The Advances in Research of Complexes of Chitosan and its Derivatives

Chitosan is a partially deacetylated polymer of acetyl glucosamine obtained byalkaline deacetylation of chitin. It displays interesting properties such as biocompatibility, biodegradability as its degradation products are non-toxic, non-immunogenic, and non-carcinogenic. It can be modified chemically for the presence of amino and hydroxyl groups to prepare functional derivatives of chitosan. Chitosan and its derivatives have good adsorption ability for metal ions due to theirs high percentage of nitrogen, amino and hydroxyl groups on their chemical structure act as chelation sites for metal ions. This article reviews the developments of the studies on coordination between chitosan, derivatives and metal ions, as well as the applications of chitosan-based complexes in many fields such as antibacterial effect, the catalysts, metal recovery and detection, and agriculture.

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Adsorpsi Logam Ni dan Cu pada Limbah Cair Laboratorium Kimia menggunakan Biosorben Batang Jagung Termodifikasi Asam Sitrat

ALCHEMY ◽

10.18860/al.v7i1.7933 ◽

2019 ◽

Vol 7 (1) ◽

pp. 13

Author(s):

Eny Yulianti ◽

RIf'atul Mahmudah ◽

Ainul Ma'rifah ◽

Ulal Azmiyani

Keyword(s):

Citric Acid ◽

Metal Ions ◽

Functional Group ◽

Liquid Waste ◽

Hydroxyl Groups ◽

Corn Stalk ◽

Adsorption Ability ◽

Chemical Laboratory ◽

Lactone Group ◽

Carboxylic Groups

Corn stalk contains 40-50% cellulose, 20-40% hemicellulose, 4-15% lignin which had potential as biosorbent in binding metal ions. In this study, demineralization and modification by adding citric acid (1.5 M and 2 M) of corn stalk were conducted to convert hydroxyl groups into carboxylic. Then, it was analyzed its functional groups using Boehm titration and FTIR. The modified corn stalk was applied directly to chemical laboratory liquid waste which contains multicomponent of heavy metal ions. By modifying the corn stalk, the number of hydroxyl and carboxylic groups increased, but the number of lactone group was constant. The success of the modification was characterized by the appearance of ester uptake at 1734 cm-1 and increased adsorption ability. The variations in the concentration of citric acid in modification corn stalk showed that biosorbent with addition 1.5 M citric acid had higher in the number of acid site than addition 2 M citric acid to absorb Ni and Cu. Keywords: Corn stalk, citric acid, biosorbent, functional group Batang jagung mengandung sekitar 40-50% selulosa, 20-40% hemiselulosa, 4-15% lignin yang berpotensi sebagai biosorben pengikat ion logam. Pada penelitian ini dilakukan demineralisasi dan modifikasi dengan penambahan asam sitrat (1,5 M dan 2 M) untuk mengubah gugus hidroksil pada selulosa membentuk karboksilat. Selanjutnya, dianalisis gugus fungsinya menggunakan titrasi Boehm dan FTIR. Hasil modifikasi diaplikasikan langsung pada limbah cair laboratorium kimia yang mengandung banyak jenis ion logam berat. Biosorben batang jagung setelah dimodifikasi mengalami peningkatan jumlah gugus fungsi hidroksil dan karboksilat, tetapi gugus lakton tetap. Keberhasilan modifikasi ditandai dengan munculnya serapan ester pada 1734 cm-1 dan peningkatan kemampuan adsorpsi. Dari hasil variasi konsentrasi asam sitrat diperoleh informasi bahwa biosorben dengan penambahan asam sitrat 1,5 M mempunyai situs asam lebih tinggi dan mempunyai kemampuan adsorpsi terhadap ion logam Ni dan Cu lebih besar dibanding penambahan asam sitrat 2 M. Kata kunci: Batang jagung, asam sitrat, biosorben, gugus fungsi

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New bio-amphiphilic structures of sucrose via amides linkages

International Journal of Research in Pharmaceutical Sciences ◽

10.26452/ijrps.v10i4.1612 ◽

2019 ◽

Vol 10 (4) ◽

pp. 3143-3154

Author(s):

Salih Mahdi Salman

Keyword(s):

Chemical Structure ◽

13C Nmr Spectroscopy ◽

Alkyl Halides ◽

Hydroxyl Group ◽

Hydroxyl Groups ◽

Staudinger Reaction ◽

Target Structure ◽

Leaving Group ◽

Derivatives Of ◽

Resolution Mass

A series of four new derivatives of sucrose have been synthesized using the straightforward methodology in order to give a mono substituted analogs of sucrose at C-6’ of fructose moiety. The synthesis was started from the reaction of sucrose with tert-butylchlorodiphenylsilane, which is able to react with an only less steric hindrance hydroxyl group at C-6’ due to its bulky structure. The other hydroxyl groups were acetylated by the reaction with acetic anhydride in pyridine. Then free the hydroxyl group at C-6’ again by the treatment with t-butylammonium fluoride in THF. The later was activated by conversion to a good leaving group via tosylation, followed by functionalized via azidation to give the precursor of the target series hepta-O-acetyl-6’-azido- sucrose. The precursor was coupled with four alkyl halides (C12, C8-4, C14, C10-8) via Staudinger reaction to produced the target structure after deacetylating. The purity and chemical structure of the synthesized compound was confirmed by CHN elemental analysis, high-resolution mass and 1H, 13C NMR spectroscopy.

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The role of secondary alcoholic groups of D-galacturonan in its degradation with exo-D-galacturonanase

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19800427 ◽

1980 ◽

Vol 45 (2) ◽

pp. 427-434 ◽

Cited By ~ 4

Author(s):

Kveta Heinrichová ◽

Rudolf Kohn

Keyword(s):

Acetyl Derivative ◽

Competitive Inhibitor ◽

Hydroxyl Groups ◽

Pectic Acid ◽

Substrate Complex ◽

Enzyme Substrate ◽

The Individual ◽

Degradation Degree ◽

Derivatives Of

The effect of exo-D-galacturonanase from carrot on O-acetyl derivatives of pectic acid of variousacetylation degree was studied. Substitution of hydroxyl groups at C(2) and C(3) of D-galactopyranuronic acid units influences the initial rate of degradation, degree of degradation and its maximum rate, the differences being found also in the time of limit degradations of the individual O-acetyl derivatives. Value of the apparent Michaelis constant increases with increase of substitution and value of Vmax changes. O-Acetyl derivatives act as a competitive inhibitor of degradation of D-galacturonan. The extent of the inhibition effect depends on the degree of substitution. The only product of enzymic reaction is D-galactopyranuronic acid, what indicates that no degradation of the terminal substituted unit of O-acetyl derivative of pectic acid takes place. Substitution of hydroxyl groups influences the affinity of the enzyme towards the modified substrate. The results let us presume that hydroxyl groups at C(2) and C(3) of galacturonic unit of pectic acid are essential for formation of the enzyme-substrate complex.

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ChemInform Abstract: BROMINATION OF FUNCTIONAL DERIVATIVES OF SOME VINYLACETYLENE HYDROCARBONS AND SILICON HYDROCARBONS

Chemischer Informationsdienst ◽

10.1002/chin.197644149 ◽

1976 ◽

Vol 7 (44) ◽

pp. no-no

Author(s):

T. R. BORONOEVA ◽

N. N. BELYAEV ◽

M. D. STADNICHUK ◽

A. A. PETROV

Keyword(s):

Functional Derivatives ◽

Derivatives Of

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Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI

Molecules ◽

10.3390/molecules26082131 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2131

Author(s):

Leonardo Dalseno Antonino ◽

Júlia Rocha Gouveia ◽

Rogério Ramos de Sousa Júnior ◽

Guilherme Elias Saltarelli Garcia ◽

Luara Carneiro Gobbo ◽

...

Keyword(s):

Experimental Work ◽

Chemical Structure ◽

31P Nmr ◽

Kraft Lignin ◽

Hydroxyl Group ◽

Hydroxyl Groups ◽

Diphenylmethane Diisocyanate ◽

Complex Chemical ◽

Heterogeneous Reactivity ◽

Phenolic Hydroxyl Groups

Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers.

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Utilization and simulation of innovative new binuclear Co(ii), Ni(ii), Cu(ii), and Zn(ii) diimine Schiff base complexes in sterilization and coronavirus resistance (Covid-19)

Open Chemistry ◽

10.1515/chem-2021-0068 ◽

2021 ◽

Vol 19 (1) ◽

pp. 772-784

Author(s):

Moamen S. Refat ◽

Ahmed Gaber ◽

Walaa F. Alsanie ◽

Mohamed I. Kobeasy ◽

Rozan Zakaria ◽

...

Keyword(s):

Schiff Base ◽

Molecular Docking ◽

Metal Ions ◽

Free Ligand ◽

Schiff Base Complexes ◽

Hydroxyl Groups ◽

Binuclear Complexes ◽

Central Metal ◽

H Nmr ◽

Biological Studies

Abstract This article aimed at the synthesis and molecular docking assessment of new diimine Schiff base ligand, namely 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxyvinyl)hydrazono) methyl)-6-methoxyphenol (methoxy-diim), via the condensation of 1-(4-chloro-phenyl)-2-hydrazino-ethenol compound with 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxy vinyl) hydrazono)methyl)-6-methoxyphenol in acetic acid as well as the preparation of new binuclear complexes of Co(ii), Ni(ii), Cu(ii), and Zn(ii). The following synthesized complexes were prepared in a ratio of 2:1 (metal/ligand). The 1H-NMR, UV-Vis, and FTIR spectroscopic data; molar conductivity measurements; and microanalytical, XRD, TGA/DTG, and biological studies were carried out to determine the molecular structure of these complexes. According to the spectroscopic analysis, the two central metal ions were coordinated with the diamine ligand via the nitrogen of the hydrazine and oxygen of the hydroxyl groups for the first metal ions and via the nitrogen of the hydrazine and oxygen of the phenol group for the second metal ions. Molecular docking for the free ligand was carried out against the breast cancer 3hb5-oxidoreductase and the 4o1v-protein binding kidney cancer and COVID-19 protease, and good results were obtained.

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Identification of Crosslinked Fibrin Degradation Products in Plasma of Patients During Fibrinolytic Therapy Using a Heat Extraction/SDS-Polyacrylamide Gradient Gel Electrophoretic Technique

10.1055/s-0039-1684842 ◽

1979 ◽

Author(s):

C.W. Francis ◽

V. J. Marder ◽

S.E. Martin

Keyword(s):

Degradation Products ◽

Fibrinolytic Therapy ◽

Heat Extraction ◽

Molecular Weights ◽

Fibrin Degradation Products ◽

Normal Plasma ◽

Electrophoretic Technique ◽

Gradient Gel Electrophoresis ◽

Derivatives Of

To quantitate plasmic degradation products of crosslinked fibrin in plasma, a technique has been developed which employs heat precipitation, SDS-polyacrylamide gradient gel electrophoresis of the dissolved, reduced heat precipitate, and quantitation by densitometrie analysis of γ-γ derivatives identified in the stained get. When studied with this sensitive electrophoretic technique, plasmic digests of purified crosslinked fibrin were found to contain a heterogeneous group of γ-γ chain derivatives with molecular weights between 76,000 and 100,000 daltons. In samples of normal plasma to which digests of crosslinked fibrin had been added, this heat extraction/ge1 electrophoretic technigue allowed the detection of γ-γ derivatives with a sensitivity of 20 µg/ml. Derivatives of γ-γ chains with molecular weights of 82,000 and 86,000 daltons have been identified in the plasma of patients with DIC and during fibrinolytic therapy but were not found in normal plasma or in normal plasma treated in vitro with urokinase. This quantitative assay can be performed in 24 hours and appears to be of value in judging the efficacy of thrombolytic therapy.

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