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Self-Assembly of Extended Networks from Molecular Lithium and Sodium Complexes

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thesis
posted on 2005-10-18, 00:00 authored by Dugald John MacDougall
This thesis is split into two sections, the first describes the synthesis and characterization of group 1 α, α′-stabilized carbanions and geminal dianions derived from organosulfonyacetonitriles, RSO2CH2CN (R = Me, t-Bu, or Ph), and bis(phenyl-sulfonyl)methane, (PhSO2)2CH2). Metallation of these ligands with one molar equivalent of MeLi, BuNa or BnK results in the formation of the corresponding mono anions, [RSO2CHCN)M] and [{(PhSO2)2CH}M] (M = Li, Na, or K). Similar reactions with two molar equivalents of the same bases leads to the generation of dianionic complexes, [(RSO2CCN)M2] (R = t-Bu, or Ph) and [{(PhSO2)2C}M2] (M = Li, Na, or K). Multinuclear NMR spectroscopic studies of these compounds in d6-DMSO confirm the successive deprotonation of the methylene units. Furthermore, electrospray mass spectroscopy and MeI quenching studies found that the geminal dianionic complexes react with DMSO to regenerate mono anions. Crystallographic analysis of the monoanions revealed polymeric structural patterns that contrast with the molecular species known for the mono-stabilized analogues. The head-to-toe linking of organic anions by metal cations is a recurring theme in the organosulfonylacetonitrile polymers. Crucially all of these structures can be derived from the rearrangement of dimers composed of two anions linked head-to-toe. The lithium and sodium bis(phenylsulfonyl)methanides form linear 1D chain structures comprised of interlinked six-membered (åáåáåáOSCSOMåáåáåá) ring chelates. Section two describes the self assembly of coordination polymers from molecular lithium or sodium aryloxides through Lewis acid/base interactions. Two approaches were investigated for network assembly, incorporation of a methoxy or cyano linker group into the aryloxide backbone, and ligation with the divergent Lewis base 1,4-dioxane. Modification of the aryloxide backbone led to the recovery of molecular compounds in unanticipated aggregation states, which could be attributed to the electronic effects of the cyano and methoxy groups. Ligation of LiOAr and NaOAr complexes with dioxane led to the inclusion of the molecular species in polymeric assemblies. In this light, tetrameric LiOAr cubanes were employed as tetrahedral nodes in the assembly of cubic diamondoid and related networks. The different ligation modes adopted by dioxane (terminal or bridging) leads to the formation of three related polymers, 1D zigzag chains, 2D (6,3) nets, and the targeted 3D cubic diamondoid array. The type of network formed is rationalized by consideration of entropic and space filling factors. The generality of this approach to network assembly was also demonstrated by the incorporation of dimeric LiOAr species into 1D, 2D and 3D polymers. Similarly, hexameric NaOAr clusters were employed as octahedral nodes in the generation of 3D cubic and related polymers.

History

Date Modified

2017-06-02

Defense Date

2005-10-14

Research Director(s)

Dr Jeanne Romero-Severson

Committee Members

Prof. Slavi C. Sevov Prof. A. G. Lappin Prof. Kenneth W. Henderson Prof. W. Robert Scheidt

Degree

  • Doctor of Philosophy

Degree Level

  • Doctoral Dissertation

Language

  • English

Alternate Identifier

etd-10182005-163959

Publisher

University of Notre Dame

Program Name

  • Chemistry and Biochemistry

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