An electronic spectral study of some Fe(II) magnetic isomers in solution and a spectral-structural correlation with their Ni(II) analogs

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dc.contributor.advisorWilson, Lon J.en_US
dc.creatorGeorges, Danaeen_US
dc.date.accessioned2018-12-18T21:22:59Zen_US
dc.date.available2018-12-18T21:22:59Zen_US
dc.date.issued1975en_US
dc.description.abstractPseudooctahedral Fe(II) Complexes of the hexadentate ligand, tris4-[(6-R)-2-pyridyl]-3-aza-3-butenylamine, where R is either H or CH^ (Figure 1) , have been studied in solution by electronic spectroscopy. The complexes represent a magnetically interesting series with Fe-I being low-spin, Fe-IV high-spin, and Fe-II and Fe-III spin equilibrium species. The d-d electronic spectrum of high-spin Fe-IV has been interpreted in terms of a strongly distorted octahedral ligand field model with 1 Dq = 11,4 cm. As evidenced by X-ray structural results, a major contribution of the reduction from symmetry appears to arise from a static molecular distortion in which the average Fe-N(imine) and Fe-N(pyridine) bond distances differ by .14. As for other low-spin tris(a-diimine)Fe(II) complexes, the spectrum of Fe-I is characterized by only Fe (II) -ยป l igand charge transfer bands whose intensities and positions obscure any d-d transitions. The spectrum of the spin equilibrium Fe-III compound displays features commensurate with a molefraction-weighted population of both high-spin and low-spin magnetic isomers with 1Dqhs (Fe-III) being ~11,7 cm-1 when the two spin states are nearly equi-energetic. The analogous Ni(II) complexes of Figure 1 have also been synthesized and characterized by elemental analysis, infrared spectroscopy, and solution conductivity, magnetic susceptibility, pmr, and d-d electronic spectral measurements. From the spectral studies, 1Dq values for the series are found to increase according to the sequence: Ni-IV (1,55 cm-1) <Ni-III (11, cm-1) < Ni-I (11,24 cm-1). Using spectral and available X-ray structural data for tha two metal ion series, it has been empirically determined that lODq a r-^ with r the average M-N bond distance. From this structure-bonding relationship, a value of 1Dqs for Fe-I has been indirectly obtained and ratios for (Fe2)/ 1Dq(Ni2) and lODqgfFe2)/ 1Dq(Ni2+) estimated as 1.7 and 1.15 respectively. By this ratio method, values of Dqg for Fe-II and Dq^g for Fe-II and Fe-III have been obtained and a 3d electron mean pairing energy, 1, is calculated to be 12,8 + 4 cm ^ for this family of Fe(II) complexes.en_US
dc.format.digitalOriginreformatted digitalen_US
dc.format.extent65 ppen_US
dc.identifier.callnoThesis Chem. 1975 Georgesen_US
dc.identifier.citationGeorges, Danae. "An electronic spectral study of some Fe(II) magnetic isomers in solution and a spectral-structural correlation with their Ni(II) analogs." (1975) Masterโ€™s Thesis, Rice University. <a href="https://hdl.handle.net/1911/104431">https://hdl.handle.net/1911/104431</a>.en_US
dc.identifier.digitalRICE2066en_US
dc.identifier.urihttps://hdl.handle.net/1911/104431en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.titleAn electronic spectral study of some Fe(II) magnetic isomers in solution and a spectral-structural correlation with their Ni(II) analogsen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentChemistryen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Artsen_US
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