Co (ii) Tetraphenyltetraphenanthroporphyrin@ MWCNTs
- Authors: Gu, Tingting , Tao, Jaiyu , Zhu, Weihua , Mack, John , Soy, Rodah C , Nyokong, Tebello , Xu, Haijin , Li, Minzhi , Liang, Xu
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234580 , vital:50210 , xlink:href="https://doi.org/10.1039/C9NJ01707K"
- Description: Herein, a cobalt(II)tetraphenyltetraphenanthroporphyrin (Co(II)TPTPP) with phenanthrene-fused pyrrole rings was synthesized and characterized. Moreover, a detailed analysis of its optical and redox properties was carried out by comparing the results obtained via optical spectroscopy and electrochemistry with the trends predicted via a series of DFT and TD-DFT calculations. The electrochemistry results demonstrated that the π-expanded Co(II)TPTPP interacted strongly with multiwall carbon nanotubes (MWCNTs), which were finally immobilized on carbon nanotubes via noncovalent interactions and further deposited on glassy carbon. This strong immobilization via π–π stacking between Co(II)TPTPP and MWCNTs leads to significantly stable electrochemically catalyzed hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), which provides a new insight into the understanding electron transfer channels.
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- Date Issued: 2019
Core-modified rubyrins with phenanthrene-fused pyrrole rings
- Authors: Yuan, Xuemei , Li, Minzhi , Meng, Ting , Mack, John , Soy, Rodah , Nyokong, Tebello , Zhu, Weihua , Xu, Haijun , Liang, Xu
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234568 , vital:50209 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.05.045"
- Description: Three fused-ring-expanded rubyrins with modified macrocyclic core have been synthesized and characterized. A series of spectroscopic, electrochemical measurements and a set of theoretical calculations demonstrate that the core-modification of the inner core of rubyrins has a large influence on the electronic structure. Colorimetric changes are observe that demonstrate that these core-modified rubyrins could be used as selective Hg2+ ion sensors. These properties can be fine-tuned by introducing lipophilic substituents on the meso-aryl rings.
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- Date Issued: 2018
Iron (iii) porphyrin electrocatalyzed enantioselective carbon-chloride bond cleavage of hexachlorocyclohexanes (HCHs): combined experimental investigation and theoretical calculations
- Authors: Liang, Xu , Li, Minzhi , Mack, John , Lobb, Kevin A , Zhu, Weihua
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447979 , vital:74688 , xlink:href="https://pubs.rsc.org/en/content/articlehtml/2018/dt/c8dt02510j"
- Description: Enantioselective electrocatalysis of α-, β-, γ- and δ-hexachlorocyclohexanes (HCHs) by tetrakis-pentafluorophenyl-Fe(III)porphyrin is described. The first example of the combined use of electrochemical measurements and theoretical calculations to determine the mechanism of the enantioselective C–Cl bond cleavage of the electrocatalysis is reported. The electrochemical measurements demonstrate that the reactivity of the HCHs follows the order γ-HCH > α-HCH > δ-HCH > β-HCH. Steric considerations and a molecular orbital theory approach can be used to rationalize the enantioselective nature of the catalysis based on the ease of approach of each Cl atom to the central Fe(I) ion and a consideration of the nodes on the C–Cl bonds that weaken these bonds in a manner that results in bond cleavage and the formation of an Fe–Cl bond.
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- Date Issued: 2018
Porphyrin dimers with a bridging chiral amide-bonded benzo-moiety
- Authors: Liang, Xu , Qin, Mingfeng , Zhou, Lin , Liu, Tingting , Li, Minzhi , Mack, John , Ndebele, Nobuhle , Nyokong, Tebello , Zhu, Weihua
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233433 , vital:50090 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.02.043"
- Description: The facile synthesis and characterization of four porphyrin dimers which introduced stereomeric centers with chiral amide-bonded para- and meta-disubstituted benzo-moiety is reported. Trends in the electronic structures and optical and redox properties are analyzed through a comparison with theoretical calculations to explore the effect of positional isomerism of the bridging benzene rings.
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- Date Issued: 2018
A2B type copper (III) corroles containing zero-to-five fluorine atoms
- Authors: Li, Minzhi , Niu, Yingjie , Zhu, Weihua , Mack, John , Fomo, Gertrude , Nyokong, Tebello , Liang, Xu
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/238275 , vital:50604 , xlink:href="https://doi.org/10.1016/j.dyepig.2016.10.044"
- Description: Four low symmetric A2B meso-substituted Cu(III)corroles with electron withdrawing meso-aryl rings have been synthesized and characterized. A detailed analysis of the optical and redox properties has been carried out by comparing their optical spectroscopy, electrochemistry and spectroelectrochemistry to a series of DFT and TD-DFT calculations. A series of experiments demonstrate that these Cu(III)corroles can be used as highly effective catalysts for hydrogen evolution reactions (HERs). Moreover, when the number of fluorine atoms at B meso-position is increased, there is a marked enhancement in the catalytic ability of the corrole complexes, which demonstrates that modification to the structures of low symmetry corroles is a useful strategy for developing new HER catalysts.
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- Date Issued: 2017
Cu (III) triarylcorroles with asymmetric push–pull meso-substitutions
- Authors: Liang, Xu , Niu, Yingjie , Zhang, Ojanchong , Mack, John , Yi, Xiaoyi , Hlatshwayo, Zweli , Li, Minzhi , Zhu, Weihua , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232947 , vital:50040 , xlink:href="https://doi.org/10.1039/C7DT00716G"
- Description: The synthesis of four low symmetry A2B type Cu (III)triarylcorroles with meso-aryl substituents that provide electron donating (push) and withdrawing (pull) properties is reported, along with their structural characterization by NMR spectroscopy and X-ray crystallography. An analysis of the structure–property relationships in the optical and redox properties has been carried out by comparing their optical spectroscopy, electrochemistry, and spectroelectrochemistry to trends predicted in DFT and TD-DFT calculations. The results demonstrate that A2B type Cu(III)triarylcorroles are highly efficient catalysts for electrocatalyzed hydrogen evolution reactions (HERs) and that their reactivity can be modulated by changing the nature of the B-position meso-substituent.
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- Date Issued: 2017
Enantioselective electrochemical carbon-chloride bond cleavage of hexachlorocyclohexanes (HCHs) catalyzed by Mn (III) Cl-phthalocyanine
- Authors: Wen, Junxia , Yu, Baoqui , Huang, Tingting , Mack, John , Wildervanck, Martijn , Nyokong, Tebello , Li, Minzhi , Zhu, Weihua , Liang, Xu
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189252 , vital:44831 , xlink:href="https://doi.org/10.1016/j.jelechem.2017.09.020"
- Description: A lipophilic and electron-rich metallophthalocyanine Mn(III)Cl(α,α′-n-OC5H11)8Pc has been synthesized and characterized. A series of electrochemical experiments demonstrate that the Mn(III)Cl(α,α′-n-OC5H11)8Pc complex can be used as a catalyst for highly efficient carbon-chloride bond cleavage of environmental toxic hexachlorocyclohexanes (HCHs) through electrochemical catalysis, and that the increased catalytic efficiency is related to the enantiomeric carbon-chloride σ-bond of HCHs.
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- Date Issued: 2017
Flexible Metal–Porphyrin Dimers (M= MnIIICl, CoII, NiII, CuII)
- Authors: Li, Minzhi , Zhang, Qian , Xu, Li , Zhu, Weihua , Mack, John , May, Aviwe K , Nyokong, Tebello , Kobayashi, Nagao , Liang, Xu
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239676 , vital:50754 , xlink:href="https://doi.org/10.1002/cplu.201600475"
- Description: Four metalloporphyrin dimers linked by bridging amide-bonded xanthene moieties and that contain either MnIII, CoII, NiII, or CuII metal centers were synthesized. Various spectroscopic, electrochemical, and spectroelectrochemical methods were used to study trends in their properties. Their electronic structure and optical properties were analyzed through a comparison of the electronic absorption and magnetic circular dichroism (MCD) spectral data with the results of time-dependent (TD)-DFT calculations.
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- Date Issued: 2017
Halogen substituted A2B type Co (III) triarylcorroles
- Authors: Niu, Yingjie , Li, Minzhi , Zhang, Qianchong , Zhu, Weihua , Mack, John , Fomo, Gertrude , Nyokong, Tebello , Liang, Xu
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233048 , vital:50051 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.02.049"
- Description: Seven low symmetry A2B type Co(III)triarylcorroles with electron withdrawing meso-aryl substituents have been synthesized and characterized. A detailed analysis of the optical and redox properties has been carried out by comparing their optical spectroscopy, electrochemistry and spectroelectrochemistry to trends predicted in a series of DFT and TD-DFT calculations. The results demonstrate that Co(III)corroles are highly effective catalysts for hydrogen evolution reactions (HERs). Moreover, there is a marked enhancement in their homogenous catalytic ability when halogen atoms are introduced at the B position, which demonstrates that facile modifying the meso-aryl rings is a effective strategy for developing new HER catalysts. The electrochemical results demonstrate that an unusual two step modulation of HER reactions can be achieved by using singly and doubly electrochemical reduced cobalt triarylcorroles anions.
- Full Text:
- Date Issued: 2017
Highly efficient CCl bond cleavage and unprecedented CC bond cleavage of environmentally toxic DDT through molecular electrochemical catalysis
- Authors: Liang, Xu , Huang, Tingting , Li, Minzhi , Mack, John , Wildervanck, Martijn , Nyokong, Tebello , Zhu, Weihua
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188921 , vital:44798 , xlink:href="https://doi.org/10.1016/j.apcata.2017.07.026"
- Description: The electrocatalytic properties of a Co(II)octaalkoxyphthalocyanine complex (Co(II)Pc) with eight strongly electron-donating substituents provide the first example of the complete dechlorination of DDT through molecular electrocatalysis, rather than the use of metal electrodes which had been achieved previously. Interaction with a highly nucleophilic [Co(I)Pc]2− species results in rapid cleavage of the C(sp3) Cl, C(sp2) Cl and aromatic C(sp2) Cl bonds. Bis(p-chlorophenyl)methanone (BPCl2) is detected in high yield along with its full dechlorination product, diphenylmethanone (BP) and the conventional C Cl bond cleavage products, due to an unprecedented C C bond cleavage reaction that is followed by the formation of a C−O bond. Theoretical calculations are used to analyze trends in the electronic structure of the Co(II)octaalkoxyphthalocyanine complex that account for the efficiency of the C Cl bond cleavage reactions, and the reaction process and mechanism are analyzed in depth.
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- Date Issued: 2017
Push–pull type manganese (III) corroles
- Authors: Liang, Xu , Fang, Junjia , Li, Minzhi , Chen, Qiuyun , Mack, John , Molupe, Nthabeleng , Nyokong, Tebello , Zhu, Weihua
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189201 , vital:44826 , xlink:href="https://doi.org/10.1142/S1088424617500778"
- Description: The synthesis of three low symmetry A2B type Mn(III)triarylcorroles with meso-aryl substituents that provide push–pull electron-donating and -withdrawing properties is reported. An analysis of the structure-property relationships for the optical and redox properties has been carried out through a comparison with the results of theoretical calculations. The results demonstrate that A2B type Mn(III)triarylcorroles interact strongly with cell-free circulating tumor deoxyribonucleic acid (ctDNA) in solution, and that the interaction constants are enhanced when a stronger electron-donating substituent is introduced at the 10-position of the meso-triarylcorrole ligand.
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- Date Issued: 2017
Spectroscopic investigations and theoretical calculations of DABCO induced xanthene bridged self-assembled zinc (II) porphyrin dimer
- Authors: Xu, Li , Huang, Tingting , Liang, Xu , Mack, John , Harris, Jessica , Nyokong, Tebello , Li, Minzhi , Zhu, Weihua
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240732 , vital:50866 , xlink:href="https://doi.org/10.1142/S1088424616500231"
- Description: An in-depth study of the electronic structure of a 1,4-diazabicyclo[2.2.2]octane (DABCO) induced molecular self-assembled xanthene-bridged and amide-bonded porphyrin dimer is reported. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations are used to identify trends in the optical spectroscopic properties. B3LYP geometry optimization predicts the formation of an almost perfectly eclipsed structure with respect to the two porphyrin rings with the analogous pyrrole nitrogens separated by 7.7–8.1 Å. The observed distinctive derivative-shaped band morphology of the pseudo-Faraday-A11 terms in the MCD spectra has been used to identify the main electronic Q and B-bands and to validate the TD-DFT calculations. The absence of a discernible splitting of the redox steps or a quenching of the fluorescence demonstrates that there is no significant exciton coupling between the two porphyrin rings.
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- Date Issued: 2016
Facile synthesis, spectroscopic and electrochemical properties, and theoretical calculations of porphyrin dimers with a bridging amide-bonded xanthene moiety
- Authors: Liang, Xu , Xu, Li , Li, Minzhi , Mack, John , Stone, Justin , Nyokong, Tebello , Jiang, Yu , Kobayashi, Nagao , Zhu, Weihua
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241390 , vital:50935 , xlink:href="https://doi.org/10.1142/S1088424615500492"
- Description: A free base porphyrin dimer bridged by a flexible amide-bonded xanthene moiety and its binuclear zinc(II) complex zinc(II) complex were synthesized and characterized. Structural characterization by MS and 1H NMR spectroscopy confirmed the bridged porphyrin dimer structure. The properties of the dimers were characterized by IR, UV-visible absorption, fluorescence and magnetic circular dichroism (MCD) spectroscopy, and electrochemistry studies. Theoretical calculations were carried out to analyze the electronic structures of porphyrin dimers with a bridging amide-bonded xanthene moiety.
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- Date Issued: 2015