Structural Characterization and Lifetimes of Triple‐Stranded Helical Coinage Metal Complexes: Synthesis, Spectroscopy and Quantum Chemical Calculations

This work reports on a series of polynuclear complexes containing a trinuclear Cu, Ag, or Au core in combination with the fac-isomer of the metalloligand [Ru(pypzH)$_{3}$](PF$_{6}$)$_{2}$ (pypzH=3-(pyridin-2-yl)pyrazole). These (in case of the Ag and Au containing species) newly synthesized compounds of the general formula [{Ru(pypz)$_{3}$}$_{2}$M$_{3}$](PF$_{6}$) (2: M=Cu; 3: M=Ag; 4: M=Au) contain triple-stranded helical structures in which two ruthenium moieties are connected by three N-M-N (M=Cu, Ag, Au) bridges. In order to obtain a detailed description of the structure both in the electronic ground and excited states, extensive spectroscopic and quantum chemical calculations are applied. The equilateral coinage metal core triangle in the electronic ground state of 2–4 is distorted in the triplet state. Furthermore, the analyses offer a detailed description of electronic excitations. By using time-resolved IR spectroscopy from the microsecond down to the nanosecond regime, both the vibrational spectra and the lifetime of the lowest lying electronically excited triplet state can be determined. The lifetimes of these almost only non-radiative triplet states of 2–4 show an unusual effect in a way that the Au-containing complex 4 has a lifetime which is by more than a factor of five longer than in case of the Cu complex 2. Thus, the coinage metals have a significant effect on the electronically excited state, which is localized on a pypz ligand coordinated to the Ru atom indicating an unusual cooperative effect between two moieties of the complex

Investigation of Luminescent Triplet States in Tetranuclear Cu-I Complexes : Thermochromism and Structural Characterization

To develop new and flexible Cu-I containing luminescent substances, we extend our previous investigations on two metal-centered species to four metal-centered complexes. These complexes could be a basis for designing new organic light-emitting diode (OLED) relevant species. Both the synthesis and in-depth spectroscopic analysis, combined with high-level theoretical calculations are presented on a series of tetranuclear Cu-I complexes with a halide containing Cu4X4 core (X=iodide, bromide or chloride) and two 2-(diphenylphosphino)pyridine bridging ligands with a methyl group in para (4-Me) or ortho (6-Me) position of the pyridine ring. The structure of the electronic ground state is characterized by X-ray diffraction, NMR, and IR spectroscopy with the support of theoretical calculations. In contrast to the para system, the complexes with ortho-substituted bridging ligands show a remarkable and reversible temperature-dependent dual phosphorescence. Here, we combine for the first time the luminescence thermochromism with time-resolved FTIR spectroscopy. Thus, we receive experimental data on the structures of the two triplet states involved in the luminescence thermochromism. The transient IR spectra of the underlying triplet metal/halide-to-ligand charge transfer (M-3/XLCT) and cluster-centered ((CC)-C-3) states were obtained and interpreted by comparison with calculated vibrational spectra. The systematic and significant dependence of the bridging halides was analyzed.Peer reviewe

Kwaliteit als een functie van de samenwerking tussen medisch specialisten en managers in Nederlandse ziekenhuizen

Ziekenhuizen staan voor een grote uitdaging (Berwick en Nolan, 1995; Shortell et. al., 2004; Kaissi, 2005). Patiënten worden steeds mondiger en eisen transparantie en optimale kwaliteit van zorg. Technologische ontwikkelingen zorgen voor meer mogelijkheden in de behandeling van ziekten, terwijl de financiering van de zorg aan banden wordt gelegd. De noodzaak voor structurele verbeteringen in de kwaliteit van zorg en zorgorganisaties wordt benadrukt door rapporten uit de Verenigde Staten zoals ‘To Err is Human’ de ‘5 Million Lives Campaigns’ (IHI, 2006 and 2008) en ‘Crossing the Quality Chasm’ (Berwick, 2004), maar de implementatie van kwaliteitsmanagement laat te wensen over. In de literatuur is beschreven dat de meeste kwaliteitsmanagement programma’s in de gezondheidszorg gefocust zijn op de structuurkant van organisaties, terwijl de meeste data wijzen op verbetering van zorg door naleving van professionele richtlijnen (Powell et al., 2009). Volgens Berwick (2004), een van de belangrijke voormannen van kwaliteitsverbeteringen in ziekenhuizen wereldwijd, is de participatie van artsen in kwaliteitsmanagement projecten een noodzakelijke voorwaarde voor succes. Een van de waarschijnlijke redenen dat de implementatie van kwaliteitsmanagement in ziekenhuizen moeizaam verloopt, is de complexiteit van de samenwerking tussen artsen en managers (Edwards, 2003). Hieronder doen wij verslag van ons onderzoek naar de moeizame verhouding tussen artsen en managers in ziekenhuizen en hoe deze gerelateerd is aan de kwaliteit van organisatie en zorg. Dit onderzoek heeft geleid tot een wetenschappelijke proefschrift (Hanneke Klopper, 2011)

Intraspecific genetic variation in the percoid teleosts Argyrosomus japonicus (Temminck&Schlegel, 1843) and Pomadasys commersonnii (Lacepède, 1801), as inferred from the mitochondrial control region

Dusky kob, Argyrosomus japonicus and spotted grunter, Pomadasys commersonnii occur off South Africa’s southern and eastern seaboard. They are the preferred target species for both shore and estuarine anglers. In order to sustain the billion rand recreational angling industry, healthy fish populations are of the utmost importance. However, A. japonicus is currently overexploited, with the species’ spawner biomass estimated at 1-4.5% of pristine levels. Pomadasys commersonnii spawner biomass is estimated at 40% of pristine levels, thus indicating that the species is not overexploited. For effective management of our marine resources, information about the population size, structure, dynamics and population history of individual species is needed. Genetic data can make a valuable contribution to a holistic stock determination, approach, as powerful tools in unraveling population history. Genetic variation gives a reflection of the evolutionary differences within and between populations and allows for indirect assessment of population connectivity and gene flow levels. The mitochondrial DNA (mtDNA) control region is a useful marker in population studies, due to its high substitution rate. The haploid nature of the mtDNA, maternal inheritance and the absence of recombination, means that the signal obtained from genetic drift is stronger than that for nuclear loci. For this reason the mtDNA control region was analysed for 133 juvenile A. japonicus and 139 P. commersonnii samples from four localities along their South African distribution, to determine the genetic diversity and differentiation among the coastal regions. Juvenile A. japonicus are resident around their natal estuaries until they reach sexual maturity. This residency of juveniles makes them ideal candidates to give a reflection of A japonicus population dynamics, especially to determine if any isolation-by-distance exists along the coast. In the case of P. commersonnii, both juveniles and adults were analysed, since adults are resident around their natal estuaries when not undertaking spawning migrations. High levels of genetic diversity were found in both A. japonicus and P. commersonnii, comparable to that observed in other marine fish species. No significant population differentiation results were obtained, possibly due to the small sample sizes collected or to lack of resolution in the marker. In A. japonicus, where spawning is known to occur off KwaZulu-Natal and off the southern Cape coast, possible isolation-by-distance was detected. This indicates that the adult A. japonicus population probably does not consist of one freely intermixing unit, but rather of geographically separated spawning units. For P. commersonnii, where spawning has only been recorded off the KwaZulu-Natal coast, no population differentiation was observed, indicating that the different regions along the South African coast are highly connected. In conclusion, through future analysis of larger sample sizes, preferably from single cohorts, some of the noise will be reduced and more conclusive answers with respect to female gene flow could be provided. In the case of A. japonicus the use of microsatellite markers which are better at detecting fine-scale differentiation and provide estimates of total gene flow, will be informative. At a broader geographic scale, it will be important to assess differentiation among Dusky kob populations from throughout the Western and Eastern Indian Ocean. As far as P. commersonnii is concerned, it is recommended that a comparison be undertaken to determine the relationship; of the South African population to that found along the Mozambican coast.Dissertation (MSc (Genetics))--University of Pretoria, 2005.Geneticsunrestricte

Evaluating the resolution power of new microsatellites for species identification and stock delimitation in the Cape hakes Merluccius paradoxus and Merluccius capensis (Teleostei : Merlucciidae)

The utility of 15 new and 17 previously published microsatellite markers was evaluated for species identification and stock delimitation in the deep-water hake Merluccius paradoxus and the shallow-water hake Merluccius capensis. A total of 14 microsatellites was polymorphic in M. paradoxus and 10 in M. capensis. Two markers could individually discriminate the species using Bayesian clustering methods and a statistical power analysis showed that the set of markers for each species is likely to detect subtle genetic differentiation (FST < 0.006), which will be valuable to delimit and characterise genetic stocks.BCLME/BENEFIT and the Department of Science and Technology African Coelacanth Ecosystem Programme (ACEP) II.University of Pretoria’s postdoctoral programme.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1095-86492016-05-31hb201

Structural Characterization and Lifetimes of Triple‐Stranded Helical Coinage Metal Complexes: Synthesis, Spectroscopy and Quantum Chemical Calculations

This work reports on a series of polynuclear complexes containing a trinuclear Cu, Ag, or Au core in combination with the fac-isomer of the metalloligand [Ru(pypzH)$_{3}$](PF$_{6}$)$_{2}$ (pypzH=3-(pyridin-2-yl)pyrazole). These (in case of the Ag and Au containing species) newly synthesized compounds of the general formula [{Ru(pypz)$_{3}$}$_{2}$M$_{3}$](PF$_{6}$) (2: M=Cu; 3: M=Ag; 4: M=Au) contain triple-stranded helical structures in which two ruthenium moieties are connected by three N-M-N (M=Cu, Ag, Au) bridges. In order to obtain a detailed description of the structure both in the electronic ground and excited states, extensive spectroscopic and quantum chemical calculations are applied. The equilateral coinage metal core triangle in the electronic ground state of 2–4 is distorted in the triplet state. Furthermore, the analyses offer a detailed description of electronic excitations. By using time-resolved IR spectroscopy from the microsecond down to the nanosecond regime, both the vibrational spectra and the lifetime of the lowest lying electronically excited triplet state can be determined. The lifetimes of these almost only non-radiative triplet states of 2–4 show an unusual effect in a way that the Au-containing complex 4 has a lifetime which is by more than a factor of five longer than in case of the Cu complex 2. Thus, the coinage metals have a significant effect on the electronically excited state, which is localized on a pypz ligand coordinated to the Ru atom indicating an unusual cooperative effect between two moieties of the complex