Reactions of (PCP)Ru(CO)(NHPh)(PMe3) (PCP = 2,6-(CH2PtBu2)2C6H3) with substrates that possess polar bonds

The Ru(II) amido complex (PCP)Ru(CO)(PMe(3))(NHPh) (1) (PCP = 2,6-(CH(2)P(t)Bu(2))(2)C(6)H(3)) reacts with compounds that possess polar C=N, C triple bond N, or C=O bonds (e.g., nitriles, carbodiimides, or isocyanates) to produce four-membered heterometallacycles that result from nucleophilic addition of the amido nitrogen to an unsaturated carbon of the organic substrate. Based on studies of the reaction of complex 1 with acetonitrile, the transformations are suggested to proceed by dissociation of trimethylphosphine, followed by coordination of the organic substrate and then intramolecular N-C bond formation. In the presence of ROH (R = H or Me), the fluorinated amidinate complex (PCP)Ru(CO)(N(Ph)C(C(6)F(5))NH) (6) reacts with excess pentafluorobenzonitrile to produce (PCP)Ru(CO)(F)(N(H)C(C(6)F(5))NHPh) (7). The reaction with MeOH also produces o-MeOC(6)F(4)CN (>90%) and p-MeOC(6)F(4)CN (<10%). Details of the solid-state structures of (PCP)Ru(CO)(F)(N(H)C(C(6)F(5))NHPh) (7), (PCP)Ru(CO)[PhNC{NH(hx)}N(hx)] (8), (PCP)Ru(CO){N(Ph)C(NHPh)O} (9), and (PCP)Ru(CO){OC(Ph)N(Ph)} (10) are reported.     

Superconducting transition temperatures of amorphous binary alloy systems based on Bi,Pb, Ga and Be

Quench condensed binary alloy films are produced by evaporation from two separated furnaces. The films contain the whole composition range of the respective alloy system in well defined arrangement.T _c is measured as a function of concentration. Eight predominantly amorphous alloy systems are studied: Bi—Ga, Pb—Ga, Pb—Bi, Be—Bi, Be—Pb, Be—Ga, Be—Al, Be—Li. In Bi—Ga and Pb—GaT _c is a linear function of concentration in the amorphous composition range. In Pb—BiT _c has a maximum. All Be-alloys show lower transition temperatures than pure quench condensed Be. Except for Be—Li all systems have aT _c minimum. The experiments are compared to aT _c calculation using tunelling spectroscopy data. Except for the Be-alloys the agreement is satisfying.     

Sn-vacancy defects in GaP

Complex¹¹⁹Sn-vacancy defects in GaP have been studied by Mössbauer-emission spectroscopy on the 24-keV γ radiation of¹¹⁹Sn. The defects were created by ion implantations of radioactive¹¹⁹In⁺ and¹¹⁹Sb⁺, which in their decays both populate the Mössbauer state of¹¹⁹Sn. The radiogenic¹¹⁹Sn-vacancy defects are proposed to consist of substitutional¹¹⁹Sn on Ga or P sites, respectively, associated with (P or Ga) vacancies.     

Geometrical description of binary reactions and large p⊥ phenomena

We study consequences of defining the impact parameter as being the variable conjugate to transverse relative c.m. momentum, p_⊥. This coincides with a proposal originally made by Chang and Raman. The dynamical information carried by these are intimately connected to the behaviour of 90° scattering. In particular, impact parameter dynamics is a priori qualitatively different from direct channel angular momentum dynamics. A phenomenological study of elastic π^±p and pp data at fixed values of longitudinal momentum, p₆, leads to a generalized geometrical scaling hypothesis. In contrast with the power behaviour predicted by parton models, the data suggest exponential behaviour of the scaling amplitudes at fixed p₆ of the type e^Rp⊥ with R ? 1 fm. Correspondingly these amplitudes are described by a pair of complex conjugate singularities on the imaginary axis in the impact parameter plane.     

Die klassisch-reguläre Lösbarkeit des Rand-Anfangswertproblems nichtlinearer Wellengleichungen mit einer Randbedingung vom gemischten Typ

Ohne ZusammenfassungFür viele wertvolle Hinweise möchte ich an dieser Stelle meinem akademischen Lehrer, Herrn Prof. Dr. W. von Wahl, danken     

A simple multifunctional valve for flow injection analysis

A simple and versatile pneumatically-operated two-layer rotary valve is described for simultaneous introduction of sample and diversion of analytical streams in flow injection analysis. Examples of application include valve configuration with time-controlled sample volume and with loop-controlled sample volumes in one or two loops; both configurations are useful in routine analyses of samples of highly varying analyte concentrations. The usefulness of the valve for ion-exchange preconcentration procedure is also demostrated.     

The (3He,n) reaction in the lower 2s1d shell

The two-proton transfer reaction (³He, n) has been measured on four gas targets, ¹⁶O, ¹⁸O, ²⁰Ne, and ²²Ne, with an incident ³He energy of 18.3 MeV. The data were taken with a neutron time-of-flight spectrometer in the angular range 0° to 40° c.m. The results for selected transitions are compared to DWBA predictions using shell-model spectroscopic amplitudes. In addition, the data for the ¹⁸O(³He, n)²⁰Ne reaction are compared to predictions of the SU(3) strong coupling model.