by Xiang Zhou. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references. / Acknowledgment --- p.i / Abstract --- p.ii / Abbreviations --- p.iii / Table of Contents --- p.iv-v / Chapter Chapter I --- Synthesis of β-substituted porphyrins --- p.1 / Chapter I-1 --- Introduction --- p.1 / Chapter I-1-1 --- Activation of alkanes: the biomimetic approach --- p.2 / Chapter I-1-2 --- Electronic effects in β-substituted porphyrins --- p.5 / Chapter I-1-3 --- Synthetic approach to β-substituted porphyrins --- p.7 / Chapter I-2 --- Results and discussions --- p.14 / Chapter I-2-1 --- Bromination of porphyrins at β-positions --- p.14 / Chapter I-2-2 --- Synthesis of boronic acids --- p.17 / Chapter I-2-3 --- Synthesis of β-substituted porphyrins --- p.18 / Chapter I-2-4 --- Uv spectra --- p.25 / Chapter I-2-5 --- "Crystal structures of H2TPP(Ph)4, H2TPP(Me)4， H2TPP(Tol)8 and H2TMP(Ph)8" --- p.26 / Chapter I-3 --- Conclusion --- p.43 / Chapter I-4 --- Experimental section --- p.44 / Chapter I-5 --- References --- p.58 / Chapter Chapter II --- Synthesis and Properties of Diporphyrins --- p.63 / Chapter II-1 --- Introduction --- p.63 / Chapter II-1-1 --- Linear dimers --- p.64 / Chapter II-1-2 --- Cofacial porphyrins (or strati-bisporphyrins) --- p.68 / Chapter II-1-3 --- Synthetic approach --- p.71 / Chapter II-2 --- Results and discussions --- p.73 / Chapter II-2-1 --- Synthetic strategy --- p.73 / Chapter II-2-2 --- Synthesis of diporphyrins via condensation and Suzuki cross- coupling --- p.75 / Chapter II-2-3 --- Synthesis of diporphyrins via Suzuki cross-coupling and condensation --- p.75 / Chapter II-2-4 --- Metalation of diporphyrins --- p.78 / Chapter II-2-5 --- Spectroscopy --- p.81 / Chapter II-3 --- Conclusion --- p.89 / Chapter II-4 --- Experimental section --- p.90 / Chapter II-5 --- Reference --- p.100 / Chapter Chapter III --- Novel Rhodium Porphyrin Complexes: Intermolecular Activation of Arene Carbon-Hydrogen Bond and Formation of a Nitrile-Bridged Coordination Polymer --- p.104 / Chapter III-l --- Introduction --- p.104 / Chapter III-1-1 --- Activation of C-H bonds --- p.104 / Chapter III-1-2 --- Activation of C-H bond by rhodium porphyrin complexs --- p.106 / Chapter III-2 --- Results and discussions --- p.108 / Chapter III-2-1 --- Synthesis of rhodium porphyrin complexes --- p.108 / Chapter III-2-2 --- Proton NMR --- p.112 / Chapter III-2-3 --- UV and binding studies of rhodium porphyrin complexes --- p.115 / Chapter III-2-4 --- IR spectra --- p.117 / Chapter III-2-5 --- Crystal structures of rhodium porphyrin complexes --- p.118 / Chapter III-3 --- Conclusion --- p.148 / Chapter III-4 --- Experimental section --- p.149 / Chapter III-5 --- References --- p.154 / Appendix --- p.157 / NMR Spectra --- p.159

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Porphyrins derivatized with electron donating and electron withdrawing groups can be used for artificial photosynthesis. Four new compounds, two electron donors and two electron acceptors, have been synthesized for prospective porphyrin linkages.

To mimic the properties of haemoglobin (Hb) and myoglobin (Mb) it has been found necessary to synthesise a five-coordinate ferrous porphyrin with a protecting structure over the sixth coordination site at iron. This thesis describes approaches to the synthesis of such a compound where the protecting structure is the "capped" moiety and where the base which occupies the fifth coordination site is held in position by two covalent linkages to the porphyrin. The preparation of the target molecule involved the synthesis of a new "capped" porphyrin and a series of difuncticnalised pyridines. These were then successfully coupled under high dilution conditions to give the "capped/strapped" porphyrin. Metallation and reduction completed the synthesis. The behaviour of the ferrous complex in the presence of dioxygen was investigated. High stability toward irreversible oxidation was found. In the presence of oxygen the ferrous complex had a half-life in excess of 40h at room temperature.

Bulk heterojunction organic solar cells (BHJ OSCs) have been recognized as one of the most promising next generation green technology alternatives to inorganic solar cells because of the low-cost, lightweight, flexibility. Specifically, the use of small molecules instead of polymers as donors in BHJ OSC have been developed very fast recently because small molecules can be facilely synthesized and easily purified, and have a determined molecular structure without batch-to-batch variations. To date, those among the most efficient small molecules were constructed as acceptor-donor-acceptor (A-D-A) structural configuration from electron-rich units such as benzodithiophene (BDT), dithienosilole (DTS), oligothiophene units, and electron-deficient units such as benzothiadiazole (BT), diketopyrrolopyrrole (DPP), isoindigo (IID) and perylenediimide (PDI). Surprisingly, porphyrins were rarely studied either in polymers or π-conjugated small molecules as donor materials, though they have unique chemistry together with excellent photochemical and electrochemical properties, such as facile functionalization of the periphery and the variation of the central atom (metal ions), strong UV-visible absorption, ultrafast photoinduced charge separation in porphyrin-fullerene systems. In this research work, we design, synthesize and characterize new porphyrin-based small molecules with acceptor-donor-acceptor (A-D-A) configuration for bulk heterojunction organic solar cells, and investigate their structure-property relationships, specifically the effect of peripheral and backbone alkyl side-chains, π-conjugated linkers as well as electron-deficient ending units on the charge mobility, film morphology and solar cell performances. In Chapter 1, a general review on the historic and recent development of BHJ OSCs was given first, including the major components and working principle of OSC, the versatile organic semiconductors and their performances in OSCs. In chapter 2, six A-D-A structural porphyrin small molecules were designed and synthesized, in which different peripheral alkyl substitutions are attached to the meso-position of porphyrin core (CS-I, CS-II, CS-III, CS-4, CS-5 and CS-6), and 3-ethylrhodanine is used as terminal group. Their UV-visible absorption in solid, energy level, blend film morphology, charge mobility and cell performance are dependent on the different peripheral substitutions. The active layer consists of these six small molecules as donor materials and PC71BM as the acceptor material with an optimized film thickness. Although all six molecules show similar optical spectrum in solutions, the introduction of linear alkyl side chains can promote thin-film nanostructural order, especially shown to shorten π-π stacking distances between backbones and increase the correlation lengths of both π-π stacking and lamellar spacing, leading to higher efficiency in this serial. Among them, the highest power conversion efficiency of 9.09% has been achieved by CS-4 based devices. In chapter 3, another two new A-D-A porphyrin small molecules (PTTR and PTTCNR) have been developed, which are similar in structure to CS-I, II and III, except that the linker is phenylethynyl in CS-I, II and III, whereas it is terthiophenylethynyl in PTTR and PTTCNR. The highest power conversion efficiency of 8.21% is achieved by PTTCNR, corresponding to a JSC of 14.30 mA cm−2, VOC of 0.82 V, and FF of 70.01%. The excellent device performances can be ascribed to the conjugated structure of porphyrin with 3,3''-dihexyl-terthiophene and the aliphatic 2-octylundecyl peripheral substitutions, which not only effectively increase the solar flux coverage between the conventional Soret and Q bands of porphyrin unit, but also optimize molecular packing through polymorphism associated with side-chain and the π-conjugated backbones, and form the blend films with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) characteristics of bi-continuous, interpenetrating networks required for efficient charge separation and transportation.;In chapter 4, we designed and synthesized a new dimeric porphyrin donor molecule (CS-DP) containing A-π2-D-π1-D-π2-A architecture by coupling of two zinc porphyrin cores through ethynyl linker. Interestingly, it can harvests the photons up to deep near-infrared (NIR) region in the absorption spectrum. From the past decades, it has been found that developing donor molecules with the absorption spectral in NIR region is a challenging key factor to get the high performance BHJ OSCs. Solar cell devices employing CS-DP as a donor exhibit a highest power conversion efficiency of 8.23%, corresponding to JSC = 15.14 mA cm-2, VOC = 0.781 mV and FF = 69.8% under AM 1.5G solar radiation. The high efficiency of this molecule is attributed to a panchromatic IPCE action spectrum from 300 nm to 1000 nm. Also, this performance is best for the reported deep NIR organic solar cells based on single small molecule and PC71BM system so far. We envision that this new small bandgap dimeric porphyrin is very promising to use in ternary and multi-junction applications as well as NIR photodetectors. In chapter 5, a series of new A-D-A structural porphyrin small molecules (CS-10, CS-11 and CS-12) have been prepared, that contain the same meso-thienyl-thioalkyl substituted porphyrin core and 3-ethylrhodanine ending unit, but varies with different numbers of phenylethynyl linker. Using them as donors for solution-processed organic solar cells, the device based on CS-10 featuring single phenyl ethynyl π-linker exhibits high power conversion efficiency (PCE) of 7.0%. The results indicate that meso-thienyl-thioalkyl substitution and controlled π-linker length is beneficial to tune the optoelectronic properties, film morphology and consequently performance of porphyrin-based BHJ OSCs. In chapter 6, two symmetrical tetra-meso-substituted porphyrin molecules (ZnP and CuP) have been prepared in gram-scale through the direct condensation of pyrrole and 4-[bis(4-methoxyphenyl)amino]benzaldehyde. Its Zn(II) and Cu(II) complexes exhibit excellent thermal and electrochemical stability, specifically, high hole mobility and very favorable energetics for hole extraction that render them attractive for implementation as new hole transporting materials in organometallic halide perovskite solar cells (PSCs). As expected, the use of ZnP as HTM in PSCs affords a competitive PCE of 17.78%, which is comparable to the most powerful HTM of Spiro-OMeTAD (18.59%) under the same working conditions. Meanwhile, the metal centers affect somewhat the photovoltaic performances that CuP as HTM produces a relative lower PCE of 15.36%. Notably, the perovskite solar cells employing ZnP show longer stability than that of Spiro-OMeTAD. Moreover, the two porphyrin-based HTMs can be prepared from relatively cheap raw materials with a facile synthetic route. The results demonstrate that ZnP and CuP can be a new class of HTMs for efficient and stable perovskite solar cells. To the best of our knowledge, this is the highest performance for porphyrin-based perovskite solar cells with PCE > 17%. The dissertation was completed with conclusions and outlooks in chapter 7.

by Yiu-bong Leung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 67-68). / Abstract --- p.i / Acknowledgment --- p.ii / Abbreviation --- p.iii / List of spectra --- p.iv / Contents --- p.v / Chapter Part 1: --- A New Synthesis of Rhodium(II) and Iridium(II) Octaethyl- porphyrin Dimers / Chapter 1.1 --- Introduction / Chapter 1.1.1 --- Objective --- p.1 / Chapter 1.1.2 --- Literature Survey --- p.1-7 / Chapter 1.2 --- Result and Discussion --- p.8-10 / Chapter 1.3 --- Conclusion --- p.11 / Chapter Part 2: --- Substituent Effect of meso-pαrα-Arylsubstituted Octabromo- tetraphenylporphyrins / Chapter 2.1 --- Introduction / Chapter 2.1.1 --- Objective --- p.12 / Chapter 2.1.2 --- Literature Survey --- p.12-17 / Chapter 2.2 --- Result and Discussion --- p.18-28 / Chapter 2.3 --- Conclusion --- p.29 / Chapter Part 3: --- "Thermolysis of [2，3，7，8,12,13,17,18-0ctachloro-5,10,15,20- tetrakis(4'-tert-butylphenyl)porphyrinato]-2-phenylethyl- rhodium(III)" / Chapter 3.1 --- Introduction / Chapter 3.1.1 --- Objective --- p.30 / Chapter 3.1.2 --- Literature Survey --- p.30-31 / Chapter 3.2 --- Result and Discussion --- p.32-45 / Chapter 3.3 --- Conclusion --- p.46 / Experimental Section --- p.47-64 / References --- p.65-68 / Spectra --- p.69-83

The experimental cancer therapeutic agent gadolinium texaphyrin (MGd) is a cationic paramagnetic expanded porphyrin currently being tested as an X-Ray sensitizing (XRS) agent, and is a compound with demonstrated tumor localization. Additionally MGd shows promise as a chemotherapeutic agent, both as a stand-alone agent, and showing activity in vitro with ascorbate via a novel ROS generating mechanism.3 This dissertation reports the synthesis, characterization, and cell studies of novel MGdfluorophore, and platinum therapeutic conjugates. Also discussed are cationic Pt agents having cytotoxic activity. In this research we set out to answer three questions: i) can fluorescent conjugates of MGd be synthesized, with observable subcellular localization, different from that of MGd, ii) can MGd-Pt conjugates with observable Pt release be synthesized?, and iii) can Pt compounds containing a cationic moiety be tuned to have efficacy comparable to traditional Pt therapeutic agents? Two MGd-xanthene fluorophore conjugates were synthesized with the goal of using them to probe sub-cellular distribution. The anionic (FITC), and cationic (Rhodamine), fluorophore conjugates demonstrated nuclear and mitochondrial localization, respectively. In an ongoing project designed to reduce non-specific agent toxicity, a platinumreleasing MGd therapeutic conjugate was synthesized. The MGd-amidopropylmalonato-Pt conjugate demonstrated efficacy equivalent to carboplatin, a classical “non-selective” agent as inferred from in-vitro studies with A549 lung cancer cells. Aqueous stability studies of this conjugate gave results in agreement with hydrolytic loss of Pt, reversible with added Pt-diaquo. Finally, Pt complexes of amino-1-benzylpyridinium salts were synthesized and found to demonstrate significant cytotoxicity in screening studies. This latter positive development led to the suggestion that complexes of this type could consititute a new class of lipophilic-quaternary-cation Pt therapeutic agents. It is hoped that this series of putative Pt anti-cancer agents will prove useful as both stand-alone therapeutic agents and as the basis for producing conjugate with biolocalizing properties. / text

The oxidation of three alkyl thioethers, phenol and 2-propanol by trans-dioxo ruthenium porphyrin species, and the synthesis, characterization and reactivity of several new ruthenium porphyrin complexes are described in this thesis. The trans-dioxo species Ru(Porp)(O)₂ [Porp= the dianions of 5,10,15,20-tetramesitylporphyrin (TMP) and 5,10,15,20-(2,6-dichlorophenyl)porphyrin (OCP)] selectively oxidize diethyl-, di-n-butyl- and decylmethyl- sulfides to the corresponding sulfoxides at room temperature. The reaction is first order in [Ru] and in [thioether]. The second order rate constants for the first O-atom transfer from the Ru(TMP) system are: 7.54xl0⁻³, 1.23xl0⁻² and 1.14x10-¹ M⁻¹ s⁻¹ respectively for the three thioethers at 20.0 °C. The activation parameters for the O-atom transfer process are also determined: for Et₂S, ∆H‡= 58.3 kJ mol⁻¹ and ∆S‡= -86 J K⁻¹ mol⁻¹; for nBu₂S, AH‡= 47.4 kJ mol⁻¹and ∆S‡= -120 J K⁻¹ mol⁻¹; for DecMeS, ∆H‡= 56.5 kJ mo⁻¹ and ∆S‡= -70 J K⁻¹ mol⁻¹. A second order rate constant of 7.23xl0⁻²M⁻¹s⁻¹ is measured at 20.0 °C for the oxidation of Et₂S by Ru(OCP)(O)₂. The intermediates Ru(TMP)(OSEt₂)₂, Ru(TMP)(OSEt₂)(OSEt₂) and the final product Ru(TMP)(0SEt₂)₂,where O and S refer to O- and S- bonded sulfoxide, are observed by ¹H nmr, and the last mentioned is isolated and characterized. A mechanism is proposed, based on electrophilic attack of the O=Ru=O moiety on :SR₂ to form bis-O-bonded species which subsequently isomerizes to bis-S-bonded species via mixed species. The Ru(TMP)(O)₂/Et₂S/O₂ system at room temperature is catalytic in complex, but produces only about 5 turnovers due to poisoning of the catalyst by the reaction product. The same system at >65 °C gives higher turnovers, but now porphyrin ligand degradation is observed, perhaps via oxidation by the O=Ru=O moiety. The Ru(OCP)(0)₂/Et₂S/O₂ system at 100 °C catalytically oxidizes Et₂S to Et₂SO and Et₂SO₂ (in ~ 4:1 ratio) and the porphyrin ligand does not undergo oxidative destruction. The Ru(TMP)(O)₂ species reacts with phenol via an observed intermediate Ru(TMP)(p-O(H)C₆H₄OH)₂ to form Ru(IV)(TMP)(OC₆H₄OH)₂, a paramagnetic (S=l) complex which is isolated and characterized. The oxidation reaction is first order in both [Ru] and [phenol] with a second order rate constant 6.90x10⁻² M⁻¹ s⁻¹at 20.0 °C. A mechanism based on electrophilic attack by the O=Ru=O moiety on the aryl ring followed by proton migration is proposed. This mechanism also explains the formation of some free para-benzoquinone and 1 equivalent of water per Ru. No ortho-benzoquinone is formed in the reaction. Preliminary ⁻H nmr studies reveal that 2-propanol is oxidized to acetone by Ru(TMP)(O)₂. A paramagnetic species (S= 1) was isolated as the only porphyrin product but not characterized. A range of novel ruthenium porphyrin complexes is also prepared. The reaction of acetylene with the four-coordinate Ru(TMP) species forms [Ru(TMP)]₂(u-C₂H₂), the first reported organometallic ruthenium porphyrin dimer. The complexes, Ru(TMP)(PhCCPh) and Ru(TMP)(PhCCH), the first π-bonded alkyne species in ruthenium porphyrin chemistry, are characterized in solution. The π-bonded alkene complexes Ru(TMP)(CH₂CH₂) OPrOH).(iPrOH) and Ru(TMP)(CH₂CH₂) are isolated and characterized, while the Ru(TMP)(cyclohexene) complex is characterized in situ. The Ru(TMP)(OSEt₂)₂ complex is isolated also by the reaction of Ru(TMP)(CH₃CN)₂with Et₂SO. The Ru(TMP)(L)₂ complexes, L= OSMe₂, OSnPr₂ and OSnBu₂ are also prepared via the above method and characterized. Some new Ru(OCP) complexes, (the monocarbonyl, the bis-acetonitrile and the dioxo- species) are also isolated and characterized. / Science, Faculty of / Chemistry, Department of / Graduate