Studies on photochromic and potentially mesogenic mercury(II) dithizonates

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dc.contributor.advisorHutton, Alan Ten_ZA
dc.contributor.authorCromhout, Natalie Lynen_ZA
dc.date.accessioned2016-08-22T12:26:13Z
dc.date.available2016-08-22T12:26:13Z
dc.date.issued1994en_ZA
dc.description.abstractThe 4-( 4 '-n-alkoxybenzylideneanilino )mercury(II) dithizonates, CₙH₂ₙ₊₁ OC₆H₄CH=C₆H₄-Hg(HDz) (n = l, 4, 12, 14 or 18), were prepared by complexation of dithizone (1,5-diphenyl- thiocarbazone, H 2 Dz) with the corresponding 4-(4'-n-alkoxybenzylideneanilino)mercury(II) acetates. The 4-( 4 '-n-alkoxybiphenyl)mercury(II) dithizonates, CₙH₂ₙ₊₁ OC6H4 C6H4- Hg(HDz) (n = 4, 5, 10, 14 or 18), were similarly prepared by reaction of dithizone with the appropriate 4-(4'-n-alkoxybiphenyl)mercury(II) bromides, although the latter compounds, derived from the 4-n-alkoxy-4'-bromobiphenyls, were not isolated. The preparation of the 4- ( 4'-n-octyloxyazobenzene)mercury(II) dithizonate, C₈H₁₇OC₆H₄N=NC₆H₄Hg(HDz),from 4-n-octyloxy-4'-bromoazobenzene was attempted but the chosen synthetic method was not successful. The thermal behaviour of those series of compounds isolated was investigated by polarized optical microscopy and differential scanning calorimetry. The organomercury(II) acetates displayed a limited, poorly-defined mesomorphism and the type of any mesophase formed remains unidentified. The 4-n-alkoxy-4'-bromobiphenyls (alkoxy = CₙH 2 n+ 1 0, n = 3-5, 10-12, 14-16 or 18) exhibited liquid crystalline behaviour within a broad temperature range for the compounds with n ~ 10 and the nature of the mesophases was tentatatively assigned as smectic D and C. The 4-n-alkoxy-4'-bromoazobenzenes (alkoxy = CₙH 2 n+I0, n = 5, 10, 12 or 14) showed monotropic (n = 5, 10 or 12) or enantiotropic (n = 14) nematic and smectic A mesophases. However, none of the dithizonate derivatives was mesomorphic and this was attributed to the geometry of the dithizonate ligand. The organomercury(II) dithizonates were photochromic in organic solvents, displaying reversible colour changes from yellow to blue on irradiation with visible light. The visible absorption spectra of these solutions were recorded and appeared to be independent of the nature of the long-chain organic ligand. This photochromism was not observed in the solid state.en_ZA
dc.identifier.apacitationCromhout, N. L. (1994). <i>Studies on photochromic and potentially mesogenic mercury(II) dithizonates</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Chemistry. Retrieved from http://hdl.handle.net/11427/21428en_ZA
dc.identifier.chicagocitationCromhout, Natalie Lyn. <i>"Studies on photochromic and potentially mesogenic mercury(II) dithizonates."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Chemistry, 1994. http://hdl.handle.net/11427/21428en_ZA
dc.identifier.citationCromhout, N. 1994. Studies on photochromic and potentially mesogenic mercury(II) dithizonates. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Cromhout, Natalie Lyn AB - The 4-( 4 '-n-alkoxybenzylideneanilino )mercury(II) dithizonates, CₙH₂ₙ₊₁ OC₆H₄CH=C₆H₄-Hg(HDz) (n = l, 4, 12, 14 or 18), were prepared by complexation of dithizone (1,5-diphenyl- thiocarbazone, H 2 Dz) with the corresponding 4-(4'-n-alkoxybenzylideneanilino)mercury(II) acetates. The 4-( 4 '-n-alkoxybiphenyl)mercury(II) dithizonates, CₙH₂ₙ₊₁ OC6H4 C6H4- Hg(HDz) (n = 4, 5, 10, 14 or 18), were similarly prepared by reaction of dithizone with the appropriate 4-(4'-n-alkoxybiphenyl)mercury(II) bromides, although the latter compounds, derived from the 4-n-alkoxy-4'-bromobiphenyls, were not isolated. The preparation of the 4- ( 4'-n-octyloxyazobenzene)mercury(II) dithizonate, C₈H₁₇OC₆H₄N=NC₆H₄Hg(HDz),from 4-n-octyloxy-4'-bromoazobenzene was attempted but the chosen synthetic method was not successful. The thermal behaviour of those series of compounds isolated was investigated by polarized optical microscopy and differential scanning calorimetry. The organomercury(II) acetates displayed a limited, poorly-defined mesomorphism and the type of any mesophase formed remains unidentified. The 4-n-alkoxy-4'-bromobiphenyls (alkoxy = CₙH 2 n+ 1 0, n = 3-5, 10-12, 14-16 or 18) exhibited liquid crystalline behaviour within a broad temperature range for the compounds with n ~ 10 and the nature of the mesophases was tentatatively assigned as smectic D and C. The 4-n-alkoxy-4'-bromoazobenzenes (alkoxy = CₙH 2 n+I0, n = 5, 10, 12 or 14) showed monotropic (n = 5, 10 or 12) or enantiotropic (n = 14) nematic and smectic A mesophases. However, none of the dithizonate derivatives was mesomorphic and this was attributed to the geometry of the dithizonate ligand. The organomercury(II) dithizonates were photochromic in organic solvents, displaying reversible colour changes from yellow to blue on irradiation with visible light. The visible absorption spectra of these solutions were recorded and appeared to be independent of the nature of the long-chain organic ligand. This photochromism was not observed in the solid state. DA - 1994 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1994 T1 - Studies on photochromic and potentially mesogenic mercury(II) dithizonates TI - Studies on photochromic and potentially mesogenic mercury(II) dithizonates UR - http://hdl.handle.net/11427/21428 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/21428
dc.identifier.vancouvercitationCromhout NL. Studies on photochromic and potentially mesogenic mercury(II) dithizonates. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Chemistry, 1994 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/21428en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Chemistryen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherChemistryen_ZA
dc.titleStudies on photochromic and potentially mesogenic mercury(II) dithizonatesen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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