SnO2 “Russian Doll” Octahedra Prepared by Metalorganic Synthesis: A New Structure for Sub‐ppm CO Detection

Micrometer‐sized hierarchical Sn₃O₂(OH)₂ octahedra, which are self‐assembled one inside the other, resembling “Russian doll” organization, have been obtained by a metalorganic approach. This synthesis is based on the controlled hydrolysis of [Sn(NMe₂)₂]₂ in the presence of an alkylamine ligand in an organic solvent (THF). The water content of the medium proved to be a key parameter for the formation of these multi‐walled octahedra. The resultant structures have been used as gas‐sensitive layers on micromachined silicon devices. During in situ heating, Sn₃O₂(OH)₂ is oxidized to SnO₂ while retaining the initial morphology. The sensors present outstanding dynamic responses at very low CO concentrations (7 % and 67 % resistance variation to 0.25 and 20 ppm CO, respectively, at an operating temperature of 500 °C). This superior gas‐sensing performance is closely related to the unique microstructure of the SnO₂ multi‐walled octahedra.     

Lewis acid promoted reaction of tetraalkynylstannanes with acyl chlorides: An effective approach towards alkynyl ketones

Tetraalkynylstannanes were found to be atom-economical nucleophilic reagents for the synthesis of α,β-acetylenic ketones. The scope and some limitations of the method are discussed.     

Photocatalytic and magnetic titanium dioxide/polystyrene/magnetite composite hybrid polymer particles

Novel multifunctional titanium dioxide (TiO₂)/polystyrene/magnetite composite hybrid polymer particle dispersions with TiO₂ nanoparticles in the surface and magnetite nanoparticles encapsulated inside the polymer matrix were produced by Pickering miniemulsion polymerization in one single step. Whereas TiO₂ nanoparticles were used to impart photocatalytic functionality and colloidal stability, magnetite nanoparticles were incorporated to allow an easy extraction for recovery and reuse of the composite multifunctional particles. The morphology of the composite particles was assessed by scanning transition electron microscopy (STEM) and energy‐dispersive X‐ray spectroscopy (EDX). The paramagnetism of the particles was analyzed using a SQUID magnetometer and their photocatalytic activity was assessed by degrading methylene blue (MB) solutions under UV light and by recovering and reusing of the particles in five consecutive cycles. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3350–3356