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Acetonitrile

About: Acetonitrile is a research topic. Over the lifetime, 11298 publications have been published within this topic receiving 175275 citations. The topic is also known as: cyanomethane & ethyl nitrile.


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Journal ArticleDOI
TL;DR: In this paper, a method for azidolysis of 1,2 epoxides with NaN3 in acetonitrile, by means of metal salts, is described.

96 citations

Journal ArticleDOI
TL;DR: The results suggested that the other nitriles examined here possess little, if any, acute toxicity in the absence of normal hepatic function and that these nit riles were activated by hepatic mechanisms to release cyanide which can account for their major acute toxic effects.

96 citations

Journal ArticleDOI
TL;DR: The observation of guest@mc5(NH 4)2 complexes via electrospray ionization Fourier transform mass spectrometry is described, showing the complex can be opened in the gas phase by use of an ionophore, and that the rate of this reaction depends on the size of the guest molecule, which likely influences how strongly the “lid” is attached.
Abstract: Cucurbiturils are of current interest as encapsulating agents, as catalysts, and as “wheel” components of rotaxanes. Most reports to date have dealt with the 6-mer cucurbituril, 2 but recently synthetic procedures for the higher homologues have been developed. 3 Only a few reports of the methylated 5-mer (Figure 1), decamethylcucurbit[5]uril (C 40H50N20O10, hereafter referred to as mc5), have appeared. 4,5 In solution, mc5 has been reported 5 to be a highly selective host for Pb 2+. Herein we describe the observation of guest@mc5(NH 4)2 complexes (Figure 2) (where guest ) N2, O2, methanol, or acetonitrile) via electrospray ionization Fourier transform mass spectrometry. Further, we show the complex can be opened in the gas phase by use of an ionophore, removing a “lid” cation and releasing the guest, and that the rate of this reaction depends on the size of the guest molecule, which likely influences how strongly the “lid” is attached. All experiments were performed using a Fourier transform ion cyclotron resonance mass spectrometer (model APEX 47e; Bruker Daltonics; Billerica, MA) and a microelectrospray ionization source modified 6 from an Analytica (Analytica of Branford; Branford, MA) design. The instrument was controlled using a MIDAS7 data system (National High Magnetic Field Ion Cyclotron Resonance Facility; Tallahassee, FL). Samples of mc5, obtained from IBC Advanced Technologies (American Fork, UT) about 1 mM in neat water, 50:50 methanol:water, 50:50 acetonitrile:water, or 50:50 ethanol:water, along with 2 mM ammonium acetate (Mallinckrodt; Paris, KY), were electrosprayed. A few samples were sprayed from 50:50 methanold1:D2O (99 and 99.9 atom %, respectively; both from Cambridge Isotope Laboratories; Andover, MA). The complex ions were also allowed to react with 18-crown-6 (Sigma; St. Louis, MO) introduced into the trapping region of the instrument via a direct-exposure probe, with partial pressures typically about 2 × 10-7 mbar. Isolation of reactant ions in the trap was performed using stored waveform inverse Fourier transform (SWIFT) techniques. 8 Reactant and product ion populations were measured as a function of reaction time to determine rate constants. Rate constants were determined both by isolating particular reactant ions, thus studying their reactions individually, and by studying a group of reactant ions concurrently. Molecular models were built usingMacromodel , ver. 7.1 (Schrodinger, Inc.: Portland, OR) and minimized using the MMFF94s force field included withMacromodel . Limited (1000 starting structures) Monte Carlo conformational searches were also carried out using this force field; these tended to find the same minimum-energy structure tens to hundreds of times. These minimum-energy structures were used as the starting point for full geometry optimizations at the semiempirical AM1 level (MacSpartan Pro,ver. 1.0.2; Wavefunction, Inc.: Irvine, CA) and at the ab initio HF/3-21G* level ( Gaussian 98, ver. A.7; Gaussian, Inc.: Pittsburgh, PA). Electrospray of mc5 along with ammonium acetate results in mass spectra composed of peaks corresponding to mc5 with one NH4 attached, mc5 with two NH 4 attached, and the latter with a guest molecule included. The complexity of the resulting mass spectrum depends on the spray solvents employed. We have observed no water inclusion complexes, even when spraying from neat water. Spraying from methanol:water solutions results almost exclusively in observation of doubly charged, doubly NH 4capped complexes with methanol included, whereas spraying from acetonitrile:water (Figure 3) yields peaks corresponding to “empty” doubly charged, doubly capped mc5 as well as guestincluded complexes of N 2, O2 (from air), or acetonitrile. The identity of the methanol guest was verified by spraying from 50: 50 methanold1:D2O, which resulted in a shift of +0.5 m/z for the doubly charged complex ion (allowing for deuteration of the caps). We observed no ethanol guests when spraying from ethanol: water solutions but observed abundant “empty” doubly ammoniated complexes and doubly ammoniated complexes containing N2 or O2. The molecular formulas of the latter two complexes † IBC Advanced Technologies; American Fork, Utah. (1) Jeon, Y.-M.; Kim, J.; Whang, D.; Kim, K. J. Am. Chem. Soc. 1996, 118, 9790-9791. (2) For a recent review, see Mock, W. L. In Comprehensi Ve Supramolecular Chemistry; Vögtle, F., Ed.; Elsevier: New York, 1996; Vol. 2, pp 477 -493. (3) Kim, J.; Jung, I.-S.; Kim, S.-Y.; Lee, E.; Kang, J.-K.; Sakamoto, S.; Yamaguchi, K.; Kim, K.J. Am. Chem. Soc. 2000, 122, 540-541. (4) Flinn, A.; Hough, G. C.; Stoddart, J. F.; Williams, D. J. Angew. Chem., Int. Ed. Engl.1992, 31, 1475-1477. (5) Zhang, X. X.; Krakowiak, K. E.; Xue, G.; Bradshaw, J. S.; Izatt, R. M. Ind. Eng. Chem. Res. 2000, 39, 3516-3520. (6) Shen, N.; Pope, R. M.; Dearden, D. V. Int. J. Mass Spectrom. 2000, 195-196, 639-652. (7) Senko, M. W.; Canterbury, J. D.; Guan, S.; Marshall, A. G. Rapid Commun. Mass Spectrom. 1996, 10, 1839-1844. (8) Chen, L.; Wang, T.-C. L.; Ricca, T. L.; Marshall, A. G. Anal. Chem. 1987, 59, 449-454. Figure 1. Structure of decamethylcucurbit[5]uril, mc5.

95 citations

Journal ArticleDOI
TL;DR: In this article, the ion-pairing effect of 1-butyl-3-methylimidazolium tetrafluoroborate ion cation was investigated.

95 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023533
20221,074
2021178
2020172
2019229
2018207