Formation of silicon nanoclusters during the reaction of β-ionone with tetrachlorosilane

The chemical reaction between β-ionone and tetrachlorosilane yields silicon nanoclusters entrapped in a polysiloxane matrix along with a cyclized product of β-ionone as a side product. The IR spectrum observed in the entire region of 1000-1200 cm-1 indicates the polymer chain length, while UV absorption at 320 nm shows the presence of extended π-conjugation in the system. Photoluminescence spectrum shows a broad band with a maximum at 724 nm and is qualitatively similar to that of porous silicon and related q-particles. Transmission electron microscopy and selected area electron diffraction analysis show the presence of embedded nanocrystalline Si particles of average particle size 50-60 nm. ESR spectrum shows a sharp signal with a g value of 2.0138 due to the dangling bonds of silicon clusters, while cyclic voltammetry gives a reversible peak with E½at +1.92 V and an irreversible peak at -0.48 V vs saturated calomel electrode (SCE) confirming the mechanism of reductive silylation of the conjugated ketones