A tetranuclear diphenyltin(IV) complex and its catalytic activity in the aerobic Baeyer-Villiger oxidation of cyclohexanone

The Baeyer–Villiger Oxidation of Cycloketones Using Hydrogen Peroxide as an Oxidant

Baeyer–Villiger oxidation can synthesize a series of esters or lactones that have essential application value but are difficult to be synthesized by other methods. Cycloketones can be oxidized to lactones using molecular oxygen, peroxy acids, or hydrogen peroxide as an oxidant. Hydrogen peroxide is one of the environmental oxidants. Because of the weak oxidation ability of hydrogen peroxide, Bronsted acids and Lewis acids are used as catalysts to activate hydrogen peroxide or the carbonyl of ketones to increase the nucleophilic performance of hydrogen peroxide. The catalytic mechanisms of Bronsted acids and Lewis acids differ in the Baeyer–Villiger oxidation of cyclohexanone with an aqueous solution of hydrogen peroxide as an oxidant.

Crystal structure of dimethyl (3aS,6R,6aS,7S)-2-pivaloyl-2,3-dihydro-1H,6H,7H-3a,6:7,9a-diepoxybenzo[de]isoquinoline-3a1,6a-dicarboxylate, C21H25NO8

C21H25NO8 , P21/n, (no. 14), a = 12.905(3) Å, b = 13.370(3) Å, c = 13.090(3) Å, β = 118.19(3)°, V = 1990.5(8) Å3, Z = 4, R gt(F) = 0.0629, wR ref(F 2) = 0.1966, T = 100(2) K.

Crystal structure and Hirshfeld surface analysis of (E)-1-[2,2-di-chloro-1-(4-nitro-phen-yl)ethen-yl]-2-(4-fluoro-phen-yl)diazene

In the title compound, C14H8Cl2FN3O2, the 4-fluoro-phenyl ring and the nitro-substituted benzene ring form a dihedral angle of 63.29 (8)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds into chains running parallel to the c axis. The crystal packing is further stabilized by C-Cl⋯π, C-F⋯π and N-O⋯π inter-actions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯O/O⋯H (15.5%), H⋯H (15.3%), Cl⋯H/H⋯Cl (13.8%), C⋯H/H⋯C (9.5%) and F⋯H/H⋯F (8.2%) inter-actions.

Crystal structure of dimethyl (3aS,6R,6aS,7S)-1H,3H,6H,7H-3a,6:7,9a-diepoxybenzo[de]isochromene-3a 1,6a-dicarboxylate, C16H16O7

C16H16O7, monoclinic, P21/n (no. 14), a = 12.830(3) Å, b = 8.1101(16) Å, c = 14.900(3) Å, β = 114.88(3)°, V = 1406.5(6) Å3, Z = 4, R gt(F) = 0.0578, wR ref(F 2) = 0.1799, T = 100(2) K.

Crystal structure and Hirshfeld surface analysis of dimethyl (3aS,6R,6aS,7S)-2-(2,2,2-tri-fluoro-acet-yl)-2,3-di-hydro-1H,6H,7H-3a,6:7,9a-di-epoxy-benzo[de]iso-quinoline-3a1,6a-di-carboxyl-ate

The title mol-ecule, C18H16F3NO7, comprises a fused cyclic system containing four five-membered (two di-hydro-furan and two tetra-hydro-furan) rings and one six-membered (piperidine) ring. The five-membered di-hydro-furan and tetra-hydro-furan rings adopt envelope conformations, and the six-membered piperidine ring adopts a distorted chair conformation. Intra-molecular O⋯F inter-actions help to stabilize the conformational arrangement. In the crystal structure, mol-ecules are linked by weak C-H⋯O and C-H⋯F hydrogen bonds, forming a three-dimensional network. The Hirshfeld surface analysis confirms the dominant role of H⋯H contacts in establishing the packing.

Crystal structure and Hirshfeld surface analysis of (E)-3-[(2,3-di-chloro-benzyl-idene)amino]-5-phenyl-thia-zolidin-2-iminium bromide

In the cation of the title salt, C16H14Cl2N3S+·Br-, the central thia-zolidine ring adopts an envelope conformation. The phenyl ring is disordered over two sites with a refined occupancy ratio of 0.541 (9):0.459 (9). In the crystal, C-H⋯Br and N-H⋯Br hydrogen bonds link the components into a three-dimensional network with the cations and anions stacked along the b-axis direction. Weak C-H⋯π inter-actions, which only involve the minor disorder component of the ring, also contribute to the mol-ecular packing. In addition, there are also inversion-related Cl⋯Cl halogen bonds and C-Cl⋯π (ring) contacts. A Hirshfeld surface analysis was conducted to verify the contributions of the different inter-molecular inter-actions.