An Investigation of the Electronic Structures of Transition Metal Complexes By Single Crystal Polarized Spectroscopy

Citation

Cowman, Charles Dane (1974) An Investigation of the Electronic Structures of Transition Metal Complexes By Single Crystal Polarized Spectroscopy. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/3FCT-A075. https://resolver.caltech.edu/CaltechETD:etd-10252005-091128

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. A technique for growing thin film single crystals using tetra-n-butylammonium as a cation is detailed. The polarizations of both ligand field and charge transfer transitions were measured at 5[degrees]K for a number of transition metal monomeric and dimeric species. The polarized spectra for the [...] square planar complexes [...] and [...] confirm the [...] nature of the charge transfer bands. Spin orbit coupling was found to be important. The d orbital ordering [...] was found. The absorption spectra of the planar chlorobridged species [...] and [...] were found to exhibit anomalously large intensities for the spin-forbidden bands in the in-plane direction perpendicular to the metal-metal axis. The observed splitting of the lowest spin allowed d-d transition confirms the existence of metal-metal interaction. The ligand field absorption spectra of the square pyramidal [...] and [...] species are dominated by the equatorial allowed [...], dyz transition. Progressions of the totally symmetric metal-nitrogen stretch are observed on the transition. The observation of an axial polarized double progression of the metal-halogen symmetric stretch requires the inclusion of spin orbit coupling. The d orbital ordering [...] is identical to that in vanadyl ion. The [...] transition in the quadruply bonded [...] and [...]. species has been positively identified by the MCD and polarization data in the [...] complexes, compared to the polarization of this band in the lower symmetry species [...]. Progressions of the totally symmetric metal-metal stretch characterize the band envelope. The related [...] and [...] species also contain an analogous temperature independent band. The applicability of the molecular orbital scheme proposed by Cotton was confirmed. The polarized spectra of the [...] anion suggest a [...] structure related to the [...] complex. The polarization of the absorption bands of [...] were distinctly different; this species is known to have a [...] confacial bioctahedral structure.

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