N3-ligated Nickel(II) Diketonate Complexes: Synthesis, Characterization and Evaluation of O2 Reactivity

Interest in O2-dependent aliphatic carbon–carbon (C–C) bond cleavage reactions of first row divalent metal diketonate complexes stems from the desire to further understand the reaction pathways of enzymes such as DKE1 and to extract information to develop applications in organic synthesis. A recent report of O2-dependent aliphatic C–C bond cleavage at ambient temperature in Ni(II) diketonate complexes supported by a tridentate nitrogen donor ligand [(MBBP)Ni(PhC(O)CHC(O)Ph)]Cl (7-Cl; MBBP = 2,6-bis(1-methylbenzimidazol-2-yl)pyridine) in the presence of NEt3 spurred our interest in further examining the chemistry of such complexes. A series of new TERPY-ligated Ni(II) diketonate complexes of the general formula [(TERPY)Ni(R2-1,3-diketonate)]ClO4 (1: R = CH3; 2: R = C(CH3)3; 3: R = Ph) was prepared under air and characterized using single crystal X-ray crystallography, elemental analysis, 1H NMR, ESI-MS, FTIR, and UV-vis. Analysis of the reaction mixtures in which these complexes were generated using 1H NMR and ESI-MS revealed the presence of both the desired diketonate complex and the bis-TERPY derivative [(TERPY)2Ni](ClO4)2 (4). Through selective crystallization 1–3 were isolated in analytically pure form. Analysis of reaction mixtures leading to the formation of the MBBP analogs [(MBBP)Ni(R2-1,3-diketonate)]X (X = ClO4: 5: R = CH3; 6: R = C(CH3)3; 7-ClO4: R = Ph; X = Cl: 7-Cl: R = Ph) using 1H NMR and ESI-MS revealed the presence of [(MBBP)2Ni](ClO4)2 (8). Analysis of aerobic acetonitrile solutions of analytically pure 1–3, 5 and 6 containing NEt3 and in some cases H2O using 1H NMR and UV-vis revealed evidence for the formation of additional bis-ligand complexes (4 and 8) but suggested no oxidative diketonate cleavage reactivity. Analysis of the organic products generated from 3, 7-ClO4 and 7-Cl revealed unaltered dibenzoylmethane. Our results therefore indicate that N3-ligated Ni(II) complexes of unsubstituted diketonate ligands do not exhibit O2-dependent aliphatic C–C bond clevage at room temperature, including in the presence of NEt3 and/or H2O

Violence against women: The perspective of academic women

<p>Abstract</p> <p>Background</p> <p>Opinion surveys about potential causes of violence against women (VAW) are uncommon. This study explores academic women's opinions about VAW and the ways of reducing violence.</p> <p>Methods</p> <p>Quantitative and qualitative methods were used in this descriptive study. One hundred-and-fifteen academicians participated in the study from two universities. A questionnaire was used regarding the definition and the causes of VAW, the risk groups and opinions about the solutions. Additionally, two authors interviewed 8 academicians from universities other than that of the interviewing author.</p> <p>Results</p> <p>Academicians discussed the problem from the perspective of "gender-based violence" rather than "family violence". The majority of the participants stated that nonworking women of low socioeconomic status are most at risk for VAW. They indicated that psychological violence is more prevalent against educated women, whilst physical violence is more likely to occur against uneducated and nonworking women. Perpetrator related factors were the most frequently stated causes of VAW. Thirty-five percent of the academicians defined themselves as at risk of some act of VAW. Recommendations for actions against violence were empowerment of women, increasing the educational levels in the society, and legal measures.</p> <p>Conclusions</p> <p>Academic women introduced an ecological approach for the explanation of VAW by stressing the importance of taking into account the global context of the occurrence of VAW. Similar studies with various community members -including men- will help to define targeted interventions.</p

Nasal Chemosensory-Stimulation Evoked Activity Patterns in the Rat Trigeminal Ganglion Visualized by In Vivo Voltage-Sensitive Dye Imaging

Mammalian nasal chemosensation is predominantly mediated by two independent neuronal pathways, the olfactory and the trigeminal system. Within the early olfactory system, spatiotemporal responses of the olfactory bulb to various odorants have been mapped in great detail. In contrast, far less is known about the representation of volatile chemical stimuli at an early stage in the trigeminal system, the trigeminal ganglion (TG), which contains neurons directly projecting to the nasal cavity. We have established an in vivo preparation that allows high-resolution imaging of neuronal population activity from a large region of the rat TG using voltage-sensitive dyes (VSDs). Application of different chemical stimuli to the nasal cavity elicited distinct, stimulus-category specific, spatiotemporal activation patterns that comprised activated as well as suppressed areas. Thus, our results provide the first direct insights into the spatial representation of nasal chemosensory information within the trigeminal ganglion imaged at high temporal resolution

Ligand, Anion, and Substituent Effects on Aliphatic Carbon-Carbon Bond Cleavage Reactions

Oxidative aliphatic carbon-carbon (C-C) bond cleavage reactions are important for potential uses in synthesis and industry. To date, these reactions often require harsh chemicals or expensive metal catalysts. In efforts to find alternate methods, studies of oxidative bond cleavage reactions involving O2 and mediated by first row transition metals are of major interest. The research outlined in this dissertation primarily focuses on the O2 reactivity of Cu(II) chlorodiketonate complexes and the effects of changing the supporting ligand, exogenous anions, and electronic effects on oxidative C-C bond cleavage. The results show that differences in the coordination sphere of the metal center has a major impact on the reactions. Changes such as these can promote or even alter the chemistry found within these systems. The outcomes from these studies include a better understanding of how tuning the features surrounding a metal center can lead to major changes in reactivity

A Study of Scan Patterns for Mobile Mapping

Mobile terrestrial scanning systems automate terrestrial laser scanning. Continous scanning mobile terrestrial systems constantly spin the terrestrial laser scanner and thus combine terrestrial scanning with kinematic laser scanning. This paper presents a scan pattern analysis for these systems. We aim at finding the most advantageous combination of terrestrial and kinematic systems. The resulting 3D point cloud depends on the scan pattern and the trajectory and velocity of the mobile system