ABSTRACTPoly(l,4-phenylene)-bridged and poly(1,6-hexylene)-bridged silsesquioxanes
(PPS and HPS) were prepared by the sol-gel process. The surface areas and
pore diameters of these porous xerogels were obtained by BET and BJH
methods, respectively. These porous materials were used as a confinement
matrix for the growth of small-sized semiconductor and transition metal
clusters. Quantum-sized CdS particles in PPS (approximately 58+12 Â) and HPS
(91+16 Â) matrices were prepared by first soaking the xerogel in a
CdCl2 solution. Following a washing with water, a Na2S
solution was then added. EDAX and electron diffraction techniques were used
to identify the CdS particles. The particle sizes of CdS in PPS and HPS were
determined by both UV measurements and from TEM images. Small-sized Cr
clusters were prepared in dried xerogels by an internal doping method. Mixed
Cr/CdS phases were also prepared by internal loading of a chromium metal
precursor. Following deposition of CdS the xerogel was heated at 120 °C
under high vacuum, resulting in formation of intimately mixed phases of Cr
metal and CdS. Changes in morphology, in particular the surface area and
pore size distribution were noted. A decrease in surface area and an
increase in pore size were observed as a result of Cr metal deposition.
Structuring of Alkyl-Triazole Bridged Silsesquioxanes