scholarly journals Binding Cellulose and Chitosan via Intermolecular Inclusion Interaction: Synthesis and Characterisation of Gel

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Jiufang Duan ◽  
Chunrui Han ◽  
Liujun Liu ◽  
Jianxin Jiang ◽  
Jianzhang Li ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Lithium Chloride ◽  
Room Temperature ◽  
Self Healing ◽  
Mild Conditions ◽  
Inclusion Interaction ◽  
Ferrocenecarboxylic Acid ◽  
Novel Method ◽  
Chitosan Gel ◽  
C Nmr

A novel cellulose-chitosan gel was successfully prepared in three steps: (1) ferrocene- (Fc-) cellulose with degrees of substitution (DS) of 0.5 wt% was synthesised by ferrocenecarboxylic acid and cellulose within dimethylacetamide/lithium chloride (DMAc/LiCl); (2) theβ-cyclodextrin (β-CD) groups were introduced onto the chitosan chains by reacting chitosan with epichlorohydrin in dimethyl sulphoxide and a DS of 0.35 wt%; (3) thus, the cellulose-chitosan gel was obtained via an intermolecular inclusion interaction of Fc-cellulose andβ-CD-chitosan in DMA/LiCl, that is, by an intermolecular inclusion interaction, between the Fc groups of cellulose and theβ-CD groups on the chitosan backbone at room temperature. The successful synthesis of Fc-cellulose andβ-CD-chitosan was characterised by13C-NMR spectroscopy. The gel based onβ-CD-chitosan and Fc-cellulose was formed under mild conditions which can engender autonomous healing between cut surfaces after 24 hours: the gel cannot self-heal while the cut surfaces were coated with a solution of a competitive guest (adamantane acid). The cellulose-chitosan complex made by this method underwent self-healing. Therefore, this study provided a novel method of expanding the application of chitosan by binding it with another polymer.

An unusual reaction of a bridged triterpenoid α-diketone with acetic anhydride

1991 ◽  
Vol 56 (12) ◽  
pp. 2917-2935 ◽  
Author(s):  
Eva Klinotová ◽  
Václav Křeček ◽  
Jiří Klinot ◽  
Miloš Buděšínský ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Acetic Anhydride ◽  
Spectral Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mild Conditions ◽  
Condensation Products ◽  
Unsaturated Lactones ◽  
C Nmr

3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.

scholarly journals Synthesis and Single Crystal X-Ray Structure of Bis[4-oxo-3- (2-ethoxycarbonylphenyl)-3,4-dihydroquinazolin-2-yl]disulfide

2009 ◽  
Vol 64 (9) ◽  
pp. 1065-1069 ◽  
Author(s):  
Mehdi Rimaz ◽  
Jabbar Khalafy ◽  
Khadijeh Tavana ◽  
Katarzyna Ślepokura ◽  
Tadeusz Lis ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Elemental Analysis ◽  
Structure Determination ◽  
Room Temperature ◽  
Sodium Ethoxide ◽  
Reaction Conditions ◽  
X Ray ◽  
Ethyl Nitroacetate ◽  
C Nmr

Diethyl 2,2´-thiocarbonyl-bis(azanediyl)dibenzoate was synthesized from the reaction of ethyl anthranilate with thiophosgene. Its treatment with sodium ethoxide in ethanol at room temperature gave ethyl 2-(4-oxo-2-thioxo-1,2-dihydroquinazolin-3(4H)-yl) benzoate, whereas in the presence of ethyl nitroacetate and under the same reaction conditions, the corresponding bis(quinazolin)disulfide was formed. Its structure was confirmed by IR, 1H and 13C NMR spectroscopy elemental analysis and single crystal X-ray structure determination.

Synthesis and Spectroscopic Studies of Pentacarbonylfumaronitrile-chromium(0), -molybdenum(0), and -tungsten(0)

1994 ◽  
Vol 49 (8) ◽  
pp. 1059-1062 ◽  
Author(s):  
İzzet A. Mour ◽  
Saim Ozkar ◽  
Cornelius G. Kreiter
Keyword(s):  
Double Bond ◽  
Nmr Spectroscopy ◽  
Nitrogen Atom ◽  
Room Temperature ◽  
Spectroscopic Studies ◽  
Carbon Double Bond ◽  
C Nmr ◽  
And Tungsten

Photolysis of hexacarbonyl-chromium(0), -molybdenum(0), and -tungsten(0) in presence of fumaronitrile yields at room temperature pentacarbonyl-fumaronitrile-chromium(0) (1), - molybdenum(0) (2), and -tungsten(0) (3). The complexes were purified by crystallization and characterized by IR and 13C-NMR spectroscopy. The fumaronitrile ligand is bonded to the M(CO)5 moiety by one nitrile nitrogen atom rather than by the carbon-carbon double bond. In toluene 2 dissociates into fumaronitrile and pentacarbonyl-molybdenum(0), which is stabi­lized by the solvent. Fumaronitrile and solvated pentacarbonyl-molybdenum(0) exist in solu­tion together with 2 in an equilibrium which lies in favour of the former species.

Reassignment of the structure of M3(CO)12(Cl)(SnCl3) (M = Ru, Os)

1989 ◽  
Vol 67 (7) ◽  
pp. 1236-1238 ◽  
Author(s):  
Anna Becalska ◽  
Roland K. Pomeroy ◽  
William A.G. Graham
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Quantitative Yield ◽  
Nmr Spectrum ◽  
C Nmr

Reaction of M3(CO)12 (M=Ru, Os) with SnCl4 in benzene at room temperature affords M3(CO)12(Cl)(SnCl3) in essentially quantitative yield. The 13C nmr spectra of these complexes indicate they have a ClM3(SnCl3) arrangement of atoms with the Cl ligand cis and the SnCl3 group trans to a linear Os3 chain. This is contrary to previously proposed structures for these compounds. The 13C nmr spectrum of Os3(CO)12(I)2 which has the iodo ligands cis to the Os3 chain is also reported for comparison. Keywords: ruthenium–tin, osmium–tin, osmium–iodine, l3C nmr spectroscopy.

Selective Carbonyl Propargylation Mediated by SnCl2/NiCl2-KI in Water

2005 ◽  
Vol 58 (8) ◽  
pp. 611 ◽  
Author(s):  
Jun Wang ◽  
Xiao-Peng Miao ◽  
Gu Yuan
Keyword(s):  
Carbonyl Compounds ◽  
Room Temperature ◽  
Environmentally Friendly ◽  
Pharmaceutical Chemistry ◽  
Mild Conditions ◽  
Homopropargylic Alcohols ◽  
Novel Method

Propargylation of carbonyl compounds to produce homopropargylic alcohols plays a very important role in synthetic organic and pharmaceutical chemistry. A novel method that carbonyl compounds and propargyl halide were mediated by SnCl2/NiCl2-KI in water at room temperature was developed by us to successfully synthesize homopropargylic alcohols in good yields. The reactions were carried out in an environmentally friendly solution and under mild conditions.

Oxidative fluorination in the Ph2SO–XeF2–Cl− system and fluorine exchange in the Ph2S(O)F2–Ph2S(O)F+ system

1996 ◽  
Vol 74 (11) ◽  
pp. 2002-2007 ◽  
Author(s):  
Xiaobo Ou ◽  
Alexander F. Janzen
Keyword(s):  
Nmr Spectroscopy ◽  
Ab Initio ◽  
Key Words ◽  
Exchange Process ◽  
Chloride Ion ◽  
Fluoride Ion ◽  
Molecular Orbital Calculations ◽  
Xenon Difluoride ◽  
Mild Conditions ◽  
C Nmr

Oxidative fluorination of diphenyl sulfoxide with xenon difluoride occurs under mild conditions in the presence of chloride ion to give Ph2S(O)F2 in quantitative yield. Chloride ion appears to react with xenon difluoride to generate fluoride ion, and a mechanism of oxidative fluorination is proposed that involves anionic Ph2S(O)F− and radical Ph2S(O)F• intermediates. Addition of cationic Ph2S(O)F+ to Ph2S(O)F2 initiates rapid fluorine exchange, presumably via a symmetrical fluorine-bridged intermediate, and this exchange process was monitored by 13C and 19F NMR spectroscopy. In the presence of chloride ion, Ph2S(O)Cl2 is formed and can be identified by 13C NMR and by its hydrolysis to Ph2SO2. Mechanisms are proposed for these reactions, and ab initio molecular orbital calculations (GAUSSIAN92) were carried out of the postulated intermediates. Key words: preparation of Ph2S(O)F2, Ph2S(O)F+, and Ph2S(O)Cl2; oxidative fluorination in the Ph2SO–XeF2–Cl− system; fluorine exchange in the Ph2S(O)F2–Ph2S(O)F+ system.

Synthesis and Spectroscopic Study of Pentacarbonyl(η2-tetracyanoethylene) Metal(0) Complexes of the Group 6 B Elements

1994 ◽  
Vol 49 (5) ◽  
pp. 717-720 ◽  
Author(s):  
İzzet A. Mour ◽  
Saim Özkar
Keyword(s):  
Double Bond ◽  
Nmr Spectroscopy ◽  
Spectroscopic Study ◽  
Spectral Data ◽  
Photochemical Reaction ◽  
Room Temperature ◽  
Carbon Double Bond ◽  
Uv Visible ◽  
Metal Ligand ◽  
C Nmr

Pentacarbonyl(η2-tetracyanoethylene) metal(0) complexes of chromium, molybdenum and tung­sten have been synthesized by the photochemical reaction of hexacarbonyl metal(o) with tetra- cyanoethylene in toluene at room temperature. The complexes were purified by chromatography and recrystallization, and characterized by UV- visible, IR and 13C NMR spectroscopy. Tetra- cyanoethylene is symmetrically bonded to the M(CO)5 unit through its carbon-carbon double bond as an η2-ligand. The spectral data are dis­cussed in terms of the metal → ligand π inter­action.

Synthesis and substitution chemistry of some bis(dithiolate) complexes of molybdenum, Mo(S2C6H3R)2(PMePh2)2, R = H, Me

1990 ◽  
Vol 68 (4) ◽  
pp. 558-564 ◽  
Author(s):  
Natalie J. Lazarowych ◽  
Robert H. Morris
Keyword(s):  
Room Temperature ◽  
Carbonyl Complex ◽  
Relative Positioning ◽  
Nmr Spectrum ◽  
Mild Conditions ◽  
Different Types ◽  
Substitution Chemistry ◽  
Dithiolate Complexes ◽  
Monodentate Ligands ◽  
C Nmr

The new bis(dithiolate) complexes Mo(1,2-S2-4-R-C6H3)2(PMePh2)2, R = H, Me, are readily synthesized from three different types of starting materials: trans-Mo(N2)2(PMePh2)4, MoCl4(PMePh2)2, and MoOCl2(PMePh2)3. The 31P NMR spectra of the dithiolate complexes at low temperature are consistent with a cis stereochemistry of the PMePh2 ligands and isomerism with respect to inversion at sulfur and relative positioning of the methyl groups on the chelating 1,2-S2-4-Me-C6H3 ligands. The singlet in the 31P NMR spectrum at room temperature arises from rapid interconversion of these isomers. Substitution of one or two of the PMePh2 ligands in the dithiolate complexes proceeds under mild conditions to give the complexes Mo(S2C6H4)2(CO)(PMePh2), Mo(S2C6H4)2(CN-t-Bu)(PMePh2), Mo(S2C6H3Me)2(dppe), Mo(S2C6H4)2(depe), Mo(S2C6H4)2(PMePh2)(PMe3), Mo(S2C6H4)2(PMePh2)(P(OMe)3), and Mo(S2C6H4)2(P(OMe)3)2. The 31P and 13C NMR spectroscopy of these bis(dithiolate) complexes suggest that they have monodentate ligands cis disposed.A reversible equilibrium exists between Mo(S2C6H4)2(PMePh2)2 and Mo(S2C6H4)2(CO)(PMePh2) in the presence of carbon monoxide in solution. Isolation of Mo(S2C6H4)2(CO)(PMePh2) is facilitated by use of CH3I as a "phosphine sponge" reagent. If the sulfur ligands are viewed as dianions, then this is the first thermally stable carbonyl complex of molybdenum(IV). Keywords: molybdenum, dithiolate, diphenylmethylphosphine, carbonyl, NMR.

The Preparation of Some Mono-and Bis(thiolate)-2-butyne Complexes of Tungsten(II) of the Types [WI(SR)(CO)(dppm )(η2-MeC2Me)] {dppm = Ph2P(CH2)PPh2; R = Et, But, Ph or CH2Ph} and [W (SR)2(CO)(dppm)(η2-MeC2Me)]

1994 ◽  
Vol 49 (11) ◽  
pp. 1544-1548 ◽  
Author(s):  
Paul K. Baker ◽  
Kevin R. Flower
Keyword(s):  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
Good Yield ◽  
Nmr Spectra ◽  
Room Temperature ◽  
H Nmr ◽  
Thiolate Complexes ◽  
C Nmr

Equimolar quantities of [WI(CO)(NCMe)(dppm)(η2-MeC2Me)][BF4] {dppm = Ph2P(CH2)PPh2) and NaSR (R = Et. But ,Ph or CH2Ph) react in CH2Cl2 at room temperature to give the neutral thiolate complexes [WI(SR)(CO)(dppm)(η2-MeC2Me)] (1 → 4) in good yield. The complex [WI(CO)(NCMe)(dppm)(η2-MeC2Me)][BF4] also reacts with two equiv­alents of NaSR (R = Et. But, Ph or CH2Ph) in CH2Cl2 at room temperature to afford the bis(thiolate) complexes [W(SR)2(CO)(dppm)(η2-MeC2Me)] (5 → 8), in good yield. Com­plexes 1→8 have been characterized by elemental analysis (C, H and N), IR and 1H NMR spectroscopy. 13C NMR spectra of selected complexes indicate that the 2-butyne ligand is donating four electrons to the metal in both [WI(SR)(CO)(dppm)(η2-MeC2Me)] and [W(SR)2(CO)(dppm)(η2-MeC2Me)] type complexes.

Übergangsmetall-Komplexe mit Schwefelliganden, XXVII Synthese und Reaktivität der Nitrosyl-und Nitrido-Ruthenium-Komplexe mit 1,2-Benzoldithiolat-Liganden [Ru(NO)(S2C6H4) 2]- bzw. [Ru(N)(S2C6H4)2]- / Transition Metal Complexes with Sulfur Ligands, XXVII Synthesis and Reactivity of the Nitrosyl- and Nitrido-Ruthenium Complexes with 1,2-Benzenedithiolate Ligands [Ru(NO)(S2C6H4)2]- and [Ru(N)(S2C6H4)2]-, Respectively

1987 ◽  
Vol 42 (3) ◽  
pp. 341-347 ◽  
Author(s):  
Dieter Sellmann ◽  
Gerhard Binker
Keyword(s):  
Nmr Spectroscopy ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Ruthenium Complexes ◽  
Nitrosyl Complex ◽  
Reduction Of No ◽  
Mild Conditions ◽  
C Nmr

The reaction of [Ru(NO)2(PPh3)2], [RuCl(NO)2(PPh3)2]PF6 or [RuCl3(NO)(PPh3)2] with 1,2- benzenedithiolate(-2), C6H4S22-, leads to the 16e--complex [Ru(NO)(S2C6H4)2]-, which was isolated as the NBu4+ salt (1). The square pyramidal anion in [NBu4)[Ru(NO)(S2C6H4)2] coordinates PMe3 with rearrangement of the sulfur ligands to give the six-coordinate cis- [NBu4][Ru(NO)(PMe3)(S2ChH4)2] (3); the rearrangement of the C6H4S22--Iigands from trans to cis coordination is proved by 13C NMR spectroscopy. [Ru(NO)(S2C6H4)2]- is rapidly reduced even under mild conditions. Reaction of 1 with NaBH4 in MeOH leads to the reduction of NO to a nitrido ligand and the concomitant oxidation of (formal) Ru(III) to Ru(VI) yielding [NBu4][Ru(N)(S2C6H4)2] (2). This compound is also formed when the nitrosyl complex is reacted withSiMe3N3.[Ru(NO)2(PPh3)2] and [RuCl(NO)2(PPh3)2]PFare denitrosylated by dttd2- (dttd2- = 2,3,8,9-dibenzo-1,4,7,10-tetrathiadecane(-2)) to give [Ru(dttd)(PPh3)2]

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