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1.
W.C. Herndon 《Tetrahedron》1973,29(1):3-12
Simple MO techniques are described that can be used to count resonance structures for unsaturated hydrocarbons, ions, and radicals. Alternant or non-alternant unsaturated species can be treated accurately and rapidly. The relationship of the structure count to the calculated values of highest filled and lowest vacant HMO energy levels is discussed. A qualitative relationship of the structure count with reactivity and stability if exemplified with several cases. A known correspondence of resonance theory and perturbational MO theory, previously limited to benzenoid and acyclic systems, is expanded to include all pi molecular systems. 相似文献
2.
A series of novel organoiron complexes has been isolated and studied by 1H NMR, 13C NMR, and IR spectroscopy. Addition of LiC(CH3)2CN to (1,3-cyclohexadiene)tricarbonyliron produces an intermediate which is only stable at low temperature and which is assigned the homoallyl—Fe(CO)3 anion structure. The intermediate rearranges on warming into a stable complex, for which full spectral data support the structure as an allyl—Fe(CO)3 anionic species. Interception of the first formed intermediate with CO gives an acylferrate complex with an olefin unit still bound to iron, and methylation then occurs at oxygen to produce an unusual internally-bound (alkene)(methoxyalkylidene)tricarbonyliron species. 相似文献
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5.
Scott C. Herndon David D. Nelson Jr Mark S. Zahniser 《Journal of Quantitative Spectroscopy & Radiative Transfer》2005,90(2):207-216
The spectral line strengths in the v2 band of H2CO (segments spanning 1720-) have been determined relative to two sets of spectral line groups in the v1 and v5 band, using tunable diode laser spectroscopy. Simultaneous detection using a dual-diode instrument with a absorption cell was employed to assure identical H2CO column density for the two spectral regions. The results in the selected regions of this study are in good agreement with the line positions and the relative intensities specified in an unpublished complete line listing for the v2 band prepared by Linda Brown (see full text for reference). Based upon measurements of individual groups of spectral lines in the P, Q and R branches, the absolute band strength has been determined to be . 相似文献
6.
[reaction: see text] The synthesis of isoquinolines through coupling of 2-alkynylbenzaldehyde derivatives with beta-cyanocarbene complexes has been examined. The reaction involves formation of an isobenzofuran followed by intramolecular Diels-Alder reaction with the nitrile, a process with limited precedent. The unique success of this process in this system has been attributed to deoxygenation of the initial adduct to form the isoquinoline ring system. 相似文献
7.
R Bonfiglio RC King TV Olah K Merkle 《Rapid communications in mass spectrometry : RCM》1999,13(12):1175-1185
A post-column infusion system was developed in order to analyze suppression of electrospray ionization (ESI) tandem mass spectrometry response in the presence of endogenous plasma interferences. By enabling direct detection of these interfering components, this experimental system was used to analyze the ability of several common extraction procedures to remove endogenous plasma components that cause changes in the ESI response of model drug substances. Methyl-t-butyl ether (MTBE) liquid-liquid, Oasis and Empore solid-phase, and acetonitrile (ACN) protein precipitation sample preparation methods were tested using the post-column infusion system. In all cases, ACN protein precipitation samples showed the greatest amount of ESI response suppression while liquid-liquid extracts demonstrated the least. In addition, the three test compounds, phenacetin, caffeine, and a representative Merck compound, demonstrated that ESI response suppression is compound dependent. Suppression was greatest with caffeine, the most polar analyte, and the smallest for the Merck compound, the least polar analyte. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
8.
Samit Mandal J Gerl H Geissel K Hauschild M Hellström Z Janas I Kojouharov Y Kopatch RC Lemmon P Mayet Z Podolyak PH Regan H Schaffner C Schlegel J Simpson HJ Wollersheim 《Pramana》2001,57(1):161-164
Feasibility of gamma-ray spectroscopy at relativistic energies with exotic heavy-ions and new generation of germanium detectors
(segmented Clover) is discussed. An experiment with such detector array and radioactive is discussed. 相似文献
9.
James W. Herndon 《Coordination chemistry reviews》2010,254(1-2):103-194
This is a review of papers published in the year 2008 that focus on the synthesis, reactivity, or properties of compounds containing a carbon-transition metal double or triple bond. 相似文献
10.
Alejandro Camacho-Davila Lalith S.R. Gamage Zhipeng Wang James W. Herndon 《Tetrahedron》2010,66(27-28):4954-4960
The coupling of highly oxygenated ortho-alkynylbenzaldehyde derivatives with γ,δ-carbene complexes was evaluated systematically. In all of the electron-rich systems investigated the exclusive product of the reaction is the dihydrophenanthrene derivative. Only the extremely electron-withdrawing methanesulfonate group can prevent this process from occurring. The use of the base additive collidine resulted in a surprising yield enhancement but no other discernable effect on the course of the reaction. Dihydrophenanthrene formation was attributed to rapid dehydration after the opening of a benzo-oxanorbornene intermediate. 相似文献