scholarly journals New Di- and Triorganotin(IV) Tyrosylalaninates as Models for Metal—Protein Interactions: Synthesis, Structural Characterization, and Potentiometric Studies of Tyrosylalanine, Glycyltyrosine, and Glycylisoleucine with Di- and Trimethyltin(IV) Moieties in Aqueous Medium

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Mala Nath ◽  
Sulaxna ◽  
Xueqing Song ◽  
George Eng
Keyword(s):  
Protein Interactions ◽  
Water Soluble ◽  
Tridentate Ligand ◽  
Spectroscopic Techniques ◽  
Complex Species ◽  
Carboxylate Oxygen ◽  
Trigonal Bipyramidal ◽  
Bipyramidal Structure ◽  
Ft Ir ◽  
Ph Range

Di- and triorganotin(IV) derivatives of tyrosylalanine (H2Tyr-Ala) with general formula R2Sn(Tyr-Ala) (where R = Me, n-Bu, n-Oct, and Ph) and R3Sn(HTyr-Ala) (where R = Me and Ph) have been synthesized and structurally characterized in the solid state as well as in solution on the basis of various spectroscopic techniques, namely. FT-IR, multinuclear (1H, 13C and 119Sn) NMR and 119Sn Mössbauer. These investigations suggest that tyrosylalanine in R2Sn(Tyr-Ala) acts as dianionic tridentate ligand coordinating through carboxylate oxygen [–C(O)O−], amino (–NH2), and (CO)Npeptide- nitrogen, while in the case of R3Sn(HTyr-Ala), the ligand acts as monoanionic bidentate coordinating through –C(O)O− and –NH2, and the polyhedron around tin in R2Sn(Tyr-Ala) and R3Sn(HTyr-Ala) is a distorted trigonal-bipyramidal. Equilibrium (pH-metric) studies of the interaction of Me2Sn(IV)2+ and Me3Sn(IV)+ with dipeptides namely, tyrosylalanine (H2Tyr-Ala), glycyltyrosine (H2Gly-Tyr), and glycylisoleucine (H2Gly-Ile), in aqueous solution (I = 0.1 M KNO3, 298 K) have also been carried out. The concentration distribution of the various complex species in solution has been evaluated as a function of pH. It has been found that in these dipeptides, [–C(O)O−, N−, NH2] coordinated complexes are dominant in the neutral pH range with a trigonal-bipyramidal structure. The complex species formed are water soluble in the pH range 2.7–10.5. In all of the studied systems, no polymeric species have been detected in the experimental pH range. Beyond pH 8.0, significant amounts of hydroxo species, namely. Me3Sn(OH) and Me2Sn(OH)2, are formed.

The Stability and Structure of Complex Species Formed in Equilibrium Reactions of Diethyltin(IV) with N-D-Gluconylamino Acids in Aqueous Solution

1995 ◽  
Vol 50 (4) ◽  
pp. 515-523 ◽  
Author(s):  
B. Gyurcsik ◽  
N. Buzás ◽  
T. Gajda ◽  
L. Nagy ◽  
E. Kuzmann ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Amino Acid ◽  
Water Soluble ◽  
Complex Formation Equilibria ◽  
Complex Species ◽  
Carboxylate Oxygen ◽  
Equilibrium Reactions ◽  
Formation Equilibria ◽  
The Stability ◽  
Ph Range

Complex formation equilibria of diethyltin(IV) with five N-D-gluconylamino acids in aqueous solution (I = 0.1 M, NaClO4) were studied and the stabilities of the species were determined by potentiometric titrations. Diethyltin(IV) complexes of α-amino acid derivatives are water-soluble in the physiological pH range, while in the presence of N-D-gluconyl-β-alanine a precipitate is formed, which dissolves with increasing pH. 13C NMR measurements showed that in the N-D-gluconyl-α-amino acid complexes the ligand is coordinated through its deprotonated carboxylate oxygen, amide nitrogen and C(2)-hydroxy group, while for the soluble N-D-gluconyl-β-alanine complex the ligand is coordinated via the deprotonated carboxylate and C(3)-, C(4)-, C(5)-hydroxy groups. Mössbauer measurements reflected the geometry of the complexes formed.

scholarly journals Synthesis of water-soluble chitosan for biomedical applications

2015 ◽  
Vol 18 (3) ◽  
pp. 170-180
Author(s):  
Anh Thi Tram Tu ◽  
Huy Thuc Ha
Keyword(s):  
Drug Delivery ◽  
Molecular Weight ◽  
Iron Oxide ◽  
Biomedical Applications ◽  
Drug Delivery Systems ◽  
Water Soluble ◽  
Oxide Nanoparticles ◽  
Wide Ph Range ◽  
Ft Ir ◽  
Ph Range

Highly deacetylated chitosan (CS) reacted with anhydride acetic (Ac2O) to produce chitosan with various degree of deacetylation (DDA) depending on the CS/Ac2O ratios. The structure of products was characterized by FT-IR, 1H NMR, 13C NMR, and the molecular weight was identified by GPC. The DDA of products decreases as the CS/Ac2O ratio increases. The products with less than 80 % DDA were soluble in water with a wide pH range. The water-soluble chitosan can be used in many biomedical applications such as manufacturing drug delivery systems or functionalized iron oxide nanoparticles.

scholarly journals Synthesis and structural characterization of organotin(IV) complexes formed with [o,o] donor atoms of carboxylic acids

2008 ◽  
Vol 73 (2) ◽  
pp. 179-187 ◽  
Author(s):  
Mukhtiar Hussain ◽  
Muhammad Zaman ◽  
Muhammad Hanif ◽  
Saqib Ali ◽  
Muhammad Danish
Keyword(s):  
Mass Spectrometry ◽  
Elevated Temperature ◽  
13C Nmr ◽  
Solid Phase ◽  
Spectroscopic Techniques ◽  
Tetrahedral Geometry ◽  
Distorted Tetrahedral Geometry ◽  
Trigonal Bipyramidal ◽  
Ft Ir

Organotin(IV) carboxylates of the general formula RnSnL4-n (where R = Me, n-Bu or Ph, and L = ?-phenyl-2,3-(methylenedioxy)cinnamate anion or 2-(2,3-dimethlylanilino)nicotinate anion) have been prepared. The mono-, di- and tri-organotin(IV) carboxylates were synthesized by the reaction of organotin(IV) oxides or hydroxides with a stoichiometric amount of the ligand acids at an elevated temperature in dry toluene. The composition of the synthesized organotin(IV) complexes, the bonding behavior of the donor groups and structural assignments were studied by elemental analysis, FT-IR, 1H-, 13C-NMR and mass spectrometry. The spectral data suggest that the ligand acts in a bidentate manner, coordinating through the oxygen atoms. These spectroscopic techniques revealed a distorted tetrahedral geometry in the solution state for the tri-organotins, while a mean coordination number between five to six for the diorganotin(IV) dicarboxylates. In the solid phase, the tri-organotins were essentially trigonal bipyramidal polymeric while the di-organotins were octa?hedral. However, mono-organotin tricarboxylates were predicted to exist in the octahedral state both in solution as well as in the solid phase.

Solubility Enhancement of Poorly Water-Soluble Antifungal Drug Acyclovir by Nanocrystal Formulation Approach

2018 ◽  
Vol 11 (2) ◽  
pp. 4036-4042
Author(s):  
Prakash Goudanavar ◽  
Ankit Acharya ◽  
Vinay C.H
Keyword(s):  
Chemical Interaction ◽  
Research Work ◽  
Antiviral Drug ◽  
In Vitro Release ◽  
Oral Route ◽  
Water Soluble ◽  
Precipitation Method ◽  
Dsc Studies ◽  
Ft Ir

Administration of an antiviral drug, acyclovir via the oral route leads to low and variable bioavailability (15-30%). Therefore, this research work was aimed to enhance bioavailability of acyclovir by nanocrystallization technique. The drug nanocrystals were prepared by anti-solvent precipitation method in which different stabilizers were used. The formed nanocrystals are subjected to biopharmaceutical characterization including solubility, particle size and in-vitro release. SEM studies showed nano-crystals were crystalline nature with sharp peaks. The formulated drug nanocrystals were found to be in the range of 600-900nm and formulations NC7 and NC8 showed marked improvement in dissolution velocity when compared to pure drug, thus providing greater bioavailability. FT-IR and DSC studies revealed the absence of any chemical interaction between drug and polymers used. 

Pigment−Pigment and Pigment−Protein Interactions in Recombinant Water-Soluble Chlorophyll Proteins (WSCP) from Cauliflower

2007 ◽  
Vol 111 (46) ◽  
pp. 13325-13335 ◽  
Author(s):  
C. Theiss ◽  
I. Trostmann ◽  
S. Andree ◽  
F. J. Schmitt ◽  
T. Renger ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Water Soluble

scholarly journals Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions

2016 ◽  
Vol 12 ◽  
pp. 549-563 ◽  
Author(s):  
Vito Rizzi ◽  
Sergio Matera ◽  
Paola Semeraro ◽  
Paola Fini ◽  
Pinalysa Cosma
Keyword(s):  
Inclusion Complexes ◽  
Pyrimidine Ring ◽  
Protective Role ◽  
Supramolecular Structures ◽  
Water Soluble ◽  
Aqueous Environment ◽  
Spectroscopic Techniques ◽  
Guest Molecules ◽  
H Nmr ◽  
Cv Measurements

Since several years the inclusion of organic compounds (guests) within the hydrophobic cavity (host) of cyclodextrins (CDs) has been the subject of many investigations. Interestingly, the formation of inclusion complexes could affect the properties of the guest molecules and, for example, the influence of the delivery system can be a method to improve/change the photochemical behavior of the guest. In particular, very recent studies have shown the protective role of CDs preventing the degradation of the encapsulated guest. Starting from this consideration, in this work, only the structure and complexation mode of the inclusion complexes involving 4-thiothymidine (S4TdR, a known photosensitizer) and five CDs, namely 2-hydroxypropyl-α-cyclodextrin (2-HP-α-CD), 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD), 2-hydroxypropyl-γ-cyclodextrin (2-HP-γ-CD), heptakis-(2,6-di-O-methyl)-β-cyclodextrin (DIMEB CD) and heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (TRIMEB CD) were investigated by different spectroscopic techniques (UV–vis, FTIR–ATR, 1H NMR) and cyclic voltammetry analysis (CV). This work is necessary for a prospective research on the photoreactivity of S4TdR in aqueous environment and in the presence of CDs to prevent its degradation under irradiation. UV–vis, FTIR–ATR and CV measurements suggested the formation of supramolecular structures involving the employed CDs and mainly the pyrimidine ring of S4TdR. 1H NMR analyses confirmed such indication, unveiling the presence of inclusion complexes. The strongest and deepest interactions were suggested when TRIMEB and DIMEB CDs were studied. The S4TdR affinity towards CDs was also evaluated by using the Benesi–Hildebrand (B–H) equation at 25 °C employing CV and 1H NMR methods. The stoichiometry of the interaction was also inferred and it appears to be 1:1 for all examined CDs.

Nano-Sized [60]Fullerene-Cyclodextrin Molecules

2001 ◽  
Vol 675 ◽  
Author(s):  
Jeong-Seo Park ◽  
Han-Chang Kang ◽  
Kurt E. Geckeler
Keyword(s):  
Biomedical Applications ◽  
Addition Reaction ◽  
Water Soluble ◽  
Separation And Purification ◽  
Subsequent Reaction ◽  
Fullerene Derivatives ◽  
Covalently Bonded ◽  
Scattering Measurements ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

ABSTRACTAs [60]fullerene is a very hydrophobic macromolecule, there have been a number of attempts to make it more hydrophilic for biomedical applications. By attaching hydrophilic moieties such as poly(oxyethylene)(POE) chains and cyclodextrin molecules to [60]fullerene, novel water-soluble and biocompatible materials have been successfully prepared [1,2].The synthesis of novel macrocyclic fullerene conjugates which are water-soluble is reported. The telechelic fullerene derivatives have been prepared via addition reaction of POE-based arms with covalently bonded β-cyclodextrin (CD) to [60]fullerene. To this end, a mono-tosylated CD derivative has been prepared in pyridine and then reacted with an amino-functional POE in the presence of triethylamine. The subsequent reaction of [60]fullerene with the hydrophilic POE-conjugated CD-derivative yielded the macrofullerene after separation and purification procedures.The macrocyclic [60]fullerene derivatives obtained were soluble in water and characterized by UV-VIS and FT-IR spectroscopy as well as light scattering measurements and thermogravimetric analysis.

Liquid Crystalline Properties of 4,4and#39;-methylenebis(N-(4-Alkanoxybenzylidene)aniline): Synthesis, Characterization, and Theoretical study

2019 ◽  
Vol 41 (6) ◽  
pp. 1107-1107
Author(s):  
Mohammed Taha Yaseen and Abdullah Hussein Kshash Mohammed Taha Yaseen and Abdullah Hussein Kshash
Keyword(s):  
Liquid Crystalline ◽  
Theoretical Study ◽  
Basis Set ◽  
Spectroscopic Techniques ◽  
Benzene Nucleus ◽  
Crystal Properties ◽  
Ft Ir ◽  
Alkoxy Groups ◽  
Gaussian Program ◽  
Mesomorphic Properties

The paper presents six homologues series of Schiff bases ether compounds distinguished by the length of terminal alkoxy groups which substituted on a side benzene nucleus. The above structures were demonstrated through the use of spectroscopic techniques, like FT- IR and 1H-NMR. Polarized hot stage optical microscopy was used to study both mesomorphic properties and phase transitions. The results showed that out of the six compounds only three (B2, B3 and B4) were pure (marble) nematic mesophase, while no liquid crystal properties for (B5, B6 and B7) compounds. The theoretical study for the electronic structures was intended to study the effects of alkyl chain length on the electronic structure by using Gaussian program, DFT and 6-31G as basis set. The theoretical results indicate that there is no effect to the terminal substituted alkoxy groups on the HOMO energies but there is an effect on LUMO energies through decreasing energy for the prepared compounds.

scholarly journals The Influence of Storage Conditions on the Biochemical Composition and Morphology of Dahlia Tubers

2016 ◽  
Vol 44 (2) ◽  
pp. 459-465 ◽  
Author(s):  
Ioana CIOBANU ◽  
Maria CANTOR ◽  
Razvan STEFAN ◽  
Erzsebet BUTA ◽  
Klara MAGYARI ◽  
...  
Keyword(s):  
Biochemical Composition ◽  
Storage Conditions ◽  
Spectroscopic Techniques ◽  
Air Humidity ◽  
Raman Spectroscopic ◽  
Pathogen Invasion ◽  
Ft Ir ◽  
Biometric Measurements ◽  
C 30 ◽  
Ft Raman

The aim of this study was to assess by means of biometric measurements and FT-IR and FT-Raman spectroscopic techniques the influence of storage conditions on the morphology and biochemical composition of Dahlia tubers. Investigated samples belong to ‘Kennemerland’ and ‘Red Pygmy’ cultivars of the Dahlia hybrida species, which were preserved over winterat 5-8 °C, 30-40% air humidity in different substrates: sand, sand and sawdust, peat and sawdust. The biometric parameters revealed that the peat and sawdust substrate is the most appropriate one for tubers storage, whereas the sand substrate is the least suitable one. The inulin signature was evidenced in all tuber samples as well as the changes of biochemical composition induced by different storage conditions. The analysis of the FT-IR and FT-Raman spectra demonstrated that the inulinaccumulation inside the tubers is favourably influenced by the sand storage, and depends on the cultivar type. Moreover, it was established that the peat and sawdust substrate favours the polyacetylene formation inside the tubers probably because it facilitates the occurrence and development of pathogens inside the tuber. It was also found that the polyacetylene concentration increased, which is associated with the plant response to the pathogen invasion, depends on the cultivar type.

scholarly journals Spectroscopic Methods in the Evaluation of Modified Vegetable Base Oils from Crambe abyssinica

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3243 ◽  
Author(s):  
Michał Szmatoła ◽  
Justyna Chrobak ◽  
Rafał Grabowski ◽  
Jolanta Iłowska ◽  
Julia Woch ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Vegetable Oil ◽  
Supercritical Co2 ◽  
Spectroscopic Methods ◽  
Spectroscopic Techniques ◽  
Chemical Transformations ◽  
Chemical Changes ◽  
Crambe Abyssinica ◽  
Oxidation Processes ◽  
Ft Ir

Raw vegetable oil from Crambe abyssinica was subjected to oxidative treatment to enhance its viscosity. The oxidation processes were carried out in the presence of N-hydroxyphthalimide with or without supercritical CO2 as a solvent. Four spectroscopic techniques (Raman, UV-VIS, FT-IR, NMR) were applied to assess the chemical changes taking place during the oxidation. Raman and NMR spectroscopy proved best in the assessment of the chemical transformations leading to increased viscosity of the modified vegetable oil.

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