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111.
L. Ramakrishnan Prof. Dr. S. Soundararajan 《Monatshefte für Chemie / Chemical Monthly》1977,108(1):225-231
Complexes of 2,6-dimethylpyridine 1-oxide with lanthanide iodides of the formulaeLn(2,6-LTNO)5I3 whereLn=La, Tb and Yb,Ln(2,6-LTNO)4I3 whereLn=Pr and Nd and Er(2,6-LTNO)4.5I3 have been prepared and characterised by chemical analysis, infrared and conductance studies. Infrared and conductance data have been interpreted in terms of dimeric (or polymeric) structures involving bridging amine oxide groups.
Mit 2 Abbildungen 相似文献
Mit 2 Abbildungen 相似文献
112.
Mavis M. Kadooka Mildred Y. Chang Hiroshi Fukami P.J. Scheuer Jon Clardy Barbara A. Solheim James P. Springer 《Tetrahedron》1976,32(8):919-924
From the bark of the endemic Hawaiian tree Sophora chrysophylla Seem. we have isolated two unprecedented quainolizidine alkaloids, mamanine (4) and pohakuline (5). Both bases are 1-hydroxymethylenequinolizidines which are linked at C-3 to α-pyridone or α-piperidone moieties. The alkaloids may be intermediates in a heretofore unknown biogenetic pathway of Sophora alkaloids. 相似文献
113.
Prof. Dr. O. Hromatka D. Binder K. Eichinger 《Monatshefte für Chemie / Chemical Monthly》1974,105(1):123-126
The synthesis of 5-(o-trifluoromethylphenyl)-1H-thieno-[3,4-e]1,4-diazepin-2(3H)-one (7) and its nitration and chlorination in pos. 8 are described. 相似文献
114.
Prof. Dr. Enrique J. Baran 《Monatshefte für Chemie / Chemical Monthly》1975,106(1):121-126
Mean amplitudes of vibration of a series of tetrahedralXY 4 molecules and ions (hydrides, halides, oxides and oxoanions) have been calculated using the “Method of the Characteristic Vibrations” ofA. Müller. The results indicate that this method leads to very good values for most of the investigated species, and especially in the cases of highM X/MY mass ratio. 相似文献
115.
H. -H. Grapengeter Prof. Dr. Robert Kosfeld H. W. Offergeld 《Colloid and polymer science》1980,258(10):1104-1110
Zusammenfassung Es wurden die longitudinalen Protonen-RelaxationszeitenT
1 der beiden Systeme Hexamethyldisiloxan und Dekamethylcyclopentasiloxan im Temperaturbereich von 20 bis 300 K untersucht. Das Relaxationsverhalten des Hexamethyldisiloxans wird in diesem Temperaturbereich durch drei Bewegungsmechanismen bestimmt: die Methylgruppenrotation um die C3-Achse, die Segmentrotation um die Si-O-Bindung und einen noch nicht näher identifizierten Bewegungsprozeß, der zu einer sprunghaften Änderung der Spin-Gitter-Relaxationszeit führt. Diese Bewegungsmechanismen werden mit Ausnahme der Segmentrotation auch beim Dekamethylcyclopentasiloxan gefunden. Es wird eine Gegenüberstellung der experimentellen Daten der beiden hier untersuchten Systeme und eines polymeren Dimethylsiloxans gegeben. Dabei ist als interessantes Ergebnis hervorzuheben, daß die Methylgruppenrotation im Hexamethyldisiloxan die stärkste Behinderung erfährt.
Mit 4 Abbildungen und 1 Tabelle 相似文献
Summary In this experiment the longitudinal proton relaxation timesT 1 of hexamethyldisiloxane and decamethylcyclopen-tasiloxane were measured in the temperature range from about 20 K up to 300 K. Three motional mechanisms, the methyl group rotation about the C3-axis, the segmental rotation about the Si-O-bond and a motional process, not yet identified, which leads to a discontinuity ofT 1 have been found to be responsible for the spin-lattice relaxation of hexamethyldisiloxane in this temperature range. With the exception of segmental rotation these motional processes also determine the spin-lattice relaxation of decamethylcyclopentasiloxane. A comparison of experimental data of the two systems actually investigated and a polymeric dimethylsiloxane is presented, showing the methyl group rotation being most strongly hindered in the case of hexamethyldisiloxane.
Mit 4 Abbildungen und 1 Tabelle 相似文献
116.
Hiroshi Ueyama 《Journal of statistical physics》1980,22(1):1-26
Based on the assumption of a kinetic equation in space, a stochastic differential equation of the one-particle distribution is derived without the use of the linear approximation. It is just the Boltzmann equation with a Langevin-fluctuating force term. The result is the general form of the linearized Boltzmann equation with fluctuations found by Bixon and Zwanzig and by Fox and Uhlenbeck. It reduces to the general Landau-Lifshitz equations of fluid dynamics in the presence of fluctuations in a similar hydrodynamic approximation to that used by Chapman and Enskog with respect to the Boltzmann equation.This work received financial support from the Alexander von Humboldt Foundation. 相似文献
117.
Prof. Dr. Edmund Hlawka 《Monatshefte für Mathematik》1980,89(1):19-44
A new proof of a theorem of W. Neiss is given that the rays of the Quadratwurzelschnecke are uniformly distributed mod 2 . The exact order of the discrepancy of the sequence is determined. Multidimensional generalizations of this sequence are also considered. It is shown that the Quadratwurzelschnecke is something like a roulette.
Mit 2 Abbildungen
Herrn Prof. R. M. Redheffer in Freundschaft zum 60. Geburtstag gewidmet 相似文献
Mit 2 Abbildungen
Herrn Prof. R. M. Redheffer in Freundschaft zum 60. Geburtstag gewidmet 相似文献
118.
Prof. Dr. Alexander Aigner 《Monatshefte für Mathematik》1977,83(2):89-91
It is shown by a simple induction that any square-free natural number is the square-free kernel of Euler's -function of infinitely many natural numbers. Furthermore every square-free natural number >1 is the square-free kernel of Euler's -function of infinitely many square-numbers. 相似文献
119.
The Mitsunobu reaction is a widely used and versatile method for the dehydrative oxidation–reduction condensation of an acid/pronucleophile usually with a primary or secondary alcohol that requires the combination of a reducing phosphine reagent together with an oxidizing azo reagent. The utility of this reaction stems from the fact that it is generally highly stereoselective and occurs with inversion of the stereochemical configuration of the alcohol starting material. Furthermore, as carboxylic acids, phenols, imides, sulfonamides, and other compounds can be used as the acid/pronucleophile, this reaction is useful for the preparation of a wide variety of functional groups. This Focus Review of the Mitsunobu reaction summarizes its origins, the current understanding of its mechanism, and recent improvements and applications. 相似文献
120.
Kaori Suzuki Takayoshi Kobayashi Hiroyuki Ohtani Hiroshi Yesaka Saburo Nagakura Yoshinori Shichida Tôru Yoshizawa 《Photochemistry and photobiology》1980,32(6):809-811
Difference spectra between squid rhodopsin and its bathorhodopsin at room temperature were measured ca. 150 ps and ca. 500 ps after the excitation at 347.2 nm by a double-beam picosecond time-resolved spectrometer. The spectra measured showed a red shift of the isosbestic point between squid rhodopsin and its bathorhodopsin and a lower ΔAmax/ΔAmin value compared with those measured at low temperatures by conventional spectrophotometry. 相似文献