Published online by Cambridge University Press: 21 February 2011
Standard sol-gel procedures have been modified to permit sol-gel synthesis to be performed at varying hydrogen ion concentrations and in a variety of organic solvents. These modifications greatly expand the variety of guest molecules that can be incorporated into nondense glassy environments. Processing conditions can be controlled such that the guest compounds generally retain their solution properties thereby allowing new molecular composites to be formed. Reported herein is the incorporation of both porphyrins and metalloporphyrins into silica matrices. Electronic absorption, vibrational, and excited state luminescence properties of the resulting composites clearly demonstrate that the molecular and electronic structure of the porphyrins and metalloporphyrins are preserved during sol-gel processing and in the ceramic matrices. This retention of properties has been shown for guest molecules doped into monoliths as well as films.