Monitoring the encapsulation of chlorin e6 derivatives into polymer carriers by NMR spectroscopy

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1576-1586 ◽  
Author(s):  
Sara Pfister ◽  
Luca Sauser ◽  
Ilche Gjuroski ◽  
Julien Furrer ◽  
Martina Vermathen
Keyword(s):  
Relaxation Time ◽  
Nmr Spectroscopy ◽  
Core Region ◽  
Chlorin E6 ◽  
Polypropylene Glycol ◽  
Polymer Carriers ◽  
H Nmr ◽  
Line Shape Analysis ◽  
Dynamic Methods ◽  
Derivatives Of

The encapsulation of five derivatives of chlorin e6 with different hydrophobicity and aggregation properties into a series of five poloxamer-type triblock copolymer micelles (BCMs) with varying numbers of polyethylene and polypropylene glycol (PEG, PPG) units was monitored using 1H NMR spectroscopy. NMR chemical shift and line shape analysis, as well as dynamic methods including diffusion ordered spectroscopy (DOSY) and T1 and T2 relaxation time measurements of the chlorin and the polymer resonances, proved useful to assess the chlorin–BCM compatibility. The poloxamers had high capability to break up aggregates formed by chlorins up to intermediate hydrophobicity. Physically entrapped chlorins were always localized in the BCM core region. The loading capacity correlated with chlorin polarity for all poloxamers among which those with the lowest number of PPG units were most efficient. DOSY data revealed that relatively weakly aggregating chlorins partition between the aqueous bulk and micellar environment whereas more hydrophobic chlorins are well retained in the BCM core region, rendering these systems more stable. T1 and T2 relaxation time measurements indicated that motional freedom in the BCM core region contributes to encapsulation efficiency. The BCM corona dynamics were rather insensitive towards chlorin entrapment except for the poloxamers with short PEG chains. The presented data demonstrate that 1H NMR spectroscopy is a powerful complementary tool for probing the compatibility of porphyrinic compounds with polymeric carriers such as poloxamer BCMs, which is a prerequisite in the development of stable and highly efficient drug delivery systems suitable for medical applications like photodynamic therapy of tumors.

Control of disaccharide conformation by π-stacking

2003 ◽  
Vol 81 (5) ◽  
pp. 364-375 ◽  
Author(s):  
Jonathan Watts ◽  
Jesús Jiménez-Barbero ◽  
Ana Poveda ◽  
T Bruce Grindley
Keyword(s):  
Nmr Spectroscopy ◽  
Molecular Modelling ◽  
Phenyl Ring ◽  
Glycosidic Linkage ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Π Stacking ◽  
Nuclear Overhauser ◽  
Derivatives Of

The conformations of a series of derivatives of the disaccharide α-L-fucopyranosyl-(1[Formula: see text]3)-2-acetamido-2-deoxy-D-glucopyranoside, part of the Lex determinant, were studied by molecular modelling using the MM3* forcefield and by 1H NMR spectroscopy. Unusually shielded O-benzyl protons were observed in the 1H NMR spectrum of phenyl 2,3,4-tri-O-benzyl-α-L-fucopyranosyl-(1[Formula: see text]3)-2-deoxy-2-phthalimido-1-thio-α-D-glucopyranoside and assigned to the 2-O-benzyl group. This observation was explained by a shift in the population of the conformational mixture present about the glycosidic linkage from the positive Ψ region in the unsubstituted disaccharide to the negative Ψ region induced by π-stacking between the phthalimide and the 2-O-benzyl phenyl ring. The experimental nuclear Overhauser enhancements confirm the accuracy of the calculations.Key words: disaccharide, conformation, π-stacking, Lex determinant, NOE measurements, MM3 calculations.

Imidazole Nucleosides, V. Synthesis of 3′-Fluoro-3′-deoxy-ribofuranosides of 4(5)-Amino-imidazoIe-5(4)carboxamide

1999 ◽  
Vol 54 (8) ◽  
pp. 1055-1060 ◽  
Author(s):  
Hans Guglielmi ◽  
Markus Dachtler ◽  
Klaus Albert
Keyword(s):  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
H Nmr ◽  
Anti Cancer ◽  
Derivatives Of ◽  
Fluoro Derivatives

The synthesis of the 3′-fluoro-derivatives of 5-amino-1-(β-D-ribofuranosyl)imidazole-4- carboxamide (AICA-riboside) and the isomeric 4-amino-1(β-D-ribofuranosyl)imidazole-5- carboxamide (iso-AICA-riboside) are described. Structures were confirmed by elemental analysis, UV and 1H NMR spectroscopy. The anti-viral and anti-cancer activities of these imidazole nucleosides were tested.

scholarly journals Unravelling cationic cellulose nanofibril hydrogel structure: NMR spectroscopy and small angle neutron scattering analyses

Soft Matter ◽  
2018 ◽  
Vol 14 (2) ◽  
pp. 255-263 ◽  
Author(s):  
James C. Courtenay ◽  
Susana M. Ramalhete ◽  
William J. Skuze ◽  
Rhea Soni ◽  
Yaroslav Z. Khimyak ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Nmr Spectroscopy ◽  
Chemical Modification ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Cellulose Nanofibril ◽  
H Nmr

The structure of cationic cellulose nanofibril gels and changes in the nanoparticle form with varying chemical modification are revealed by neutron scattering, rheological and 1H NMR T1 relaxation time analyses.

Enantioselective fluorescent sensors for chiral carboxylates based on BINOL — Synthesis and chiral recognition

2010 ◽  
Vol 88 (4) ◽  
pp. 367-374 ◽  
Author(s):  
Kuo-xi Xu ◽  
Yu-xia Wang ◽  
Shu-yan Jiao ◽  
Jin Zhao ◽  
Chao-jie Wang
Keyword(s):  
Nmr Spectroscopy ◽  
Chiral Recognition ◽  
Fluorescent Sensors ◽  
Enantioselective Recognition ◽  
H Nmr ◽  
Recognition Ability ◽  
Chiral Materials ◽  
Fluorescent Recognition ◽  
Derivatives Of ◽  
C Nmr

The four novel derivatives of 1,1′-bi-2-naphthol (BINOL) have been prepared, and the structures of these compounds have been characterized by IR, MS, 1H and 13C NMR spectroscopy, and elemental analysis. The enantioselective recognition of these receptors has been studied by fluorescence titration and 1H NMR spectroscopy. The receptors exhibited different chiral-recognition abilities towards some enantiomers of chiral materials and formed 1:1 complexes between host and guest. The receptors exhibit excellent enantioselective fluorescent-recognition ability towards the amino acid derivatives.

Carbamoyl and Thiocarbamoyl Derivatives of 3-Aminopropyl-dimethyl-phosphine Oxide

2004 ◽  
Vol 59 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Victoria Lachkova ◽  
Helmut Keck ◽  
Rosario Scopelliti ◽  
Wolfgang Kläui ◽  
Sabi Varbanov ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Phosphine Oxide ◽  
Elemental Analysis ◽  
Phosphine Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Derivatives Of

A series of fourteen new 3-[N-substituted carbamoyl (or thiocarbamoyl)]-aminopropyl-dimethyl-phosphine oxides have been synthesized and characterized. The compounds were prepared via reaction of the 3-aminopropyl-dimethyl-phosphine oxide with the corresponding isocyanates or isothiocyanates. The composition of the compounds was proved by elemental analysis and the structures were confirmed by IR, 1H, 31P, 31P{1H} NMR spectroscopy and by mass spectrometry. The structures of 3[(N-phenyl-thiocarbamoyl)amino]propyl-dimethyl-phosphine oxide (5), 3[(N-4- chlorophenyl-thiocarbamoyl)amino]propyl-dimethyl-phosphine oxide (6), and 3[(N-benzyl-thiocarbamoyl) amino]propyl-dimethyl-phosphine oxide (9) have been confirmed by X-ray diffraction.

Arene–manganese and arene–rhenium compounds of formula (arene)M(CO)2(SiCl3)

1997 ◽  
Vol 75 (5) ◽  
pp. 531-535 ◽  
Author(s):  
Valerie M. Hansen ◽  
Jonathan L. Male ◽  
Roland K. Pomeroy
Keyword(s):  
Nmr Spectroscopy ◽  
Metal Atom ◽  
Good Yield ◽  
Free Rotation ◽  
Nmr Spectrum ◽  
Manganese Compound ◽  
Restricted Rotation ◽  
H Nmr ◽  
Arene Ligand ◽  
Derivatives Of

Derivatives of formula (arene)M(CO)2(SiCl3) (M = Mn, Re) have been prepared in moderate to good yield by the reaction of M(CO)5(SiCl3) and the appropriate arene (with heptane in those cases where the arene was a solid) in an evacuated sealed tube at 230–260 °C for 12–24 h, depending on the arene and the metal. Carefully purified reagents were necessary to obtain satisfactory yields. The (η6-1,4-C6H4tBu2)M(CO)2(SiCl3) complexes in solution exhibit free rotation of the arene ring about the metal atom to −120 °C as ascertained by 1H NMR spectroscopy. The manganese compound did show the onset of decoalescence of two of the signals due to the arene ligand in the 13C{1H} NMR spectrum in CD2Cl2, solution below −90 °C. This, however, is interpreted in terms of restricted rotation of the tert-butyl substituent rather than restricted rotation of the arene ring. Keywords: arene, manganese, rhenium, restricted rotation.

An NMR study on the mechanisms of freezing and melting of water confined in spherically mesoporous silicas SBA-16

2016 ◽  
Vol 18 (27) ◽  
pp. 18555-18562 ◽  
Author(s):  
Tatsuya Miyatou ◽  
Ryutaro Ohashi ◽  
Tomonori Ida ◽  
Shigeharu Kittaka ◽  
Motohiro Mizuno
Keyword(s):  
Relaxation Time ◽  
Nmr Spectroscopy ◽  
Dynamic Properties ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Mesoporous Silicas ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
H Nmr ◽  
Nmr Study

Thermodynamic and dynamic properties of water confined in mesoporous silica glass SBA-16 were investigated by DSC and 1,2H NMR spectroscopy and 2H NMR spin–lattice relaxation time as a function of pore size.

Preparation of 1-α-D-Arabinofuranosylbenzimidazole and Its 5,6-Dichloro Derivative, and the Direct Bromination of Benzimidazole Nucleosides

1980 ◽  
Vol 35 (1-2) ◽  
pp. 30-35 ◽  
Author(s):  
Zygmunt Kazimierczuk ◽  
Lech Dudycz ◽  
Ryszard Stolarski ◽  
David Shugar
Keyword(s):  
Nmr Spectroscopy ◽  
Acid Hydrolysis ◽  
Absorption Spectra ◽  
Nmr Spectra ◽  
Biologically Active ◽  
Trimethylsilyl Derivative ◽  
Initial Product ◽  
H Nmr ◽  
Derivatives Of ◽  
Dichloro Derivative

Abstract Arabinofuranosyl Benzim idazole N ucleosides, Direct Bromination of Benzim idazole N ucleosides, 1H NMR Spectroscopy, Ultraviolet Spectra The 1-a-D-arabinofuranosides of benzim idazole and 5,6-dichlorobenzim idazole, analogues of the biologically active 5,6-dichloro-l-β-D-ribofuranosylbenzimidazole, have been synthesized by condensation of the trimethylsilyl derivative of the appropriate benzim idazole in the presence of SnCl4 with 1-O-m ethyl-2,3,5-tribenzoyl-a-D-arabinoside.The 5(6)-m onobrom o and the 5,6-dibrom o derivatives of 1-β-D-ribofuranosylbenzimidazole and 1-α-D-arabinofuranosylbenzimidazole were then prepared by direct bromination of the latter. With 1-β-D-ribofuranosylbenzimidazole, the initial product of bromination was a 1:1 mixture of the 5-bromo and 6 -brom o derivatives; the final product was the desired 5,6-dibromo analogue. In the case of 1-αβ-D-arabinofuranosylbenzimidazole, the initial product of bromination was the 5-(or 6 -)brom o derivative, and the 5,6-dibrom o derivative the final product. The monobrom o derivatives were easily separated from the dibrom o by chromatography on Am berlite XAD-4. Identification of all of these was based on several criteria, including detailed analyses of the 1H NMR spectra.The benzim idazole nucleoside are considerably m ore resistant to acid hydrolysis than the cor­ responding purine nucleosides. The effects of halogenation on the ultraviolet absorption spectra of the benzim idazole nucleosides are described.

(Aminoethinyl)metallierimgen, IX [1] Umsetzungen von Inaminen mit Cyanketenen / (Aminoethynyl)metallations, IX [1] Reactions of Ynamines with Cyanoketenes

1981 ◽  
Vol 36 (2) ◽  
pp. 218-225 ◽  
Author(s):  
Gerhard Himbert ◽  
Lothar Henn Fachbereich
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Triple Bond ◽  
Diazo Compound ◽  
Cycloaddition Reactions ◽  
H Nmr ◽  
Derivatives Of

Ynamines 2 bearing methyl or phenyl groups at their C/C triple bond react with tert-butylcyanoketene 1a to give the cyclobutenones 3 and/or the allene carboxamides 4. 3 and 4 are the products of two different [2 + 2] cycloaddition reactions. β-Silylated, β-germylated and β-stannylated ynamines 5 add the cyanoketenes 1 under "(aminoethynyl)metallation" to furnish the new enynamines 6. These compounds were characterized by IR and 1H NMR spectroscopy and partly by mass spectrometry. The stannyl derivatives of 6 hydrolyze very easily to the corresponding acyl ynamines 7 and react with 4-nitrobenzoyl chloride to give the 1-(aminoethynyl)vinyl benzoates 8. The diazo compound 9 is formed by the interaction of tosyl azide on the enynamine 6 c, which is probably first hydrolyzed to 7a. N,N-Diethyl-N-(triphenylsilylethynyl)amine (5e) reacts with two molecules of tert-butylcyanoketene (1a) to give the allene derivative 10, probably via the corresponding enynamine 6 (R1 = R2 = Et, MR33 = SiPh3, R4 -tBu).

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