This thesis describes the synthesis and properties of some extended donor-acceptor dyads with the donor being a ferrocenyl moiety and a fluorescent naphthalimide group as the acceptor. Two series of extended ferrocenyl-naphthalimide dyads were prepared in reasonable yield depending on the synthetic route. The first are a series of three ferrocenyl-CH=CH-spacer-C[triple bond]C-naphthalimide dyads in which the spacers are phenyl, biphenyl and anthryl and the second are a series of three ferrocenyl-C[triple bond]C-spacer-C[triple bond]C-naphthalimide dyads in which the spacers are 2,2� -bithiophene, 2,5-dimethoxybenzene and tetrafluorobenzene groups. The molecular structures of some compounds have been determined by X-ray diffraction although with many challenges because of the extensive [pi]-[pi] stacking of molecules that leads to ready aggregation in the solid state, particularly for the ferrocenyl-CH=CH-spacer-C[triple bond]C-naphthalimide dyads, in which the naphthalimide bears a methyl head group. In order to reduce the [pi]-[pi] stacking effect between the molecules and also to produce chiral molecules for the potential nonlinear optical applications, a chiral α-methylbenzylamine was introduced as the head group of naphthalimide for the ferrocenyl-C[triple bond]C-spacer-C[triple bond]C-naphthalimide dyads. The resulting comounds successfully gave crystals of sufficient quality for X-ray structural investigation. While the oxidative electrochemistry of the ferrocenyl compound in the two series of dyads was largely predictable (E� ~ 0.55 V for ferrocenyl-CH=CH- and ~ 0.72 V for ferrocenyl-C[triple bond]C-), the presence of spacers in the dyads appeared to afford stability to the reduced naphthalimide species. This was exhibited by the appearance of chemically reversible one-electron reduction processes for each of the compounds investigated. Similar unusual chemical reversibility was also shown by the spacer-C[triple bond]C-naphthalimide precursor systems. For the ferrocenyl-CH=CH-spacer-C[triple bond]C-naphthalimide dyads, the oxidation and reduction potentials closely resembled those of the simple ferrocenyl-CH=CH-spacer systems. This suggested that augmentation of the simple ferrocenyl-CH=CH-phenyl, -biphenyl and -anthryl systems with an alkyne linked naphthalimide unit showed little influence on the oxidation of the ferrocenyl moiety or the reduction of the naphthalimide unit. However, for the ferrocenyl-C[triple bond]C-spacer-C[triple bond]C-naphthalimide dyads, the oxidation and reduction potentials are influenced by the inductive effects of the spacers. While an anodic shift was observed for the dyad with the electron-withdrawing spacer tetrafluorobenzene, a cathodic shift was displayed for the dyads with the electron-donating spacers 2,2�-bithiophene and 2,5-dimethoxybenzene compared to that in the simple ferrocenyl-C[triple bond]C-naphthalimide system. The spectroscopic properties of the ferrocenyl-CH=CH-spacer-C[triple bond]C-naphthalimide dyads showed that interpolation of the aromatic spacers does not interfere with the internal charge separation. Oxidation of the ferrocenyl moiety resulted in bleaching of the metal-to-ligand charge transfer band at ~ 500 nm and the growth of a new band in the near infrared region at ~ 1000 nm. This new band can be assigned to a ligand-to-metal charge transfer transition, where the ferrocenium now acts as an acceptor to the naphthalimide donor. For the ferrocenyl-C[triple bond]C-spacer-C[triple bond]C-naphthalimide dyads, the spectroscopic properties showed that the mutually electron-withdrawing tetrafluorobenzene and naphthalimide units had little interaction despite their connection by a conductive alkyne link. In contrast, the dyads containing the electron-donating 2,2�-bithiophene and 2,5-dimethoxybenzene showed some degree of interaction between the spacer and the naphthalimide fragments. This was evidenced by the appearance of a broad absorption band in the range 410 - 440 nm, which is associated with an orbital that is delocalised between the spacer and the naphthalimide fragments. Again, the roles of donor and acceptor were reversed on oxidation of the ferrocenyl moiety. This resulted in the growth of a new near infrared band at ~750 mn for the dyad containing the tetrafluorobenzene spacer and at ~ 1000 nm for the dyads with 2,2�-bithiophene and 2,5 -dimethoxybenzene spacers. The ferrocenyl unit went from being a net donor to ferrocenium, which was acting as an acceptor, with the tetrafluorobenzene spacer adopting the donor role more reluctantly than the delocalised 2,2�-bithiophene-C[triple bond]C-naphthalimide and 2,5-dimethoxybenzene-C[triple bond]C-naphthalimide moieties. 1,3,5-Tri- and 1,2,4,5-tetra-substituted benzene cores were also used as spacers for the preparation of extended arrays of ferrocenyl-naphthalimide dyads. Utilisation of the 1,3,5 -tri-substituted benzene core enabled the core to be embellished in three directions, resulting in Y-motif extended arrays containing either one ferrocenyl unit [(ethenylferrocenyl)-C₆H₃-(C[triple bond]C-C₆H₅)₂] or one naphthalimide moiety [(4-piperidino-N-propargyl-naphthalimide)-C₆H₃-(Br)₂]. With the 1,2,4,5-tetra-substituted benzene core, the extension of the core was possible in four directions and gave extended arrays in an X-motif. Again, these systems contained either ferrocenyl units [bis(alkoxyferrocenyl)-C₆H₂-(C[triple bond]C-C₆H₅)₂] or naphthalimide moieties [(tetrakis-naphthalimide)-C₆H₂]. Attempts to incorporate both ferrocenyl and naphthalimide fragments into the X- or Y-motif extended arrays were unsuccessful. By adding C₂Co₂(CO)₆dppm across the triple bonds of two of the four alkyne groups in the X-motif naphthalimide system [(tetrakis-naphthalimide)-C₆H₂], it was possible to incorporate two oxidisable C₂Co₂(CO)₄dppm cluster units into the molecule. The electrochemistry of the resulting system showed two discrete oxidation processes, suggesting the possibility of some interaction between the dicobalt cluster redox centres.

In this thesis a series of diphenol phenanthroline (Dpp) peptide conjugates were synthesized and then coupled to ferrocene to give the corresponding organometallic conjugates. The first step of the synthesis was achieved by esterification of peptides with the phenol group of the Dpp. The next step was the removal of the protecting Boc group and the addition of ferrocene acid chloride at high dilutions to give the desired macrocycles of the type Dpp-(peptide)2 Fc. (peptide = Leu-Leu (3), Leu-Leu-Leu (5) ). However, the syntheses proceeded in low yields where only small quantities of the desired products were obtained. A suitable crystal of compound 3 was grown from CHCl3 which shows a number of intra and intermolecular hydrogen bonding interactions between peptides strands.In addition, the system [Dpp-Fc]2 (1) was syntheised by refluxing Dpp and Fc[COCl]2 in dichloromethane. A suitable crystal was grown which has ð-ð interactions between intramolecular Dpp units as well as a number of CH-ð interactions which determine the crystal packing. The electrochemical experiments on compound 1 show a cathodic shift upon addition of Zn2+ to a solution of 1. This observation is believed to occur because of a conformational change in 1. The last area of synthesis that was done was the attempt at â-sheet formation using Fc as a scaffold to align peptide strands. Two systems were studied in this thesis [Fc(n-AA-OMe)(1-AA)]2-1,4butyl diamine. (AA =Ala (8), Gly (9)). Both were studied by 1H NMR to evaluate the presence of hydrogen bonding interactions. The results indicate the presence of intramolecular H-bonding, which is believed to form â-sheet like structures in solution.

In this thesis a series of diphenol phenanthroline (Dpp) peptide conjugates were synthesized and then coupled to ferrocene to give the corresponding organometallic conjugates. The first step of the synthesis was achieved by esterification of peptides with the phenol group of the Dpp. The next step was the removal of the protecting Boc group and the addition of ferrocene acid chloride at high dilutions to give the desired macrocycles of the type Dpp-(peptide)2 Fc. (peptide = Leu-Leu (3), Leu-Leu-Leu (5) ). However, the syntheses proceeded in low yields where only small quantities of the desired products were obtained. A suitable crystal of compound 3 was grown from CHCl3 which shows a number of intra and intermolecular hydrogen bonding interactions between peptides strands.In addition, the system [Dpp-Fc]2 (1) was syntheised by refluxing Dpp and Fc[COCl]2 in dichloromethane. A suitable crystal was grown which has ð-ð interactions between intramolecular Dpp units as well as a number of CH-ð interactions which determine the crystal packing. The electrochemical experiments on compound 1 show a cathodic shift upon addition of Zn2+ to a solution of 1. This observation is believed to occur because of a conformational change in 1. The last area of synthesis that was done was the attempt at â-sheet formation using Fc as a scaffold to align peptide strands. Two systems were studied in this thesis [Fc(n-AA-OMe)(1-AA)]2-1,4butyl diamine. (AA =Ala (8), Gly (9)). Both were studied by 1H NMR to evaluate the presence of hydrogen bonding interactions. The results indicate the presence of intramolecular H-bonding, which is believed to form â-sheet like structures in solution.

No description available.

An alternative use for an amperometric enzyme electrode is as an anodic half-cell of a fuel cell. A biofuel cell based upon the oxidation of methanol by the quinoprotein alcohol dehydrogenase was developed.

This thesis describes the synthesis and properties of some extended donor-acceptor dyads with the donor being a ferrocenyl moiety and a fluorescent naphthalimide group as the acceptor. Two series of extended ferrocenyl-naphthalimide dyads were prepared in reasonable yield depending on the synthetic route. The first are a series of three ferrocenyl-CH=CH-spacer-C[triple bond]C-naphthalimide dyads in which the spacers are phenyl, biphenyl and anthryl and the second are a series of three ferrocenyl-C[triple bond]C-spacer-C[triple bond]C-naphthalimide dyads in which the spacers are 2,2� -bithiophene, 2,5-dimethoxybenzene and tetrafluorobenzene groups. The molecular structures of some compounds have been determined by X-ray diffraction although with many challenges because of the extensive [pi]-[pi] stacking of molecules that leads to ready aggregation in the solid state, particularly for the ferrocenyl-CH=CH-spacer-C[triple bond]C-naphthalimide dyads, in which the naphthalimide bears a methyl head group. In order to reduce the [pi]-[pi] stacking effect between the molecules and also to produce chiral molecules for the potential nonlinear optical applications, a chiral α-methylbenzylamine was introduced as the head group of naphthalimide for the ferrocenyl-C[triple bond]C-spacer-C[triple bond]C-naphthalimide dyads. The resulting comounds successfully gave crystals of sufficient quality for X-ray structural investigation. While the oxidative electrochemistry of the ferrocenyl compound in the two series of dyads was largely predictable (E� ~ 0.55 V for ferrocenyl-CH=CH- and ~ 0.72 V for ferrocenyl-C[triple bond]C-), the presence of spacers in the dyads appeared to afford stability to the reduced naphthalimide species. This was exhibited by the appearance of chemically reversible one-electron reduction processes for each of the compounds investigated. Similar unusual chemical reversibility was also shown by the spacer-C[triple bond]C-naphthalimide precursor systems. For the ferrocenyl-CH=CH-spacer-C[triple bond]C-naphthalimide dyads, the oxidation and reduction potentials closely resembled those of the simple ferrocenyl-CH=CH-spacer systems. This suggested that augmentation of the simple ferrocenyl-CH=CH-phenyl, -biphenyl and -anthryl systems with an alkyne linked naphthalimide unit showed little influence on the oxidation of the ferrocenyl moiety or the reduction of the naphthalimide unit. However, for the ferrocenyl-C[triple bond]C-spacer-C[triple bond]C-naphthalimide dyads, the oxidation and reduction potentials are influenced by the inductive effects of the spacers. While an anodic shift was observed for the dyad with the electron-withdrawing spacer tetrafluorobenzene, a cathodic shift was displayed for the dyads with the electron-donating spacers 2,2�-bithiophene and 2,5-dimethoxybenzene compared to that in the simple ferrocenyl-C[triple bond]C-naphthalimide system. The spectroscopic properties of the ferrocenyl-CH=CH-spacer-C[triple bond]C-naphthalimide dyads showed that interpolation of the aromatic spacers does not interfere with the internal charge separation. Oxidation of the ferrocenyl moiety resulted in bleaching of the metal-to-ligand charge transfer band at ~ 500 nm and the growth of a new band in the near infrared region at ~ 1000 nm. This new band can be assigned to a ligand-to-metal charge transfer transition, where the ferrocenium now acts as an acceptor to the naphthalimide donor. For the ferrocenyl-C[triple bond]C-spacer-C[triple bond]C-naphthalimide dyads, the spectroscopic properties showed that the mutually electron-withdrawing tetrafluorobenzene and naphthalimide units had little interaction despite their connection by a conductive alkyne link. In contrast, the dyads containing the electron-donating 2,2�-bithiophene and 2,5-dimethoxybenzene showed some degree of interaction between the spacer and the naphthalimide fragments. This was evidenced by the appearance of a broad absorption band in the range 410 - 440 nm, which is associated with an orbital that is delocalised between the spacer and the naphthalimide fragments. Again, the roles of donor and acceptor were reversed on oxidation of the ferrocenyl moiety. This resulted in the growth of a new near infrared band at ~750 mn for the dyad containing the tetrafluorobenzene spacer and at ~ 1000 nm for the dyads with 2,2�-bithiophene and 2,5 -dimethoxybenzene spacers. The ferrocenyl unit went from being a net donor to ferrocenium, which was acting as an acceptor, with the tetrafluorobenzene spacer adopting the donor role more reluctantly than the delocalised 2,2�-bithiophene-C[triple bond]C-naphthalimide and 2,5-dimethoxybenzene-C[triple bond]C-naphthalimide moieties. 1,3,5-Tri- and 1,2,4,5-tetra-substituted benzene cores were also used as spacers for the preparation of extended arrays of ferrocenyl-naphthalimide dyads. Utilisation of the 1,3,5 -tri-substituted benzene core enabled the core to be embellished in three directions, resulting in Y-motif extended arrays containing either one ferrocenyl unit [(ethenylferrocenyl)-C₆H₃-(C[triple bond]C-C₆H₅)₂] or one naphthalimide moiety [(4-piperidino-N-propargyl-naphthalimide)-C₆H₃-(Br)₂]. With the 1,2,4,5-tetra-substituted benzene core, the extension of the core was possible in four directions and gave extended arrays in an X-motif. Again, these systems contained either ferrocenyl units [bis(alkoxyferrocenyl)-C₆H₂-(C[triple bond]C-C₆H₅)₂] or naphthalimide moieties [(tetrakis-naphthalimide)-C₆H₂]. Attempts to incorporate both ferrocenyl and naphthalimide fragments into the X- or Y-motif extended arrays were unsuccessful. By adding C₂Co₂(CO)₆dppm across the triple bonds of two of the four alkyne groups in the X-motif naphthalimide system [(tetrakis-naphthalimide)-C₆H₂], it was possible to incorporate two oxidisable C₂Co₂(CO)₄dppm cluster units into the molecule. The electrochemistry of the resulting system showed two discrete oxidation processes, suggesting the possibility of some interaction between the dicobalt cluster redox centres.

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.

Thesis (Ph. D.)--University of Canterbury, 2005. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Oxidation of a ferrocenyl group in conjugation to another metal centre can alter the electron density at that metal centre and lead to a change in overall reactivity of a complex. Herein, the synthesis and characterization of redox active symmetrical and unsymmetrical ferrocenylalkene derivatives is described. A change in the standard redox potential of ferrocene (465 mV), to more positive potentials in vinylferrocene 1 (478 mV) and 4-phenylvinylferrocene 3 (499 mV), showed how manipulation of a redox potential can be effected on the ferrocenyl moiety by just using conjugation effects. A shift by +13 mV is observed in 1 and this potential more than doubled in 3 (+34 mV). Ferrocenylderived ruthenium alkylidene complexes were also prepared in a cross metathesis of 1 and 3 with Grubbs’ 1 (676.5 mV) to give complexes Ferrocenylidenebis( tricyclohexylphosphine)dichlororuthenium 14, 4-ferrocenylphenylidene-bis (tricyclohexylphosphine)dichlororuthenium 15 respectively. The extent of the electronic communication between the ferrocenyl group and the ruthenium centre was then estimated by looking at the positive or negative redox potential shifts of 14 and 15 as a result of 1 and 3. A large positive potential shift by 180 mV in 14 indicated that there was a strong electronic communication between the two metal centres, while the smaller, yet significant positive potential shift by 89.5 mV in 15 showed 3 to have a lesser effect on the ruthenium centre. Compounds 14 and 15 were tested in a Ring Closing Metathesis (RCM) of diethyldiallylmalonate showed enhanced reactivity.

The preparation, characterization, and catalytic properties of some soluble and polymer-bound palladium and platinum complexes of ferrocene derivatives are described. Special emphasis has been placed on studies of the mixed "hard-soft" ligands such as PPFA and ISOPFA. [Formula Omitted] The soluble complexes (L-L)MC1₂ (L-L = BPPF, PPFA, ISOPFA, BPPFA; M = Pd, Pt) and [(L-L)PdS₂][C10₄]₂ (L-L = BPPF, PPFA; S = DMF, py) have been characterized by microanalyses, NMR and IR spectroscopic techniques. The cationic palladium(II) complex [(L-L)PdS₂][C10₄]₂ (L-L = PPFA, S = DMF) is an effective catalyst precursor for the hydrogenation of simple olefins at 30°C and 1 atm pressure. The rate of styrene hydrogenation depends on the substrate concentration, catalyst concentration and the solvent. The results are consistent with a homogeneous catalytic system. Platinum(II) complexes (L-L)PtCl₂ (L-L = (S,R)-PPFA, (S,R)-ISOPFA) are effective catalyst precursors for the hydrosilylation of aromatic ketones with Ph₂SiH₂. The complexes with mixed "hard-soft" ligands are better catalyst precursors than those with di(tertiary phosphine) ligands. Under the same conditions the hydrosilylation of ferrocenyl ketones results in further reduction and affords mainly the alkylferrocene products. The stable carbonium ion FcC⁺HCH₃ (Fc = Fe-(C₅H₅)(C₅H₄)-) is reduced by Ph₂SiH₂ to FcCH₂CH₃ in a thermal reaction which is catalyzed by the complex (PPFA)PtCl₂. The reaction of Ph₂SiH₂ with (L-L)PtCl₂ (L-L = PPFA, ISOPFA) yields a stable platinum(IV) hydride, which eliminates Ph₂SiHCl in solution to afford (L-L)PtHCl. The mechanistic implications of these observations are discussed. Polymers functionalized with ferrocene and ferrocene derivatives have been prepared. Mossbauer spectroscopic techniques and microanalyses are used to characterize these polymers and their palladium and platinum complexes. In a number of cases these results are confirmed by the cross-polarization/magic-angle spinning ¹³C NMR spectroscopic technique. The palladium(II) and platinum(II) derivatives of the ferrocenyl-amine and -phosphine containing polymers are effective catalysts for the hydrogenation and hydrosilylation of olefins. All the catalysts can be easily separated from the reaction mixture and can be recycled with no loss of activity. The pronounced effect of the attached ligand in the palladium based polymers indicates that free metal is not involved. However, in the case of platinum based catalysts, it is likely that reduction to platinum metal takes place. / Science, Faculty of / Chemistry, Department of / Graduate