Objectives: The objective of this identification is to identify the decomposition products using standard identification techniques.
Methods: Bis[2-(3{7-oxabicyclo[4.1.0]heptyl})ethyl]methylphenyl silane was synthesized by heating solution of 4-vinyl-1-cyclohexene 1,2-epoxide, methylphenylsilane, toluene, and Wilkinson's catalyst to 100 °C for 24 h using a modified procedure of Crivello.1 The reaction was monitored for completion by IR spectroscopy for disappearance of the Si-H peak at 2160 cm-1. Column chromatography was used (silica gel; solvent, 90:10 hexane:ethyl acetate), followed by removal of the solvent under vacuum to isolate pure product (41% yield).
Results: Even though the product was kept at 0 °C and under argon, new peaks in the 1H NMR spectrum were observed. These peaks increase with respect to time, and the decomposition products can be removed using column chromatography as described previously. When the pure bis[2-(3{7-oxabicyclo[4.1.0]heptyl})ethyl]methylphenyl silane is mixed in equal proportions with 2,4,6,8-tetrakis(2-(7-oxabicyclo[4.1.0]heptan-3-yl)ethyl)-2,4,6,8-tetramethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane, the material is stable for over two weeks. The degradation products will be further elucidated using NMR spectroscopy as well as other standard identification techniques.
Conclusion: It was found that bis[2-(3{7-oxabicyclo[4.1.0]heptyl})ethyl]methylphenyl silane is not stable even with the exclusion of light and air. It is only stable for no more than four days. When mixed in equal proportions of 2,4,6,8-tetrakis(2-(7-oxabicyclo[4.1.0]heptan-3-yl)ethyl)-2,4,6,8-tetramethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane, the mixture is stable for over two weeks.
This work was supported in part by NIH/NIDCR Grant R21 DE018336, NIH/NIDCR T32 (DE07294), and Missouri Life Science Research Board Grant (#13234-2007).
1. J.V. Crivello and D. Bi, J. Poly. Sci.: Part A: Poly Chem. 1994, 32, 683-697.