantanylb ishydroperoxide. The crystal structures of both the hydroperoxides are reported for the first time. Crystallographic studies revealed that thesep eroxides are stabilized by extensive intra-and intermolecular hydrogen bonds, which are combined in hydrogen-bonded double layers. These bilayers envelop the hydrophilic interiors consisting of sensitivep eroxy groups with the outer surface covered by hydrophobic adamantane groups. The bilay-ers are held together by weak van der Waals interactions at the layer boundary,w hichf urther enhances the thermal stability.T hermal studies demonstrate the remarkable stability of crystalline hydroperoxides at room temperature. Ac omputational study rationalizes the stability of these peroxides. NCI (non-covalent interactions) plots help to decipher the nature of the interaction between the adamantane units as stabilizing dispersion contacts. QTAIM (quantum theory of atoms in molecules) topological analysisa lso indicates the presence of strong intermolecular hydrogen bonds along with anumber of weak dihydrogenc ontacts. Results and DiscussionAdamant-2-one was chosen as an appropriate precursor for the presenti nvestigation because the higher molecular weight[a] C.

Synthesis and Photodimerization of 2- and 2,3-Disubstituted Anthracenes: Influence of Steric Interactions and London Dispersion on Diastereoselectivity

“…Obviously, the Diels–Alder reaction had produced the isomer with adamantyl substituents in adjacent positions as the major product (67%) while the allegedly less crowded product only formed to minor extent (12%). This result appears to be in contrast to the expectation based on steric arguments and it was suggested that attractive, noncovalent dispersion forces arising from large, polarizable substituents (dispersion energy donors, DEDs) could be important for the formation of 6 . , …”

“…This result appears to be in contrast to the expectation based on steric arguments and it was suggested 23 that attractive, noncovalent dispersion forces 24 arising from large, polarizable substituents (dispersion energy donors, DEDs) could be important for the formation of 6. 23,25 There is currently considerable interest in elucidating the effect of London dispersion on the structural, energetic, and chemical properties of organic, organometallic, and inorganic compounds. 23,26,27 While the influence of attractive dispersive interactions can be substantial, in particular in the gas phase, there is evidence that the effect can be attenuated by solvents.…”

One-Stage Catalytic Oxidation of Adamantane to Tri-, Tetra-, and Penta-Ols

“…By analogy with the oxidation of cyclohexane [64][65][66], such compounds could include mono-and di-hydroperoxide groups in their composition. For example, a scheme for the oxidation of 0 with the participation of its primary and secondary hydroperoxides is proposed [66], the formation of thermally stable 1-adamantylhydroperoxide (2d) [67] and 2,2-dihydroperoxy-adamantane (4a') is described [68,69].…”