Pyrolytic Production of Fluorescent Pyrone Derivatives Produced in the Confined Space of Super-Microporous Silicas

Abstract

Fluorescent pyrone derivatives were extracted from the pyrolitic product of citric acid confined in supermicroporous silicas (SMPSs). We utilized the tiny spaces of SMPSs to produce fluorescent molecules as small fragments of carbogenic dots. We characterized their optical properties and investigated their structual information. The obtained molecule was determined as a pyrone derivative. The isolated product showed similar optical properties to those of reported carbogenic dots. Therefore, we suggest that the pyrone structure is the key fragment structure of carbogenic dots.

One-step solvent-free synthesis of carbon dot-based layered composites exhibiting color-tunable photoluminescence

“…[19][20][21][33][34][35][36][37][38][40][41][42][43][44][45][46][47][48] CD-based composites with enhanced stability and functions have been prepared by combining CDs with inorganic materials. [49][50][51][52][53][54][55][56][57][58][59][60] Although the combination of layered clay minerals and CDs was reported, [57][58][59][60] little is known about one-step solvent-free approach to the synthesis of luminescent CD-based composites. We envisaged that this approach would lead to facile, economical, and green production of CD-based nanostructured composites as well as improvement of thermal and photoluminescence properties.…”

Excitation-Independent Blue-Emitting Carbon Dots from Mesoporous Aminosilica Nanoreactor for Bioanalytical Application

“…20 Interesting research was published recently in which silicas with very small pores (1.2 and 3.0 nm) have been used as a host for the templated synthesis of C-dots from citric acid. 58 It can be seen from the above that application of mesoporous materials for the synthesis of C-dots allows confining the growth of embedded C-dots and preventing their agglomeration. However, the method still results in C-dots having different chemical natures and thus PL properties 11,20,21,26,59 that make their application in analytical science very doubtful.…”

“…Thus, the concept of C-dots requires further development, and better separation of the particles is needed before their application. For example, chromatographic separation of as-prepared C-dots allows obtaining nanoparticles with excitation-independent PL, 9,32,58 which is crucial for their applications in bioimaging and for the development of optical sensors. 2,33,35,63 In the current research, silica gels with covalently immobilized aminosilane (SiO 2 −NH 2 ) have been used for the first time for size-controlled synthesis C-dots from CA.…”

“…Recently it was demonstrated that nanoreactor synthesis of C-dots in the mesoporous template does not require high-temperature treatment (usually 170–250 °C) and oxidizing agents. ,,, For example, monodispersed spherical mesoporous silica with pores 3.1 nm was used for the templated synthesis of C-dots from (3-aminopropyl)­triethoxysilane on air at 250 °C . Dissolution in a HF nanocomposite resulted in luminescent C-dots with 3.5 ± 0.9 nm particles, that perfectly fit the size of the pores .…”

Benefit of porous silica nanoreactor in preparation of fluorescence carbon dots from citric acid

“…They have suitable pore size (from 1.5 to 11 nm) and hydrophilic surface, about 99% of the total silica gel surface is the area of mesopores. Thus, templated synthesis of CDs using mesoporous silicas attracts the most attention [46][47][48][49][50][51].…”