Search results for " infrared"

Synthesis, characterization and conformational analysis of chloro-bis(glycylglycinate)germanium(IV) chloride

2011

Chloro-bis(glycylglycinate)germanium(IV) chloride, [Cl(glygly)2Ge]Cl, was synthesized and characterized in the solid state by elemental analysis, thermogravimetry and infrared spectroscopy. Solution studies were also performed by 1H-NMR and 13C-NMR in dimethylsulfoxide (DMSO-d6) and by electric conductivity. The structural determination of the complex and the interpretation of the spectroscopic results were performed by employing an integrated computational approach, based on a systematic conformational search analysis on the [Cl(glygly)2Ge]+ ion performed by the Systematic Conformational Search Algorithm (SCSA) code, working at the hybrid B3LYP/6-31G(d,p) level. The combination of experime…

The shell matrix of the freshwater mussel Unio pictorum (Paleoheterodonta, Unionoida). Involvement of acidic polysaccharides from glycoproteins in na…

2007

13 pages; International audience; Among molluscs, the shell biomineralization process is controlled by a set of extracellular macromolecular components secreted by the calcifying mantle. In spite of several studies, these components are mainly known in bivalves from only few members of pteriomorph groups. In the present case, we investigated the biochemical properties of the aragonitic shell of the freshwater bivalve Unio pictorum (Paleoheterodonta, Unionoida). Analysis of the amino acid composition reveals a high amount of glycine, aspartate and alanine in the acid-soluble extract, whereas the acid-insoluble one is rich in alanine and glycine. Monosaccharidic analysis indicates that the in…

GRAPHENE-BASED TRANSISTORS AND DETECTORS: FABRICATION AND CHARACTERIZATION

Carbon and carbon-based systems have always attracted great attention thanks to the almost unlimited different structures they can be arranged in and the equally varied physical properties they own. These characteristics are mainly related to the flexibility of carbon bonding, which makes carbon an extremely versatile “building block” material. Most of the typical properties of each carbon-based system are mainly associated with the dimensionality of the structure itself. In this framework, graphene, the first two-dimensional atomic crystal available to the scientific community, has revealed to play a key role in terms of fundamental physics and potential applications, despite its short sto…

Complexes of Glycolic Acid with Nitrogen Isolated in Argon Matrices. I. Structures and Thermal Effects.

2019

Molecular complexes between glycolic acid and nitrogen were studied in a low-temperature argon matrix with FTIR spectroscopy, and supported by MP2 and BLYPD3 calculations. The calculations indicate 11 and 10 stable complex structures at the MP2 and BLYPD3 levels of theories, respectively. However, only one hydrogen-bonded complex structure involving the most stable SSC conformer of glycolic acid was found experimentally, where the nitrogen molecule is bound with the carboxylic OH group of the SSC conformer. The complex shows a rich site structure variation upon deposition of the matrix in different temperatures and upon annealing experiments, which provide interesting prospects for site-sel…

Experimental FTIR-MI and Theoretical Studies of Isocyanic Acid Aggregates

2023

Homoaggregates of isocyanic acid (HNCO) were studied using FTIR spectroscopy combined with a low-temperature matrix isolation technique and quantum chemical calculations. Computationally, the structures of the HNCO dimers and trimers were optimized at the MP2, B3LYPD3 and B2PLYPD3 levels of theory employing the 6-311++G(3df,3pd) basis set. Topological analysis of the electron density (AIM) was used to identify the type of non-covalent interactions in the studied aggregates. Five stable minima were located on the potential energy surface for (HNCO)2, and nine were located on the potential energy surface for (HNCO)3. The most stable dimer (D1) involves a weak, almost linear N-H⋯N hydrog…

Co-reductive fabrication of carbon nanodots with high quantum yield for bioimaging of bacteria

2018

A simple and straightforward synthetic approach for carbon nanodots (C-dots) is proposed. The strategy is based on a one-step hydrothermal chemical reduction with thiourea and urea, leading to high quantum yield C-dots. The obtained C-dots are well-dispersed with a uniform size and a graphite-like structure. A synergistic reduction mechanism was investigated using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The findings show that using both thiourea and urea during the one-pot synthesis enhances the luminescence of the generated C-dots. Moreover, the prepared C-dots have a high distribution of functional groups on their surface. In this work, C-dots proved …

Characterization of Rabbit Mesenchymal Cell Attachment on Calcium Phosphate Surface

2014

In the current study, the effect of three different treated surfaces of hydroxyapatite and β-tricalcium phosphate on mesenchymal cell attachment has been investigated. Calcium phosphate powders have been synthesized, uniaxially pressed, polished and sintered. Mesenchymal cells have been seeded onto unpolished, polished and polished-thermally etched ceramic samples. The ceramic samples have been characterized by XRD, FTIR and SEM. Results have shown that the best cell attachment and morphology are on the unpolished surface indicating that relatively rough surface is better for cell application.

Metal ions modulate thermal aggregation of betalactoglobulin: a join chemical and physical characterization

2014

Abstract Molecular basis of the role played by Cu 2 + and Zn 2 + ions during the thermal aggregation processes of beta-lactoglobulin (BLG) was studied by using a joint application of different techniques. In particular, Raman spectroscopy was very useful in identifying the different effects caused by the two metals at molecular level (i.e. changes in His protonation state, disulfides bridge conformation, and micro-environment of aromatic residues), evidencing the primary importance of the protein charge distribution during the aggregation process. Both metal ions are able to act on this factor and favor the protein aggregation, but Zn 2 + is able to alter the natural conformational state of…

Preparation of 2,3-seco-5α-cholestane-2,3-diol and 4α-methyl-2,3-seco-5α-cholestane-2,3-diol and its reactions with o-nitrophenyl selenocyanate

1984

The reaction of 2,3-seco-5 alpha-cholestane-2,3-diol and 4 alpha-methyl-2,3-seco-5 alpha-cholestane-2,3-diol with o-nitrophenyl selenocyanate was studied. The diols were synthesized from cholesterol.

Optimized bath for electroless deposition of palladium on amorphous alumina membranes

2006

A new bath for the electroless deposition of palladium on anodic alumina (AA) membranes is proposed. It was found that the optimal conditions for the uniform deposition of palladium, with minimal damage to the AA membranes, were under conditions of pH 8.4 and plating times shorter than 30 min. The deposited Pd layer was detected by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis. The morphology of the AA membrane before and after plating was examined by scanning electron microscopy (SEM). EDX analysis revealed that palladium was deposited only on the surfaces of the membrane and Sn ions, coming from the sensitizing bath, were incorporated into the palladium layer. EDTA in…