published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

The electronic structures and bonding interactions in the syn and anti isomers of Mo₂S₄(edt)₂²⁻ (edt = ethanedithiolato, (SCH₂CH₂S)²⁻) were examined and compared through Fenske-Hall and extended Huckel molecular orbital calculations. The electronic structures of a hypothetical closed isomer and the fragment MoS₃(edt)³⁻ were calculated as well. A molybdenum-molybdenum bonding interaction accounts for the diamagnetism of the complexes and is important in determining the relative stabilities of the isomers (syn > closed > anti). The structure of the syn isomer of (P(C₆H₅)₄)₂W₂S₄(edt)₂ was determined by X-ray crystallography. The compound crystallizes in the space group P2₁/n with a = 16.126(7)A, b = 25.03(1)A, c = 13.021(6)A, β = 101.73(4)°, and Z = 4. The calculated and observed densities are 1.755 and 1.757 g cm⁻³. Full-matrix least squares refinement of the 7414 data with Fₒ² > 3σ(Fₒ²) gave R = 0.039 and R(w) = 0.046. Each tungsten atom is ligated by five sulfur atoms in approximate tetragonal-pyramidal geometry. The W-W distance is 2.862(1)A, indicating a metal-metal bond. The average W-S(terminal) distance is 2.144(2)A, the average W-S(bridging) is 2.328(2)A, and the average W-S(edt) distance is 2.404(2)A. A variety of sulfur compounds, including hydrogen sulfide, aromatic and aliphatic thiols, cysteine, and bisulfite reduced MoO(TTP)OR, oxoalkoxotetratolylporphinatomolybdenum(V) (R = H, CH₃, C₂H₅, C₅H₁₁, MoO(TTP)), to the corresponding Mo(IV) species, MoO(TTP). The kinetics of the redox reaction between MoO(TTP)OC₂H₅ and RSH (R = C₂H₅, C₆H₅) were monitored at ambient temperature. The rate law d(Mo(IV))/dt = k₂(Mo(V))(RSH), with k₂ = 8.0 x 10⁻¹³ M⁻¹sec⁻¹ for C₂H₅SH and k₂ = 8.2 M⁻¹sec⁻¹ for C₆H₅SH describes the kinetic data. Sulfur compounds also reduced MoO₂(TTP). The kinetics of the redox reaction of the novel compound MoO(TTP)HSO₃ were monitored in chloroform solution at ambient temperature. The rate law d(Mo(IV))/dt = k₂(Mo(V))² with k₂ = 3.4 x 10² M⁻¹sec⁻¹ describes the kinetic data. Oxidation of MoO(TTP) to Mo(V) occurs in the presence of air. Oxidation catalysis by oxomolybdenum porphyrins was demonstrated for the substrates C₂H₅SH, C₆H₅SH, and HSO₃⁻. Mechanisms for these reactions are proposed.

A pulsed-beam fourier transform microwave spectrometer was used to measure the rotational spectra of iodine heptafluoride, iodine pentafluoride, and the weakly bound complex, HCl...NNO. For IF7, only five rotational transitions were observed, and no resolvable hyperfine structure was detected. Based on this data, the A, B, and C rotational constants were determined to be 1746(3) MHz, 1732.0(8) MHz, and 1553.0(2) MHz, respectively. The existence of a pure rotational spectrum confirms that this molecule undergoes polar distortions. Twenty-two hyperfine components of the IF5 spectrum were recorded. The B rotational constant for this molecule was determined to be 2727.421(3) MHz, and the quadrupole coupling constant was found to be 1069.35(13) MHz. Though the work is still in progress on HCl...NNO, nine transitions have been recorded. In addition, five transitions have been recorded for an apparent trimer species composed of HCl, NNO, and an as yet unidentified third species.

As part of a continuing study of the synthesis and chemistry of new, substituted pentacyclo(5.4.0.0²，⁶.0³，¹º.0⁵，⁹)undecanes, the following compounds have been synthesized: 1: X=O, Y=SiMe_3; 2: X=CH_2, Y=SiMe_3; 3: X=O, Y=Cl; 6: X=OAc, Y=H; 8: X=OC(O)Ph, Y=H; 9: X=OSO_2Ph, Y=H; 11: X=OH, Y=H; 12: X=OMe, Y=H; 14: X=CHSiMe_3, Y=SiMe_3; 15: X=OH, Y=Cl; 16: X=OAc, Y=Cl; 17: X=OMe, Y=Cl. An important objective of this work is to prepare new polycyclic cage compounds which can be utilized as intermediates for the synthesis of new, substituted tricyclopentanoid natural products (triquinanes) and related systems. Compounds 1-4 were identified as target molecules in this connection.

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Chemistry. / Vita. / Includes bibliographical references. / Ph.D.

Lau Cheuk Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 93-98). / Abstracts in English and Chinese. / Table of Contents --- p.i / Acknowledgements --- p.iii / Abbreviations --- p.iv / Structural Abbreviations for Porphyrin Complexes --- p.v / Abstract --- p.vi / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- General Introduction --- p.1 / Chapter 1.2 --- Activation of Carbon-Hydrogen Bond (CHA) by Transition Metal --- p.2 / Chapter 1.2.1 --- Application of CHA by Transition Metals --- p.3 / Chapter 1.2.2 --- Thermodynamic in CHA by Transition Metals --- p.5 / Chapter 1.2.3 --- Types of Carbon-Hydrogen Activations --- p.6 / Chapter 1.3 --- Carbon-Hydrogen Bond Activation of Aldehydes --- p.14 / Chapter 1.3.1 --- Catalytic Application of CHA of Aldehydes by Transition Metals --- p.14 / Chapter 1.3.2 --- Stability of Intermediate M(COR) --- p.15 / Chapter 1.3.3 --- Issue in Selectivity --- p.16 / Chapter 1.4 --- Structural Features of Rhodium Porphyrins --- p.23 / Chapter 1.5 --- Objective of the work --- p.24 / Chapter Chapter 2 --- Carbon-Hydrogen Activation of Aldehydes by Rh(ttp)Cl and Rh(ttp)Me / Chapter 2.1 --- Introduction --- p.26 / Chapter 2.2 --- CHA of Aldehydes by Rh(ttp)Cl --- p.27 / Chapter 2.2.1 --- Preparation of Rh(ttp)Cl --- p.27 / Chapter 2.2.2 --- Solvents Screening --- p.27 / Chapter 2.2.3 --- Results and Discussion --- p.30 / Chapter 2.3 --- CHA of Aldehydes by Rh(ttp)Me --- p.33 / Chapter 2.3.1 --- Preparation of Rh(ttp)Me --- p.34 / Chapter 2.3.2 --- Results and Discussion --- p.35 / Chapter 2.4 --- Mechanistic Studies --- p.37 / Chapter 2.4.1 --- CHA of Aldehydes by Rh(ttp)Cl --- p.37 / Chapter 2.4.2 --- CHA of Aldehydes by Rh(ttp)R --- p.42 / Chapter 2.5 --- Comparison of the u(C=0) --- p.48 / Chapter 2.6 --- X-ray Data --- p.49 / Chapter 2.7 --- Summary --- p.50 / Chapter Chapter 3 --- CHA of Aldehydes by Rh(ttp)CH2CH2OH and Rh(ttp)+X- / Chapter 3.1 --- Introduction --- p.52 / Chapter 3.2 --- CHA of Aldehydes by Rh(ttp)CH2CH2OH --- p.53 / Chapter 3.2.1 --- Results and Discussion --- p.53 / Chapter 3.2.2 --- Mechanistic Studies --- p.61 / Chapter 3.3 --- CHA of Aldehydes by Rh(ttp)+X- --- p.65 / Chapter 3.4 --- Summary --- p.67 / Conclusion --- p.68 / Experimental --- p.69 / Reference --- p.93 / Appendix I Crystal Data and Processing Parameters --- p.99 / List of Spectra --- p.141 / Spectra --- p.143

1H and 13C{1H} NMR spectra of all the new compounds and crystallographic data are given in the Appendix. / Chapter 1 presents an overview of phthalocyanines including their general synthesis, properties, and applications. Special attention has been placed on the unsymmetrical analogues, and those which are efficient photosensitizers in photodynamic therapy. A brief account on BODIPYs as another versatile class of functional dyes is also given. / Chapter 2 describes the synthesis, spectroscopic characterization, photophysical properties, and in vitro photodynamic activities of three novel amphiphilic zinc(II) phthalocyanines substituted with one or two 3,4,5-tris(3,6,9-trioxadecoxy)benzoxy group(s). These compounds exhibit significantly higher photodynamic activities toward HepG2 and HT29 cell lines. The alpha-substituted analogue is particularly potent with IC50 values as low as 0.02 microM. The higher photodynamic activity of this compound can be attributed to its lower aggregation tendency in the culture media as shown by absorption spectroscopy and higher cellular uptake as suggested by the stronger intracellular fluorescence, resulting in a higher efficiency to generate reactive oxygen species inside the cells. / Chapter 4 focuses on a related series of 1,4-disubstituted zinc(II) phthalocyanines. These compounds possess two oligoethylene glycol methyl ether chains with various length at the 1,4-di-alpha-positions. The effects of the chain length on their aggregation, photophysical properties, cellular uptake, and in vitro photodynamic activities have been explored. / Chapter 5 presents the synthesis, characterization, and photophysical properties of another series of zinc(II) phthalocyanines conjugated with one, two or four isopropylidene protected glucofuranose unit(s) through a tetraethylene glycol linker. With these hydrophilic substituents, these macrocycles are highly soluble in common organic solvents and biological media. Their in vitro photodynamic activities toward HT29 and HepG2 cells have also been evaluated. Compared with the tetra-glucosylated phthalocyanines, which are almost nonphotocytotoxic, the mono- and di-glucosylated analogues exhibit a higher photodynamic activity. The di-alpha-substituted analogue is particularly potent with IC50 values as low as 0.03 microM. / Chapter 6 reports the synthesis, characterization, and photophysical properties of two novel conjugates of subphthalocyanine substituted axially with a BODIPY or distyryl-BODIPY moiety. Both systems absorb over a broad range in the visible region. They also exhibit a highly efficient photo-induced energy transfer process either from the excited BODIPY to the subphthalocyanine core or from the excited subphthalocyanine to the distyryl-BODIPY unit. The energy transfer quantum yields are close to unity for both of these conjugates. / Chapter 7 describes the preparation and photophysical properties of another two BODIPY and monostyryl-BODIPY conjugates which are linked to a silicon(IV) phthalocyanine core. These conjugates serve as excellent artificial photosynthetic models for the study of energy and electron transfer processes. Depending on the axial substituents, these conjugates exhibit predominantly a photo-induced energy or electron transfer process in toluene. / The related studies of a series of novel di-alpha-substituted zinc(II) phthalocyanines having two biocompatible triethylene glycol methyl ether chains or glycerol moieties are described in Chapter 3. Compared with the unsubstituted analogue, these compounds have a red-shifted Q band, and exhibit a relatively weaker fluorescence emission and higher efficiency to generate singlet oxygen. As a result, these compounds are promising candidates for photodynamic therapy. In vitro studies on HepG2 and HT29 cells have shown that they are highly photocytotoxic with IC50 values as low as 0.06 microM. / This thesis describes my synthetic studies on several series of functional zinc(II) phthalocyanines and boron dipyrromethenes (BODIPYs). Their applications as efficient photosensitizers in photodynamic therapy and light harvesting systems have also been explored. / Liu, Jianyong. / Adviser: Dennis Keepui Ng. / Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0326. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

Chapter 1 describes the reactivities of bisgermavinylidene [(Me 3SiN=RPh2)2C=Ge→Ge=C(PPh2=NSiMe 3)2] (25). With the use of CpMnCO2(THF), Mn2(CO)10 and group 11 metal halides, manganese-germavinylidene complexes and germavinylidyl group 11 metal complexes were prepared respectively. Radical reaction of 25 with 2,2,6,6-tetramethylpiperidine N-oxide affords [(Me3SiN=RPh2)2C=Ge(ONCMe2C 3H6CMe2)2] (40). Cycloadditon reactions of 25 were studied. The reaction of 25 with benzil, azobenzene or 3,5-di-tert-butyl-o-benzoquinone affords [(Me3SiN=PPh2)2C=Ge{O(Ph)C=C(Ph)O}] (41), [(Me3SiN=PPh2)2C=Ge( o-C6H4NHNPh)](42) and [(Me 3SiN=PPh2)2C=Ge=C-(PPh2=NSiMe 3)2] (44), respectively. The C=Ge bond of 25 can undergo cycloaddition reactions with Me3SiN 3, Me3SiCHN2 or AdNCO (Ad = adamantly) to give [(Me3SiN=PPh2)2CGeN(SiMe3)N=N] (46), [(Me3SiN=PPh2)2C-GeN=NCH-SiMe 3] (48) and [(Me3SiN=PPh2)2 CGeN(Ad)C-O] (47), respectively. Furthermore, 1,2-addition products of rhodium(I) and tin(IV) complexes were prepared from the reaction of 25 with (cod)RhCl and (nBu) 3SnN3, respectively. The syntheses of bimetallic chlorides [(Me3SiN=PPh2)2(GcCl)CMn(mu-Cl)]2 (51) and [(Me3SiN=PPh2)2(GeCl)CFeCl] (52) are also reported. / Chapter 2 concerns the reactivities of bis(iminophosphorano)methanide tin(II) chloride [HC(PPh2=NSiMe3)2SnCl] ( 79). The reactivity of the lone pair in 79 was studied. The reaction of 79 with benzil or 3,5-di-tert-butyl- o-benzoquinone gives the corresponding cycloaddition products. Treatment of 79 with NaN3 or AgOSO2CF3 affords the corresponding substituted heteroleptic stannylenes. The reaction of 79 with W(CO)5THF gives an adduct [HC(PPh 2=NSiMe3)2(Cl)Sn→W(CO)5] ( 81). Compound 79 reacts with Fe{N(SiMe3) 2}2 to afford [HC(PPh2=NSiMe3) 2Fe(mu-Cl)]2 (86). Moreover, treatment of 79 with LiC≡CPh gives [HC(PPh2=NSiMe3) 2C(Sn)=C(Ph)Sn(C≡CPh)2]2 (87). / Chapter 3 deals with the preparation and characterization of group 14 bis(thiophosphinoyl) metal complexes. The newly developed ligand [(S=PPr i2CH2)2-C5H 3N-2,6] (126) undergoes metalation with nBuLi or (nBu)2Mg to afford the lithium complex [Li{(S=PPri 2CH)(S=PPi2CH2)C 5H3N-2,6}(Et2O)] (127) and magnesium complex [Mg(S=PPri2CH)2C 5H3N-2,6] (128), respectively. 1,3-Distannylcyclobutane and 1,3-diplumbacyclobutane were prepared from treatment of 126 with M{N(SiMe3)2}2 (M Sn, Pb) by the amine-elimination reaction. Furthermore, compound 127 reacts with GeCl2.dioxane or SnCl2 to afford digermylgermylene Ge[GeCl2{(S=PPr i2CH)(S=PPri 2CH2)C5H3N-2,6}]2 ( 131) and ionic tin(II) complex [{C5H3N-2,6-(CH 2PPri2=S)(CHPPr i2=S)}SN+][SnCl3 -] (134), respectively. / Chapter 4 describes the conclusion of the first three chapters. The future works of the first three chapters were also reported. / This thesis is focused on four areas: (i) the reactivities of bisgermavinylidene; (ii) the reactivities of bis(iminophosphorano)methanide tin(II) chloride; (iii) the synthesis of group 14 bis(thiophosphinoyl) metal complexes and (iv) conclusions and future works. / Kan, Kwok Wai. / "Aug 2007." / Adviser: Kevin W. P. Leung. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1007. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

本論文主要研究銥和銠卟啉絡合物與鹵代苯 (ArX, X = Cl, Br, I)的碳-鹵鍵(Ar-X)的斷裂反應及其應用。本論文分為四個部分：（1）銠卟啉絡合物與鹵代苯(ArX, X = Cl, Br, I)之間的碳-鹵鍵(Ar-X)斷裂反應；（2）氟氯化苯的碳-氟鍵(Ar-F)與碳-氯鍵(Ar-Cl)斷裂的競爭反應；（3）氟取代基對金屬（銥和銠）-芳香碳(M-Ar)鍵強弱的影響；以及（4）銥卟啉氟硼荧絡合物的合成。 / 第一部分闡述了銠卟啉絡合物(Rh(ttp)Cl)與鹵代苯(ArX, X = Cl, Br, I) 之間的碳-鹵鍵 (Ar-X) 斷裂反應以及反應機理。在鹼性條件下，無論富電子還是缺電子的鹵代苯都能與Rh(ttp)Cl反應，生成Ar-X鍵斷裂的產物──銠卟啉芳基絡合物(Rh(ttp)Ar) 。機理研究顯示， Rh(ttp)Cl 首先與氫氧根離子反應生成Rh(ttp)OH，進而通過二聚反應生成[Rh(ttp)]₂。[Rh(ttp)]₂在加熱條件下與Rh(ttp)自由基可以互相轉化，產生的Rh(ttp)自由基與鹵代苯進行原位取代反應，生成銠卟啉芳基絡合物(Rh(ttp)Ar)和鹵素自由基。鹵素自由基可以和另一個Rh(ttp)自由基反應生成Rh(ttp)X，在氫氧根離子存在的條件下，Rh(ttp)X將再次轉化為Rh(ttp)OH繼續反應。 / 第二部分描述了氟氯化苯中碳-氟鍵(Ar-F)與碳-氯鍵(Ar-Cl)斷裂的競爭反應。機理研究顯示碳-氟鍵(Ar-F)斷裂的中間體是M(por)⁻，而碳-氯鍵(Ar-Cl)斷裂的中間體是MII(por)。因此，我們可以通過改變反應條件而控制生成物。例如，在較低溫度下和強鹼性的極性溶劑中，以M(por)⁻前體作為反應物，可以獲得較多的碳-氟鍵(Ar-F)斷裂的產物；而在較高溫度下和弱鹼性的非極性溶劑中，可以獲得較多的碳-氯鍵(Ar-Cl)斷裂的產物。 / 第三部分敘述了間位氟取代基對金屬-芳香碳(M-Ar)鍵的增強作用。有間位氟取代基的金屬（銥，銠）卟啉芳基絡合物(M(ttp)ArF)是最穩定的同分異構體。在250°C條件下，當反應30天後，Ir(ttp)C₆H₄F的三個異構體達到平衡狀態，其鄰位:間位:對位的比例大約為0:5:1。理論計算的結果也顯示Ir(ttp)(3-fluorophenyl)相對Ir(ttp)(2-fluorophenyl)和Ir(ttp)(4-fluorophenyl)有更低的能量。氟取代基在鄰位時，氟與卟啉之間空間位阻較大，減弱了金屬-芳香碳(M-Ar)鍵的鍵能。與氟取代基在對位相比，在間位時具有更好的吸電子效應，從而增加了金屬-芳香碳(M-Ar)鍵的極性，增強了金屬-芳香碳(M-Ar)鍵鍵能。 / 第四部分描述了利用碳-鹵鍵 (Ar-X) 的斷裂，合成銥卟啉氟硼荧絡合物的反應。銥卟啉氟硼荧絡合物的產率可以達到70%。銥卟啉氟硼荧絡合物在生物成像和放射療法都有潛在的應用。銥卟啉氟硼荧絡合物是用金屬自由基與氟硼荧反應合成的。 / This thesis focuses on the reaction scopes, mechanistic investigations and applications of base-promoted aryl carbon-halogen (Ar-X) bond cleavage with iridium and rhodium porphyrin complexes. This thesis is divided into four parts: (1) Ar-X (X = Cl, Br, I) bond cleavage with Rh(ttp)Cl; (2) competitive Ar-F and Ar-Cl bond cleavage with iridium and rhodium porphyrins; (3) fluorine substituent effect on the M-Ar (M = Ir, Rh) bond strength; and (4) synthesis of iridium porphyrin BODIPY complexes. / Part I describes the reaction scopes and mechanism of Ar-X (X = I, Br, Cl) bond cleavage with Rh(ttp)Cl (ttp = 5,10,15,20-tetratolylporphyrinato dianion). Under basic conditions, both electron-rich and electron-deficient ArX undergo Ar-X bond cleavage to give Rh(ttp)Ar in good yields. [with diagram] / The mechanistic investigations suggest that RhIII(ttp)Cl first undergoes ligand substitution by OH- to give RhIII(ttp)OH, which forms [RhII(ttp)]₂ through reductive dimerization. RhII(ttp) radical, which is in equilibrium with [RhII(ttp)]₂, cleaves the Ar-X (X = I, Br, Cl) bond through metalloradical ipso-substitution and gives RhIII(ttp)Ar and X radical. X radical recombines with another RhII(ttp) radical to generate RhIII(ttp)X, which gives back RhIII(ttp)OH through ligand substitution by OH-. [with diagram] / Part II describes the competitive Ar-F and Ar-X (X = Cl, Br) bond cleavage reactions of fluorochlorobenzenes with iridium and rhodium porphyrin complexes. Mechanistic studies suggest that M(por)⁻ is the intermediate for the Ar-F bond cleavage while MII(por) is the intermediate for the Ar-X bond cleavage. By taking advantage of the difference in mechanisms of the Ar-F and Ar-X bond cleavages, the selectivity of bond cleavage can be controlled by varying the reaction conditions. The Ar-F bond cleavage is favored in a polar solvent with a stronger base at lower temperatures with M(por)⁻ precursor, and the Ar-X bond cleavage is favored under non-polar conditions with a weaker base and at higher temperatures. [with diagram] / Part III describes the meta-fluorine substituent effect on strengthening the M-Ar (M = Ir, Rh) bond of M(ttp)ArF. M(ttp)ArF with meta-fluorine substituent are the most stable isomers among the isomeric Ar-H bond cleavage products. At 250 °C for 30 days, the three isomers of Ir(ttp)C₆H₄F reached an equilibrium with o : m : p = 0 : 5 : 1. The theoretical calculations also suggest that Ir(ttp)(3-fluorophenyl) is of lower energy than Ir(ttp)(2-fluorophenyl) and Ir(ttp)(4-fluorophenyl). The ortho-fluorine substituent exhibits steric effect which weakens the M-Ar bond. The meta-fluorine, which is more electron-withdrawing than para-fluorine, enhances the polarity of the M-C(ipso) bond and thus strengthens the M-Ar bond. [with diagram] / Part IV describes the application of Ar-I bond cleavage with Ir(ttp)(CO)Cl in synthesizing iridium porphyrin boron-dipyrromethene (BODIPY) complexes, which are potential photosensitizers for biological imaging and photodynamic therapy. The clinically interested iridium porphyrin BODIPY complexes have been prepared by a radical process of metalloradical with BODIPY. [with diagram] / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Qian, Yingying. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references. / Abstracts also in Chinese.