N-Aryl-substituted 5-aza-2,8-dioxasilabicyclo[3.3.01.5]octanes: syntheses, molecular structures, DFT calculations and cyclovoltammetric studies

Abstract

The reaction of the silanes X2SiCl2 (X=H, Cl) with the dilithium salts of N-phenyldiethanolamine (1) and N-4-fluorophenyl-di-(2-dimethylpropan-2-ol)amine (2), respectively, gave the novel 5-aza-2,8-dioxasilabicyclo[3.3.01.5]octanes RN(CH2CR′2O)2SiX2 (3, R=Ph, R′=X=H; 4, R=Ph, R′=H, X=Cl; 5, R=4-FC6H4, R′=Me, X=H). These compounds were characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction analysis (1–4). The molecular structures of the dialkanolamines 1 and 2 are characterized by intra- and intermolecular O-H ··· O(H) hydrogen bridges giving rise to formation of eight-membered O4H4 rings (1) and polymeric chains (2). The 5-aza-2,8-dioxasilabicyclo[3.3.01.5]octanes show intramolecular N→Si interactions at distances of 2.961(2) (3) and 2.970(2) (4) Å, respectively. Also reported is the molecular structure of the hexachloridostannate salt [Ph(H)N(CH2CH2OH)2]2SnCl6 (6a) that was serendipitously obtained from the reaction of compound 3 with Ph3CSnCl5 under non-inert reaction conditions. Furthermore, DFT calculations on 3 and 4 as well as cyclovoltammetric studies were performed.

Keywords

• 5-aza-2,8-dioxasilabicyclo[3.3.01.5]octanes
• cyclic voltammetry
• dft calculations
• hypercoordinated silicon
• x-ray diffraction analysis