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The reductive part of artificial photosynthesis, the reduction of protons into H2, is a two electron two proton process. It corresponds basically to the reactions occurring in natural photosystem I. We show in this review a selection of involved processes and components which are mandatory for making this light-driven reaction possible at all. The design and the performances of the water reduction catalysts is a main focus together with the question about electron relays or sacrificial electron donors. It is shown how an original catalyst is developed into better ones and what it needs to move from purely academic homogeneous processes to heterogeneous systems. The importance of detailed mechanistic knowledge obtained from kinetic data is emphasized.

Due to its long half-life of 2.111×105 y, technetium, i.e. 99Tc, offers the excellent opportunity of combining fundamental and ' classical ' organometallic or coordination chemistry with all methodologies of radiochemistry. Technetium chemistry is inspired by the applications of its short-lived metastable isomer 99mTc in molecular imaging and radiopharmacy. We present in this article examples about these contexts and the impact of purely basic oriented research on practical applications. This review shows how the chemistry of this element in the middle of the periodic system inspires the chemistry of neighboring elements such as rhenium. Reasons are given for the frequent observation that the chemistries of 99Tc and 99mTc are often not identical, i.e. compounds accessible for 99mTc, under certain conditions, are not accessible for 99Tc. The article emphasizes the importance of macroscopic technetium chemistry not only for research but also for advanced education in the general fields of radiochemistry.

The shape and energy of frontier orbitals determine the reactivity of molecular systems. Combining orbital tomography based on photoelectron spectroscopy with electron diffraction and DFT, the authors investigate a complex multi-configurational adsorbate system revealing adsorptions geometries and hierarchy and geometry of molecular orbitals.

Objetivo: El objetivo principal de esta investigación es obtener bacterias del género Pseudomona spp. con capacidad biodegradora de hidrocarburos en muestras de agua superficial de la Bahía de Cartagena de Indias. Material y Método: Diseño observacional, descriptivo, transversal y prospectivo. Se tomaron tres muestras de agua superficial de la Bahía de Cartagena de indias, se sembraron para preadaptacion y adaptación biológica de las bacterias en medio con sales minerales, ACPM 1% v/v y petróleo crudo 1% v/v, como única fuente de carbono y energía. Resultados: Las bacterias que crecieron en los medios con petróleo crudo fueron identificadas en 31 morfotipos de colonias bacterianas, de las cuales solo el 19,4% dio positivo para la presencia de Pseudomona spp., y el 80,6% restante, pertenecientes a otros grupos bacterianos. Discusión: Se evidenció un cambio de color en el agar nutritivo durante el procedimiento de aislamiento de las bacterias de la muestra 2 relacionado con la presencia de especies de Pseudomonas en especial P. aeruginosa. Conclusión: Se reporta la presencia del género de Pseudomona spp. con capacidad biodegradadora de petróleo en una de las muestras de agua recolectadas en la Bahía de Cartagena. Este estudio abre la posibilidad de futuros trabajos de bioprospección e identificación metabólica de las cepas aisladas.

Two new operation modes, “pink beam” excitation, which has the energy bandwidth defined by X-ray mirrors and filters, and “broadband beam”, where the energy bandwidth is defined by the reflection from a multilayer monochromator, were implemented at the SuperXAS beamline of the Swiss Light Source (SLS). These setups allow measuring non-resonance X-ray emission spectra (XES) with 2–3 orders of magnitude higher incident flux than non-resonant XES measurements with a monochromatic incident beam. For the broadband beam mode, a Mo/Si multilayer structure was designed, with which the energy can be tuned in the 5–17 keV range. The multilayer demonstrates a relatively large energy bandwidth of 4 ± 0.2% through the whole energy range and a reflectivity of 23–60%, which increases with energy. We show that by using pink beam mode one can investigate the electronic structure of photocatalytic intermediates through time-resolved core-to-core XES experiments of diluted samples with a concentration of the element of interest of ~1 mM. Broadband beam mode is optimal for valence-to-core XES experiments and allow to avoid the excitation of additional KLβ satellites that can complicate the interpretation of spectra.

Atomically disperse catalysts can offer promising activity due to the high exposure of active sites. Here, iridium complexes in solution undergo a binding equilibrium with a nickel oxide surface resulting in atomically disperse iridium and high turnover frequencies for oxygen evolution.

Proton reduction by [CoII(BPyPy2COH)(OH2)2]2+ (BPyPy2COH = [2,2'-bipyridin]-6-yl-di[pyridin-2-yl]methanol) proceeds through two distinct, pH-dependent pathways involving proton-coupled electron transfer (PCET), reduction and protonation steps. In this account we give an overview of the key mechanistic aspects in aqueous solution from pH 3 to 10, based on electrochemical data, time-resolved spectroscopy and ab initio molecular dynamics simulations of the key catalytic intermediates. In the acidic pH branch, a PCET to give a CoIII hydride is followed by a reduction and a protonation step, to close the catalytic cycle. At elevated pH, a reduction to CoI is observed, followed by a PCET to a CoII hydride, and the catalytic cycle is closed by a slow protonation step. In our simulation, both CoI and CoII–H feature a strong interaction with the surrounding solvent via hydrogen bonding, which is expected to foster the following catalytic step.

Photosynthesis or the storage of solar energy in chemical bonds is a process which, in its essence, goes far beyond a conversion of CO2 and water into dioxygen and glucose or other organic products. Photosynthesis is a process which comprises elementary features of most of the chemical reactions and some physical processes we are looking at in higher education; light absorption, proton transfer, redox reactions and making and breaking of bonds amongst others. Metals and main group elements are involved and the entire process is embedded in a biological environment that involves proteins and membranes. In this article, we will focus on two key aspects of natural photosynthesis, namely the absorption of light (photons) and the separation of the excitons into electrons and holes based on P680 along with the electrochemical energetics. Further, we will present an artificial light driven catalytic process which mimics PSI for the reduction of water to H2, the inorganic congener of nicotinamide adenine dinucleotide phosphate (NADPH). This light-driven reductive process shall show the mechanistic complexity of the 'easy' reaction 2H+ + 2e– ? H2.

Taking advantage of the radiation properties of 99mTc and 186/188Re and the photophysical characteristics of the {M(CO)3}+ moiety (M = Re), we developed a multifunctional silica platform with the theranostic pair 99mTc/Re with high potential for (nano)medical applications. Starting with a general screening to evaluate the most suitable mesoporous silica construct and the development of appropriate chelate systems, multifunctional mesoporous silica microparticles (SBA-15) were synthesized. These particles act as a model towards the synthesis of the corresponding nanoconstructs. The particles can be modified at the external surface with a targeting function and labeled with the {M(CO)3}+ moiety (M = 99mTc, Re) at the pore surface. Thus, a silica platform is realized, whose bioprofile is not altered by the loaded modalities. The described synthetic procedures can be applied to establish a target-specific theranostic nanoplatform, which enables the combination of fluorescence and radio imaging, with the possibility of radio- and chemotherapy.

Se presenta un estudio exploratorio sobre la toma de decisiones al determinar los procesos de evaluación formativa. Se eligió al azar el trabajo realizado por 20 equipos de trabajo (102 estudiantes) en la materia Evaluación del aprendizaje de un programa de posgrado en educación, en la modalidad en línea. Se optó por métodos mixtos; se analizaron 20 tablas de especificaciones que albergaron 60 objetivos de aprendizaje. Asimismo, se examinaron 60 justificaciones que fundamentaban las decisiones sobre la elección de organizadores gráficos o productos escritos que coadyuvan a inferir el logro de los objetivos de aprendizaje. Los resultados indicaron que en el proceso de planeación existió una alta tendencia a la emisión de objetivos de aprendizaje que demandan procesos de pensamiento de baja complejidad. Además, al tomar decisiones sobre los productos, el proceso fue mayormente bien conducido. Esto puede deberse a la inclusión de elementos teóricos que contribuyeron a la comprensión del proceso de aprendizaje y las necesidades a cubrir en el marco de la evaluación formativa. Se exhorta a continuar con investigaciones relacionadas con la toma de decisiones en cuanto a la elección de organizadores gráficos, en especial sobre aquellos que presentaron resultados inesperados, como fue el caso del mapa conceptual.

The Chemical Institutes of the University of Zurich celebrate the 100th anniversary of the Nobel prize award to Alfred Werner in 1913.

Im Dezember jährt sich die Verleihung des Chemienobelpreises an Alfred Werner zum hundertsten Mal. Wer war der Mann, der die theoretischen Grundlagen der anorganischen Koordinationschemie legte?

Cyclopentadienyl complexes of 99mTc became accessible via a retro Diels-Alder synthetic approach of dimerized cyclopentadiene derivatives. So far, this approach was limited to derivatives comprising a carboxylic acid group, directly conjugated to the Cp-ring, leading to complexes [(C5H5COOH) 99m Tc(CO)3] and [(C5H5CONH-R)99mTc(CO)3], respectively. The introduction of an –NCO group via Curtius rearrangement and subsequent in situ reactions with alcohols or amines gave [(C5H5NHCO-OR)2] and [(C5H5NHCO-NHR)2]. To increase the spacer lengths between the Cp-ring and the functional groups, methylene and ethylene spacers were introduced to yield C5H5-CH2COOH and C5H5-C2H4COOH respectively. The latter Cp-derivatives reacted with [99mTcO4)]- and in the presence of CO releasing/reducing agents to the corresponding [(C5H5-spacer-COOH) 99mTc(CO)3] complexes. The carboxylato groups can be derivatized with targeting functions, leading to structurally altered receptor binding complexes, with 99mTc for imaging and with rhenium for therapy. The nature of the 99mTc complexes was assessed by HPLC comparison with the corresponding rhenium compounds.

The asymmetric unit of the title compound, (C8H20N)[Tc(C10H6NO2)Cl(CO)3], consists of two crystallographically independent technetium complexes related via a pseudo-inversion centre and two tetraethylammonium cations. The Tc atoms have slightly distorted octahedral coordination geometries, and they are linked with the cations by intermolecular C—H...O and C—H...Cl hydrogen-bonding contacts, forming two-dimensional columns, which lie approximately parallel to (001) in the crystal structure. The isochinolate (isoquinoline-1-carboxylate) ligands link the columns by partial π–π stacking [centroid–centroid distance 4.3733 (11) Å], forming a three-dimensional network structure.

Despite the apparent and well-known toxic effects of carbon monoxide (CO), studies on the intriguing biological roles of this molecule are rapidly emerging. Recent investigations have brought to the limelight various physiological effects of CO which include, among others, vasorelaxation and inhibition of organ rejection after transplantation. The importance of CO in biology can be compared with another gas, nitric oxide (NO), an essential and ubiquitous signalling molecule. This parallelism led to the tantalising concept of using CO for therapeutic purposes wherein compounds that transport and deliver this gas to a target tissue would clearly facilitate both the clinical feasibility and the specificity of CO therapy. Sodium boranocarbonate, Na[H3 BCO2H] (1) was the first water-soluble and non-transition metal containing CO-releasing molecule (CO-RM) to be identified. In order to tune the rate of CO release, we modified 1 and synthesised and characterized various derivatives which release CO under physiological conditions but at rates different from the parent compound 1. The synthesis, structure and CO-releasing properties of ester and amide derivatives of 1 will be presented together with some biological studies carried out with a selection of the compounds.

Inorganic chemistry has a long-standing tradition at the University of Zurich starting with Carl Jacob Löwig, the first professor of chemistry. The influence of Nobel Prize winner Alfred Werner in coordination, organometallic, and bioinorganic chemistry extends right up to the present day as can be seen in many of the research fields of the current professors and young research scientists. With all due respect for the long tradition in inorganic chemistry the Institute of Inorganic Chemistry is also looking forwards to define its role to meet the challenges of the future.

RheManTec, the First Symposium on the Chemistry and Application of the Elements down the Manganese Triad was held near Bloemfontein in South Africa from November 19–24, 2007. The main objective was an open presentation of actual research achievements and interests from the field of metal-containing anti-cancer drugs and catalysis in order to elucidate future joint research opportunities in public health and biomedicine. The symposium emerged from the joint efforts of the Swiss National Science Foundation and the National Research Foundation of South Africa to strengthen bilateral co-operation.

The cisplatin adduct of vitamin B12, cis-[PtCl(NH3)2B12]+ (1) reacts with dansyl-imidazole to form cis-[Pt(dansyl-imidazole)(NH3)2B12] (2). In a spectroelectrochemical assay, Co(III) in 2 was reduced to Co(II) under concomitant release of the Pt(II) complex. Since similar reduction occurs in the intracellular space, 2 can be used for studying cell uptake monitored by fluorescent microscopy. The insertion of a fluorescent marker into the platinum moiety will also facilitate the isolation of the platinum complex released from B12 and therefore to characterize its chemical authenticity.

In this article we briefly describe our recent results concerning the interaction of mononuclear [M(CO)3]+ (M = Re, 99Tc and 99mTc) based complexes with guanine and plasmid DNA for chemo- and/or radiotherapeutic purposes. Furthermore, studies with mono- and dinuclear, coordinatively unsaturated Ni(II) and Cu(II) complexes inducing B- to Z-DNA transitions are outlined. The strong interaction of [M(CO)3]+ with one guanine allows the direct introduction of this core into oligodeoxynucleotides (ODN), without their previous derivatization, for further elucidation of their biological behavior. Vectors labeled in this way can later be used in radioimaging or -therapy studies. The [M(CO)3]+ core can also mediate the introduction of further biologically active or, for analytical purposes, fluorescent molecules. Alternatively, ODNs can be derivatized with amino acid based chelators such as histidine. We describe the induction of structural changes in plasmid DNA observed after reaction with the [M(CO)3]+ moiety. This indicates a cisplatin-like behavior useful for future chemotherapy. Finally, studies of the interaction of mono- and dinuclear complexes with ODN inducing B- to Z-DNA transitions are described and compared to the effect of common electrolytes alone. A clear correlation between salt type and salt concentration was found. These complexes have a strong potential to be used for analytical or biological purposes as well.

A new method for 99mTc-labeling using solid-phase technology is described. It allows the separation of unlabeled from labeled bioactive molecules by simple filtration. The procedure is based on a site-specific C–N bond cleavage reaction initiated by the formation of [TcI(CO)3L]-complexes.