Synthesis and investigations of cyclophosph(III)azane macrocycles

The primary aim of this thesis was to synthesise new hybrid-style cyclophosph(III)azane macrocycles composed to cyclophosph(III)azane units joined by difunctional linkers. The synthesis of the new macrocycles [{P(<i>μ</i>-N<i><sup>t</sup></i>-N<i><sup>...

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Bibliographic Details
Main Author: Dodds, F. E.
Published: University of Cambridge 2009
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Online Access:http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598575
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Summary:The primary aim of this thesis was to synthesise new hybrid-style cyclophosph(III)azane macrocycles composed to cyclophosph(III)azane units joined by difunctional linkers. The synthesis of the new macrocycles [{P(<i>μ</i>-N<i><sup>t</sup></i>-N<i><sup>t</sup></i>Bu)}<sub>2</sub>{1,5-(NH)<sub>2</sub>C<sub>10</sub>H<sub>6</sub>}]<sub>3</sub>, [{P(<i>μ</i>-N<i><sup>t</sup></i>Bu)}<sub>2</sub>{1,4-(NH)<sub>2</sub>C<sub>6</sub>H<sub>4</sub>}]<sub>4</sub>, [{P(<i>μ</i>-N<i><sup>t</sup></i>Bu)}<sub>2</sub>{1,4-O<sub>2</sub>C<sub>6</sub>H<sub>4</sub>}]<sub>3</sub> and [{P(<i>μ</i>-N<i><sup>t</sup></i>Bu)}<sub>2</sub>{(4,4’-NHC<sub>6</sub>H<sub>4</sub>)<sub>2</sub>O}]<sub>2</sub> was achieved using [CIP(<i>μ</i>-N<i><sup>t</sup></i>Bu)]<sub>2</sub> as the cyclophosph(III)azane precursor. These species include the largest cyclic oligomers known in this family of compounds. The synthesis of [{P(<i>μ</i>-NCy)}<sub>2</sub>{1,5-O<sub>2</sub>C<sub>10</sub>H<sub>6</sub>}]<sub>3</sub> showed that other cyclophosph(III)azane precursors can be used in these systems. Attempts to extend the same synthetic strategies to pyridyl-substituted cyclophosph(III)azanes, however, led to unexpected results which shed light on the reactivity of 2-pyridyl substituted cyclophosph(III)azanes. The new chain species [(C1{P(<i>μ</i>-N-4-Py)}<sub>2</sub>)<sub>2</sub>N-4-Py] represents a model intermediate in the formation of the previously reported bicyclic compound [Cl<sub>2</sub>P<sub>4</sub>(<i>μ</i>-N-2-Py)<sub>5</sub>] and is a potential new precursor for the synthesis of macrocycles. The second aim of this thesis was to investigate the potential for forming 3D-cage structures using trimeric cyclophosph(III)azanes like [CIP(<i>μ</i>-Net)<sub>3</sub> as precursors. Extensive rearrangement of the P<sub>3</sub>N<sub>3</sub> framework of the precursors and the tendency for oxidative hydrolysis caused major problems in this area. Finally, preliminary investigations of the coordination chemistry of the new macrocycles were carried out. The inclusion of solvent molecules <i>via</i> CH-arene interactions in the cavities of [{P(<i>μ</i>-N<i><sup>t</sup></i>Bu)}<sub>2</sub>{1,5-(NH)<sub>2</sub>C<sub>10</sub>H<sub>6</sub>}]<sub>3</sub> and [{P(μ-NCy)}<sub>2</sub>{1,5-O<sub>2</sub>C<sub>10</sub>H<sub>6</sub>}]<sub>3</sub> in the solid state, along with the intra- and intermolecular hydrogen-bonding interactions observed in the solid-state structures of [{P(<i>μ</i>-N<i><sup>t</sup></i>Bu)}<sub>2</sub>{1,4-(NH)<sub>2</sub>C<sub>6</sub>H<sub>4</sub>}] and [{P(<i>μ</i>-N<i><sup>t</sup></i>Bu)}<sub>2</sub>{(4,4’-NHC<sub>6</sub>H<sub>4</sub>)<sub>2</sub>O}], highlight the potential of these macrocycles to act as hosts to a range of guest species.