Ga III triarylcorroles with push–pull substitutions
- Authors: Niu, Yingjie , Wang, Lin , Guo, Yingxin , Zhu, Weihua , Soy, Rodah C , Babu, Balaji , Mack, John , Nyokong, Tebello , Xu, Haijun , Liang, Xu
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300079 , vital:57890 , xlink:href="https://doi.org/10.1039/D2DT01262F"
- Description: Two A2B type H3corroles and two GaIIItriarylcorroles with carbazole substitutions at 10-positions were synthesized and characterized. An analysis of structure–property relationships of the corroles has been carried out by investigating the optical spectroscopy of the dyes to trends predicted in DFT and TD-DFT calculations. Interestingly, the photodynamic therapy (PDT) and photodynamic antimicrobial chemotherapy (PACT) activity properties of the GaIIItriarylcorroles were determined against the MCF-7 breast cancer line, and Staphyloccocus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The cationic G-2Q species exhibited the most favorable properties with an IC50 value of 7.8 μM against MCF-7 cells, and Log reduction values of 7.78 and 3.26 against planktonic S. aureus and E. coli at 0.5 and 10 μM, respectively.
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- Date Issued: 2022
Structural modification of RhIIItriarylcorroles for enhanced electrocatalyzed hydrogen evolution reactions
- Authors: Zhu, Weihua , Li, Lihua , Wang, Yu , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229933 , vital:49724 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.110046"
- Description: A series of A3 type RhIIItriarylcorroles 2a-c with different meso-substituents with differing electron-donating and withdrawing properties and two A2B type RhIIItriarylcorroles 4a-b with meso-methylthiophenyls at the B position have been prepared and characterized. An analysis of structure-property relationships of 2a-c and 4a-b has been carried out by comparing the optical spectroscopy and electrochemistry of the dyes to trends predicted in DFT and TD-DFT calculations. Rational structural modification strategies that enhance the suitability of 2a-c for use as highly efficient catalysts for hydrogen evolution reactions on glassy carbon electrodes coated with 2a-c/reduced graphene oxide composites and of 4a-b in surface-modified Au electrodes are explored.
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- Date Issued: 2022
Modulation of the optical properties of chiral porphyrin dimers by introducing bridged chiral amide-bonds
- Authors: Qin, Mingfeng , Zhang, Zhen , Zhu, Weihua , Mack, John , Soy, Rodah C , Nyokong, Tebello , Liang, Xu
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190815 , vital:45031 , xlink:href="https://doi.org/10.1142/S1088424620500492"
- Description: The d/l-enantiomers of a series of three Zn(II)tetraarylporphyrin dimers were synthesized and isolated by incorporating a bridging amide-bonded xanthene moiety at the para-position of one of the meso-aryl rings. The electronic structures and optical properties were modulated by incorporating chiral amino acid moieties into the amide-bonding moieties of the xanthene bridge that contain methyl, tolyl and 2-methylindole substituents. A cofacial dimer was formed in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) resulting in a significant red shift of the B band, due to a relative destabilization of the HOMO, which has large MO coefficients on the pyrrole nitrogens. The sign sequences observed in the B band region of the CD spectra due to the presence of the chiral amino acid moieties were modified due to this change in geometry. Significant CD intensity is also observed in the B band region of the CD spectra of anion radical species during in situ spectroelectrochemical measurements.
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- Date Issued: 2021
Push-pull type Co (III) corroles
- Authors: Niu, Yingjie , Zhu, Weihua , Mack, John , Dubazana, Nadine , Nyokong, Tebello , Fu, Bo , Xu, Haijun , Liang, Xu
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190826 , vital:45032 , xlink:href="https://doi.org/10.1142/S1088424621500279"
- Description: The rational design and preparation of three A2B type Co(III)triarylcorroles with push- and pull-substituents are reported. The structure-property relationships were identified by comparing their optically spectroscopic and electrochemical properties to trends predicted in DFT and TD-DFT calculations. The results demonstrate that the Co(III)triarylcorroles are highly efficient catalysts for electrocatalyzed hydrogen evolutions (HERs) and oxygen reductions (ORRs), and that their reactivity can be modulated by changing the meso-B-substituent of the Co(III)Corroles.
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- Date Issued: 2021
Chiral Modulation from Molecular to Macroscopic levels by synthetic chiral-amide-bonded porphyrin dimers
- Authors: Liang, Xu , Qin, Mingfeng , Zhang, Xiaomei , Mack, John , Soy, Rodah , Nyokong, Tebello , Zhu, Weihua
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186802 , vital:44535 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.107637"
- Description: Six different nanoarchitectures were constructed by a series of synthetic bio-inspired chiral porphyrin dimers through molecular self-assembly behaviour. A plausible mechanism of chiral expression from the molecular to the macroscopic levels was investigated through an analysis of the optical spectroscopy and theoretical calculations.
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- Date Issued: 2019
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
Synthesis and properties of chiral amide-bonded porphyrin dimers with various functional bridging blocks
- Authors: Zhu, Weihua , Haider, Syed Najeeb-uz-Zaman , Zhang, Honglin , Attatsi, Isaac K , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Song, Yuting , Xu, Haijun , Liang, Xu
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186791 , vital:44534 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.107740"
- Description: Eight porphyrin dimers with various functional bridging blocks and chiral amide-bonds were synthesized and characterized. An analysis of the spectroscopy and electrochemistry has been carried out to demonstrate that the chiral properties can be modified by changing the interchromophoric through-space coupling distance between the two porphyrin chromophores by introducing various bonding and bridging blocks.
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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.
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- 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
Lipophilic M(α,α′-OC5H11)8phthalocyanines (M = H2 and Ni(II)): synthesis, electronic structure, and their utility for highly efficient carbonyl reductions
- Authors: Jiang, Yu , Li, Minzhi , Liang, Xu , Mack, John , Wildervanck, Martijn , Nyokong, Tebello , Qin, Mingfeng , Zhu, Weihua
- Date: 2015-10-07
- Subjects: Dalton Transactions (2015), 44, 18237-18246, doi:10.1039/c5dt03256c
- Language: English
- Type: Article
- Identifier: vital:7282 , http://hdl.handle.net/10962/d1020322
- Description: A lipophilic and electron-rich phthalocyanine (α,α′-n-OC5H11)8-H2Pc and its nickel(II) complex (α,α′-n-OC5H11)8-Ni(II)Pc have been synthesized and characterized. Detailed analyses of the electronic structure were carried out by spectroscopy, electrochemistry, spectroelectrochemistry, and TD-DFT calculations. A series of experiments demonstrate that the (α,α′-n-OC5H11)8-Ni(II)Pc complex can be used as a catalyst for highly efficient carbonyl reductions. , Original publication is available at http://dx.doi.org/10.1039/C5DT03256C
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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