Fast Quantum Approach for Evaluating the Energy of Non-Covalent Interactions in Molecular Crystals: The Case Study of Intermolecular H-Bonds in Crystalline Peroxosolvates.

Energy/enthalpy of intermolecular hydrogen bonds (H-bonds) in crystals have been calculated in many papers. Most of the theoretical works used non-periodic models. Their applicability for describing intermolecular H-bonds in solids is not obvious since the crystal environment can strongly change H-bond geometry and energy in comparison with non-periodic models.

dl-Piperidinium-2-carboxyl-ate bis-(hydrogen peroxide): unusual hydrogen-bonded peroxide chains.

The title compound, CHNO·2HO, is the richest (by molar ratio) in hydrogen peroxide among the peroxosolvates of aliphatic α-amino acids. The asymmetric unit contains a zwitterionic pipecolinic acid mol-ecule and two hydrogen peroxide mol-ecules. The two crystallographically independent hydrogen peroxide mol-ecules form a different number of hydrogen bonds: one forms two as donor and two as acceptor ([2,2] mode) and the other forms two as donor and one as acceptor ([2,1] mode).

Annulation-Induced Cascade Transformation of 5-Iodo-1,2,3-triazoles to 2-(1-Aminoalkyl)benzoxazoles.

Base-mediated cyclization of (5-iodo-1,2,3-triazolyl)phenols was proposed as a new synthetic strategy for the in situ generation of diazoimines via electrocyclic ring opening of the fused heterocycle. Cu-catalyzed amination of the intermediate diazoalkanes was employed to develop an efficient cascade approach to functionalized benzoxazoles.

Crystal structure of 2,3,5,6-tetra-kis-(pyridin-2-yl)pyrazine hydrogen peroxide 4.75-solvate.

The structure of the title co-crystal, CHN·4.75HO, consists of a 2,3,5,6-tetra-kis-(pyridin-2-yl)pyrazine coformer and hydrogen peroxide solvent mol-ecules in an overall ratio of 1:4.75.

Hydrogen Peroxide Insular Dodecameric and Pentameric Clusters in Peroxosolvate Structures.

Peroxosolvates of 2-aminonicotinic acid (I) and lidocaine N-oxide (II) including the largest insular hydrogen peroxide clusters were isolated and their crystal structures were determined by single-crystal X-ray diffraction. An unprecedented dodecameric hydrogen peroxide insular cluster was found in I. An unusual cross-like pentameric cluster was observed in the structure of II.

Crystal structure of 4-[(3-methyl-but-3-eno-yl)-oxy]phenyl 4--hexyl-oxybenzoate.

The structure of the title compound, CHO or CH=C(CH)-C(O)O-CH-O(O)C-CH-OCH, has been determined. The mol-ecule is non-planar and the dihedral angle between the phenyl rings is 50.72 (4)°.