Mise au point de la spectroscopie RMN des molecules orientees dans des cristaux liquides de 1975 a 1982: Methodologie, perspective limitation et application

NMR Spectroscopy of Molecules Oriented in Liquid Crystalline Solvents

Bioactive glass (BG) has recently been proposed to be used for wound healing with Vaseline®. To accelerate the wound healing by incorporation of the Zinc (Zn) into BG, undoped and 5 wt% zinc-doped 45S5 BG (16 wt%) were prepared with Vaseline® to create the ointments for wound healing as a VBG and VBG-Zn, respectively. The results showed that desired composition, irregular form, and no porous surface have obtained for BGs. FT-IR spectrum of Zn-doped BG demonstrates increasing Network Connectivity due to Zn incorporation. Ointments exhibited pseudoplastic behaviour and viscoelastic characteristic, indicating that ointments have good topical application. Ointments did not toxic effect towards L929 cells in terms of biocompatibility for topical applications. In vitro wound healing assays revealed that VBG-Zn promotes wound healing thanks to incorporation of the Zn accelerates skin wound closure. All findings point to VBG-Zn ointment having a greater potential for wound healing applications. Graphical abstract

Development, structural and rheological characterization, and in vitro evaluation of the zinc-doped 45S5 bioactive glass-vaseline ointment for potential wound healing applications

This study aimed to develop novel topical formulations based on a natural component (0.5% of Siberian pine essential oil) and to assess its wound-healing capacity through macroscopic, histopathological, and biochemical examination. The phytochemical profile of Pinus sibirica essential oil (PSEO) and rheological analysis and safety potential of formulations were determined. The wound-healing effect was evaluated on an excision wound model in diabetic Wistar albino rats randomly divided into the following groups topically treated with (1) untreated, (2) 1% silver sulfadiazine, (3) ointment base, (4) gel base, (5) PSEO ointment, and (6) PSEO gel. Formulations containing PSEO were stable and safe for skin application. Three weeks of treatment with both PSEO formulations (ointment and gel) led to a significant reduction in wound size (98.14% and 96.28%, respectively) and a remarkably higher level of total hydroxyproline content (9.69 µg/mg and 7.26 µg/mg dry tissue, respectively) relative to the control group (65.97%; 1.81 µg/mg dry tissue). These findings were in correlation with histopathological results. Topically applied PSEO formulations were associated with a significant reduction in most of the measured pro-oxidants and enhanced activity of the antioxidant defense system enzymes (p < 0.05). Our findings showed that gel and ointment with PSEO demonstrated significant wound-repairing capabilities in the excision wound model.

Topical Application of Siberian Pine Essential Oil Formulations Enhance Diabetic Wound Healing

NMR spectra of 15N-methyl (13C) formamide (13C) in isotropic as well as liquid crystalline nematic phases have been studied. The NMR and the structural parametes are derived.

Nmr Spectra Of Isotopically Enriched N-Methyl Formamide In Isotropic And Nematic Media

The polarized FT-IR spectra of Mn2(CO)10, M(CO)6 (M = Cr, W), and CpM'(CO)3 (Cp = η5-C5H5; M' = Mn, Re) dissolved in a nematic liquid crystal solvent (Merck 1132 TNC) have been recorded at room temperature. Definitive vibrational assignments have been made for the CO stretching modes of the complexes on the basis of their observed polarization behavior. For Mn2(CO)10, assignments are also proposed for MnCO bending modes. The group VIB metal hexacarbonyls are shown to be tetragonally distorted in Merck 1132 TNC. Dichroic spectra were obtained for the CO stretching modes of the CpM'(CO)3 complexes with the use of both Merck 1132 TNC and Kodak X11643 liquid crystal solvents. The complexes orient perpendicularly to the long axes of the components of the Merck liquid crystal and parallel to those of the Kodak one. The dichroic spectra show that the known distortions of the Cp' rings in these complexes are apparently accompanied by deformation of the M'(CO)3 moieties.

Polarized FT-IR Spectra of Transition Metal Carbonyl Complexes Oriented in Nematic Liquid Crystal Solvents

Structural, rheological and therapeutic properties of pluronic F127 hydrogel and beeswax based lavender oil ointment formulations

The use of the technique of NMR spectroscopy of molecules oriented in the nematic phase of liquid crystals for the study of the ‘planarity’ of the three bonds meeting at the nitrogen atom in a peptide unit has been suggested1 and applied to the simplest member, namely, N-methyl formamide. Such studies are of fundamental importance since in most of the theoretical calculations, a peptide unit is assumed to be completely planar whereas the necessity of considering non-planar distortions in such a unit has been pointed out.2. For N-methyl formamide, using reasonable values of the bond lengths and the bond angles, it was found that the results are consistent with the molecule having a plane of symmetry which may arise, either from the H.CO.NH.C moiety of the molecule being rigidly planar or from a ‘rapid inversion’ through the nitrogen atom. The results support the fromer if there is a ‘free’ rotation of the CH3 group about the N-CH3 bond. However, if the methyl group rotation is hindered in a 3-fold...

The Amide Planarity as Studied by NMR of Oriented Molecules - The Spectrum of N-Methylacetamide

1H-NMR spectra including 13C-H satellites in the natural abundance of 13C in π-cyclopentadienyl manganese tricarbonyl dissolved in a nematic solvent are reported. In addition, the 13C-NMR spectrum of the compound in the natural abundance of 13C, in an isotropic medium is studied. Values of the direct and the indirect HH and 13CH couplings are given. Information on the molecular geometry of the ring skeleton thus obtained is discussed. Contributions of the molecular vibrations to the observed dipolar couplings are estimated. The direct dipolar coupling between the carbonyl 13C and the ring protons are used to derive the distance between the plants containing these carbons and the cyclopentadienyl ring.

NMR Spectra of π-Cyclopentadienyl Manganese Tricarbonyl in Nematic and Isotropic Solvents

PMR studies of N, p-chlorophenylmaleimide in a nematic solvent have been undertaken. The structural and the conformational informations are derived. The distance-ratios of the phenyl protons show significant distortions from corresponding values in benzene. The data indicate that the molecule has a twisted conformation with C2-symmetry and that an exchange between energetically equivalent conformations takes place. Assuming a rigid conformation the angle θ between phenyl and maleimide moieties is estimated to be 54.5°C. The data can also be interpreted by an exchange between planar (θ = 0,180) and perpendicular (θ = ±90) conformations. This possibility is discarded on the basis of theoretical considerations of the stability of conformations.

Structure and Conformation of N, p-Chlorophenylmaleimide in a Nematic Solvent by Proton Magnetic Resonance

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Papers

Structural, rheological and therapeutic properties of pluronic F127 hydrogel and beeswax based lavender oil ointment formulations

The Amide Planarity as Studied by NMR of Oriented Molecules - The Spectrum of N-Methylacetamide

NMR Spectra of π-Cyclopentadienyl Manganese Tricarbonyl in Nematic and Isotropic Solvents

Structure and Conformation of N, p-Chlorophenylmaleimide in a Nematic Solvent by Proton Magnetic Resonance