Synthesis and characterization of heterometallic metal organic frameworks

Thesis (Ph. D.)--Syracuse University, 2009. / "Publication number: AAT 3381593."

<p> Doping Praseodymium into Al-Si glass has potential applications in permanent holographic data storage and other optical devices. For this we are using the sol-gel method to produce glass monoliths at relatively low temperatures. The silicon precursor is tetraethylorthosilicate (TEOS) and aluminum tri-sec butoxide (ATSB) is the aluminum precursor. TEOS is hydrolyzed in ethanol with HCl as a catalyst. ATSB is then added, as well as praseodymium chloride in water. To prevent cracking we use dimethyl formamide (DMF) as a drying control chemical additive (DCCA). The solution is poured into a polymethylpentene cylinder and maintained at 40&deg;C and the temperature is raised to 150&deg;C to dry and shrink the sample. Samples prepared by this method are amorphous, as indicated by X-ray diffraction. The final aim of this research is to produce optically clear, fracture less monoliths by varying aging, shape and drying conditions.</p>

No description available.

<p> Paramagnetic cations serve as useful and efficient NMR probes of coordination environment and can also give insight into dynamics on the millisecond timescale. In an effort to extend the powerful analytical techniques employed with the lanthanide series, work has been performed with small, doubly contained volumes of actinide cations. A series of novel fundamental magnetic susceptibility studies spanning all of the readily accessible actinide cations in the liquid phase is also reported. Variable temperature data collected as a probe of the ground electronic states of the cations is reported for a range of temperatures relevant in nuclear reprocessing. The effects of the counter anion in solution are discussed as they relate to softness and the apparent reduction in free electron character on the metal.</p>

<p>Enzymes are capable of exquisite selectivity in catalysis chemical reactions because of a well-evolved mechanism that binds substrates in internal active sites based on size and shape complementarity. The cavities of these enzymes are decorated with organic or inorganic groups which can promote reactivity once the substrate is non-covalently bound. Synthetic molecular hosts to date have been able to bind to substrates in a similar, biomimetic fashion, but functionalized molecular hosts are still virtually unknown. </p><p> One convenient way to prepare molecular hosts is by the self-assembly of organic coordinating ligands with suitable metal salts. The reversible dative bonds holding these cage structures together allow incorrect products to break apart and reform, favoring creation of the most thermodynamically stable product. This leads to discrete, solution phase cages that can function as cavity-containing hosts. Some of these hosts have shown efficacy as catalysts for pericyclic reactions due to favorable transition states of the bound substrates. These cages, however, fail to orient reactive functional groups into their interiors. Truly biomimetic cages will require modifying traditional self-assembled targets to incorporate these reactive functionalities. </p><p> This work explores the self-assembly of metal-organic cages displaying covalent modifications on their interior. Incorporation of unreactive and poorly reactive groups was found to have a significant impact on the outcome of the self-assembly process. Cages with endohedral alcoholic functionality were found to have different binding properties than unfunctionalized analogs. Cages with introverted alcohol groups were also exploited for their ability to self-catalyze reactions <i>on the interior</i> of the hosts. The metal vertices themselves could also be used as functional groups, and showed the ability to sense neutral analytes in hybrid dative/hydrogen bonded self-assemblies. </p>

<p> The first part of this thesis is a story about the design and optimization of synthetic methodology for the preparation of complex secondary and tertiary phosphine oxides. A scalable, single-step, acid-catalyzed addition-rearrangement cascade that couples aldehydes with primary phosphines to give racemic unsymmetrical secondary phosphine oxides (SPOs) was developed based on the observations and hypotheses reported in a collection of papers published in the early 1960s. Most of this work was reported in a communication published in Organometallics (<i>Organometallics</i>, <b>2010</b>, <i>29</i>, 4193-4195).</p><p> A general method for kinetic resolution of racemic SPOs by asymmetric catalytic arylation was the next target, but this required a catalyst and conditions that would operate at room temperature. After finding that a Xantphos-Pd complex suited this purpose, and demonstrating broad utility and stereospecific coupling, an optically active analog of Xantphos was designed and synthesized. When combined with palladium, this "Slantphos" catalyzed the arylation of racemic SPOs, with modest stereoenrichment. Much of this work was reported in a communication published in Organic Letters (<i>Org. Lett.</i>, <b> 2012</b>, <i>14</i>, 4370-4373).</p><p> The second part of this dissertation details the discovery of a novel class of materials, some of which are highly active catalysts for the electrochemical oxidation of water. The most active of these catalysts was selected for detailed electrochemical studies in several different electrolytes. At pH 7, borate was found to be superior. Several studies were also undertaken to characterize the material before and after catalysis, but the structure remains undetermined. Most of this work was reported in a full paper published in the New Journal of Chemistry (published online January 15, 2014).</p>

Thesis (Ph. D.)--Indiana University, Dept. of Chemistry, 2007. / Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5940. Adviser: Daniel J. Mindiola. Title from dissertation home page (viewed May 12, 2008).

Thesis (Ph. D.)--University of Missouri - Columbia, 2006. / (UMI)AAI3242738. Adviser: Jerry L. Atwood. Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6405.

Thesis (Ph.D.)--Indiana University, Dept. of Chemistry, 2008. / Title from PDF t.p. (viewed on May 13, 2009). Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4763. Adviser: P. Andrew Evans.