Luminescent porphyrinosilica obtained by the sol–gel method

Fluorescent porphyrins covalently bound to silica xerogel matrices

“…2). In the first step, the porphyrin molecule was bound to -f to create the H 2 P-f precursor [47,48]; this was performed at 70°C and times up to 72 h and under a N 2 atmosphere and using a 1:40 molar ratio between the H 2 T(S)PP species and -F (IPTES or APTES). The H 2 T(o-NH 2 )PP species was bound to IPTES (gels 1-6, Table 1) while the H 2 T(p-COOH)PP species was linked to APTES (gels 7-11, Table 1); the evolution of each of these reactions was monitored by FTIR spectroscopy.…”

“…The sol-gel process has allowed the preparation of gel-derived optical silica components, such as the type VI gels (optically transparent porous silica gel) [27,28], and a large number of systems consisting of organic and biological molecules inserted in oxide networks [17,19,20]. However, only in recent years major attention has been conferred to the problem of effectively trapping or binding porphyrins onto inorganic metal oxides [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48], the optimization of these systems and their technological applications.…”

“…water or alcohols, appropriate chemical substituent groups (S = -F, -NO 2 , -NH 2 , -OH, -COOH, -SO 3 H) can be placed around the periphery of the macrocycle. In this way, it is then possible to insert or binding porphyrins and other macrocyclic species in metal oxide powders as well as in thin films, and monolithic xerogels [19,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48].…”

“…At this respect, some methods have been reported but still the formation of covalent bonds in systems of this sort has not yet been clearly proved [34][35][36][37][41][42][43]. Here, we have carefully followed by FTIR spectroscopy the reaction between the porphyrin molecule of interest and the functionalized alkoxide (-f) in order to create a precursory H 2 P-f species, in which some appropriate substituent groups of the porphyrin molecules and the organic functional group of -f are covalently bound [47,48]. The present work describes the development of efficient methods to synthesize silica xerogels with the H 2 T(p-OH)PP, H 2 T(p-COOH)PP, or H 2 T(o-NH 2 )PP species covalently bound inside the pore structure.…”

Homogeneous and Heterogeneous Free-Based Porphyrins Incorporated to Silica Gel as Fluorescent Materials and Visible Light Catalysts Mimic Monooxygenases

“…Such materials have many potential applications due to their catalytic, biosensing, optical, photo-electronic, photonic, and nanobiophotonic properties (Lan et al, 1999;Gill & Ballesteros, 2000;Ariga et al, 2007;Escribano et al, 2008). Porphyrins have been encapsulated in sol-gel materials (either in monolithic blocks or as thin layers on various supports) because of their ability of photoconduction and photoemission, in the context of their application as fluorescent materials (Papkovsky et al, 2000;García-Sánchez et al, 2006;De la Luz et al, 2007) optical sensors (Delmarre & BiedCharreton, 2000;Im et al, 2005), dye sensitive solar cells (Grätzel, 2001;Ray et al, 2001), and non-linear absorption (Sun et al, 1997), mesoporous materials (Ariga et al, 2007), as well as sensitizers in photodynamic therapy (PDT) (Reisfeld, 2001;Podbielska et al, 2006).…”