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oai:www.ideals.illinois.edu:2142/21096 2023-07-10 col_2142_5131 col_2142_14789 com_2142_5130 com_2142_14788 com_2142_8903

Made available in DSpace on 2011-05-07T12:58:15Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712399.pdf: 6112917 bytes, checksum: 8710d51cba58a5e941a2d63d6e735ca7 (MD5) Previous issue date: 1996 Kenneth S. Suslick Patel, Bimal Ramesh 2011-05-07T12:58:15Z 2011-05-07T12:58:15Z 10000-01-01 1996 "A new family of tetraarylporphyrins has been synthesized. The key distinguishing feature of these porphyrins is the presence of carboxylic functionality at the eight meta-phenyl positions of tetraphenylporphyrin (TPP). The base porphyrin is called 5,10,15,20-tetrakis(3$\sp\prime,5\sp\prime$-dicarboxyphenyl)porphyrin (H$\sb2$DCarPP). The octa-meta-phenyl substitution pattern allows substituents at the meta positions to direct out and away from the molecular center in three dimensions. These outward-directed alkyl groups created pockets above and below the porphine plane. The ""bis-pocket"" shape is the critical design feature that gives this family of porphyrins novel and exciting properties." The synthesis and characterization of H$\sb2$DCarPP, starting with mesitylene, is presented in Chapter 2. A benchtop process for oxidizing mesitylene to uvitic acid has been developed, and it is the key step to obtaining H$\sb2$DCarPP on a gram scale. An unusual crystal structure of an octapyridine-H$\sb2$DCarPP complex is also presented. This host-guest structure shows large, solvent-filled channels in one dimension, and porphyrin-pyridine-porphyrin layers in the other dimensions. Octa-n-alkyl esters of H$\sb2$DCarPP have also been prepared. The synthesis and characterization of these alkyl H$\sb2$DCarPP derivatives are presented in Chapters 3 and 4. The C$\sb{10}$ to C$\sb{22}$ octa-n-alkyl esters are liquid crystals. In fact, the C$\sb{10}$ and C$\sb{12}$ derivatives are liquid crystalline at room temperature. The C$\sb{10}$ derivative has a liquid crystalline temperature range from $-3\sp\circ$C to 120$\sp\circ$C, the largest range of the series. The bis-pocket shape of the $\rm C\sb{12}\ H\sb2$DCarPP allows it to retain its liquid crystalline properties when metalated with five-coordinate metal ions like the vanadyl ion (VO$\sp{\rm II}$). By comparison, $\rm C\sb{12}\ H\sb2$TCPP (5,10,15,20-tetrakis(p-carboxyphenyl)porphyrin), a relatively flat molecule, loses its liquid crystalline properties when it is metalated with the vanadyl ion. The alkyl H$\sb2$DCarPP liquid crystals were studied by polarized microscopy. A model for the structure of the liquid crystalline phase is developed from analysis of the birefringence textures of the homologous series of alkyl H$\sb2$DCarPP liquid crystals. X-ray diffraction studies contribute additional information about the mesophase structure. The electron paramagnetic resonance of the C$\sb{12}$ DCarPPVO complex at room temperature gives a broad isotropic signal with lack of hyperfine structure. Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:48:27Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:21:56-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only 9780591200140 AAI9712399 (UMI)AAI9712399 http://hdl.handle.net/2142/21096 eng Copyright 1996 Patel, Bimal Ramesh Chemistry, Inorganic Chemistry, Organic Engineering, Materials Science Porphyrin liquid crystals text Chemistry Chemistry University of Illinois at Urbana-Champaign Dissertation Ph.D.