We utilized the tripodal ligand (tris-(3,5-di-tert-butyl-2-hydroxy-phenyl)- phosphine) H3[O3P] to react with 1 equiv of AlR3 (R = Cl, Me, Et, iBu and OiPr). From NMR and X-ray data proved, we could give the stable Al(III) complexes [O3P-H]AlR (R = Cl, Me, Et and iBu). [O3P-H]AlR is a zwitterionic complexes. Because the phenolato phosphine ligand bond a proton at the phosphorous, and Al(III) coordinated three RO- (tris phenolate group) and one alkyl- substituent group. So the Al(III) metal could be carried -1 charge and the phosphorous could be carried +1 charge. When H3[O3P] reacted with AlR3, the original trisphenolato phosphine ligand ([O3P]3-) was changed into a trisphenoato phosphonium ligand ([O3P-H]2-). The [O3P-H]AlMe in the trisphenoato phosphonium group has a proton, and we attempted to use a bese to deprotonate the acidic proton. We chose n-BuLi to react with [O3P-H]AlMe, and successfully gave {[O3P:]AlMe}- ionic complexe. In the {[O3P:]AlMe}- complexe, the lone pair electron of phenolato phosphine group is a nucleophile,It reacted with MeOTf of electrophile. The product of the reaction could give [O3P-Me]AlMe.In this reactions, the original trisphenoato phosphonium ligand ([O3P-H]2-) was changed into a new methyl trisphenoato phosphonium ligand ([O3P-Me]2-). We could utilize H3[O3P] to react with 1 equiv MeOTf in diethyl ether, and gave a new tripodal ligand {H3[O3P-Me]}OTf. Also, we utilized the {H3[O3P-Me]}OTf to react with 1 equiv of AlR3 (R = Cl, Me, Et and iBu). We gave that Al(III) complexes [O3P-Me]AlR (R = Cl, Me, Et and iBu).

The polydentate ligands containing both thiolato and phosphino groups have been used in catalysis and enzyme mimetic studies. We have synthesized two tetradentate thiophosphine ligands : tris(2-thiophenyl)- phosphine¡]H3L1¡^ and tris(3-trimethylsilyl-2-thiophenyl)phosphine (H3L3) and one tridentate thiophosphine ligand (bis(2-thiophenyl)- phenylphosphine¡]H2L2¡^. These ligands formed a series of germanium and tin metal complexes. We are thus exploring a range of syntheses of tin and germanium complexes. The ligand H3L1 react with SnCl4 to give trimeric tin units with bridging methoxyl group and oxo group. The ligand H2L2 react with SnCl4 or GeCl4 to give ML2 type complexes. H3L3 with germanium and tin metal complexes were synthesized and characterised by NMR spectra and mass spectra. We also obtained crystal structure of complexes GeCl(L3) and GeEt(L3). The structure was trigonal bipyramidal.

In this study, we took four diamines of different carbon chain lengthes to synthesize several thiosalen derived zinc(II) complexes, i.e. N, N¡¦-Bis- (2-thio-benzylidene)- 1,3-propylenediaminato-zinc(II)(1),N,N¡¦-Bis(2-thio-benzylidene)-2,2-dimethyl- 1,3-propylenediaminato-zinc(II)(2),N,N¡¦-Bis-(2-thio-benzylidene)-1,2-ethylene- diaminato-zinc(II)(3),andN,N¡¦-Bis(2-thio-benzylidene)-1-methyl-1,2-ethylene- diaminato-zinc(II)(4). The crystal structure of 1 was shown to be trimeric. We then used NaBH4 to reduced complexes1, 2, and 4 to get complexes 5, 6, and 7 respectively for reactivity and structure studies. To expand our current study, we also synthesized nickel analogue (8) of complex 1 by transmetallation.

Late transition metal complexes bearing nitrogen-containing ligands have many applications in biotechnology or industrial catalysis. Imidazole is one of the most common biofunctional ligands to play critical roles in meta1loenzymes, since the imidazole moiety of the histidyl residues often constitutes all or part of the binding sites of various transition metal ions. We use the newly synthesized tetradentate ligand containing the imidazolyl and pyridyl functional group to react with zinc, copper, nickel, and iron ions in order to carry out biomimetic studies. We have obtained two crystal structures via different methods of crystallization. One of them is a mononuclear complex while the other is a polymeric structure. The polymeric structure has demonstrated the spontaneous deprotonation on the imidazolyl nitrogen on binding to the metal ion followed by the intermolecular self-assembly process.We believe that the imidazolate -bridged complexes undergo the pH-dependent interconversions between mononuclear (protonated ligand) and self-assembled oligomer (deprotonated ligand). In addition, we have measured the titration curves of the tetradentate ligand and its corresponding metal complexes to determine the preferential binding sites at varying pH. From the titration processes, we got the protonation constant of ligand and stability constants of its corresponding metal complexes.

Tri(2-thiophenyl)phosphine (P(C6H4-2-SH)3, PS3) was designed at 1989. Recently chemists use this ligand for enzyme models because it provides rich sulfur environment. Some chemists use PS3 to synthesize novel metal complexes. Others study the transmetalation of PS3 tin complexes with FeCl3. As a continuation of our long time interest in these tin complexes as alkylation reagents, this thesis reports the synthesis and characterization of the tin-PS3 complexes. Reactions using SnCl3Me or SnCl3Bu as metal sources when dissolved in DMSO gave DMSO adduct of PS3 tin complex while sublimation gave reductive elimination products with alkyl groups transferred onto sulfur atom. The butyl transferred product and its methyl analogous are similar in morphology but different in skeletal arrangement. Reaction of SnCl4 with PS3 gave two different crystals after long standing. One is the hydrolysed product, [Sn(OH)(PS3)]2, with bridging hydroxyl groups and thiolate groups. The other is the product with oxidized ligand. Reaction of SnBr4 with PS3 gave analogous ligand-oxidized product. Reaction of two mole of SnCl3Bu with PS3 resulted in a bimetallic tin complex.

Controlling the absolute stereochemistry of molecules is a major challenge to contemporary chemists. Achieving high enantioselectivity with catalytic amounts of a chirality transfer (or inducing) agent, and the ease of regenerating such catalysts is yet another challenge. Due to the involvement of various transition metal complexes, the relatively young field of enantioselective catalysis has emerged as a powerful tool for organic chemistry. In our efforts towards the synthesis of a universal catalyst, O'Donnell Schiff base derived tetradentate ligands were shown to catalyze dialkylzinc additions to aldehydes in high selectivity. The three pot synthesis of bifurcated dipeptides in very good yields and the mechanistic aspects of diethylzinc additions to aromatic aldehydes are described in this dissertation. The chiral Lewis acidic behavior of these ligands was supported by a mechanistic study done examining the nonlinear effect. Unlike bidentate ligands such as (-)-3-exo-N,N-dimethylaminoisoborneol (DAIB), the tetradentate ligands in this study show strictly linear behavior. Also, the linear free energy relationships studied by observing the enantioselectivity with respect to electron donating or withdrawing substituents on the benzaldehyde substrates supported a Lewis acid role for the zinc complexes. A negative slope was obtained when ee's were plotted against sigma values of the substituted benzaldehydes. Since they bind to various bivalent transition metal cations, these ligands can be viewed as privileged structures, and may potentially become catalysts for various asymmetric reactions. As catalyst screening can be greatly facilitated by heterogeneous catalysis, solid phase ligands were synthesized using Wang and Merrifield resin supports. The synthetic methodology was developed using a diarylketimine linker with the aid of on-bead characterization techniques such as 13C NMR and UV-VIS spectroscopy. The ligands were shown to asymmetrically catalyze the alkenylzinc additions to aromatic aldehydes. In situ generation of alkenylzinc reagents by boron to zinc transmetalation followed by the addition to benzaldehyde in the presence chiral zinc complexes resulted in enantiomerically enriched allylic alcohols. The preliminary results for this transformation resulted in 3:1 selectivity in favor of S-isomer.

This thesis is a report on the design, synthesis and molecular structure of a set of chiral Co(III) metal complexes, in the solution and solid state. The complexes that have been synthesised will potentially intercalate between the base pairs of DNA. The structure of the bound tetradentate ligand, S,S-picchxnMe2 in the solid state was investigated to determine the flexibility of this seemingly rigid ligand. The bidentate ligands, R- and S-glu, were also bound to the Co complex and the differences in the tetradentate ligand were observed. The differences observed in the bonded tetradentate ligands were due to the chirality of the bonded amino acid. The aromatic amino acids, R- and S-phe, were used as bidentate ligands because of their ability to intercalate with DNA. Several scientific experiments were conducted and the results analysed in great depth / Doctor of Philosophy (PhD)

Influenza A (IVA) continues to pose a growing global threat even as current medications are becoming less effective. One of the main avenues of research into new anti-IVA drugs is its homotetrameric Matrix 2 proton channel (M2A), without which the virus would be unable to release its viral RNA into the host cell. The drug amantadine used to bind and block M2A until near-ubiquitous resistance formed as an M2A-S31N mutation, starting around 1995 and proceeding to 2005 when amantadine was disallowed for use as an anti-IVA drug. The standard organic structure currently being used for M2A inhibitor research comprises an adamantyl foot group, a heterocyclic aryl body group, and a cyclic head group. A sample set of compounds with this standard structure was compared and reviewed, focusing on positive and negative moieties and modifications. Modifications on the foot group were all more or less detrimental, body groups with two heteroatoms were advantageous, and larger head groups appeared better. Four other scaffolds known to literature were proposed for further study due to beneficial aspects of each. Where most anti-M2A research deals exclusively with organic compounds, metals and their potential in drugs have been almost entirely ignored due to the increased toxicity they bring. Free copper was found in past research to be the only first-row transition metal to show significant M2A-inhibitory activity, proposed to do so by binding the H37 cluster that acts as a pH-dependent control switch for the channel. Six overall-neutral copper complexes were synthesized as a combination of amantadine, cyclooctylamine, and null scaffolds with two of either acetate or acetamide arms as chelators. The complexes were found to block both M2A-WT and M2A-S31N. Along with CuCl¬¬2, though, they had little to no effect on M2A-H37A, providing confirming evidence that the copper binds at the H37 tetrad. Only one complex, Cu(cyclooctylamineiminodiacetate), outperformed CuCl2 in channel block studies and efficacy against two IVA strains, but all of the complexes were found to have lower cytotoxicity. Because M2-H37 is highly conserved, these complexes show promise for further testing against all strains of influenza A. Five net-divalent copper complexes were then synthesized with multiple aza or amine groups as chelators. The complexes failed to show any significant activity against M2A, however, which was thought to be due to size or polarity rejection or electromagnetic repulsion. One of the ligands, though, an adamantyl derivative of a tetraaza macrocycle, was a novel compound, and its copper complex, along with two others, were unknown to the CCDC database. The three complexes were characterized by X-ray diffraction and discussed.

Influenza A (IVA) continues to pose a growing global threat even as current medications are becoming less effective. One of the main avenues of research into new anti-IVA drugs is its homotetrameric Matrix 2 proton channel (M2A), without which the virus would be unable to release its viral RNA into the host cell. The drug amantadine used to bind and block M2A until near-ubiquitous resistance formed as an M2A-S31N mutation, starting around 1995 and proceeding to 2005 when amantadine was disallowed for use as an anti-IVA drug. The standard organic structure currently being used for M2A inhibitor research comprises an adamantyl foot group, a heterocyclic aryl body group, and a cyclic head group. A sample set of compounds with this standard structure was compared and reviewed, focusing on positive and negative moieties and modifications. Modifications on the foot group were all more or less detrimental, body groups with two heteroatoms were advantageous, and larger head groups appeared better. Four other scaffolds known to literature were proposed for further study due to beneficial aspects of each. Where most anti-M2A research deals exclusively with organic compounds, metals and their potential in drugs have been almost entirely ignored due to the increased toxicity they bring. Free copper was found in past research to be the only first-row transition metal to show significant M2A-inhibitory activity, proposed to do so by binding the H37 cluster that acts as a pH-dependent control switch for the channel. Six overall-neutral copper complexes were synthesized as a combination of amantadine, cyclooctylamine, and null scaffolds with two of either acetate or acetamide arms as chelators. The complexes were found to block both M2A-WT and M2A-S31N. Along with CuCl¬¬2, though, they had little to no effect on M2A-H37A, providing confirming evidence that the copper binds at the H37 tetrad. Only one complex, Cu(cyclooctylamineiminodiacetate), outperformed CuCl2 in channel block studies and efficacy against two IVA strains, but all of the complexes were found to have lower cytotoxicity. Because M2-H37 is highly conserved, these complexes show promise for further testing against all strains of influenza A. Five net-divalent copper complexes were then synthesized with multiple aza or amine groups as chelators. The complexes failed to show any significant activity against M2A, however, which was thought to be due to size or polarity rejection or electromagnetic repulsion. One of the ligands, though, an adamantyl derivative of a tetraaza macrocycle, was a novel compound, and its copper complex, along with two others, were unknown to the CCDC database. The three complexes were characterized by X-ray diffraction and discussed.