Stabilities and coordination modes of glycinephosphonic acid in copper(II) heteroligand complexes with ethylenediamine, diethylenetriamine or N,N,N′,N′,N″-pentamethyldiethylene triamine in aqueous solution

Solution equilibrium studies on the Cu(II)-polyamine-(aminomethyl)phosphonic acid (glycinephosphonic acid) ternary systems (polyamine: ethylenediamine (en), diethylenetriamine (dien), N,N,N′,N′,N″-pentamethyldiethylenetriamine (Me₅dien)) have been performed by pH-potentiometry, UV–vis spectrophotometry and EPR methods. The obtained results suggest the formation of the heteroligand complexes with [Cu(A)(Gly(P))] stoichiometry in all studied systems. Additionally, in the systems with dien the protonated [Cu(dien)(H–Gly(P))]⁺ species also exists in acid solution and in the system with en the [Cu(en)(Gly(P))H_-1]⁻ species is formed in the basic solution. Our spectroscopic results indicate the tetragonal geometry for the [Cu(en)(Gly(P))] species, the geometry slightly deviated from square pyramidal for the [Cu(dien)(Gly(P))] complex and strongly deviated from square pyramidal towards trigonal bipyramidal for the [Cu(Me₅dien)(Gly(P))] species. The coordination modes in these heteroligand complexes are discussed.     

γ Spectroscopy of 209Pb with deep inelastic reactions

High spin states in nuclei around ²⁰⁸Pb were populated in deep inelastic collisions of ⁷⁶Ge, ¹³⁶Xe, and ²⁰⁸Pb projectiles with ²⁰⁸Pb targets at beam energies about 12% above the Coulomb barrier. New states in ²⁰⁹Pb were found by measuring γ-γ-coincidences. They are interpreted as the yrast states that originate from the coupling of one neutron to the lowest excitations of the ²⁰⁸Pb core. The results are discussed in the frame of the shell model. Received: 22 November 1997     

Molecular genetics ofPhanerochaete chrysosporium

InPhanerochaete chrysosporium ME446 lignin degradation is a secondary metabolic event triggered by carbon and nitrogen limitation. It is therefore possible to study lignin degradation at the level of gene expression by comparing mRNA populations produced during primary and secondary growth in both wild-type strains and in strains mutant in lignin degradation. We have isolated mutants deficient in phenol oxidase activity. These mutants fall into three phenotypic categories with respect to lignin degradation: (1) negative, (2) delayed onset after nitrogen starvation, (3) enhanced. Polyacrylamide gel electrophoresis of rabbit reticulocyte polypeptide translation products ofPhanerochaete mRNA shows differences between populations from primary and secondary growth. Differences in the range of polypeptides (and therefore of mRNA) have also been demonstrated between a mutant and its wild-type progenitor under identical conditions. A gene bank has been prepared from P.chrysosporium strain ME446 genomic DNA using a bacteriophage λ vector. This gene bank is being screened with labeled mRNA from secondary growth mycelium in the presence of excess competing cold RNA from primary growth mycelium. Using this method (and/or using labeled cDNA probes), we hope to isolate clones carrying sequences expressed only during lignin degradation. A gene bank has also been constructed fromSporotrichum pulverulentum (Novobranova), which is on morphological criteria considered to be the imperfect form ofP. chrysosporium. DNA probes from randomly chosen clones of both gene banks have been hybridized to restricted and electrophoresed total DNA of the two “gene bank” strains and of two other isolates ofP. chrysosporium on Southern blots. We found very strong DNA homology between the two “gene bank” strains, but far less homology between these two strains and the two others. These degrees of relationships were supported by the analysis of mitochondrial DNA from the four strains. We thank the Agricultural Research Council and the British Petroleum Venture Research Unit for support.     

Particle hole yrast states in146Gd and147Gd and the Z=64 shell closure

The level structures of¹⁴⁶Gd and¹⁴⁷Gd have been investigated by in-beamγ-ray ande ^? spectroscopy with (α, xn) reactions on enriched Sm targets. Detailed level schemes up to ～4 MeV, which differ radically from earlier schemes, are reported. The energy levels are characterized as particle-hole excitations using empirical single particle energies and two nucleon interactions. Analysis of pure 1p 1h proton excitations demonstrates that theZ=64 andN=82 energy gaps are about equally large.     

Production of high multiplicity yrast isomers in147Gd and146Gd in a-particle induced reactions

High spin isomers in ¹⁴⁷ Gd and ¹⁴⁶ Gd have been produced in (α, xn)reactions, and their half-lives, excitation energies and maximum spins have been determined. It is proposed that these isomers are identical with those recently observed in bombardments with ⁵⁰ Ti and ⁴⁰ Ar projectiles.     

The two particle-phonon multiplet πh 11/2 νf 7/2 × 3− and higher-lying four-nucleon yrast states in the doubly-odd nucleus 146 63 Eu83

The isotopes¹⁵B,¹⁸C,^19,20N,^34,35Al and³⁹P have been produced as projectile-like fragments from the interaction of a⁸⁶Kr beam of 45 MeV/u from GANIL with a¹⁸¹Ta target. Separated by the 0° magnetic analyser LISE, the nuclei are identified by means of aΔE- E semiconductor telescope. It is surrounded, in a geometry close to 4π, by a thin plastic scintillator (NE 102) and a large volume liquid scintillator (NE 213) for the detection of betas and neutrons, respectively, from the decay of the implanted nuclei. By observation of theβ-delayed neutrons, the half-livesT _1/2 and neutron emission probabilitiesP _n have been measured. TheT _1/2 of¹⁸C,²⁰N,³⁵Al,³⁹P and P_n of¹⁸C,^19,20N,^34,35Al and³⁹P are determined for the first time. For the isotopes¹⁷C,^36,37Si and³⁸P upper limits of P_n are deduced.     

Gamma spectroscopy of neutron-rich nuclei from the vicinity of the “island of inversion” atN=20

Neutron-richsdf shell nuclei produced by deep-inelastic processes in collision of 230 MeV³⁷Cl ions on a thick²⁰⁸Pb target have been studied via in-beam spectroscopic methods. Candidates for negative parity states in³²Si and³²Al have been identified. Yrast states with spins up to 13/2 have been located in the previously unknown³⁷P nucleus.     

Dynamical deformation of nuclei participating in deep-inelastic collisions

TheN/Z equilibration process taking place in deep-inelastic heavy ion collisions above the Coulomb barrier was studied by means of thick target gamma spectroscopy method. The analysis of gamma coincidence data obtained for four heavy ion systems gave complete distributions of primary reaction products which allowed to extract the most probableN/Z ratios as a function of mass. The comparison of experimentalN/Z values with expectations based on potential energy minimization leads to conclusion that during the crucial interaction time the involved nuclei are dynamically deformed.     

Level structure of proton-richN=83 Nuclei150Ho and152Tm

The yrast levels of theN=83 odd-odd nuclei¹⁵⁰Ho and¹⁵²Tm have been studied byγ-ray spectroscopy following reactions induced by 240–250 MeV⁶⁰Ni ions. Isomers have been identified in¹⁵⁰Ho at 1.096, 2.625 and ～8.0 MeV and in¹⁵²Tm at 2.555 and ～ 6.3 MeV, and the level schemes of both nuclei have been established up to 2.6 MeV. The level spectra are interpreted using the shell model in terms of the coupling of anf _7/2,h _9/2 or i_13/2 valence neutron to the yrast excitations of the neighboring N=82 nuclei.