Determination of New IR and UV/VIS Spectroscopic Parameters of the C84-D2:22 Isomer for Its Quantitative Assessment, Identification and Possible Applications

The stable isomers of the higher fullerenes C76-D2 and C84-D2:22, as well as fullerenes C60 and C70 were isolated from carbon soot by the new and improved extraction and chromatographic methods and processes. Characterizations of the C84-D2:22 isomer in this study were performed by infrared and electronic absorption spectroscopy. All of the experimentally observed IR and UV/VIS bands were in excellent agreement with the semi-empirical, DFT and TB potential theoretical calculations for this molecule. The molar extinction coefficients and the integrated molar extinction coefficients of the observed larger number of completely separated infrared absorption maxima and shoulders of fullerene C84-D2:22, as well as of its main convoluted maxima, in different and new relevant entire integration ranges, including neighboring, and all surrounding absorption shoulders were determined and their relative intensities compared. In addition, the molar absorptivity of the electronic absorption bands of this carbon cluster was found. The new IR and UV/VIS spectroscopic parameters that are significant for the quantitative determination, identification and numerous possible applications of C84-D2:22 are obtained and their changes compared to C76-D2 observed. Isolated and characterized C84-D2:22, as well as other fullerenes from this research can be used in electronic, optical, chemical and biomedical devices, superconductors, semiconductors, batteries, catalysts, polymers, sensors, solar cells, nanophotonic lenses with better optical transmission, refraction and wettability, diagnostic and therapeutic pharmaceutical substances, such as those against diabetes, cancer, neurodegenerative disorders, free radical scavenging, radio nuclear, antibacterial and antiviral agents that can inhibit HIV 1, HSV, COVID-19, influenza, malaria and so forth.

Nitrogen Reduction by the Fe Sites of Synthetic [Mo3S4Fe] Cubes

N2 fixation by Nature, which is a crucial process to supply bio-available forms of nitrogen, is performed by nitrogenase. This enzyme employs a unique transition metal-sulfur-carbon cluster as its active-site cofactor ([(R-homocitrate)MoFe7S9C], FeMoco), and the sulfur-surrounded Fe atoms have been postulated to capture and reduce N2. Whereas synthetic counterparts of FeMoco, metal-sulfur clusters, have displayed binding of N2 in a few examples, the reduction of N2 by any synthetic metal-sulfur clusters or even by the extracted form of FeMoco have remained elusive despite a near-50-year history of research. Here we show that the Fe atoms in our synthetic [Mo3S4Fe] cubes capture an N2 molecule and catalyze N2 silylation to form N(SiMe3)3 under treatment with excess Na and Me3SiCl. These results exemplify the first catalytic N2 reduction by a synthetic metal-sulfur cluster with an Fe center supported only by S ligands. This work demonstrates the N2-reducing capability of Fe atoms in a S-rich environment, which Nature has selected to accomplish a similar purpose. This work also suggests some critical features for successful by metal-sulfur compounds, which serve as clues to understand the origin of N2 fixation on Earth.

Flexible Methyl Cellulose/Polyaniline/Silver Composite Films with Enhanced Linear and Nonlinear Optical Properties

In order to potentiate implementations in optical energy applications, flexible polymer composite films comprising methyl cellulose (MC), polyaniline (PANI) and silver nanoparticles (AgNPs) were successfully fabricated through a cast preparation method. The composite structure of the fabricated film was confirmed by X-ray diffraction and infrared spectroscopy, indicating a successful incorporation of AgNPs into the MC/PANI blend. The scanning electron microscope (SEM) images have indicated a homogenous loading and dispersion of AgNPs into the MC/PANI blend. The optical parameters such as band gap (Eg), absorption edge (Ed), number of carbon cluster (N) and Urbach energy (Eu) of pure MC polymer, MC/PANI blend and MC/PANI/Ag films were determined using the UV optical absorbance. The effects of AgNPs and PANI on MC polymer linear optical (LO) and nonlinear optical (NLO) parameters including reflection extinction coefficient, refractive index, dielectric constant, nonlinear refractive index, and nonlinear susceptibility are studied. The results showed a decrease in the band gap of MC/PANI/AgNPs compared to the pure MC film. Meanwhile, the estimated carbon cluster number enhanced with the incorporation of the AgNPs. The inclusion of AgNPs and PANI has enhanced the optical properties of the MC polymer, providing a new composite suitable for energy conversion systems, solar cells, biosensors, and nonlinear optical applications.

Flexible Methyl Cellulose/Polyaniline/Silver composite films with Enhanced Linear and Nonlinear Optical Properties

In order to potentiate implementations in optical energy applications, flexible polymer composite films comprising methyl cellulose (MC), polyaniline (PANI) and silver nanoparticles (AgNPs) were successfully fabricated through a solution cast preparation method. The composite structure of the fabricated film was confirmed by X-ray diffraction and infrared spectroscopy, indicating a successful incorporation of AgNPs into the MC/PANI blend. The optical parameters such as band gap (Eg), absorption edge (Ed), number of carbon cluster (N) and Urbach energy (Eu) of pure MC polymer, MC/PANI blend and MC/PANI/Ag film were determined by using the UV optical absorbance in the wavelength range 200 to 110 nm. The influence of AgNPs and PANI on linear optical (LO) and nonlinear optical (NLO )parameters such as reflection extinction coefficient, refractive index, dielectric constant, nonlinear refractive index and nonlinear susceptibility of MC polymer were also investigated. The results showed a decrease in the band gap of MC/PANI/AgNPs compared to the pure MC film. Meanwhile, the estimated carbon cluster number enhanced with the incorporation of the AgNPs. The addition of AgNPs and PANI also improved the optical parameters of MC polymer, a trait that makes the current composite a convenient material for optical energy applications.