Effects of pyrene on the photophysical and two-photon absorption-based nonlinear optical properties of indium(III) phthalocyanines
- Sanusi, Kayode, Nyokong, Tebello
- Authors: Sanusi, Kayode , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7314 , http://hdl.handle.net/10962/d1020540
- Description: Photophysical and two-photon-dependent nonlinear absorption properties of two chloroindium(III) phthalocyanines bearing pyrene units have been investigated. The tetra- (3) and the tri- (4) pyrene-substituted phthalocyanines exhibit strong triplet absorption with high triplet yields () of 0.79 and 0.83, respectively. The measured nonlinear optical data, such as the two photon absorption cross-sections, the third- and second-order nonlinearities were found to be comparable with those of literature, thus, making the compounds promising candidates for a broad range of nonlinear optical applications. , Original publication is available at http://dx.doi.org/10.1080/00958972.2014.959509
- Full Text: false
- Date Issued: 2014
- Authors: Sanusi, Kayode , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7314 , http://hdl.handle.net/10962/d1020540
- Description: Photophysical and two-photon-dependent nonlinear absorption properties of two chloroindium(III) phthalocyanines bearing pyrene units have been investigated. The tetra- (3) and the tri- (4) pyrene-substituted phthalocyanines exhibit strong triplet absorption with high triplet yields () of 0.79 and 0.83, respectively. The measured nonlinear optical data, such as the two photon absorption cross-sections, the third- and second-order nonlinearities were found to be comparable with those of literature, thus, making the compounds promising candidates for a broad range of nonlinear optical applications. , Original publication is available at http://dx.doi.org/10.1080/00958972.2014.959509
- Full Text: false
- Date Issued: 2014
Optical nonlinearities in non-peripherally substituted pyridyloxy phthalocyanines: a combined effect of symmetry, ring-strain and demetallation
- Sanusi, Kayode, Antunes, Edith M, Nyokong, Tebello
- Authors: Sanusi, Kayode , Antunes, Edith M , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7301 , http://hdl.handle.net/10962/d1020375
- Description: The optical nonlinearities of six non-peripherally-substituted pyridyloxy phthalocyanines have been studied at 532 nm using a nanosecond Z-scan technique in a dimethyl sulphoxide solution. Ring-strain effects and the absence of a metal center were found to greatly reduce the inherent high nonlinearities expected of some of these phthalocyanine complexes. Of the six molecules investigated, 1(4),8(11),15(18),22(25)-tetrakis-(2-pyridyloxy)phthalocyaninato lead(II) 3, 1(4),8(11),15(18),22(25)-tetrakis-(2-pyridyloxy)phthalocyanine 5, and 1(4),8(11),15(18),22(25)-tetrakis-(4-pyridyloxy)phthalocyanine 6 were found to exhibit negligible nonlinear optical behavior, due to either the absence of asymmetry or central metal and/or the presence of a ring-strain effect. A two-photon absorption process was found to be the major contributor to the observed reverse saturable absorption (RSA) in 1(4),8(11),15(18),22(25)-tetrakis-(4-pyridyloxy)phthalocyaninato lead(II) 4, 1(4)-mono-(2-pyridyloxy)phthalocyaninato lead(II) 7, and 1(4)-mono-(4-pyridyloxy)phthalocyaninato lead(II) 8, with large two-photon absorption cross-section, high hyperpolarizability and high third-order susceptibility values in the range of 4.53 × 10−43–5.33 × 10−42 cm4 s per photon, 1.61 × 10−28–1.89 × 10−27 esu and 9.73 × 10−12–7.05 × 10−11 esu respectively. , Original publication is available at http://dx.doi.org/10.1039/C3DT52462K , Arbortext Advanced Print Publisher 9.1.520/W Unicode , Acrobat Distiller 10.0.0 (Windows); modified using iText� 5.3.3 �2000-2012 1T3XT BVBA (AGPL-version)
- Full Text:
- Authors: Sanusi, Kayode , Antunes, Edith M , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7301 , http://hdl.handle.net/10962/d1020375
- Description: The optical nonlinearities of six non-peripherally-substituted pyridyloxy phthalocyanines have been studied at 532 nm using a nanosecond Z-scan technique in a dimethyl sulphoxide solution. Ring-strain effects and the absence of a metal center were found to greatly reduce the inherent high nonlinearities expected of some of these phthalocyanine complexes. Of the six molecules investigated, 1(4),8(11),15(18),22(25)-tetrakis-(2-pyridyloxy)phthalocyaninato lead(II) 3, 1(4),8(11),15(18),22(25)-tetrakis-(2-pyridyloxy)phthalocyanine 5, and 1(4),8(11),15(18),22(25)-tetrakis-(4-pyridyloxy)phthalocyanine 6 were found to exhibit negligible nonlinear optical behavior, due to either the absence of asymmetry or central metal and/or the presence of a ring-strain effect. A two-photon absorption process was found to be the major contributor to the observed reverse saturable absorption (RSA) in 1(4),8(11),15(18),22(25)-tetrakis-(4-pyridyloxy)phthalocyaninato lead(II) 4, 1(4)-mono-(2-pyridyloxy)phthalocyaninato lead(II) 7, and 1(4)-mono-(4-pyridyloxy)phthalocyaninato lead(II) 8, with large two-photon absorption cross-section, high hyperpolarizability and high third-order susceptibility values in the range of 4.53 × 10−43–5.33 × 10−42 cm4 s per photon, 1.61 × 10−28–1.89 × 10−27 esu and 9.73 × 10−12–7.05 × 10−11 esu respectively. , Original publication is available at http://dx.doi.org/10.1039/C3DT52462K , Arbortext Advanced Print Publisher 9.1.520/W Unicode , Acrobat Distiller 10.0.0 (Windows); modified using iText� 5.3.3 �2000-2012 1T3XT BVBA (AGPL-version)
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Nonlinear optical behaviour of indium-phthalocyanine tethered to magnetite or silica nanoparticles
- Sanusi, Kayode, Stone, Justin M., Nyokong, Tebello
- Authors: Sanusi, Kayode , Stone, Justin M. , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7259 , http://hdl.handle.net/10962/d1020268
- Description: Nonlinear absorption and optical limiting properties of indium phthalocyanine (complex 1) tethered to magnetite (SiMNP-1) or silica (SiNP-1) nanoparticles have been investigated using 10 ns pulses at 532 nm laser excitation. The optical limiting behaviours of the nanocomposites and the bare phthalocyanine are compared. Investigation of the triplet state dynamics revealed highly efficient triplet state absorption in the SiMNP-1 dyad. A large nonlinear absorption (βeff) that increased with decrease in the peak input fluence was observed for SiMNP-1. The SiNP-1 composite showed a slight increase in βeff with decreasing peak input fluence. The nonlinear optical data obtained for the SiNP-1 are within the same range of those of the indium phthalocyanine alone. The nanosecond nonlinear absorption and the optical limiting of the nanocomposites are shown to be dominated by a strong excited state absorption from a two-photon pumped state. Nonlinear scattering effects and strong excited state absorption from a two-photon pumped state account for the enhanced optical limiting behaviour of SiMNP-1 relative to the phthalocyanine alone. , Original publication is available at http://dx.doi.org/10.1039/C4NJ01619J
- Full Text: false
- Authors: Sanusi, Kayode , Stone, Justin M. , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7259 , http://hdl.handle.net/10962/d1020268
- Description: Nonlinear absorption and optical limiting properties of indium phthalocyanine (complex 1) tethered to magnetite (SiMNP-1) or silica (SiNP-1) nanoparticles have been investigated using 10 ns pulses at 532 nm laser excitation. The optical limiting behaviours of the nanocomposites and the bare phthalocyanine are compared. Investigation of the triplet state dynamics revealed highly efficient triplet state absorption in the SiMNP-1 dyad. A large nonlinear absorption (βeff) that increased with decrease in the peak input fluence was observed for SiMNP-1. The SiNP-1 composite showed a slight increase in βeff with decreasing peak input fluence. The nonlinear optical data obtained for the SiNP-1 are within the same range of those of the indium phthalocyanine alone. The nanosecond nonlinear absorption and the optical limiting of the nanocomposites are shown to be dominated by a strong excited state absorption from a two-photon pumped state. Nonlinear scattering effects and strong excited state absorption from a two-photon pumped state account for the enhanced optical limiting behaviour of SiMNP-1 relative to the phthalocyanine alone. , Original publication is available at http://dx.doi.org/10.1039/C4NJ01619J
- Full Text: false
Electrocatalysis of oxidation of 2-mercaptoethanol, L-cysteine and reduced glutathione by adsorbed and electrodeposited cobalt tetra phenoxypyrrole and tetra ethoxythiophene substituted phthalocyanines
- Sehlotho, Nthapo, Nyokong, Tebello, Zagal, Jose H, Bedioui, Fethi
- Authors: Sehlotho, Nthapo , Nyokong, Tebello , Zagal, Jose H , Bedioui, Fethi
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6593 , http://hdl.handle.net/10962/d1004342
- Description: Catalytic activity of cobalt tetra ethoxythiophene and cobalt tetra phenoxypyrrole phthalocyanine complexes towards oxidation of 2-mercaptoethanol, L-cysteine and reduced glutathione is reported. It was found that the activity of the complexes depends on the substitution of the phthalocyanine ring, pH, film thickness and method of electrode modification. The high electrocatalytic activity obtained with adsorbed complexes in alkaline medium clearly demonstrates the necessity of modifying bare carbon electrodes to endow them with the desired behaviour.
- Full Text:
- Date Issued: 2006
- Authors: Sehlotho, Nthapo , Nyokong, Tebello , Zagal, Jose H , Bedioui, Fethi
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6593 , http://hdl.handle.net/10962/d1004342
- Description: Catalytic activity of cobalt tetra ethoxythiophene and cobalt tetra phenoxypyrrole phthalocyanine complexes towards oxidation of 2-mercaptoethanol, L-cysteine and reduced glutathione is reported. It was found that the activity of the complexes depends on the substitution of the phthalocyanine ring, pH, film thickness and method of electrode modification. The high electrocatalytic activity obtained with adsorbed complexes in alkaline medium clearly demonstrates the necessity of modifying bare carbon electrodes to endow them with the desired behaviour.
- Full Text:
- Date Issued: 2006
The synthesis and electrochemical behaviour of water soluble manganese phthalocyanines: Anion radical versus Mn(I) species
- Sehlotho, Nthapo, Durmuş, M, Ahsen, N, Nyokong, Tebello
- Authors: Sehlotho, Nthapo , Durmuş, M , Ahsen, N , Nyokong, Tebello
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6596 , http://hdl.handle.net/10962/d1004345
- Description: The following MnPc derivatives were synthesized: 1,(4)-tetra-(2-mercaptopyridine) phthalocyaninato manganese(III)(OH) (5a), quaternized 1,(4)-tetra-(2-mercaptopyridine) phthalocyaninato manganese(III)(OH) (5b), 2,(3)-tetra-(2-mercaptopyridine) phthalocyaninato manganese(III)(OH) (6a) and quaternized 2,(3)-tetra-(2-mercaptopyridine) phthalocyaninato manganese(III)(OH)(6b). Spectro-electrochemistry shows that the reduction of Mn(II)Pc to Mn(I)Pc occurs only when the complexes are in their quaternized form (5b and 6b). The reduction (to Mn(I)Pc(−2)) of the quaternized form occurs at a lower potential than that (to Mn(II)Pc(−3)) of the unquaternized form. This observation suggests that metal reduction (to Mn(I)Pc(−2)) versus ligand reduction (to Mn(II)Pc(−3)) in Mn(II)Pc complexes depends on the nature of the ring substituents.
- Full Text:
- Date Issued: 2008
- Authors: Sehlotho, Nthapo , Durmuş, M , Ahsen, N , Nyokong, Tebello
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6596 , http://hdl.handle.net/10962/d1004345
- Description: The following MnPc derivatives were synthesized: 1,(4)-tetra-(2-mercaptopyridine) phthalocyaninato manganese(III)(OH) (5a), quaternized 1,(4)-tetra-(2-mercaptopyridine) phthalocyaninato manganese(III)(OH) (5b), 2,(3)-tetra-(2-mercaptopyridine) phthalocyaninato manganese(III)(OH) (6a) and quaternized 2,(3)-tetra-(2-mercaptopyridine) phthalocyaninato manganese(III)(OH)(6b). Spectro-electrochemistry shows that the reduction of Mn(II)Pc to Mn(I)Pc occurs only when the complexes are in their quaternized form (5b and 6b). The reduction (to Mn(I)Pc(−2)) of the quaternized form occurs at a lower potential than that (to Mn(II)Pc(−3)) of the unquaternized form. This observation suggests that metal reduction (to Mn(I)Pc(−2)) versus ligand reduction (to Mn(II)Pc(−3)) in Mn(II)Pc complexes depends on the nature of the ring substituents.
- Full Text:
- Date Issued: 2008
Effects of ring substituents on electrocatalytic activity of manganese phthalocyanines towards the reduction of molecular oxygen
- Sehlotho, Nthapo, Nyokong, Tebello
- Authors: Sehlotho, Nthapo , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6594 , http://hdl.handle.net/10962/d1004343
- Description: Reduction of oxygen electrocatalyzed by adsorbed films of manganese phthalocyanine complexes is reported. The complexes studied were: manganese phthalocyanine (MnPc, 1); manganese tetraamino phthalocyanine (MnTAPc, 2); manganese tetrapentoxy pyrrole phthalocyanine (MnTPePyrPc, 3); manganese tetra phenoxy pyrrole phthalocyanine (MnTPPyrPc, 4); manganese tetra mercaptopyrimidine phthalocyanine (MnTMPyPc, 5) and manganese tetra ethoxy thiophene phthalocyanine (MnTETPc, 6). The reaction was conducted in buffer solutions of pH range 1–12. Rotating disk electrode voltammetry revealed two electron reduction in acidic and slightly alkaline media due to the formation of hydrogen peroxide. In highly basic media, water is the major product formed via four electron transfer. The reaction was found to be first order in the diffusing analyte oxygen.
- Full Text:
- Date Issued: 2006
- Authors: Sehlotho, Nthapo , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6594 , http://hdl.handle.net/10962/d1004343
- Description: Reduction of oxygen electrocatalyzed by adsorbed films of manganese phthalocyanine complexes is reported. The complexes studied were: manganese phthalocyanine (MnPc, 1); manganese tetraamino phthalocyanine (MnTAPc, 2); manganese tetrapentoxy pyrrole phthalocyanine (MnTPePyrPc, 3); manganese tetra phenoxy pyrrole phthalocyanine (MnTPPyrPc, 4); manganese tetra mercaptopyrimidine phthalocyanine (MnTMPyPc, 5) and manganese tetra ethoxy thiophene phthalocyanine (MnTETPc, 6). The reaction was conducted in buffer solutions of pH range 1–12. Rotating disk electrode voltammetry revealed two electron reduction in acidic and slightly alkaline media due to the formation of hydrogen peroxide. In highly basic media, water is the major product formed via four electron transfer. The reaction was found to be first order in the diffusing analyte oxygen.
- Full Text:
- Date Issued: 2006
Synthesis, photophysical and nonlinear optical behavior of neodymium based trisphthalocyanine
- Sekhosana, Kutloano E, Amuhaya, Edith K, Khene, M Samson, Nyokong, Tebello
- Authors: Sekhosana, Kutloano E , Amuhaya, Edith K , Khene, M Samson , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7243 , http://hdl.handle.net/10962/d1020247
- Description: Tris-{1(4),8(11),15(18),22(25)-tetra(4-tertbutylphenoxy) phthalocyaninato} dineodymium (III) was synthesised and its nonlinear optical and fluorescence behavior was studied. Low fluorescence quantum yield (ФF = 0.03) was obtained with a fluorescence lifetime τF = 4.31 ns for this complex. Nonlinear optical parameters for the complex were determined using the Z-scan technique and the values of Im[χ(3)] and γ were of the order of 10−10 and 10−28 esu, respectively. Square wave voltammetry revealed three reduction and two oxidation couples for the complex. , Original publication is available at http://dx.doi.org/10.1016/j.ica.2014.11.029
- Full Text: false
- Authors: Sekhosana, Kutloano E , Amuhaya, Edith K , Khene, M Samson , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7243 , http://hdl.handle.net/10962/d1020247
- Description: Tris-{1(4),8(11),15(18),22(25)-tetra(4-tertbutylphenoxy) phthalocyaninato} dineodymium (III) was synthesised and its nonlinear optical and fluorescence behavior was studied. Low fluorescence quantum yield (ФF = 0.03) was obtained with a fluorescence lifetime τF = 4.31 ns for this complex. Nonlinear optical parameters for the complex were determined using the Z-scan technique and the values of Im[χ(3)] and γ were of the order of 10−10 and 10−28 esu, respectively. Square wave voltammetry revealed three reduction and two oxidation couples for the complex. , Original publication is available at http://dx.doi.org/10.1016/j.ica.2014.11.029
- Full Text: false
Nanosecond nonlinear optical limiting properties of new trinuclear lanthanide phthalocyanines in solution and as thin films
- Sekhosana, Kutloano Edward, Amuhaya, Edith, Nyokong, Tebello
- Authors: Sekhosana, Kutloano Edward , Amuhaya, Edith , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7267 , http://hdl.handle.net/10962/d1020276
- Description: 2,4,6-Tris[3-thio-9,10,16,17,23,24-hexa(4-tertbutylphenoxy) phthalocyaninato ytterbium (III) chloride]-s-triazin (3) and its lutetium counterpart (4) were synthesized. The nonlinear optical behavior of 3 and 4 were characterized in solution and when embedded in polymer as thin films. Thin films of complexes 3 and 4 in poly(bisphenol A carbonate) showed improved nonlinear optical properties when compared to solution. Complex 3 showed a lower threshold for optical limiting intensity (Ilim) than complex 4, and for phthalocyanines in general. Ilim values were even lower in films compared to solutions. , Original publication is available at http://dx.doi.org/10.1016/j.poly.2014.08.047
- Full Text: false
- Authors: Sekhosana, Kutloano Edward , Amuhaya, Edith , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7267 , http://hdl.handle.net/10962/d1020276
- Description: 2,4,6-Tris[3-thio-9,10,16,17,23,24-hexa(4-tertbutylphenoxy) phthalocyaninato ytterbium (III) chloride]-s-triazin (3) and its lutetium counterpart (4) were synthesized. The nonlinear optical behavior of 3 and 4 were characterized in solution and when embedded in polymer as thin films. Thin films of complexes 3 and 4 in poly(bisphenol A carbonate) showed improved nonlinear optical properties when compared to solution. Complex 3 showed a lower threshold for optical limiting intensity (Ilim) than complex 4, and for phthalocyanines in general. Ilim values were even lower in films compared to solutions. , Original publication is available at http://dx.doi.org/10.1016/j.poly.2014.08.047
- Full Text: false
The nonlinear absorption in new lanthanide double decker pyridine-based phthalocyanines in solution and thin films
- Sekhosana, Kutloano Edward, Nyokong, Tebello
- Authors: Sekhosana, Kutloano Edward , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7299 , http://hdl.handle.net/10962/d1020366
- Description: The optical behavior of bis-{2(3), 9(10), 16(17), 23(24)-(tetrapyridin-4-yloxy phthalocyaninato)} lanthanum (III) (2) and its ytterbium (3) counterpart in dimethyl sulfoxide are presented and compared to bis-{1(4), 8(11), 15(18), 22(25)-(tetrapyridin-4-yloxy phthalocyaninato)} ytterbium (III) (4). We report on the third-order susceptibility, second-order hyperpolarizability and the limiting threshold values. The nonlinear optical limiting threshold values of complexes 2, 3 and 4 showed improvement in the solid state (thin films), with complex 4 giving the best value at 0.033 J cm−2. , Original publication is available at http://dx.doi.org/10.1016/j.optmat.2015.05.022
- Full Text: false
- Authors: Sekhosana, Kutloano Edward , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7299 , http://hdl.handle.net/10962/d1020366
- Description: The optical behavior of bis-{2(3), 9(10), 16(17), 23(24)-(tetrapyridin-4-yloxy phthalocyaninato)} lanthanum (III) (2) and its ytterbium (3) counterpart in dimethyl sulfoxide are presented and compared to bis-{1(4), 8(11), 15(18), 22(25)-(tetrapyridin-4-yloxy phthalocyaninato)} ytterbium (III) (4). We report on the third-order susceptibility, second-order hyperpolarizability and the limiting threshold values. The nonlinear optical limiting threshold values of complexes 2, 3 and 4 showed improvement in the solid state (thin films), with complex 4 giving the best value at 0.033 J cm−2. , Original publication is available at http://dx.doi.org/10.1016/j.optmat.2015.05.022
- Full Text: false
Optical nonlinearities and photophysicochemical behaviour of green and blue forms of lutetium bisphthalocyanines
- Sekhosana, Kutloano Edward, Amuhaya, Edith, Mack, John, Nyokong, Tebello
- Authors: Sekhosana, Kutloano Edward , Amuhaya, Edith , Mack, John , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7316 , http://hdl.handle.net/10962/d1020543
- Description: A rare earth sandwich-type phthalocyanine: bis-{2,3,9,10,16,17,23,24-octa(4-tert-butylphenoxy) phthalocyaninato} lutetium(III) has been synthesized. The photophysical and nonlinear optical behavior of both the “green” and “blue” forms ([LuIIIPc2] and [LuIIIPc2]−, respectively) of the complex have been investigated. High triplet state and singlet oxygen quantum yield values were obtained for the neutral blue form which contains no unpaired electrons. Relatively high third order susceptibility and hyperpolarizability values of the order of 10−10 and 10−28 esu were obtained for both the green and blue forms, respectively. A very low threshold intensity of 0.00051 J cm−2 was obtained for the blue form. Hence the complex shows promise for non-linear optical applications. , Original publication is available at http://dx.doi.org/10.1039/C4TC00505H
- Full Text:
- Authors: Sekhosana, Kutloano Edward , Amuhaya, Edith , Mack, John , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7316 , http://hdl.handle.net/10962/d1020543
- Description: A rare earth sandwich-type phthalocyanine: bis-{2,3,9,10,16,17,23,24-octa(4-tert-butylphenoxy) phthalocyaninato} lutetium(III) has been synthesized. The photophysical and nonlinear optical behavior of both the “green” and “blue” forms ([LuIIIPc2] and [LuIIIPc2]−, respectively) of the complex have been investigated. High triplet state and singlet oxygen quantum yield values were obtained for the neutral blue form which contains no unpaired electrons. Relatively high third order susceptibility and hyperpolarizability values of the order of 10−10 and 10−28 esu were obtained for both the green and blue forms, respectively. A very low threshold intensity of 0.00051 J cm−2 was obtained for the blue form. Hence the complex shows promise for non-linear optical applications. , Original publication is available at http://dx.doi.org/10.1039/C4TC00505H
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Like a bolt from the blue : phthalocyanines in biomedical optics
- Sekkat, N, Van den Berg, H, Nyokong, Tebello, Lange, N
- Authors: Sekkat, N , Van den Berg, H , Nyokong, Tebello , Lange, N
- Date: 2012
- Subjects: Biomedical optics Fluorescence diagnosis Phthalocyanines NIR dyes Photodynamic therapy
- Language: English
- Type: Article
- Identifier: vital:6597 , http://hdl.handle.net/10962/d1004346 , http://dx.doi.org/10.3390/molecules17010098
- Description: The purpose of this review is to compile preclinical and clinical results on phthalocyanines (Pcs) as photosensitizers (PS) for Photodynamic Therapy (PDT) and contrast agents for fluorescence imaging. Indeed, Pcs are excellent candidates in these fields due to their strong absorbance in the NIR region and high chemical and photo-stability. In particular, this is mostly relevant for their in vivo activation in deeper tissular regions. However, most Pcs present two major limitations, i.e., a strong tendency to aggregate and a low water-solubility. In order to overcome these issues, both chemical tuning and pharmaceutical formulation combined with tumor targeting strategies were applied. These aspects will be developed in this review for the most extensively studied Pcs during the last 25 years, i.e., aluminium-, zinc- and silicon-based Pcs.
- Full Text:
- Date Issued: 2012
- Authors: Sekkat, N , Van den Berg, H , Nyokong, Tebello , Lange, N
- Date: 2012
- Subjects: Biomedical optics Fluorescence diagnosis Phthalocyanines NIR dyes Photodynamic therapy
- Language: English
- Type: Article
- Identifier: vital:6597 , http://hdl.handle.net/10962/d1004346 , http://dx.doi.org/10.3390/molecules17010098
- Description: The purpose of this review is to compile preclinical and clinical results on phthalocyanines (Pcs) as photosensitizers (PS) for Photodynamic Therapy (PDT) and contrast agents for fluorescence imaging. Indeed, Pcs are excellent candidates in these fields due to their strong absorbance in the NIR region and high chemical and photo-stability. In particular, this is mostly relevant for their in vivo activation in deeper tissular regions. However, most Pcs present two major limitations, i.e., a strong tendency to aggregate and a low water-solubility. In order to overcome these issues, both chemical tuning and pharmaceutical formulation combined with tumor targeting strategies were applied. These aspects will be developed in this review for the most extensively studied Pcs during the last 25 years, i.e., aluminium-, zinc- and silicon-based Pcs.
- Full Text:
- Date Issued: 2012
Electrocatalysis of asulam on cobalt phthalocyanine modified multi-walled carbon nanotubes immobilized on a basal plane pyrolytic graphite electrode
- Siswana, Msimelelo P, Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Siswana, Msimelelo P , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6595 , http://hdl.handle.net/10962/d1004344
- Description: This work describes the electrochemical properties of cobalt tetra-aminophthalocyanine (CoTAPc) complex electropolymerized at the surface of multi-walled carbon nanotube (MWCNT) abrasively immobilized onto a basal plane pyrolytic graphite electrode (BPPGE). The constructed electrode displayed excellent electrocatalytic behaviour towards the oxidation of the herbicide, asulam, as evidenced by the enhancement of the oxidation peak current (~6 times) and the shift in the oxidation potential to lower values (by ~120 mV) in comparison with the bare BPPGE. The chronoamperometric detection of asulam which was carried out in 0.10 M phosphate buffer (pH 7.0) at a fixed potential of 0.65 V (versus Ag|AgCl) yielded excellent analytical parameters; a linear concentration range of 4.5–20 μM, a sensitivity of 241 × 10[superscript −3] μA/μM, a detection limit of 1.15 μM asulam (using the Y[subscript B] + 3σ criterion) and a response time of ~2 s.
- Full Text:
- Date Issued: 2006
- Authors: Siswana, Msimelelo P , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6595 , http://hdl.handle.net/10962/d1004344
- Description: This work describes the electrochemical properties of cobalt tetra-aminophthalocyanine (CoTAPc) complex electropolymerized at the surface of multi-walled carbon nanotube (MWCNT) abrasively immobilized onto a basal plane pyrolytic graphite electrode (BPPGE). The constructed electrode displayed excellent electrocatalytic behaviour towards the oxidation of the herbicide, asulam, as evidenced by the enhancement of the oxidation peak current (~6 times) and the shift in the oxidation potential to lower values (by ~120 mV) in comparison with the bare BPPGE. The chronoamperometric detection of asulam which was carried out in 0.10 M phosphate buffer (pH 7.0) at a fixed potential of 0.65 V (versus Ag|AgCl) yielded excellent analytical parameters; a linear concentration range of 4.5–20 μM, a sensitivity of 241 × 10[superscript −3] μA/μM, a detection limit of 1.15 μM asulam (using the Y[subscript B] + 3σ criterion) and a response time of ~2 s.
- Full Text:
- Date Issued: 2006
Electrocatalytic behaviour of carbon paste electrode modified with iron(II) phthalocyanine (FePc) nanoparticles towards the detection of amitrole
- Siswana, Msimelelo P, Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Siswana, Msimelelo P , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6591 , http://hdl.handle.net/10962/d1004340
- Description: This paper describes the construction of a carbon paste electrode (CPE) impregnated with nanoparticles of iron(II) phthalocyanine (nanoFePc). The new electrode (nanoFePc-CPE) revealed interesting electrocatalytic behaviour towards amitrole; pure catalytic diffusion-controlled process, with high Tafel slope (235 mV/decade) suggesting strong binding of amitrole with nanoFePc catalyst. The effects of catalyst loading, varying pH and electrolytes were studied. The mechanism for the interaction of amitrole with the nanoFePc is proposed to involve the Fe[superscript (III)]Pc/Fe[superscript (II)]Pc redox process. Using chronoamperometry (E = +0.42 V versus Ag/AgCl) technique, the sensor was reliably employed for amitrole assay at pH 12.0 phosphate buffer (with sodium sulphate as the supporting electrolyte) for up to 12 nM amitrole with excellent sensitivity (ca. 3.44 μA/nM) and low detection limit (3.62 ± 0.11 nM, i.e. 0.305 μg L[superscript (−1)] using the YB + 3σB criterion and 0.85 ± 0.03 nM, i.e. 70 ng/L with the Y[subscript B] + 2[subscript σB] criterion) as well as satisfactory amperometric selectivity coefficient (K[subscript amp] ≈ 7.4 × 10[superscript (−4)] for ammonium thiocyanate, a component of many amitrole herbicides, and 3.2 × 10[superscript (−3)] for asulam pesticide). The surface of the electrode can easily be regenerated by simple polishing on an alumina paper, obtaining a fresh surface ready for use in a new assay. The proposed electrode was successfully applied in the quantification of amitrole in its commercial formulation as well as in tap water samples.
- Full Text:
- Date Issued: 2006
- Authors: Siswana, Msimelelo P , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6591 , http://hdl.handle.net/10962/d1004340
- Description: This paper describes the construction of a carbon paste electrode (CPE) impregnated with nanoparticles of iron(II) phthalocyanine (nanoFePc). The new electrode (nanoFePc-CPE) revealed interesting electrocatalytic behaviour towards amitrole; pure catalytic diffusion-controlled process, with high Tafel slope (235 mV/decade) suggesting strong binding of amitrole with nanoFePc catalyst. The effects of catalyst loading, varying pH and electrolytes were studied. The mechanism for the interaction of amitrole with the nanoFePc is proposed to involve the Fe[superscript (III)]Pc/Fe[superscript (II)]Pc redox process. Using chronoamperometry (E = +0.42 V versus Ag/AgCl) technique, the sensor was reliably employed for amitrole assay at pH 12.0 phosphate buffer (with sodium sulphate as the supporting electrolyte) for up to 12 nM amitrole with excellent sensitivity (ca. 3.44 μA/nM) and low detection limit (3.62 ± 0.11 nM, i.e. 0.305 μg L[superscript (−1)] using the YB + 3σB criterion and 0.85 ± 0.03 nM, i.e. 70 ng/L with the Y[subscript B] + 2[subscript σB] criterion) as well as satisfactory amperometric selectivity coefficient (K[subscript amp] ≈ 7.4 × 10[superscript (−4)] for ammonium thiocyanate, a component of many amitrole herbicides, and 3.2 × 10[superscript (−3)] for asulam pesticide). The surface of the electrode can easily be regenerated by simple polishing on an alumina paper, obtaining a fresh surface ready for use in a new assay. The proposed electrode was successfully applied in the quantification of amitrole in its commercial formulation as well as in tap water samples.
- Full Text:
- Date Issued: 2006
Electrochemical characterisation of tetra- and octa-substituted oxo(phthalocyaninato)titanium(IV) complexes
- Tau, Prudence Lerato, Nyokong, Tebello
- Authors: Tau, Prudence Lerato , Nyokong, Tebello
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6598 , http://hdl.handle.net/10962/d1004347
- Description: The synthesis and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)- {tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (5b); 2,(3)- (tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-{tetrakis[4- (benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (6b). The electrochemical characterisation of complexes octa-substituted with 4-(benzyloxy)phenoxy (9b), phenoxy (9c) and tert -butylphenoxy (9d) groups is also reported. The cyclic voltammograms of the complexes exhibit reversible couples I–III and couple IV is quasi-reversible for complexes 5a, 5b, 6a and 6b. The first two reductions are metal-based processes, confirmed by spectroelectrochemistry to be due to Ti IV Pc 2 − /Ti III Pc 2 − and Ti III Pc 2 − /Ti II Pc 2 − redox processes and the last two reductions are ring-based processes due to Ti II Pc 2 − /Ti II Pc 3 − and Ti II Pc 3 − /Ti II Pc 4 − . Chronocoulometry confirmed a one-electron transfer at each reduction step. The electrochemistry of the above complexes is also compared to the previously reported 5c, 5d, 6c and 6d.
- Full Text:
- Date Issued: 2007
- Authors: Tau, Prudence Lerato , Nyokong, Tebello
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6598 , http://hdl.handle.net/10962/d1004347
- Description: The synthesis and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)- {tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (5b); 2,(3)- (tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-{tetrakis[4- (benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (6b). The electrochemical characterisation of complexes octa-substituted with 4-(benzyloxy)phenoxy (9b), phenoxy (9c) and tert -butylphenoxy (9d) groups is also reported. The cyclic voltammograms of the complexes exhibit reversible couples I–III and couple IV is quasi-reversible for complexes 5a, 5b, 6a and 6b. The first two reductions are metal-based processes, confirmed by spectroelectrochemistry to be due to Ti IV Pc 2 − /Ti III Pc 2 − and Ti III Pc 2 − /Ti II Pc 2 − redox processes and the last two reductions are ring-based processes due to Ti II Pc 2 − /Ti II Pc 3 − and Ti II Pc 3 − /Ti II Pc 4 − . Chronocoulometry confirmed a one-electron transfer at each reduction step. The electrochemistry of the above complexes is also compared to the previously reported 5c, 5d, 6c and 6d.
- Full Text:
- Date Issued: 2007
Fluorescence Behaviour of an Aluminium Octacarboxy Phthalocyanine - NaYGdF4:Yb/Er Nanoparticle Conjugate
- Taylor, Jessica, Litwinski, Christian, Nyokong, Tebello, Antunes, Edith M
- Authors: Taylor, Jessica , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Language: English
- Type: Article
- Identifier: vital:7247 , http://hdl.handle.net/10962/d1020252
- Description: Using a methanol assisted thermal decomposition approach, sphere shaped NaYGdF4:Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized. The chemical, spectroscopic and fluorescence properties of the UCNPs were fully characterized. Characteristic upconversion fluorescence emissions were produced by the NPs in the green, red and NIR regions and the NPs were also shown to possess paramagnetic properties. The influence of the UCNPs on the spectroscopic and fluorescence properties of an aluminium octacarboxy phthalocyanine AlOCPc was investigated. Covalent conjugation to an AlOCPc resulted in a large blue shift of the phthalocyanine’s Q band, which was accompanied by a decrease in the Pc’s fluorescence lifetime in DMSO. By combining the phthalocyanine and upconversion nanoparticle, we present a system capable of multimodal imaging, using both the upconversion nanoparticle’s and phthalocyanine’s emission, and magnetic resonance imaging (as a result of doping the upconversion nanoparticles with Gd3+ ions). , Original publication is available at http://dx.doi.org/10.1007/s10895-015-1539-8
- Full Text: false
- Authors: Taylor, Jessica , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Language: English
- Type: Article
- Identifier: vital:7247 , http://hdl.handle.net/10962/d1020252
- Description: Using a methanol assisted thermal decomposition approach, sphere shaped NaYGdF4:Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized. The chemical, spectroscopic and fluorescence properties of the UCNPs were fully characterized. Characteristic upconversion fluorescence emissions were produced by the NPs in the green, red and NIR regions and the NPs were also shown to possess paramagnetic properties. The influence of the UCNPs on the spectroscopic and fluorescence properties of an aluminium octacarboxy phthalocyanine AlOCPc was investigated. Covalent conjugation to an AlOCPc resulted in a large blue shift of the phthalocyanine’s Q band, which was accompanied by a decrease in the Pc’s fluorescence lifetime in DMSO. By combining the phthalocyanine and upconversion nanoparticle, we present a system capable of multimodal imaging, using both the upconversion nanoparticle’s and phthalocyanine’s emission, and magnetic resonance imaging (as a result of doping the upconversion nanoparticles with Gd3+ ions). , Original publication is available at http://dx.doi.org/10.1007/s10895-015-1539-8
- Full Text: false
Synthesis and characterization of Na(Y,Gd)F4 upconversion nanoparticles and an investigation of their effects on the photophysical properties of an unsubstituted tetrathiophenoxy phthalocyanine
- Taylor, Jessica M, Litwinski, Christian, Nyokong, Tebello, Antunes, Edith M
- Authors: Taylor, Jessica M , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Language: English
- Type: Article
- Identifier: vital:7253 , http://hdl.handle.net/10962/d1020261
- Description: Sphere- and star-shaped Na(Y,Gd)F4:Yb/Er(Tm)upconversion nanoparticles (UCNP) were successfully synthesized utilizing a methanol-assisted thermal decomposition approach and their spectroscopic (absorption, emission and luminescence lifetime) properties fully characterized. The factors affecting the size and shape of the UCNPs were studied and discussed in detail. The size of the nanoparticles was determined using TEM primarily and found to be approximately 19 and 30 nm for the Er and Tm spheres, respectively, while the Er and Tm “stars” were found to be much larger with sizes ranging from 110 to 240 nm, respectively (as determined along the width of the nanoparticle). In addition, their influence on the spectroscopic properties of an unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) was investigated. The UCNP were found to produce characteristic upconversion luminescence emissions in the blue, green, red and NIR regions. Simple mixing with an H2Pc in toluene was found to exert no obvious changes in the spectroscopic properties of the Pc, although a considerable increase in the radiative lifetimes is observed for the Pc in the presence of the UCNPs. The singlet oxygen generation mediated by the red light excitation of the H2Pc mixed with UCNP was found to decrease in the presence of the NPs. , Original publication is available at http://dx.doi.org/10.1007/s11051-015-2889-5
- Full Text: false
- Authors: Taylor, Jessica M , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Language: English
- Type: Article
- Identifier: vital:7253 , http://hdl.handle.net/10962/d1020261
- Description: Sphere- and star-shaped Na(Y,Gd)F4:Yb/Er(Tm)upconversion nanoparticles (UCNP) were successfully synthesized utilizing a methanol-assisted thermal decomposition approach and their spectroscopic (absorption, emission and luminescence lifetime) properties fully characterized. The factors affecting the size and shape of the UCNPs were studied and discussed in detail. The size of the nanoparticles was determined using TEM primarily and found to be approximately 19 and 30 nm for the Er and Tm spheres, respectively, while the Er and Tm “stars” were found to be much larger with sizes ranging from 110 to 240 nm, respectively (as determined along the width of the nanoparticle). In addition, their influence on the spectroscopic properties of an unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) was investigated. The UCNP were found to produce characteristic upconversion luminescence emissions in the blue, green, red and NIR regions. Simple mixing with an H2Pc in toluene was found to exert no obvious changes in the spectroscopic properties of the Pc, although a considerable increase in the radiative lifetimes is observed for the Pc in the presence of the UCNPs. The singlet oxygen generation mediated by the red light excitation of the H2Pc mixed with UCNP was found to decrease in the presence of the NPs. , Original publication is available at http://dx.doi.org/10.1007/s11051-015-2889-5
- Full Text: false
The Photophysical Properties of Multi-Functional Quantum Dots-Magnetic Nanoparticles—Indium Octacarboxyphthalocyanine Nanocomposite
- Tshangana, Charmaine, Nyokong, Tebello
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7248 , http://hdl.handle.net/10962/d1020254
- Description: This work presents the development of a multifunctional hybrid nanoparticle made of L-glutathione capped quantum dots (GSH-CdSe@ZnS), amino functionalized Fe3O4 magnetic nanoparticles and indium octacarboxy phthalocyanine (ClInPc(COOH)8). In this work we investigate the photophysical properties of the individual components and the hybrid nanoparticle, in addition we study the energy transfer (Förster Resonance Energy Transfer (FRET)) in the complex. FRET efficiencies of ~48 % were obtained for energy transfer between the QDs (when alone or linked to MNPs). Both triplet yields and lifetimes of ClInPc(COOH)8 increase in the nanocomposite, with a decrease in fluorescence lifetime. The hybrid nanoparticle showed improved photophysical properties and as a result can be used in photodynamic therapy. , Original publication is available at http://dx.doi.org/10.1007/s10895-014-1497-6
- Full Text: false
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7248 , http://hdl.handle.net/10962/d1020254
- Description: This work presents the development of a multifunctional hybrid nanoparticle made of L-glutathione capped quantum dots (GSH-CdSe@ZnS), amino functionalized Fe3O4 magnetic nanoparticles and indium octacarboxy phthalocyanine (ClInPc(COOH)8). In this work we investigate the photophysical properties of the individual components and the hybrid nanoparticle, in addition we study the energy transfer (Förster Resonance Energy Transfer (FRET)) in the complex. FRET efficiencies of ~48 % were obtained for energy transfer between the QDs (when alone or linked to MNPs). Both triplet yields and lifetimes of ClInPc(COOH)8 increase in the nanocomposite, with a decrease in fluorescence lifetime. The hybrid nanoparticle showed improved photophysical properties and as a result can be used in photodynamic therapy. , Original publication is available at http://dx.doi.org/10.1007/s10895-014-1497-6
- Full Text: false
Photophysical properties gallium octacarboxy phthalocyanines conjugated to CdSe@ZnS quantum dots
- Tshangana, Charmaine, Nyokong, Tebello
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7287 , http://hdl.handle.net/10962/d1020335
- Description: l-Glutathione (GSH) capped core CdSe (2.3 nm) and core shell CdSe@ZnS quantum dots (QDs) (3.0 nm and 3.5 nm) were coordinated to gallium octacarboxy phthalocyanine (ClGaPc(COOH)8) to form ClGaPc(COOH)8–QDs conjugates. An efficient transfer of energy from the QDs to the Pcs was demonstrated through Förster resonance energy transfer (FRET), the FRET efficiencies in all cases was above 50%. The photophysical parameters (triplet state and fluorescence quantum yields and lifetimes) were also determined for the conjugates. There was a decrease in the fluorescence lifetimes of ClGaPc(COOH)8 in the presence of all the QDs, due to the heavy atom effect. The triplet quantum yields increased in the conjugates. The lifetimes also became longer for the conjugates compared to Pc alone. , Original publication is available at http://dx.doi.org/10.1016/j.saa.2015.06.086
- Full Text: false
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7287 , http://hdl.handle.net/10962/d1020335
- Description: l-Glutathione (GSH) capped core CdSe (2.3 nm) and core shell CdSe@ZnS quantum dots (QDs) (3.0 nm and 3.5 nm) were coordinated to gallium octacarboxy phthalocyanine (ClGaPc(COOH)8) to form ClGaPc(COOH)8–QDs conjugates. An efficient transfer of energy from the QDs to the Pcs was demonstrated through Förster resonance energy transfer (FRET), the FRET efficiencies in all cases was above 50%. The photophysical parameters (triplet state and fluorescence quantum yields and lifetimes) were also determined for the conjugates. There was a decrease in the fluorescence lifetimes of ClGaPc(COOH)8 in the presence of all the QDs, due to the heavy atom effect. The triplet quantum yields increased in the conjugates. The lifetimes also became longer for the conjugates compared to Pc alone. , Original publication is available at http://dx.doi.org/10.1016/j.saa.2015.06.086
- Full Text: false
Improved triplet state parameters for indium octacarboxy phthalocyanines when conjugated to quantum dots and magnetite nanoparticles
- Tshangana, Charmaine, Nyokong, Tebello
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7252 , http://hdl.handle.net/10962/d1020260
- Description: Fe3O4 magnetic nanoparticles (MNPs) and glutathione (GSH) capped CdSe@ZnS quantum dots (QDs) were separately coordinated to indium octacarboxy phthalocyanine (InPc(COOH)8) to form ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The photophysical parameters (triplet state and fluorescence quantum yields and lifetimes) were determined for the conjugates. The triplet quantum yields increased from ΦT = 0.49 for InPc(COOH)8 alone to ΦT = 0.61 and 0.56 for InPc(COOH)8 in the conjugates: ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The lifetimes also became longer for the conjugates compared to Pc alone. , Original publication is available at http://dx.doi.org/10.1016/j.molstruc.2015.02.040
- Full Text: false
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7252 , http://hdl.handle.net/10962/d1020260
- Description: Fe3O4 magnetic nanoparticles (MNPs) and glutathione (GSH) capped CdSe@ZnS quantum dots (QDs) were separately coordinated to indium octacarboxy phthalocyanine (InPc(COOH)8) to form ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The photophysical parameters (triplet state and fluorescence quantum yields and lifetimes) were determined for the conjugates. The triplet quantum yields increased from ΦT = 0.49 for InPc(COOH)8 alone to ΦT = 0.61 and 0.56 for InPc(COOH)8 in the conjugates: ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The lifetimes also became longer for the conjugates compared to Pc alone. , Original publication is available at http://dx.doi.org/10.1016/j.molstruc.2015.02.040
- Full Text: false
Optical properties and electronic structures of axially-ligated group 9 porphyrins
- Wang, Bei-Bei, Zuo, Huiping, Mack, John, Majumdar, Poulomi, Nyokong, Tebello, Chan, Kin Shing, Shen, Zhen
- Authors: Wang, Bei-Bei , Zuo, Huiping , Mack, John , Majumdar, Poulomi , Nyokong, Tebello , Chan, Kin Shing , Shen, Zhen
- Language: English
- Type: Article
- Identifier: vital:7295 , http://hdl.handle.net/10962/d1020358
- Description: A series of group 9 metal tetra-(p-tolyl)-porphyrin (M(ttp), M = Co(II), Rh(III), Ir(III)) complexes with axial phenyl substituents have been synthesized and characterized. An aryl bromide cleavage reaction of transition metal complexes was used to prepare the complexes from Co(ttp), Rh(ttp)Cl and Ir(ttp)COCl, respectively. Magnetic circular dichroism (MCD) spectroscopy and TD-DFT calculations have been used to study trends in the optical spectra and electronic structures. The effect of introducing different para-substituents on the phenyl substituents was examined. During fluorescence emission studies, phosphorescence was observed for the Ir(III) complexes in the near infrared (NIR) region. , Original publication is available at http://dx.doi.org/10.1142/S108842461550073X
- Full Text: false
- Authors: Wang, Bei-Bei , Zuo, Huiping , Mack, John , Majumdar, Poulomi , Nyokong, Tebello , Chan, Kin Shing , Shen, Zhen
- Language: English
- Type: Article
- Identifier: vital:7295 , http://hdl.handle.net/10962/d1020358
- Description: A series of group 9 metal tetra-(p-tolyl)-porphyrin (M(ttp), M = Co(II), Rh(III), Ir(III)) complexes with axial phenyl substituents have been synthesized and characterized. An aryl bromide cleavage reaction of transition metal complexes was used to prepare the complexes from Co(ttp), Rh(ttp)Cl and Ir(ttp)COCl, respectively. Magnetic circular dichroism (MCD) spectroscopy and TD-DFT calculations have been used to study trends in the optical spectra and electronic structures. The effect of introducing different para-substituents on the phenyl substituents was examined. During fluorescence emission studies, phosphorescence was observed for the Ir(III) complexes in the near infrared (NIR) region. , Original publication is available at http://dx.doi.org/10.1142/S108842461550073X
- Full Text: false