Preparation and characterization of urea-oxalic acid solid form

Yadav

Photochem & Photobiology

et al. 2021

An efficient photocatalytic regeneration of nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH) has been carried out by two-electron reduction and protonation of NAD + /NADP + , induced by photons in the visible light region. This functional artificial photosynthetic counterpart of the complete energy-trapping occurring in natural photosystem I (PS I) is achieved with nitrogen-enrich graphene quantum dot (N-EGQD) as the light-harvesting photocatalyst. In buffer aqueous solution, this compound photo catalytically recycles a rhodium hydride complex of the type [Cp*Rh(bpy)H] + (Cp* = pentamethylcyclopentadienyl, bpy = 2,2 0 -bipyridine) which can mediate hydride transfer processes leading to nucleotide co-factor reduction. Very promising yields of 73.31%/78.45% of NADH/NADPH with the excellent thermal stability of N-EGQD photocatalyst is observed. Thus, in this work, an efficient light-harvesting photocatalyst is synthesized for the regeneration of nicotinamide cofactor that has pharmaceuticals application.

Section: Resultsmentioning

confidence: 99%

“…The electrons and proton transferred from PS I reduces NAD+/NADP+ to NADH/NADPH via ferredoxin reductase enzyme (Scheme 1a) (18). In the light-independent reaction, the produced NADH/NADPH is used as a hydride source for the synthesis of glucose (19,20).…”

Section: Resultsmentioning

confidence: 99%

One‐Pot Highly Efficient Synthesis of N‐Enrich Graphene Quantum Dots as a Photocatalytic Platform for NAD+/NADP+ Reduction

Yadav

Photochem & Photobiology

et al. 2021

“…Moreover, the bands at 2927 and 2851 cm −1 are much weaker in the ZnS film deposited on AAO_oxalic with smaller D c and D p parameters as compared to the ones deposited on AAO_phosphoric. Besides, in the IR spectra there are other peaks related to the AAO porous ceramic anodized in oxalic acid solution [46,47]. The bands at 2339 and 2263 cm −1 in pure AAO_oxalic sample may come from v(CH) vibrations of the absorbed hydrogen [48].…”

Section: Resultsmentioning

confidence: 99%

Infrared Absorption Study of Zn–S Hybrid and ZnS Ultrathin Films Deposited on Porous AAO Ceramic Support

2020

Infrared (IR) spectroscopy is a powerful technique to characterize the chemical structure and dynamics of various types of samples. However, the signal-to-noise-ratio drops rapidly when the sample thickness gets much smaller than penetration depth, which is proportional to wavelength. This poses serious problems in analysis of thin films. In this work, an approach is demonstrated to overcome these problems. It is shown that a standard IR spectroscopy can be successfully employed to study the structure and composition of films as thin as 20 nm, when the layers were grown on porous substrates with a well-developed surface area. In contrast to IR spectra of the films deposited on flat Si substrates, the IR spectra of the same films but deposited on porous ceramic support show distinct bands that enabled reliable chemical analysis. The analysis of Zn-S ultrathin films synthesized by atomic layer deposition (ALD) from diethylzinc (DEZ) and 1,5-pentanedithiol (PDT) as precursors of Zn and S, respectively, served as proof of concept. However, the approach presented in this study can be applied to analysis of any ultrathin film deposited on target substrate and simultaneously on porous support, where the latter sample would be a reference sample dedicated for IR analysis of this film.

“…Thus, it is a popular functional molecule for cocrystal design especially in the pharmaceutical industry. 23 Uracil has two carbonyl sites and two amino groups available for hydrogen bonds. Therefore, there is a high possibility for the formation of a cocrystal between urea and uracil with assembly driven through hydrogen bonds.…”

Section: Resultsmentioning

confidence: 99%

“…Urea has the ability to trap many organic compounds. Thus, it is a popular functional molecule for cocrystal design especially in the pharmaceutical industry . Uracil has two carbonyl sites and two amino groups available for hydrogen bonds.…”

Section: Resultsmentioning

confidence: 99%

Molecular Recognition and Interaction between Uracil and Urea in Solid-State Studied by Terahertz Time-Domain Spectroscopy

Yang

Zhao

et al. 2014

J. Phys. Chem. A

Using terahertz time-domain spectroscopy characterization, we observe that urea is able to recognize and interact with uracil efficiently even in the solid phase without involving water or solvents. A cocrystal configuration linked by a pair of hydrogen bonds between uracil and urea was formed. The terahertz absorption spectrum of the cocrystal shows a distinct new absorption at 0.8 THz (26.7 cm(-1)), which originates from the intermolecular hydrogen bonding. Both mechanical milling and heating can accelerate the reaction efficiently. Density functional theory was adopted to simulate the vibrational modes of the cocrystal, and the results agree well with the experimental observation. Multiple techniques, including powder X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy, were performed to investigate the reaction process, and they presented supportive evidence. This work enables in-depth understanding of recognition and interaction of urea with nucleobases and comprehension of the denaturation related to RNA. We also demonstrate that terahertz spectroscopy is an effective and alternative tool for online measurement and quality control in pharmaceutical and chemical industries.