Amide-tethered organosilatranes: Syntheses, structural characterization and photophysical properties

• New trialkoxysilanes and silatranes containing amide linkage were successfully synthesized and fully characterized.
• UV–Vis absorption and fluorescence emission of the silatranes were measured.
• All silatranes possess metal ion chelating sites.

A series of trimethoxysilanes and silatranes coupled with distinct aromatic moieties (biphenyl, thiophene, pyrazine and pyridine) through amide linkage are reported. The synthetic approach involved the amidation of 3-aminopropyltrimethoxysilane (APTMS) with various carboxylic acids via acid chlorides (1a–1g) to generate amidopropylsilanes (2a–2g). Transesterification of the resultant silanes with triethanolamine and tris(isopropanolamine) yielded unsubstituted (3a–3g) and 3,7,10-trimethylsubstitued organosilatranes (4a–4g), respectively. The compounds were successfully characterized by various spectroscopic techniques [IR, NMR (1H, 13C) and Mass] and elemental analysis. The complete structure elucidation for compounds 3a, 3c·H2O and 3f was carried out using single crystal X-ray diffraction analysis. The photophysical response was studied by UV–Vis absorption and fluorescence spectroscopy. These organosilatranes possess metal ion binding sites and can be put forth for advanced analytical applications.

Amidopropyltrimethoxysilanes derived from the amidation reaction of various carboxylic acids were converted successfully into corresponding unsubstituted and 3,7,10-trimethylsubstituted silatranes. The compounds were fully characterized by elemental analysis, IR, NMR (1H, 13C), mass spectroscopy and molecular structures were also authenticated using X-ray crystallographic studies. The prepared compounds were explored further for photophysical properties.Figure optionsDownload as PowerPoint slide