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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Ferrocenes of Substituted Indenyl Ligands

Fern, Glen Matthew January 2005 (has links)
This thesis describes the preparation and characterization of a variety of methyl-, trimethylsilyl-, and diphenylphosphino-substituted indenes. The indenes were then used in the preparation of bis(indenyl)iron(II) complexes. The bis(indenyl)iron(II) complexes were characterized by ¹H, ¹³C, and ³¹P-NMR, UV/visible spectroscopy, cyclic voltammetry, and mass spectrometry. The cyclic voltammetry shows an approximately linear relationship between the oxidation potential and the type of substituent and its ring position, but with increasing substitution leads to lower than expected oxidation potentials. The UV/visible spectra show two absorption bands in the visible region. The position of the bands are essentially unaffected by methyl-substitution, but the low energy band red-shifts with trimethylsilyl- and diphenylphosphino-substitution. Di(2-methylindenyl)iron(II), bis(4,7-dimethyl-indenyl)iron(II), bis(1,3-bis(trimethylsilyl)indenyl)iron(II), rac-bis(1-diphenyl-phosphinoindenyl)iron(II), rac-bis(1-diphenylphosphino-3-methylindenyl)iron(II), and rac-bis(1-diphenylphosphino-2,3-dimethylindenyl)iron(II) were characterized by X-ray crystallography.The planar chiral ferrocenylphosphine bis(1-diphenylphosphinoindenyl)iron(II) is observed to undergo a facile ring-flipping isomerization from the meso isomer to the racemic isomer in THF at ambient temperature. The isomerization is slowed by the addition of the noncoordinating solvent chloroform, but is accelerated by the addition of LiCl. Rate and activation parameters for the isomerization have been determined to be: kobs = 1.6 x 10⁻⁵ s⁻¹ at 23 ℃, ΔH‡ = 58 ± 4 kJ mol⁻¹, ΔS‡ = −140 ± 15 J mol⁻¹ K⁻¹. Deuterium labeling of bis(1-diphenylphosphinoindenyl)iron(II) in the 3- and 3ʹ-position ruled out the isomerization proceeding by [1,5]-proton shifts or dissociative mechanisms. The proposed mechanism for the isomerization proceeds via coordination of two THF ligands with ring-slippage of one of the indenyl ligands until it is coordinated through the phosphine. Coordination of the indenyl ligand by the other face leads to the formation of the other isomer.The heterobimetallic complexes (bis(1-diphenylphosphinoindenyl)iron(II))-cis-dichloropalladium(II), (bis(1-diphenylphosphinoindenyl)iron(II))-cis-dichloro-platinum(II), and [(cyclooctadiene)(rac-bis(1-diphenylphosphinoindenyl)iron(II))-rhodium(I)] tetraphenylborate were prepared. Attempts to prepare dichloro(bis(1-diphenylphosphinoindenyl)iron(II))nickel(II) lead to the formation of trans-dichloro(bis(1-diphenylphosphinoindene))nickel(II). The complex (bis(1-diphenyl-phosphinoindenyl)iron(II))-cis-dichloropalladium(II) is able to catalyze the cross-coupling of bromobenzene with n-/sec-butylmagnesium chloride. However. the reaction is not selective with isomerization of the alkyl group and reduction of the halide occurring via a β-hydride elimination mechanism.
122

The reversible electrochemical promotion of the catalytic oxidation of carbon monoxide over platinum supported yttria-stabilised zirconia

Luke, Ronald John Campbell January 1996 (has links)
No description available.
123

New diphosphines with acenaphthene and phenylene backbones

Basra, Sandeep January 2002 (has links)
No description available.
124

NMR studies on the dynamics of small molecules in zeolite ZSM-5

Fergie-Woods, J. W. January 1985 (has links)
No description available.
125

The Fries rearrangement : added-ion effects and spectroscopic investigations

Waddington, C. R. January 1985 (has links)
No description available.
126

Efficient and inefficient intramolecular reactions

Williams, Nicholas Hendrik January 1992 (has links)
No description available.
127

Reactions and laser activation of carbon acids in hydrogen bonding environments

White, M. S. January 1986 (has links)
No description available.
128

The nature of a selective (amm)oxidation catalyst - iron antimony oxide

Allen, Matthew David January 1996 (has links)
No description available.
129

Preparation and characterisation of zirconium pillared interlayered clays

Warburton, C. I. January 1985 (has links)
No description available.
130

Heteroatom-substituted aluminophosphates

Wyles, Joanna Kay January 2000 (has links)
No description available.

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