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1.
Nitrocellulose (NC)-based propellants require stabilizers to avoid early decomposition or even explosion during storage. A series of novel fullerene-malonamide derivatives with different carbon chain lengths on the p-position of the benzene ring was synthesized as stabilizers for NC-based propellants through the Bingel reaction because of the excellent thermal stability and strong ability of these derivatives to eliminate free radicals. The molecular structures of these fullerene-malonamide derivatives were verified via 1H nuclear magnetic resonance (NMR) spectroscopy, 13C NMR spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet–visible spectroscopy, and high-resolution mass spectrometry. Meanwhile, their stability was investigated using methyl violet, vacuum stability, and weight loss tests. Results indicated that the stability of the novel fullerene-malonamide derivatives was considerably better than that of traditional stabilizers, such as N,N′-dimethyl-N,N′-diphenylurea and diphenylamine. Moreover, these derivatives exhibited excellent thermal stability at high temperatures. The stability of the fullerene-malonamide derivatives also improved as the carbon chain length on the p-position of the benzene ring on C60 increased. In addition, the stability mechanism of the fullerene-malonamide derivatives was studied through electron paramagnetic resonance spectroscopy, FT-IR spectroscopy, and liquid chromatography-mass spectrometry. Results turned out that the fullerene-malonamide derivatives could react with nitroxide radicals released from the pyrolysis of NC. Hence, these novel fullerene-malonamide derivatives can be used as promising stabilizers for NC-based propellants.  相似文献   

2.
This study reports the synthesis and characterization of hydrophobic derivatives of dextran in which long alkyl chains substituted a proportion of the hydroxyl groups. These derivatives were characterized by 13C and 1H NMR and infrared spectroscopy. Information about hydrophobic associations in aqueous solutions was obtained by fluorescence spectroscopy in the presence of pyrene and nabumetone probes. These results, in addition to the swelling‐index data of derivatives, showed that there are perspectives of using them as a starting point for models of drug delivery.  相似文献   

3.
Synthesis of nine new benzimidazole derivatives was reported. The products were identified by 1H NMR, mass spectroscopy, and infrared spectroscopy.  相似文献   

4.
By reaction of a series of triols and monosaccharides with 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphorinane their tris-phosphorylated derivatives were synthesized, and the simplest chemical transformations of the latter were studied. Structures of the obtained P(V) derivatives were confirmed by 1H, 13C and 31P NMR spectroscopy and by the MALDI TOF mass spectrometry and X-ray structural analysis.  相似文献   

5.
In the present study, a group of polysubstituted furopyran derivatives possessing ether spacer groups were synthesized under good-to-exceptional yields via cycloaddition of bisarylidene Meldrum's acid derivatives (1 mmol) with isocyanides (6 mmol) within dichloromethane (CH2Cl2) for 3 to6 hours at room temperature with no assistance from any type of catalysts. The structure of the products was then confirmed by Fourier Transform-infrared spectroscopy, 1H-nuclear magnetic resonance spectroscopy, 13C-nuclear magnetic resonance spectroscopy, and elemental analysis. Moreover, the 5c , 5d , and 5f compounds exhibited favorable pharmaceutical behavior as antibacterial.  相似文献   

6.
A series of cyclometallated 2-phenylpyridine Pt(II) complexes having N-benzoyl thiourea derivatives as ancillary ligands were prepared and characterised by elemental analysis, IR and UV–Vis spectroscopy, 1H and 13C NMR spectroscopy as well as by X-ray diffraction on single-crystal. All complexes were obtained as a single isomer with N atom of the 2-phenylpyridine ligand and S atom of the N-benzoyl thiourea derivatives coordinated in trans positions to the platinum metal as evidenced by using X-ray crystallography and NMR spectroscopy. All Pt(II) complexes show good luminescence properties at room temperature, both in dichloromethane solution and in solid state.  相似文献   

7.
Abstract

Two novel cyclotriphosphazene derivatives were synthesized from hexachloro cyclotriphosphzene. Their structures were characterized by 1H, 31P, and 13C NMR spectroscopy as well as by IR spectroscopy and electrospray ionization-mass spectrometry (ESI-MS). The Zn complex of 4d was effective in hydrolytic DNA cleavage reactions.  相似文献   

8.
New nitrogen-containing and hydroxy derivatives of quinopimaric acid were synthesized, and their structure was determined by 1H and 13C NMR spectroscopy.  相似文献   

9.
A series of new stannylated derivatives of dimethylaminomethylferrocene (DMAMF) and N,N-dimethylbenzylamine have been synthesised and their structures investigated by 1H, 13C and 119Sn NMR together with 57Fe and 119Sn Mössbauer spectroscopy. Polystannylated derivatives were synthesised from DMAMF and BuLi in the presence of TMED. The methylene protons of the CH2NMe2 group were diastereotopic for all the DMAMF derivatives synthesised. The chemical shift differences of these protons is discussed in terms of conformational changes. 13C and 119Sn shifts were used to establish the substitution patterns in the polystannylated derivatives. 13C shifts for the 2-substituted derivatives of both DMBA and DMAMF were reasonably additive, for both the free amines and the quaternary ammonium salts. The Mössbauer data show no evidence of pentacoordination in any of the derivatives.  相似文献   

10.
The ortho- and para-hydroxybenzoic acid thiosemicarbazide derivatives which are potentially biologically active substances were obtained by the reaction of the corresponding hydrazides with various isothiocyanates. Their structures were determined using IR, 1H NMR spectroscopy, and mass spectrometry. Pronounced antimicrobial activity of synthesized derivatives was revealed.  相似文献   

11.
New derivatives of protoberberine alkaloids were prepared by nucleophilic addition of some azoles (differing in bulkiness) to the iminium functionality of the quaternary protoberberine alkaloids. Compounds were structurally characterized mainly by 1H and 13C NMR spectroscopy, and the structure of 8-carbazol-1-yl-7,8-dihydroberberine was determined using single-crystal X-ray diffraction. Additionally, conformational behaviors of five derivatives varying in bulkiness of the azole moiety have been investigated by low temperature NMR spectroscopy and quantum chemical calculations. Ring current effects of pyrrole and carbazole moieties on selected 1H NMR resonances have been characterized, visualized, and discussed.  相似文献   

12.
Abstract

The 4-H, 4-methyl and 4-phenyl derivatives of benzo-α-pyrone of 12-crown-4 and 15-crown-5 were synthesised starting from 4-substituted-6,7-dihydroxy- and 7,8-dihydroxybenzo-α-pyrones which reacted with dichloropolyethylene glycols in DMF/water/alkali carbonate. The coumarin-macrocycles were identified by elemental analysis, IR, EI-GC-MS as well as 1H, 13C NMR spectroscopy. The full experimental and spectral data is reported along with ion binding data studied in acetonitrile using fluorescence spectroscopy. The binding of the fluorogenic coumarin-crowns with Li+, Na+ and K+ were recognized as specific alterations on their fluorescence spectra that strongly originated from the structures. The observed CEQFS depending on the bound cation radii and macrocycle size evidenced the rules of cationic recognition of macrocycles. Some 15-crown-5 derivatives exhibited interesting Li+ and Na+ binding selectivities.  相似文献   

13.
Abstract

A series of symmetrical 1,3-bis thiourea 1a–e and 1,4-bis thiourea derivatives 2a–e have been successfully synthesized from the reactions of amines with 3-acetylbenzoyl isothiocyanate and 4-acetylbenzoyl isothiocyanate, respectively. All the synthesized compounds were characterized by FT-IR spectroscopy and 1H and 13C NMR spectroscopy. The compounds were screened for their antibacterial activity by turbidimetric method using gram-negative bacteria (E. coli ATCC 8739) using turbidimetric method. The newly synthesized bis-thiourea derivatives bearing aryl side chains showed good antibacterial activity against E. coli. The effect of the molecular structure of the synthesized compounds on the antibacterial activity is discussed.  相似文献   

14.
Novel oligomeric and polymeric siloxanephosphazenes are synthesized by the catalytic hydrosilylation of eugenol derivatives of hexachlorocyclotriphosphazene with mono- and dihydridesiloxanes and are characterized by 1H and 29Si NMR spectroscopy and laser mass spectroscopy.  相似文献   

15.
Conclusions Trimethylsilyl derivatives of the dimethylhydrazides of aromatic acids have been prepared.1H,13C, and29Si NMR spectroscopy were used to establish that these derivatives are the dimethylhydrazones of the trimethylsilyl esters of the aromatic acids exclusively in the Z configuration.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 460–461, February, 1988.  相似文献   

16.
Four novel derivatives of 1,1′-bi-2-naphthol have been prepared and the structures of these compounds characterised by IR, MS, 1H and 13C NMR spectroscopy and elemental analysis. The enantioselective recognition of these sensors has been studied by fluorescence titration and 1H NMR spectroscopy. The sensors exhibited different chiral recognition abilities towards N-Boc-protected amino acid anions and formed 1:1 complexes between the host and the guest. Sensors exhibit excellent enantioselective fluorescent recognition ability towards the amino acid derivatives.  相似文献   

17.
GAO  Fang  YANG  Liufeng  WANG  Jianchao  XU  Xiaofang  LI  Hongru  ZHANG  Shengtao 《中国化学》2009,27(10):1929-1936
The synthesis, characterization and spectroscopy of a range of novel substituted p‐nitro‐stilbene derivatives with different bridging bonds were presented. The molecular structure characterization was carried out with 1H NMR, 13C NMR and elemental analysis. The ultraviolet/visible spectroscopy and photoluminescence of the compounds were investigated in various solvents. The maximal absorption wavelength of the nitro‐stilbene derivatives with an ether bond exhibited approximate 30 to 40 nm bathochromic shift compared to that of nitro‐stilbene dyes with an ester bond. Furthermore, the nitro‐stilbene derivatives with an ether bond displayed obvious photoluminescence, while the nitro‐stilbene derivatives with an ester bond showed weak fluorescence emission. The detection of the cyclic voltammograms of the nitro‐stilbene derivatives showed that the nitro‐stilbene compounds with different linking bonds exhibited different redox proceses at various scan rates. The theroretical calculations of HOMO and LUMO energy of nitro‐stilbene derivatives showed that the energy gaps between HOMO and LUMO of 3 and 4 were lower than those of 1 and 2 . The electron density of the frontier orbitals of nitro‐stilbene derivatives was observed to be affacted by the linking bonds, which thus made it possible to tune the spectroscopy of these dyes with chemical strategy. The differential scanning calorimetry and thermogravimetry showed that the thermal stabilities of these dyes were not much affected by the linking bond. The results presented in this paper would be great interest in development of ideal nitro‐stilbene derivatives for special purposes.  相似文献   

18.
The four novel derivatives of BINOL have been prepared and the structures of these compounds 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 N‐Boc‐protected amino acid anions and formed 1:1 complexes between host and guest. Receptor s exhibit excellent enantioselective fluorescent recognition ability towards the amino acid derivatives.  相似文献   

19.
A series of tri-substituted thiourea derivatives were synthesized by the reaction of 1,3,5-triacetylbenzoyl isothiocyanate with aminoacids and aniline derivatives. All thiourea derivatives were characterized by FT-IR, 1H and 13C NMR spectroscopy. Antibacterial activities against wild-type Escherichia coli American Type Culture Collection 8739 were determined by use of the turbidimetric methodto evaluate the effect of varying amino groups on the synthesized thioureas. Tris-thiourea derivatives bearing ortho-chloroaryl substituents showed excellent antibacterial activity against E. coli with minimal inhibitory concentration (MIC) of 96 ppm. The optimum inhibition was dependent on the type of amines and the position of the halogen in aniline.  相似文献   

20.
4-H, 4-methyl and 4-phenyl-1-benzopyran-2-one derivatives of [18]crown-6 derivatives were synthesised from 6,7- and 7,8-dihydroxy-1-benzopyran-2-one reacting with pentaethylene glycol ditosylate in K2CO3/DMF/water. The products were identified by elemental analysis, EI-GC-mass spectra and 1H-NMR spectroscopy. The Na+ association constants of some coumarin derivatives were determined with an ion selective electrode in water. The Na+ , K+, Ba2+ and Sr2+ binding role of such compounds were particularly observed as remarkable alterations in acetonitrile. The 1 : 1 associations constants of K+ and Na+ with some coumarin-[18]crown-6 derivatives estimated by this way in acetonitrile exhibited the utility of complexing enhanced quenching fluorescence spectra for the ion binding power of the such macrocycles.  相似文献   

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