by Xiu Chun Wang. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1989. / Bibliography: p. 108-114.

by Xiao-min Wang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 82-88). / Acknowledgements --- p.i / Contents --- p.ii / Abstract --- p.iii / Chapter I. --- Introduction --- p.1 / Chapter I-l. --- Background --- p.1 / Chapter I-2. --- Evidence for Aromaticity --- p.2 / Chapter I-3. --- Source and Theories of Paramagnetic Ring Current --- p.4 / Chapter I-4. --- Nonplanar Structure of Cyclooctatetraene (COT) --- p.6 / Chapter I-5. --- Fully Conjugated Planar Eight-membered Ring Compounds --- p.8 / Chapter I-6. --- Stabilization of Cyclooctynes --- p.14 / Chapter I-7. --- The aim of present work --- p.20 / Chapter II. --- Results and Discussion --- p.22 / Chapter II-1. --- "Synthesis of 5,6-Didehydro-1,1,14,14-tetramethyl-10,11 -methano -lH-benzo[5,6]cycloocta[l,2,3,4-def]fluorene(48)" --- p.22 / Chapter II-2. --- "Synthesis of 5,6-Didehydro-10,l 1-methano -lH-benzo[5,6]cycloocta[l,2,3,4-def]fluorene-l,14-dione(49)" --- p.49 / Chapter II-3. --- "Attempted Synthesis of l,14-Bis(dicyanomethylene)-5,6- didehydro-10,11 -methano- 1H- benzo [5,6] cycloocta[ 1,2,3 A-def] fluorene (89) and l,14-Bis(N-cyanoiminyl)-5,6-didehydro- 10,11-methano-lH-benzo[5,6]cycloocta[l,2,3,4-def]fluorene (90)" --- p.56 / Chapter III. --- Conclusion --- p.59 / Chapter IV. --- Experimental --- p.60 / Chapter V. --- References --- p.82 / List of Spectra --- p.89 / Spectra --- p.91

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by Chun-yip Leung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 72-76). / Acknowledgements --- p.1 / Chapter Part 1). --- The Chemistry of A Planar Cyclooctatetraene Derivatives Fused to Phenanthrene Ring --- p.2 / Chapter (I). --- Abstract --- p.2 / Chapter (II). --- Introduction --- p.3 / Chapter (III). --- Results and Discussion --- p.9 / Chapter (IV). --- Conclusion --- p.18 / Chapter (V). --- Experimental Section --- p.19 / Chapter Part 2). --- "Regiospecific Synthesis of 2,3-Disubstituted and 2,3,5-Trisubstituted Furans from 2,4-Bis(trimethyl- silyl)furan" --- p.28 / Chapter (I). --- Abstract --- p.28 / Chapter (II). --- Introduction --- p.29 / Chapter (A). --- Reactions of Furan --- p.29 / Chapter (1). --- Reactions with Electrophiles --- p.29 / Chapter (2). --- Reactions with Nucleophiles --- p.30 / Chapter (3). --- Cycloaddition Reactions --- p.31 / Chapter (B). --- Synthesis of Polysubstituted Furans --- p.32 / Chapter (1). --- By Ag(I)-Catalyzed Cyclization --- p.33 / Chapter (2). --- By Base-Catalyzed Isomerization of Alkynyloxiranes --- p.33 / Chapter (3). --- By Base-Catalyzed Cyclization- Isomerization of γ-Alkynyl Allylic Alcohol --- p.36 / Chapter (4). --- "By Palladium-Catalyzed Coupling of 2- Propargyl-l,3-dicarbonyl Compounds and Vinylic, Aryl Triflates or Halide" --- p.36 / Chapter (5). --- "From α,β-Unsaturated Ketones" --- p.38 / Chapter (C). --- Recent Achievement --- p.39 / Chapter (III). --- Results and Discussion --- p.44 / Chapter (A). --- "Attempted Synthesis of 2,4-Disubstituted Furans" --- p.44 / Chapter (B). --- "Synthesis of 2,3,5-Trisubstituted Furans" --- p.45 / Chapter (1). --- Synthesis of 2-benzyl-3-m-anisyl-5- p-tolyl-furan (30) --- p.45 / Chapter (2). --- Synthesis of 2-benzyl-3-trans-hexen- l-yl-5-p-tolyl-furan (31) --- p.51 / Chapter (3). --- "Synthesis of 2-(3,5-dimethyl)benzyl-3- p-methoxycarbonylbenzyl-5-hexyl- furan (32)" --- p.52 / Chapter (4). --- "Synthesis of 2-benzyl-3-[3,4-(methyl- enedioxy)]benzyl-furan (33)" --- p.57 / Chapter (IV). --- Conclusion --- p.60 / Chapter (V). --- Experimental Section --- p.61 / References --- p.7 2 / List of Spectra --- p.7 7 / Spectra --- p.7 9

by Cheng Kin Tak Samuel. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1988. / Bibliography: leaves 61-64.

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While investigating strategies to prepare precursors to highly strained buckybowls, we focused our attention on the Lewis acid aldol cyclization of 1-acenaphthenone derivatives which has been shown to produce a cyclic tetramer as a byproduct. Surprisingly, despite the interesting structural and electronic properties that have recently been observed as a result of the incorporation of eight-membered rings into polycyclic aromatic hydrocarbons, this cyclic tetramer has largely been ignored. As a result of this, we set our sights on the isolation and characterization of this cyclic tetramer. The initial approach employed subjecting 1-acenaphthenone to the most common conditions used in trimerization—TiCl4 in boiling o-dichlorobenzene. Surprisingly, this resulted in exclusive formation of the cyclic tetramer, which we have named tridecacyclene. The results of these studies were promising, establishing structural characterization and supramolecular assemblies with C60 in the solid-state. The optoelectronic properties revealed a significantly lower reduction potential (~0.4 eV) than the trimeric species of 1-acenaphthenone. This is attributed to the central eight-membered ring of tridecacyclene. Reduction proceeded through two single-electron processes. Further examining the electrochemical properties, we were able to gain new insight into the relation of structure and aromaticity. Reduction of tridecacyclene with potassium metal allowed us to characterize the radical anion and dianion through NMR and UV-Vis spectroscopy. Solid-state analysis of the dipotassium adduct revealed that despite the propensity of the reduced form of cyclooctatetraene derivatives to flatten as the molecule adopts a Hückel aromatic core, tridecacyclene maintains its tub shape. Significant bond equalization was observed in the center eight-membered ring—a strong indication of a delocalized π-system. This was supported by harmonic oscillator model of aromaticity calculations of the central ring with the value increasing from 0.09 to 0.48 where a value of 1 indicates a fully aromatic ring. Tridecacyclene represents the precursor to a fragment of the fullerene C240. A broad variety of reactions to facilitate the necessary strain inducing C–C bonds to formthe fragment have been attempted. To date, we have not been able to synthesize the fragment. However, the parent molecule tridecacyclene shows great promise in the development of non-aqueous redox flow batteries and is currently being explored for this purpose in our laboratory.

A series of cis- and trans-bis(ethynyl)platinum complexes containing dimethyldihydropyrene (DHP) photochromic compounds were synthesized from RDHPCCH (R = H, CH3CO, PhCO, 1-naphthoyl and benzo[e]) and platinum chloride with appropriate ancillary ligands (PEt3, PPh3, dppe, bipy and phen). The complexes were studied using mass spectrometry, NMR spectroscopy (1H, 13C, 31P and 195Pt) and IR. The X-ray structural information for bis(DHP-ethynyl) platinum complexes 44, 45, 47, 49, and 52 revealed that the Pt complexes possessed a square planar geometry at the metal centers. These platinum complexes are T type photochromic compounds. The BDHP-derived platinum complexes 48, 49, and 52 open completely when irradiated by visible light (λ > 590 nm). The photoopening rates for the platinum complexes are about 4 times slower than the corresponding DHP-alkynes. All the alkynyl platinum complexes close thermally faster than the corresponding free alkynes, and the closing rate is not affected substantially by changing the ancillary phosphine ligands. The BDHP-ethynyl platinum complexes with PEt3, PPh3 and dppe ligands have similar thermal closing half lives at 25°C of τ1/2 = 42 h, 38 h and 33 h, respectively, in contrast to the half life τ1/2 = 62 h of the BDHP-ethyne 40. The first cyclobutadienyl cobalt substituted dihydropyrenes were prepared by CpCo(CO)2 cyclization of a series of dihydropyrenyl ethynes. When the other alkyne substituent was small (methyl or carboxyethyl) only cis (head-to-head) isomers were obtained, but with larger sized groups, mixed head-to-head and head-to-tail isomers were obtained. The crystal structure of complex 21 indicated some unusually short bond distances were present. By comparison of the NMR and bond length data for complexes 21 or 69 with those for phenyl-DHP 60, the aromaticity of the cyclobutadienyl cobalt fragment was estimated quantitatively to be at least as large as that of benzene. The organometallic fragment [Cbd-Co-Cp] substantially slowed the DHP photoopening reaction of complex 72 relative to precursors 67 or 35. DHP[e]tropone, 17, DHP[e]tropylium cation, 18 and DHP[e]cyclooctatetraene dianion, 20 were synthesized to study the relative bond localizing abilities of COT dianion 80 (105 % relative to benzene), tropylium cation 15 (55 % relative to benzene), tropone 79 (13 % relative to benzene) using DHP as the NMR probe. The internal methyl protons of DHP resonated at δ -3.56 for 17, δ -2.61 for 18 and δ -1.38 for 20. Cycloheptatrienyl anions 111, 112 and 19 were made from cyclohepta-2,4,6-triene (CHT) isomers 107 and 108 (for two anions, 112 and 19). The internal methyl protons of their DHP resonated at δ -2.52, 2.67 for 111, δ -0.80, -0.84 for 112 and δ +2.10 for 19. The anion 19 was best taken as a 20π electron paratropic system. The homo-aromaticity of the CHT isomers 107, 108 and 117 was estimated based on the NMR data and X-ray structural data. Obvious anisotropic effects existed and the bond localization ability of the CHT (24% based on NMR data for 108) may have a large error. The ring inversion barriers of the COT 82 and CHT 77 were measured using variable temperature NMR spectroscopy as 13.9 and 8.7 kcal/mol, respectively. Five X-ray crystallography structures were obtained for 99B, 17, 108, 117 and 125 and the information was used in estimating the bond localization abilities and in establishing absolute stereochemistry / Graduate

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