The structures of four 4aβ,5,8,8aβ-tetrahydro-1 -naphthoquin-4-ol derivatives have been studied and related to their observed photochemical reactivity. H-abstractions are dominant in the solid state photolyses of these compounds because of their conformations and the topochemical control by the lattice. All structures have been solved by direct methods and refined by least squares procedures. The 2,3,6,7-tetramethyl-4α-ol derivative, C₁₄H₂₀O₂, is monoclinic, space group C2/c, a = 13.898(3), b = 5.228(1), c = 17.316(3) Å, β = 97.442(7)° and Z = 4. This structure was refined to R = 0.058 for 888 reflections. The 2,3- and 6,7-dimethyl-4α-ol compounds-C₁₂H₁₆O₂, are orthorhombic, space group P2₁2₁2₁, and monoclinic, space group 2₁/c, respectively. For the 2,3-derivative, a = 5.148(1), b = 12.269(2), c = 16.478(3) Å, Z = 4 and the refinement of 671 data led to an R of 0.031. The 6,7-compound, a = 9.242(3), b = 22.724(3), c = 5.139(2) Å, β = 102.7(1)°, Z = 4, was refined to R = 0.032 for 626 data. 2,3,4σ,4aβ,6,7,8aβ-heptamethyl-4β-ol, C₁₇H₂₆0₂, is monoclinic, space group P2₁/c, a = 7.497(2), b = 16.792(3), c = 12.687(3) Å, β = 105.30(1)° and Z = 4. An R-value of 0.041 was obtained from the refinement of 1934 reflections. The above compounds have similar conformations which are favorable to H-abstraction reactions. The 6,7-dimethyl-1α,4α-diol C₁₂H₁₈0₂, crystallizes in the monoclinic system, space group P2₁/c, a = 13.870(2), b = 18.025(4), c = 9.236(1) Å, β = 108.098(6)° , Z = 8 and was refined to R = 0.032 for 1461 reflections. The diol compound adopts the same conformation as those above but is not photoreactive. The following four compounds were derived from either tetrahydronaphthoquinol progenitors or their oxidized forms, tetrahydronaphthoquinones. A twistane-1ike structure, twistenone C₁₀H₁₀0₂, was found to crystallize in the monoclinic system, space group P2₁/n, a = 6.381(2), b = 19.454(2), c = 6.708(2) Å, β = 1 06.24( 1 )° and Z = 4. Refinement of 930 reflections converged at R = 0.037. 5-(2,3-dimethylphenyl)-ƴ-butyrolactone crystals, C₁₂H₁₅O₂ are monoclinic, space group P2₁/n, a = 10.847(3), b = 6.924(1), c = 13.654(4) Å, β = 95.22(1)° and Z = 4. The structure was refined to R = 0.057 for 569 reflections. It was hoped that elucidation of this structure would aid in determining the intermediate compound from which it was formed. The methylene ketone C₁₇H₂₄0, derived from the acetylation product of the previously described heptamethyl-4β-ol, is monoclinic, space group P2₁/a, a = 12.374(2), b = 8.771(1), c = 13.743(2) Å, β = 104.027(6)° , Z = 4 and refined to R = 0.037 for 1369 data. A reaction designed to pinacolize a diketone cage compound resulted in a different product from which the hydroxy mesylate derivative C17H280„S, was formed. The crystals are monoclinic, space group P2,/c, a = 9.246(2), b = 10.938(1), c = 17.335(4) Å, β = 102.11(1)° and Z = 4. Refinement converged at R = 0.042 for 2995 reflections. / Science, Faculty of / Chemistry, Department of / Graduate

ABSTRACT Part one of this thesis contains the x-ray crystal structure analyses of six compounds related to natural product chemistry. The first three analyses were performed in order to identify two isomers, separated by chromatography, that were potential intermediates in the syntheses, of stemodin. and aphidicolin, and differed only in the orientation of a cyclobutyl moiety. The first eluted isomer was shown to be a β-cyclobutyl tricyclic enone (C₂₂H₃₂O₃ monoclinic, space group P2₁/n, a = 11.832(1), b = 11.423(1), c = 14.637(1) Å, β = 98.71(2)°, Z = 4, solved by direct methods and refined to R = 0.034 for 2052 observed reflections). The second eluted isomer was the c-cyclobutyl species (C₂₂H₃₂O₃, monoclinic, space group P2₁/n, a = 15.722(4), b = 7.463(2), c = 17.213(6) Å, β =- 104.67(1) ⁰, Z = 4, solved by direct methods- and- refined to R = 0.040 for 702 observed reflections). The third analysis was of the p-bromobenzoate derivative of the second eluted isomer, and confirmed the c-cyclobutyl structure (C₂₉H₃₇BrO₄, triclinic, space group PT, a = 11.023(2), b = 11.877(1), c = 10.900(1) Å, α = 90.461(8), β = 111.57(1), ƴ = 80.51(1)°, Z = 2, solved by Patterson methods and refined to R = 0.032 for 2715 observed reflect ions). The fourth structure was also a p-bromobenzoate derivative of a system involving a four-membered ring, and was undertaken to verify the 1,4-homoenol structure of camphor-1,4-homoenol p-bromobenzoate (C ₁₇H₁₉BrO₂, orthorhombic, space group P2₁2₁2₁, a = 6.875(1), b = 8.522(2), c = 26.658(6) Å, Z = 4, solved by both direct and Patterson methods and refined to R =0.045 for 697 observed reflections). The last two structures of this part proved to be crystallographically difficult. One was the previously unknown structure of raucubaine, an indole alkaloid isolated from the plant Rauwolfia salicifolia griseb. (C₂₀H2₂₄N₂0₃, monoclinic, space group P2₁, a = 7.2179(3), b = 12.8169(7), c = 9.1996(2) Å, β = 93.040(3)°, Z = 2, solved by direct methods (with great difficulty) and refined to R = 0.046 for 1700 observed reflections). The other was a sugar that had remained unsolved for fourteen years (C₂₄H₂₄Cl₂O₈, monoclinic, space group P2₁, a = 5.752(3), b = 15.436(3), c = 13.698(3) Å, β = 93.74(3)°, Z = 2, solved by direct methods (with great difficulty) and refined to R = 0.042 for 898 observed reflections). Part two contains two optically active structures as part of a project concerning spontaneous resolution in binaphthyl systems: the first being naphthidine (C₂₀H₁₆N₂, tetragonal, space group P4₁2₁2 or P4₃2₁2, a = 7.945(1), c = 24.264(5) Å, Z = 4, solved by direct methods and refined to R = 0.068 for 548 reflections) and the other 1, 1'-binaphthyl (C₂₀H₁₄, tetragonal, space group P4₁2₁2 or P4₃2, a = 7.164(2), c = 27.70(1) Å, Z = 4, solved by direct methods and refined to R = 0.030 for 562 observed reflections). These structures are compared to those of several related compounds. / Science, Faculty of / Chemistry, Department of / Graduate

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Thesis (M.Phil.)--Chinese University of Hong Kong. / Bibliography: leaves 78-83.

Transition metals are crucial components of several metabolic pathways and are critical for DNA, RNA and protein synthesis. However, when found in excess, these metal ions are toxic. To maintain the physiological concentration of metal ions at non-toxic concentration, bacteria rely on members of the Ferric uptake regulator (Fur) family of metalloregulators. Intriguingly, despite being coined as “metalloregulator”, specific members of the Fur family activate and repress gene expression in presence or absence of regulatory metals. Based on these observations, we hypothesized that the ability of these transcription factors to adopt different structural conformations underlies their ability to display different functions in presence and absence of metal ions. To address this important question, we solved the crystal structure of apo-Fur protein from Campylobacter jejuni. Structural analysis revealed that the protein adopts a V-shaped conformation harboring an evolutionary conserved cluster of positively charged residues on the surface. Using an extensive library of mutants and electrophoretic mobility shift analysis, we found that substituting residues forming the positively charged surface is detrimental for Fur interaction with DNA. Furthermore, our in vivo studies suggest that these positively charged residues are important for the regulation of CjFur target genes and that different mechanisms modulate the activity of Fur family of metalloregulators depending on the number of occupied metal binding sites. We showed that the disruption of metal binding sites of CjFur significantly reduces DNA binding in vitro and is deleterious for the repression of Fur target genes and gut colonization by C. jejuni. Finally, based on initial findings that adding a tag at the N-terminus of CjFur significantly reduces its ability to incorporate regulatory metal ions and bind DNA, we developed a new protocol for the purification of a highly active untagged CjFur protein. Overall, our studies shed new lights on the mechanistic basis controlling Fur gene regulatory activity in C. jejuni.

by Feng Xue. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 76-84). / ACKNOWLEDGMENTS --- p.I / ABSTRACT --- p.II / TABLE OF CONTENTS --- p.III / LIST OF TABLES --- p.V / LIST OF FIGURES --- p.VI / Chapter CHAPTER 1: --- INTRODUCTION --- p.1 / Chapter 1. --- supramolecular chemistry --- p.1 / Chapter 2. --- Infinite multi-dimensional architecture --- p.10 / Chapter 3. --- Chemistry of pseudohalides --- p.15 / Chapter 4. --- Chemistry of hexamethylenetetramine --- p.20 / Chapter 5. --- Objectives of the present research --- p.24 / Chapter CHAPTER 2: --- EXPERIMENTAL --- p.25 / Chapter 1. --- Preparation --- p.25 / Chapter 1.1 --- Materials --- p.25 / Chapter 1.2 --- Preparation of the compounds --- p.25 / Chapter 2. --- X-ray crystallography --- p.26 / Chapter CHAPTER 3: --- DESCRIPTION OF CRYSTAL STRUCTURES --- p.28 / Chapter 1. --- isostructural compounds K2[FEII(CN)6] ´Ø 2[(CH2)6n4H] ´Ø 4H2 O(1) and K2[FEIII(CN)6] ´Ø [(CH2)6N4H] ´Ø [(CH2)6N4] ´Ø 4H2O (2) --- p.28 / Chapter 2. --- Crystal structure of NA2[FEIII(CN)6] ´Ø [(CH2)6N4H] ´Ø [(CH2)6N4] ´Ø 5H2O (3) --- p.33 / Chapter 3. --- Crystal structure of K3[FEIII(CN)6] ´Ø 2[(CH2)6N4] ´Ø 4H2O (4) --- p.37 / Chapter 4. --- Crystal Structure of ferricyanic acid-HMT adduct H3[FEIII(CN)6] ´Ø 2[(CH2)6N4] ´Ø 2H2O (5) --- p.43 / Chapter 5. --- "Crystal structure of cadmium chloride-HMT adduct, Cd2[C6H12N4H2]Cl6´Ø 3H2O (6)" --- p.48 / Chapter 6. --- "Crystal structure of cadmium bromide-HMT adduct, CdBr2 ´Ø 2[(CH2)6N4] ´Ø 2H2O (7)" --- p.53 / Chapter 7. --- "Crystal structure of cadmium iodide-HMT adduct, 3CdI2 ´Ø 2[(CH2)6N4] ´Ø 4H2O (8)" --- p.57 / Chapter 8. --- Crystal structure of cadmium thiocyanate-HMT adduct Cd(SCN)2 ´Ø 1(CH2)6N4] ´Ø MeOH (9) --- p.61 / Chapter 9. --- Crystal structure of cobalt cyanate-HMT adduct Co(NCO)2 ´Ø [(CH2)6N4] ´Ø 2H2O (10) --- p.67 / Chapter CHAPTER 4: --- SUMMARY AND DISCUSSIONS --- p.72 / REFERENCES --- p.76 / TABLE A1 Crystallographic data for compounds 1 ~5 --- p.85 / TABLE A2 Crystallographic data for compounds 6~10 --- p.86 / APPENDIX 1 Atomic Coordinates (Ax 104) and Equivalent Isotropic Thermal Parameters (A 2x103) --- p.87 / APPENDIX 2 Anisotropic thermal parameters (A2x 103) --- p.92 / APPENDIX 3 H-atom coordinates (x 104) and isotropic thermal parameters (A2x 103) --- p.96

2-Indolylphosphines are unique ligands which have the capability for further phosphine modification by introducing substituents on an indolyl nitrogen centre. Substituents can vary in electronics, sterics, chirality, and can contain amino or phosphino groups which result in a multidentate (P,N)- or (P,P)-2-indolylphosphine. X-ray crystallography was used predominantly to examine and analyze the structural features of 2-indolyphosphines and their metal complexes. While the cone angles could not be determined crystallographically, the sum of the <CPC bond angles provided some information on the steric crowding around a phosphorus atom in selected 2-indolylphosphines. The symmetric tris-2-(3-methylindolyl)phosphine demonstrated anion binding ability through its three indolyl NH sites. Titrations to a series of selected anions were carried out; it was determined that tris-2-(3-methylindolyl)phosphine binds to these selected anions in a 1 : 1 receptor to anion binding ratio. Crystal structures of the fluoride and acetate complexes confirm the binding stoichiometry, and demonstrate the cooperative interaction of all three indolyl NH sites with the anion guest. Synthetic routes to new anion receptors with three or two indolyl NH donors were explored. The second type yielded a molecular cleft that was used in anion binding studies. The net basicity of a 2-indolylphosphine was determined through formation of a Ni(CO)3L complex. Net basicity can be tuned by changing the substituents on phosphorus or on an indolyl nitrogen centre. The [Cu(tris-2-(3-methylindolyl)phosphine)(phenanthroline)]BF4 complex is a discrete ion pair complex, exhibiting coordination chemistry at the phosphorus centre of the phosphine, while simultaneously hydrogen bonding through the indolyl NH sites to the BF4- anion. Complexes of the type [Pd(L)Cl(mu-Cl)]2 were analyzed by crystallography and the effect of net basicity on Pd-P bond length examined. The solid-state structures of (P,N)- and (P,P)-2-indolylphosphines were evaluated. In general, the sum of the <CPC bond angles increased from the parent unfunctionalized 2-indolylphosphine. The metal complexes of (P,N)- and (P,P)-2-indolylphosphines were assessed by crystallography to find possible trends of trans-influence. Lastly, a tetradentate tripodal ligand was synthesized by furnishing diphenylphosphino substituents on the indolyl nitrogen centres of tris-2-(3-methylindolyl)phosphine. The coordination of the tetradentate tripodal ligand to Pt(II) or Rh(I) resulted in five-coordinate trigonal bipyramidal complexes.

2-Indolylphosphines are unique ligands which have the capability for further phosphine modification by introducing substituents on an indolyl nitrogen centre. Substituents can vary in electronics, sterics, chirality, and can contain amino or phosphino groups which result in a multidentate (P,N)- or (P,P)-2-indolylphosphine. X-ray crystallography was used predominantly to examine and analyze the structural features of 2-indolyphosphines and their metal complexes. While the cone angles could not be determined crystallographically, the sum of the <CPC bond angles provided some information on the steric crowding around a phosphorus atom in selected 2-indolylphosphines. The symmetric tris-2-(3-methylindolyl)phosphine demonstrated anion binding ability through its three indolyl NH sites. Titrations to a series of selected anions were carried out; it was determined that tris-2-(3-methylindolyl)phosphine binds to these selected anions in a 1 : 1 receptor to anion binding ratio. Crystal structures of the fluoride and acetate complexes confirm the binding stoichiometry, and demonstrate the cooperative interaction of all three indolyl NH sites with the anion guest. Synthetic routes to new anion receptors with three or two indolyl NH donors were explored. The second type yielded a molecular cleft that was used in anion binding studies. The net basicity of a 2-indolylphosphine was determined through formation of a Ni(CO)3L complex. Net basicity can be tuned by changing the substituents on phosphorus or on an indolyl nitrogen centre. The [Cu(tris-2-(3-methylindolyl)phosphine)(phenanthroline)]BF4 complex is a discrete ion pair complex, exhibiting coordination chemistry at the phosphorus centre of the phosphine, while simultaneously hydrogen bonding through the indolyl NH sites to the BF4- anion. Complexes of the type [Pd(L)Cl(mu-Cl)]2 were analyzed by crystallography and the effect of net basicity on Pd-P bond length examined. The solid-state structures of (P,N)- and (P,P)-2-indolylphosphines were evaluated. In general, the sum of the <CPC bond angles increased from the parent unfunctionalized 2-indolylphosphine. The metal complexes of (P,N)- and (P,P)-2-indolylphosphines were assessed by crystallography to find possible trends of trans-influence. Lastly, a tetradentate tripodal ligand was synthesized by furnishing diphenylphosphino substituents on the indolyl nitrogen centres of tris-2-(3-methylindolyl)phosphine. The coordination of the tetradentate tripodal ligand to Pt(II) or Rh(I) resulted in five-coordinate trigonal bipyramidal complexes.