Novel Layered Organic−Inorganic Hybrid Materials with Bridged Silsesquioxanes as Pillars

Layered organic−inorganic hybrid materials were synthesized by pillaring with viologen and nitroaniline compounds which are intercalated between magadiite layers. The bridged silsesquioxanes, 4,4‘-bis(trimethoxysilylpropyl)viologen and 4-nitro-N,N‘-bis(3-trimethoxysilyl)propylaniline react with the surface silanol groups of the inorganic layers of silicate, bonding covalently with them. The preparation process was followed by DRX, and the pillarization was corroborated using chemical and thermogravimetrical analyses. The presence of viologen and nitroaniline organic linkers covalently bonded to inorganic layers was confirmed by 13C and 29Si NMR spectroscopy. UV−visible diffuse reflectance permitted to observe the high stabilization achieved by the intercalated organic fragments. Micro- and mesoporosity were also generated because of the existence of interlayer galleries conformed by homogenously distributed organic linkers into the interlayer space. The layered organic−inorganic hybrids exhibited a thermally stable network, and the organic spacers remained after elimination of the swelling agents by acid extraction. The resultant materials can be of interest as sensors and for nonlinear optics.