On the crystal structure solution and characterization of ECS-2, a novel microporous hybrid organic-inorganic material

摘要

The structure of ECS-2, a new crystalline microporous hybrid organic-inorganic material, is described. The new phase was extensively characterized by X-ray powder diffraction (XRPD), Nuclear Magnetic Resonance (NMR) spectroscopy, high resolution transmission electron microscopy (HRTEM) and chemical analysis. Preliminary ~(29)Si MAS NMR analyses confirmed that the bis-silylated organic group maintains its integrity. The crystal structure of ECS-2 was solved using direct methods and high resolution powder diffraction data collected on the beam line ID-31, at ESRF in Grenoble (λ = 0.80175(2)A). The XRPD pattern has been indexed using a monoclinic unit cell with parameters a = 7.908, b = 19.5339, c = 7.8758 A and β = 108.72°. Analysis of the systematic absences indicated the P2_1/n as the possible space group. The crystal structure of ECS-2 can be rationalized by the stacking of alumino-silicate layers held together by phenylene groups and it is characterized by the presence of large non-interconnected cages, allowing classifying ECS-2 as a clathrate-like structure.