New building blocks for molecular spintronics

In der vorliegenden Arbeit werden die drei generellen Schritte beim Aufbau neuer Materialien aus funktionellen Bausteinen an Beispielen nachvollzogen. Im Einzelnen sind dies die Verknüpfung bekannter Funktionselemente und die Identifikation der Strukturelemente neuer Funktionen, die Darstellung von funktionalen Bausteinen mit Verknüpfungsstellen und die Verknüpfung der Bausteine und der Nachweis, dass die Funktion dadurch nicht verloren geht. Die Synthese von neuen Bausteinen steht dabei ebenso im Fokus wie die ausgedehnte Analyse erhaltener Verbindungen. Zwei neue Ligandgerüste werden beschrieben, die hochfunktionale Triphenylamineinheiten enthalten. Des Weiteren werden Verbindung auf der Basis von Triaminobenzen, Triaminoguanidin, Mesalen-artigen Liganden und acetylsubstituierten Phloroglucin untersucht und sorgfältig bezüglich ihrer magnetischen Eigenschaften charakterisiert. Erhaltene Ergebnisse konnten anschließend erfolgreich in andere Materialklassen übertragen werden: Die magnetische Anomalität, wie sie in Verbindungen basierend auf Triaminobenzen gefunden wird, konnte erfolgreich in Carbazolverbindungen integriert werden. Ein übergreifendes Ergebnis dieser Arbeit sind die Eigenschaften, die sich beim Einbau von Sulfonatgruppen in Verbindungen ergeben: Die Lösungseigenschaften der erhaltenen Verbindungen werden stark geändert, wobei die wasserlöslichen Produkte in Polyvinylalkoholfolien eingebettet werden können, was einen viel versprechenden Ansatz für zukünftige Materialien darstellt. Die Sulfonatsubtitution begünstigt auf Grund der Koordinationsfähigkeiten der Sulfonatgruppe die Ausbildung ausgedehnter Strukturen und bietet neue Strukturen durch die Bindung von Ammoniumgruppen mittels mehrfacher Wasserstoffbrückenbindungen an Mesalenartige Metallkomplexe

Der FachRef-Assistent : personalisiertes, fachspezifisches und transparentes Bestandsmanagement

Im Rahmen dieser Masterarbeit wurde eine personalisierte Webanwendung zur Bestandspflege von gedruckten und Online-Medien entwickelt: der FachRef-Assistent. Dieser führt automatisiert Analysen des Bestandes durch und erstellt Aussonderungsund Erwerbungsvorschläge. Dabei wurde besonderer Wert auf Individualisierung, Transparenz der Parameter, bibliothekarische Standards und generische Funktionen gelegt. Die Personalisierung erlaubt es, sowohl fachspezifische Nutzungseigenschaften als auch Unterschiede zwischen verschiedenen Bereichen innerhalb eines Fachbereiches zu berücksichtigen. Die verwendeten Parametersätze zur Analyse des Bestandes und zur Erstellung von Aussonderungs- und Erwerbungslisten werden grundsätzlich im XML-Format gespeichert und in die erzeugten Listen (ebenfalls im XML-Format) integriert, um eine Nachverfolgung und Transparenz der Analysen auf lange Zeit zu gewährleisten. Um die Anwendung so generisch wie möglich zu gestalten, wurden alle Bibliothekssystem-spezifischen Funktionen in einem separaten Paket zusammengefasst. Durch Adaption der entsprechenden Klassen lassen sich daher prinzipiell auch andere Bibliothekssysteme befragen. Auch die Integration spezifischer Bedingungen wie Standort, Aufstellungssystematik und Nutzergruppen wurde möglichst generisch gestaltet. Insgesamt stellt der in dieser Arbeit beschriebene FachRef-Assistent ein umfangreiches Werkzeug zum datenbasierten Bestandsmanagement dar. Der Grad an Automatisierung lässt sich dabei in vielen Schattierungen anpassen. Der FachRef- Assistent hilft, durch die Aggregation von objektiven Kriterien eine höhere Effizienz zu erreichen und setzt dadurch sowohl Finanz- als auch Zeitressourcen frei, die somit für andere Aufgaben zur Verfügung stehen.In the course of this master thesis a personalized web application for the weeding of printed and online resources has been developed: the FachRef-Assistant. Special attention has been paid to the criteria individualization, transparency of the parameters used, library standards and generic funtions. The personalization allows for the inclusion of subject specific usage properties as well as the differences between different collections within one subject area. The parameter sets used to analyze the stock and to prepare deinventarization and purchase proposal lists are stored as XML files and are included in the generated lists. These lists are similarly produced in XML format, ensuring a high degree of reproducibility and transparency for an extended period of time. To keep the application as generic as possible, all procedures specific to the local library system have been collected in one package. Hence simple adaption of this package renders the FachREf-Assistant compatible to other library systems. The inclusion of library specific properties such as collections and systematics have been designed to be highly generic. In summary, the FachRef-Assistent described in this thesis offers an extensive tool for evidence based stock management. The dgegree of automation can be chosen and adjusted in a wide range. The FachRef-Assistent supports the library staff by aggregation of objective criteria to achieve a higher work efficency, setting free additonal financial and time resources that may be used for new tasks and challenges

Ionothermal Synthesis, Crystal Structure, and Magnetic Study of Co2PO4OH Isostructural with Caminite

A new framework cobalt(II) hydroxyl phosphate, Co2PO4OH, was prepared by ionothermal synthesis using 1-butyl-4-methyl-pyridinium hexafluorophosphate as the ionic liquid. As the formation of Co2PO4F competes in the synthesis, the synthesis conditions have to be judiciously chosen to obtain well-crystallized, single phase Co2PO4OH. Single-crystal X-ray diffraction analyses reveal Co2PO4OH crystallizes with space group I41/amd (a = b = 5.2713(7) Å, c = 12.907(3) Å, V = 358.63(10) Å3, and Z = 4). Astonishingly, it does not crystallize isotypically with Co2PO4F but rather isotypically with the hydroxyl minerals caminite Mg1.33[SO4(OH)0.66(H2O)0.33] and lipscombite Fe2–yPO4(OH) (0 ≤ y ≤ 2/3). Phosphate tetrahedra groups interconnect four rod-packed face-sharing ∞1{CoO6/2} octahedra chains to form a three-dimensional framework structure. The compound Co2PO4OH was further characterized by powder X-ray diffraction, Fourier transform–infrared, and ultraviolet–visible spectroscopy, confirming the discussed structure. The magnetic measurement reveals that Co2PO4OH undergoes a magnetic transition and presents at low temperatures a canted antiferromagnetic spin order in the ground state

Azobenzene-Based Organic Salts with Ionic Liquid and Liquid Crystalline Properties

Two sets of new azobenzene-based bromide salts are synthesized, and their thermal photochromic properties are studied. Both sets are based on the imidazolium cation. The first set (1) features a symmetric biscation where two imidazolium head groups (Im) with different alkyl chains (Cn) are connected to a central azobenzene unit (Azo): [Azo(C1-Im-Cn)2]; n = 6, 8, 10, 12, 14. The other one contains an n-alkyl-imidazolium cation (Cn-Im) bearing a terminal azobenzene unit (C1-Azo) substituted with an alkoxy chain (O-Cm) of either two (2) or six (3) carbon atoms: [C1-Azo-O-Cm-Im-Cn]; m = 2, n = 8, 10, 12 and m = 6, n = 8, 10, 12, 14, 16. For both cation classes, the influence of alkyl chains of varying length on the thermal phase behavior was investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). For five compounds (Azo(-C1-Im-C12)2 (1d), Azo(-C1-Im-C12)2 (1e), C1-Azo-O-C2-Im-C10 (2b), C1-Azo-O-C2-Im-C12 (2c), and C1-Azo-O-C6-Im-C16 (3e)), the formation of a liquid crystalline phase was observed. The biscationic salts (1) are all comparatively high melting organic salts (180–240 °C), and only the two representatives with long alkylchains (C12 and C14) exhibit liquid crystallinity. The monocationic salts with an O–C2 bridge (2) melt between 140 and 170 °C depending on the alkyl chain length, but from an alkyl chain of 10 and more carbon atoms on they form a smectic A liquid crystalline phase. The representatives of the third set with a O–C6 bridge qualify as ionic liquids with melting points less than 100 °C. However, only the representative with a hexadecyl chain forms a liquid crystalline phase. Representative single crystals for all sets of cations could be grown that allowed for single crystal structure analysis. Together with small-angle X-ray scattering experiments they allow for a more detailed understanding of the thermal properties. Through irradiation with UV-light (320–366 nm) all compounds undergo trans–cis isomerization, which reverses under visible light (440 nm).Reprinted (adapted) with permission from Cryst. Growth Des., 2015, 15 (9), pp 4701–4712. Copyright 2015 American Chemical Society.</p

DuEPublicA: Automated bibliometric reports based on the University Bibliography and external citation data

This paper describes a web application to generate bibliometric reports based on the University Bibliography and the Scopus citation database. Our goal is to offer an alternative to easy-to-prepare automated reports from commercial sources. These often suffer from an incomplete coverage of publication types and a difficult attribution to people, institutes and universities. Using our University Bibliography as the source to select relevant publications solves the two problems. As it is a local system, maintained and set up by the library, we can include every publication type we want. As the University Bibliography is linked to the identity management system of the university, it enables an easy selection of publications for people, institutes and the whole university. The program is designed as a web application, which collects publications from the University Bibliography, enriches them with citation data from Scopus and performs three kinds of analyses: 1. A general analysis (number and type of publications, publications per year etc.), 2. A citation analysis (average citations per publication, h-index, uncitedness), and 3. An affiliation analysis (home and partner institutions) We tried to keep the code highly generic, so that the inclusion of other databases (Web of Science, IEEE) or other bibliographies is easily feasible. The application is written in Java and XML and uses XSL transformations and LaTeX to generate bibliometric reports as HTML pages and in pdf format. Warnings and alerts are automatically included if the citation analysis covers only a small fraction of the publications from the University Bibliography. In addition, we describe a small tool that helps to collect author details for an analysis

The FachRef-Assistant: Personalised, subject specific, and transparent stock management

We present in this paper a personalized web application for the weeding of printed resources: the FachRef-Assistant. It offers an extensive range of tools for evidence based stock management, based on the thorough analysis of usage statistics. Special attention is paid to the criteria individualization, transparency of the parameters used, and generic functions. Currently, it is designed to work with the Aleph-System from ExLibris, but efforts were spent to keep the application as generic as possible. For example, all procedures specific to the local library system have been collected in one Java package. The inclusion of library specific properties such as collections and systematics has been designed to be highly generic as well by mapping the individual entries onto an in-memory database. Hence simple adaption of the package and the mappings would render the FachRef-Assistant compatible to other library systems. The personalization of the application allows for the inclusion of subject specific usage properties as well as of variations between different collections within one subject area. The parameter sets used to analyse the stock and to prepare weeding and purchase proposal lists are included in the output XML-files to facilitate a high degree of transparency, objectivity and reproducibility

Ionothermal Synthesis, Crystal Structure, and Magnetic Study of Co2PO4OH Isostructural with Caminite

A new framework cobalt(II) hydroxyl phosphate, Co2PO4OH, was prepared by ionothermal synthesis using 1-butyl-4-methyl-pyridinium hexafluorophosphate as the ionic liquid. As the formation of Co2PO4F competes in the synthesis, the synthesis conditions have to be judiciously chosen to obtain well-crystallized, single phase Co2PO4OH. Single-crystal X-ray diffraction analyses reveal Co2PO4OH crystallizes with space group I41/amd (a = b = 5.2713(7) Å, c = 12.907(3) Å, V = 358.63(10) Å3, and Z = 4). Astonishingly, it does not crystallize isotypically with Co2PO4F but rather isotypically with the hydroxyl minerals caminite Mg1.33[SO4(OH)0.66(H2O)0.33] and lipscombite Fe2–yPO4(OH) (0 ≤ y ≤ 2/3). Phosphate tetrahedra groups interconnect four rod-packed face-sharing ∞1{CoO6/2} octahedra chains to form a three-dimensional framework structure. The compound Co2PO4OH was further characterized by powder X-ray diffraction, Fourier transform–infrared, and ultraviolet–visible spectroscopy, confirming the discussed structure. The magnetic measurement reveals that Co2PO4OH undergoes a magnetic transition and presents at low temperatures a canted antiferromagnetic spin order in the ground state.Reprinted with permission from Inorg. Chem., 2014, 53 (6), pp 3072–3077. Copyright 2014 American Chemical Society.</p

Azobenzene-Based Organic Salts with Ionic Liquid and Liquid Crystalline Properties

Two sets of new azobenzene-based bromide salts are synthesized, and their thermal photochromic properties are studied. Both sets are based on the imidazolium cation. The first set (1) features a symmetric biscation where two imidazolium head groups (Im) with different alkyl chains (Cn) are connected to a central azobenzene unit (Azo): [Azo(C1-Im-Cn)2]; n = 6, 8, 10, 12, 14. The other one contains an n-alkyl-imidazolium cation (Cn-Im) bearing a terminal azobenzene unit (C1-Azo) substituted with an alkoxy chain (O-Cm) of either two (2) or six (3) carbon atoms: [C1-Azo-O-Cm-Im-Cn]; m = 2, n = 8, 10, 12 and m = 6, n = 8, 10, 12, 14, 16. For both cation classes, the influence of alkyl chains of varying length on the thermal phase behavior was investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). For five compounds (Azo(-C1-Im-C12)2 (1d), Azo(-C1-Im-C12)2 (1e), C1-Azo-O-C2-Im-C10 (2b), C1-Azo-O-C2-Im-C12 (2c), and C1-Azo-O-C6-Im-C16 (3e)), the formation of a liquid crystalline phase was observed. The biscationic salts (1) are all comparatively high melting organic salts (180–240 °C), and only the two representatives with long alkylchains (C12 and C14) exhibit liquid crystallinity. The monocationic salts with an O–C2 bridge (2) melt between 140 and 170 °C depending on the alkyl chain length, but from an alkyl chain of 10 and more carbon atoms on they form a smectic A liquid crystalline phase. The representatives of the third set with a O–C6 bridge qualify as ionic liquids with melting points less than 100 °C. However, only the representative with a hexadecyl chain forms a liquid crystalline phase. Representative single crystals for all sets of cations could be grown that allowed for single crystal structure analysis. Together with small-angle X-ray scattering experiments they allow for a more detailed understanding of the thermal properties. Through irradiation with UV-light (320–366 nm) all compounds undergo trans–cis isomerization, which reverses under visible light (440 nm).Reprinted (adapted) with permission from Cryst. Growth Des., 2015, 15 (9), pp 4701–4712. Copyright 2015 American Chemical Society.</p