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Mononuclear titanium oxide species in faujasites of different Si/Al ratios are prepared by reaction of dehydrated zeolites with TiCl4 at 100 °C. The analysis of UV−vis diffuse reflectance spectra in combination with Raman spectroscopy and X-ray diffraction reveals the presence of three different types of titanium oxide species in the faujasite structure exhibiting excitation energies for the charge transfer from the 2p orbitals of oxygen ligands to the 3d orbitals of Ti of around 36 000, 45 000 and 49 000 cm-1. A reliable evaluation of diffuse reflectance spectra requires the calculation of the Kubelka−Munk spectra from the absolute reflectance of the sample. The different titanium oxide types are proposed to result from monofunctional, bifunctional, and multifunctional bonding of TiCl4 to isolated or neighboring OH groups or to hydroxyl nests with coordination numbers ranging from four to six. The blue shifts in the UV−vis spectra of mononuclear titanium oxide species can be discriminated from those of quantum-sized titania particles.

Adsorption isotherms of cyclopentane and nitrogen on a new porous crystalline aluminosilicate from the family MCM-41 are characterized by the volume filling of channels by capillary condensation without hysteresis, which commences in the region prior to the lower closure point at the hysteresis loop.

Molecular sieves, such as nanoporous AlPO4-5, can host a wide variety of laser active dyes. We embedded pyridine 2 molecules as a representative of a commercially available dye which fits into the channel pores of the host matrix. Many efficient dye molecules, such as rhodamines, do not fit into the pores. But modifying the structure of the dyes to appear like the used templates allows to increase the amount of encapsulated dyes. The properties of resulting microlasers depend on size and shape of the microresonators, and we discuss a model for microscopic hexagonal ring resonators. In terms of pump needed to reach lasing threshold molecular sieve microlasers are comparable to VCSELs. For dyes which fit into the pores we observed a partial regeneration of photo-induced damage.