Crystal Chemistry of the Copper Oxalate Biomineral Moolooite: The First Single-Crystal X-ray Diffraction Studies and Thermal Behavior.

Moolooite, Cu(CO)·HO, is a typical biomineral which forms due to Cu-bearing minerals coming into contact with oxalic acid sources such as bird guano deposits or lichens, and no single crystals of moolooite of either natural or synthetic origin have been found yet. This paper reports, for the first time, on the preparation of single crystals of a synthetic analog of the copper-oxalate biomineral moolooite, and on the refinement of its crystal structure from the single-crystal X-ray diffraction (SCXRD) data. Along with the structural model, the SCXRD experiment showed the significant contribution of diffuse scattering to the overall diffraction data, which comes from the nanostructural disorder caused by stacking faults of Cu oxalate chains as they lengthen.

Local Structures of Two-Dimensional Zeolites-Mordenite and ZSM-5-Probed by Multinuclear NMR.

Mesostructured pillared zeolite materials in the form of lamellar phases with a crystal structure of mordenite (MOR) and ZSM-5 (MFI) were grown using CTAB as an agent that creates mesopores, in a one-pot synthesis; then into the CTAB layers separating the 2D zeolite plates were introduced by diffusion the TEOS molecules which were further hydrolyzed, and finally the material was annealed to remove the organic phase, leaving the 2D zeolite plates separated by pillars of silicon dioxide. To monitor the successive structural changes and the state of the atoms of the zeolite framework and organic compounds at all the steps of the synthesis of pillared MOR and MFI zeolites, the nuclear magnetic resonance method (NMR) with magic angle spinning (MAS) was applied. The Al and Si MAS NMR spectra confirm the regularity of the zeolite frameworks of the as synthetized materials.

Relative Reactivity of Benzothiophene-Fused Enediynes in the Bergman Cyclization.

To find promising analogues of naturally occurring enediyne antibiotics with a sufficient reactivity in the Bergman cyclization and moderately stable under isolation and storage, a scale of relative enediynes reactivity was created on the basis of calculated free activation energies for the Bergman cyclization within 12 known and new benozothiophene, benzene, and cinnoline annulated 9- and 10-membered enediynes. To verify the predicted reactivity/stability balance, three new carbocyclic enediynes fused to a benzothiophene core bearing 3,4,5-trimethoxybenzene, fluoroisopropyl, and isopropenyl substituents were synthesized using the Nicholas-type macrocyclization. It was confirmed that annulation of a 3,4,5-trimethoxybenzene moiety to a 10-membered enediyne macrocycle imparts high reactivity to an enediyne while also conferring instability under ambient temperature.