Luminescent hybrid porphyrinosilica obtained by sol gel chemistry

Abstract

The sol-gel process is a methodology used to obtain organic-inorganic hybrid solids, which open new possibilities in the field of material science. The sol-gel technique offers a low temperature attractive approach for introducing organic molecules into amorphous materials. In order to introduce tetrakis (2-hydroxy-5-nitrophenyl)porphyrin covalently bounded to a silicate matrix, the inorganic precursor 3-isocyanatopropyltriethoxysilane was added (molar ratio 2:1) to the porphyrin solution in anhydrous dimethylformamide and triethylamine. The isolated porphyrin and the hybrid porphyrinosilica have excitation maximum centred at 400 nm and 424 nm, respectively and the emission spectra for both materials has bands centred at 650 nm and 713 nm. The formation of hybrid matrix was investigated by FTIR.

Crossed and Linked Histories of Tetrapyrrolic Macrocycles and Their Use for Engineering Pores within Sol-Gel Matrices

“…Although diverse investigations were made in the past, it was until the end of the last century, and specifically during the last decade that a serious development of methodologies to covalently bond tetrapyrrole macrocycles to inorganic networks through the sol-gel process was undertaken.The Brazilian group of Serra et al . [ 401 , 402 , 403 , 404 , 405 ] was perhaps the most persistent research group in this respect.…”

“…Due to the well defined characteristics of model mesoporous materials, these substrates have potential applications as catalysts, adsorbents, trapping agents, in chromatography, optics, sensors and other interesting applications. In particular, several authors have investigated the possibility of synthesizing hybrid materials for catalysis based on porphyrin and phthalocyanine species trapped or bonded to the metal oxide inorganic mesoporous networks [ 394 , 395 , 396 , 397 , 398 , 399 , 400 , 401 , 402 , 403 , 404 , 405 , 417 , 418 , 419 , 420 , 421 ].…”

Nanostructured Glasses Based on Hybrid Silica Materials Incorporating a New Asymmetrical Phenyl-Substituted Porphyrin

“…A benefit brought by nanomaterials is their ability of varying their fundamental properties e.g. magnetization, optical properties, hardness, relative to bulk materials without a change in chemical composition, that enable the nanoporous materials to be used widely in mutual applications, such as luminescent materials [1], catalysts [2] versatile stationary phases in liquid chromatography [3], sensing of oxygen [4] or NO 2 at ppm levels [5], transducers in sensing systems [6] and so on. State of the art of nanomaterials research are based on techniques that afford the self-assembly of nanoscale species [7,8] exhibiting a high surface areas and tunable, uniform pore sizes (2-10 nm) [9].…”

Physicochemical properties of Mg-phthalocyanine molecules covalently bonded to the surface of nanopores in a silicate gel matrix

“…Two widely used methods for incorporating dyes into nanoporous xerogels are the direct synthesis method (when the initial sol-gel reaction mixture is dyed) and the method of impregnation of the xerogels from an external solution. Although they each have their own disadvantages (the limited number of suitable solvents and the low-temperature heat treatment conditions for the first, and also the nonuniversality of the second for different classes of dyes), nevertheless they are promising for use in production of xerogels as dye-based laser-active media [2], optical limiters [3], materials for optical recording and storage of information [4], sensors [5], and other materials.In recent years, a new method for dyeing inorganic xerogels has been developed: the method of chemical "grafting" of the dye molecules to the surface of the nanopores in the xerogel [6][7][8][9][10][11][12][13][14][15][16]. In this case, metal alkoxide derivatives are used with two different types of functional groups: one that can react with "suitable" reactive substituents of the dye molecule, and a second (the alkoxy group) that can participate in hydrolysis and condensation reactions.…”

“…In recent years, a new method for dyeing inorganic xerogels has been developed: the method of chemical "grafting" of the dye molecules to the surface of the nanopores in the xerogel [6][7][8][9][10][11][12][13][14][15][16]. In this case, metal alkoxide derivatives are used with two different types of functional groups: one that can react with "suitable" reactive substituents of the dye molecule, and a second (the alkoxy group) that can participate in hydrolysis and condensation reactions.…”