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Photophysical properties of newly synthesized fluorinated zinc phthalocyanines in the presence of CdTe quantum dots and the accompanying energy transfer processes

  • Authors: Erdoğmuş, Ali , Moeno, Sharon , Litwinski, Christian , Nyokong, Tebello
  • Date: 2010
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/262671 , vital:53543 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.12.014"
  • Description: The photophysical properties of two newly synthesized phthalocyanines (Pcs) were studied in the presence and the absence of 3-mercaptopropionic acid (MPA) capped quantum dots (QDs). Energy transfer processes resulting from the combination of QDs and the Pcs: 4-(tetrakis-5-(trifluoromethyl)-2-mercaptopyridinephthalocyaninato)zinc(II) (TtfmMPyZnPc, 3) and 4-(tetrakis-5-(trifluoromethyl)-2-pyridyloxyphthalocyaninato) zinc(II) (TtfmPyZnPc, 4) were also studied. The photophysical properties of the Pcs in the presence of QDs were enhanced and Förster resonance energy transfer (FRET) was observed with the phthalocyanines used. The efficiency of FRET between the QDs and TtfmMPyZnPc and TtfmPyZnPc was found to be 0.31% and 0.45% in DMSO and 0.24% and 0.32% in pyridine, respectively. The triplet state quantum yields for TtfmMPyZnPc and TtfmPyZnPc were found to be 0.86 and 0.74 in DMSO and 0.83 and 0.76 in pyridine.
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  • Date Issued: 2010

The photophysical studies of Pluronic F127/P123 micelle mixture system loaded with metal free and Zn 5, 10, 15, 20-tetrakis [4-(benzyloxy) phenyl] porphyrins

  • Authors: Managa, Muthumuni , Ngoy, Bokolombe P , Nyokong, Tebello
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/188932 , vital:44799 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.02.018"
  • Description: Binary mixtures of Pluronics are studied as drug nanocarriers in this work. H2 and Zn 5,10,15,20-tetrakis[4-(benzyloxy) phenyl] porphyrin were encapsulated onto binary micelle mixture of Pluronic F127/P123. The fluorescence and singlet oxygen generating behaviour of the porphyrins were investigated following incorporation. The fluorescence quantum yield for H2TBnOPP (ΦF = 0.034) was higher than that of ZnTBnOPP (ΦF = 0.023) and decreased when ZnTBnOPP or H2TBnOPP when in the presence of Pluronic F127/P123 binary mixtures. The kq values were 2.8 × 108 and 3.7 × 108 M−1 s−1, for H2TBnOPP + Pluronic F127/P123 and ZnTBnOPP + Pluronic F127/P123 in water, respectively. The binding constants (Kb) were 1.58 × 105 M−1 and 1.02 × 105 M−1 for ZnTBnOPP + Pluronic F127/P123 and H2TBnOPP + Pluronic F127/P123, respectively.
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  • Date Issued: 2017

Interaction of nitric oxide with cobalt (II) phthalocyanine

  • Authors: Vilakazi, Sibulelo L , Nyokong, Tebello
  • Date: 1998
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/293579 , vital:57100 , xlink:href="https://doi.org/10.1016/S0277-5387(98)00244-7"
  • Description: The coordination of nitric oxide (NO) to cobalt(II) phthalocyanine (CoPc) in dimethyl sulphoxide (DMSO) has been studied. CoPc coordinates with NO in a 1:1 ratio, forming a CoPc(NO) species. The IR band observed at 1680 cm−1 is assigned to the coordinated NO. In the presence of excess NO, pseudo first order kinetics were followed. The observed rate constant, kf, was determined to be 15.0±0.3 dm−3 mol−1 s−1 and the equilibrium constant was K=5.4±0.4×104dm3 mol−1. Solution or adsorbed CoPc catalyses the reduction of NO. The products of reduction include NH3 and NH2OH.
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  • Date Issued: 1998

Fluorescence “turn on” probe for bromide ion using nanoconjugates of glutathione-capped CdTe@ ZnS quantum dots with nickel tetraamino-phthalocyanine

  • Authors: Adegoke, Oluwasesan , Nyokong, Tebello
  • Date: 2013
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/190479 , vital:44998 , xlink:href="https://doi.org/10.1016/j.jphotochem.2013.05.013"
  • Description: In this paper, three differently sized glutathione (GSH)-capped CdTe@ZnS quantum dots (QDs) have been successfully conjugated to nickel tetraamino-phthalocyanine (NiTAPc) to form different QDs-NiTAPc nanocomplexes. Several techniques such as TEM, FT-IR, time-resolved fluorescence measurement and electronic spectroscopy were employed to characterize the nanocomplex. Bromide ion was chosen as a model anion to test the efficacy of the nanoprobe. The fluorescence of the nanoconjugate was “turned off” upon binding but was progressively “turned on” upon interaction with varying concentrations of bromide ion. Experimental results showed that the quantum size effect of nanocrystal QD determined the overall sensitivity and selectivity of the nanoprobe and followed the order QD563-NiTAPc > QD605-NiTAPc > QD621-NiTAPc. The mechanism of reaction is proposed.
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  • Date Issued: 2013

Selection and characterization of suitable lipid excipients for use in the manufacture of didanosine-loaded solid lipid nanoparticles and nanostructured lipid carriers

  • Authors: Kasongo, Kasongo W , Pardeike, Jana , Muller, Rainer H , Walker, Roderick B
  • Date: 2011
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/184016 , vital:44156 , xlink:href="https://doi.org/10.1002/jps.22711"
  • Description: This research aimed to evaluate the suitability of lipids for the manufacture of solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) loaded with the hydrophilic drug, didanosine (DDI). The crystalline state and polymorphism of lipids with the best‐solubulizing potential for DDI was investigated using differential scanning calorimetry (DSC) and wide‐angle X‐ray scattering (WAXS). DSC and WAXS were also used to determine potential interactions between the bulk lipids and DDI. Precirol® ATO 5 and Transcutol® HP showed the best‐solubilizing potential for DDI. Precirol® ATO 5 exists in the β‐modification before heating; however, a mixture of both α‐ and β‐modifications were detected following heating. Addition of Transcutol® HP to Precirol® ATO 5 changes the polymorphism of the latter from the β‐modification to a form that exhibits coexistence of the α‐ and β‐modifications. DDI exists in a crystalline state when dispersed at 5% (w/w) in Precirol® ATO 5 or in a Precirol® ATO 5/Transcutol® HP mixture. DSC and WAXS profiles of DDI/bulk lipids mixture obtained before and after exposure to heat revealed no interactions between DDI and the lipids. Precirol® ATO 5 and a mixture of Precirol® ATO 5 and Transcutol® HP may be used to manufacture DDI‐loaded SLN and NLC, respectively.
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  • Date Issued: 2011

A mathematical model and application for fire risk management in commercial complexes in South Africa

Photoreduction of tin (IV) phthalocyanines

  • Authors: Nyokong, Tebello
  • Date: 1994
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/293413 , vital:57083 , xlink:href="https://doi.org/10.1016/S0277-5387(00)83491-9"
  • Description: Photolysis of Sn(IV)Pc(OH)2 (Pc = phthalocyanine dianion) and Sn(IV)Pc(Cl)2 using a tungsten lamp, and in the presence of SnCl2·2H2O as an electron donor results in the reduction of these complexes of π anion radical species. The reduction shows second order dependence on the concentration of the Sn(IV)Pc complexes and a first order dependence on SnCl2·H2O.
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  • Date Issued: 1994

Synthesis, photophysical and nonlinear optical properties of microwave synthesized 4-tetra and octa-substituted lead phthalocyanines

  • Authors: Modibane, Desmond K , Nyokong, Tebello
  • Date: 2009
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/263452 , vital:53629 , xlink:href="https://doi.org/10.1016/j.poly.2009.03.013"
  • Description: This work presents the photophysical and nonlinear optical behaviour of newly synthesized complexes: 2,(3)-tetrakis(4-benzyloxyphenoxyphthalocyaninato) lead (5a) and 2,3-octakis(4-benzyloxyphenoxyphthalocyaninato) lead (6a). The nonlinear optical behaviour of complexes 5a and 6a are compared with those of 2,(3)-tetraphenoxyphthalocyaninato lead (5b), 2,(3)-tetrakis(4-t-butylphenoxyphthalocyaninato) lead (5c), 2,3-octaphenoxyphthalocyaninato lead (6b) and 2,3-octakis(4-t-butylphenoxyphthalocyaninato) lead (6c). The synthesis of 5a and 6a was performed using microwave irradiation. Photophysical properties were studied for these complexes in dimethylsulfoxide, dimethylformamide, toluene, tetrahydrofuran and chloroform. The fluorescence spectra were different from excitation spectra due to demetallation upon excitation. High triplet quantum yields ranging from 0.80 to 0.86 (in DMSO, DMF and toluene) and low triplet lifetimes (20–50 μs in DMSO, and more than 10 μs in the rest of the solvents) were observed due to the presence of heavy atom. Nonlinear optical properties were studied in dimethylsulfoxide. The optical limiting threshold intensity (Ilim) for the PbPc derivatives were calculated and ranged from 2.1 to 6.6 W/cm2.
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  • Date Issued: 2009

Voltammetric characterisation of the self-assembled monolayers (SAMs) of benzyl-and dodecyl-mercapto tetra substituted metallophthalocyanines complexes

  • Authors: Agboola, Bolade , Westbroek, Philippe , Ozoemena, Kenneth I , Nyokong, Tebello
  • Date: 2007
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/281414 , vital:55723 , xlink:href="https://doi.org/10.1016/j.elecom.2006.08.047"
  • Description: Voltammetric characterisations of cobalt, iron, manganese, nickel and zinc phthalocyanine complexes tetra substituted with benzyl- and dodecyl-mercapto ring substituents and immobilisation on gold electrodes via the self-assembling technique are presented. The self-assembled films are stable and showed blocking characteristics towards the following Faradaic processes; gold surface oxidation, under potential deposition of copper and solution redox chemistry of [Fe(H2O)6 3+ ]/[Fe(H2O)6 2+ ]. The solution chemistry of [Fe(CN)6]−3/[Fe(CN)6]−4 redox process was used to study the orientation of the CoPcs-SAMs and this revealed a possible deviation from flat orientation of the complexes on the gold electrodes when the SAM formation times were greater than 24 h. For SAM formation time at 24 and 48 h, CoTDMPc-SAM showed more inhibition of the [Fe(CN)6]−3/[Fe(CN)6]−4 redox process than the CoTBMPc-SAM counterpart, indicating more blocking characteristics of the dodecylmercapto ring substituents compared to the benzylmercapto counterpart. To avoid SAM desorption, the potential application should be limited to −0.2 to +0.8 V vs. Ag∣AgCl (NaCl, sat’d) in acidic and neutral pH.
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  • Date Issued: 2007

Symmetry effect of cobalt phthalocyanines on the aluminium corrosion inhibition in hydrochloric acid

  • Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/231323 , vital:49877 , xlink:href="https://doi.org/10.1016/j.matlet.2021.130892"
  • Description: The aluminium corrosion retardation potentials of phthalocyanine-based dyes, cobalt (II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (D1) and cobalt (II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (D2) in 1 M hydrochloric acid were evaluated. Results from potentiodynamic polarization measurements show that inhibition efficiency increased with inhibitor concentration at 28 °C with values of 91.9 % and 87.0 % values respectively for D1 and D2 at 10 μM.
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  • Date Issued: 2022

More than just fields: Reframing deagrarianisation in landscapes and livelihoods

  • Authors: Hebinck, Paul , Mtati, Nosiseko , Shackleton, Charlie M
  • Date: 2018
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/180322 , vital:43353 , xlink:href="https://doi.org/10.1016/j.jrurstud.2018.01.004"
  • Description: This paper discusses the emergent properties of deagrarianisation processes in two villages in the central Eastern Cape, South Africa. The claim of is that much of the deagrarianisation literature and debate does not acknowledge the importance of landscapes and the interaction between their constituent elements, notably people, forests, grasslands, fields, grazing lands, open spaces, built environments and homesteads, all of which contribute to shaping and, in turn, are shaped by livelihoods. Conceptualising a landscape as a spatial entity and associated assemblage of practices, discourses and history, this paper dissects the landscape in terms of land uses for residential and cultural purposes, growing, grazing and gathering. These land use categories together represent the rural domain to which the villagers are attached as a place and a home. Their use of the land is not necessarily oriented to fully exploring its productive potential. The article explores the transformation from a productive landscape to one which largely hinges on consumption. The blurring of boundaries between the formally designated land use categories signifies the transformations occurring in many of the rural areas in the former homelands of South Africa.
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  • Date Issued: 2018

Synthesis and photophysicochemical properties of novel axially di-substituted silicon (IV) phthalocyanines and their photodynamic antimicrobial chemotherapy (PACT) activity against Staphylococcus aureus

  • Authors: Sen, Pinar , Sindelo, Azole , Mafukidze, Donovan M , Nyokong, Tebello
  • Date: 2019
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186757 , vital:44531 , xlink:href="https://doi.org/10.1016/j.synthmet.2019.116203"
  • Description: In this study, novel silicon (IV) phthalocyanine axially di-substituted with benzimidazole moieties (3) and its quaternized derivative (4) have been synthesized and fully characterized. The photophysical and photochemical properties of both phthalocyanines such as absorption, fluorescence and, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were investigated in solutions. These new silicon phthalocyanines exhibited low fluorescence but produced high singlet oxygen yields in both DMSO (compound 3 and 4) and aqueous media (compound 4). The quaternization of Si(IV)Pc (3) improved the triplet state quantum yield (ΦT) 0.61 to 0.83, consequently singlet oxygen generation (ΦΔ) increased to 0.69 from 0.42. Photodynamic antimicrobial chemotherapy activities (PACT) of Si(IV)Pc photosensitizers were determined towards Staphylococcus aureus. The higher efficiency was obtained with cationic derivative (4) giving reduction percentage value of 99.75%.
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  • Date Issued: 2019

Electrochemical, microscopic and spectroscopic characterization of benzene diamine functionalized single walled carbon nanotube-cobalt (II) tetracarboxy-phthalocyanine conjugates

  • Authors: Mugadza, Tawanda , Nyokong, Tebello
  • Date: 2011
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/247859 , vital:51624 , xlink:href="https://doi.org/10.1016/j.jcis.2010.10.057"
  • Description: In this paper we report on the synthesis and characterization of 1,4-benzene diamine (BDA) functionalized single walled carbon nanotubes linked to cobalt (II) tetracarboxy-phthalocyanine. The characterization of the conjugate was through UV–vis, FTIR and X-ray diffraction (XRD) spectroscopies and by transmission electron microscope (TEM) and electrochemical methods. The conjugate is used for the electrochemical characterization of diuron. The catalytic rate constant for diuron was 4.4 × 103 M−1 s−1 and the apparent electron transfer rate constant was 18.5 × 10−6 cm s−1. The linear dynamic range was 1.0 × 10−5–2.0 × 10−4 M, with a sensitivity of ∼0.42 A mol−1L cm−2 and a limit of detection of 0.18 μM using the 3δ notation.
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  • Date Issued: 2011

Iron perchlorophthalocyanine and tetrasulfophthalocyanine catalyzed oxidation of cyclohexane using hydrogen peroxide, chloroperoxybenzoic acid and tert-butylhydroperoxide as oxidants

  • Authors: Grootboom, Natasha , Nyokong, Tebello
  • Date: 2002
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/289606 , vital:56653 , xlink:href="https://doi.org/10.1016/S1381-1169(01)00404-6"
  • Description: Polychlorophthalocyanine (Cl16PcFeII) and tetrasulfophthalocyanine ([FeIITSPc]4−) complexes of iron are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), m-chloroperoxybenzoic acid (m-CPBA) and hydrogen peroxide as oxidants. Catalysis using the Cl16PcFeII was performed in a dimethylformamide:dichloromethane (3:7) solvent mixture. For the [FeIITSPc]4−catalyst, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative yields of the products depended on oxidant and the catalyst. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. The mechanism of the oxidation of cyclohexane in the presence of the Cl16PcFeII and [FeIITSPc]4− involves the oxidation of these catalysts, forming an Fe(III) phthalocyanine species as an intermediate. Higher yields were observed when [FeTSPc]4− was employed as a catalyst, which is more soluble than the perchlorinated iron phthalocyanine catalyst.
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  • Date Issued: 2002

“Turn on” fluorescence enhancement of Zn octacarboxyphthaloyanine-graphene oxide conjugates by hydrogen peroxide

  • Authors: Shumba, Munyaradzi , Mashazi, Philani N , Nyokong, Tebello
  • Date: 2016
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/190438 , vital:44994 , xlink:href="https://doi.org/10.1016/j.jlumin.2015.11.001"
  • Description: Zn octacarboxy phthalocyanine-reduced graphene oxide or graphene oxide conjugates were characterized by absorption spectroscopy, transmission electron microscopy, fluorescence spectroscopy, X-ray diffraction, thermo gravimetric analysis and X-ray photon spectroscopy. The presence of reduced graphene oxide or graphene oxide resulted in the quenching (turn on) of Zn octacarboxy phthalocyanine fluorescence which can be explained by photoinduced electron transfer. Zn octacarboxy phthalocyaninereduced graphene oxide or graphene oxide conjugates “turned on” fluorescence showed a linear response to hydrogen peroxide hence their potential to be used as sensors. The nanoprobe developed showed high selectivity towards hydrogen peroxide in the presence of physiological interferences.
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  • Date Issued: 2016

Syntheses and electrochemical characterization of new water soluble octaarylthiosubstituted manganese phthalocyanines

  • Authors: Booysen, Irvin N , Matemadombo, Fungisai , Durmus, Mahmut , Nyokong, Tebello
  • Date: 2011
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/247614 , vital:51600 , xlink:href="https://doi.org/10.1016/j.dyepig.2010.09.012"
  • Description: This paper reports on the synthesis and characterization of new manganese phthalocyanine (MnPc) complexes: 2,3-octakis-[(2-mercaptopyridine) phthalocyaninato] acetato manganese (III) (1) and its quaternized (hence water soluble) derivative: 2,3-octakis-{[(N-methyl-2-mercaptopyridine) phthalocyaninato] acetato manganese (III)} sulphate (2). The complexes were used to form self assembled monolayers (SAMs). Voltammetry proved that both of the SAMs are well packed, strongly passivating and act as selective and efficient barriers to ion permeability. Furthermore, surface coverage studies confirmed that the MPc macrocycles adsorb onto the gold electrode as monolayers. Both MPc SAMs were successfully used as electrochemical sensors of nitrite.
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  • Date Issued: 2011

Comparative electrooxidation of nitrite by electrodeposited Co (II), Fe (II) and Mn (III) tetrakis (benzylmercapto) and tetrakis (dodecylmercapto) phthalocyanines on gold electrodes

  • Authors: Agboola, Bolade , Nyokong, Tebello
  • Date: 2007
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/281212 , vital:55702 , xlink:href="https://doi.org/10.1016/j.aca.2007.01.031"
  • Description: This work reports on the electrooxidation of nitrite using Co(II), Fe(II) and Mn(III) tetrakis (benzylmercapto) and tetrakis (dodecylmercapto) phthalocyanines electrodeposited onto a gold electrode. Good catalytic activity (in terms of lowering overpotential) was obtained for these molecules when compared to previously reported MPc catalysts. The catalytic current was found to vary linearly with nitrite concentration in the range employed in this work (0.1–1 mM) and high sensitivities ranging from 6.9 to 9.9 μA mM−1 were observed for all the modified electrodes.
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  • Date Issued: 2007

Physicochemical and photodynamic antimicrobial chemotherapy studies of mono-and tetra-pyridyloxy substituted indium (III) phthalocyanines

  • Authors: Osifeko, Olawale , Durmus, Mahmut , Nyokong, Tebello
  • Date: 2015
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/189547 , vital:44856 , xlink:href="https://doi.org/10.1016/j.jphotochem.2014.12.011"
  • Description: The synthesis and photophysicochemical properties of mono- and tetra-pyridyloxy substituted indium(III) phthalocyanines (InPcs) are presented in this study. General trends are described for quantum yields of fluorescence, triplet, singlet oxygen and photodegradation as well as lifetimes of fluorescence and triplet state of these compounds. The complexes exhibited high singlet oxygen quantum yields (ФΔ) ranging from 0.44 to 0.66 in DMF, and from 0.44 to 0.69 in DMSO and ФΔ = 0.31 for the quartenized tetra substituted InPc which is soluble in water. The triplet quantum yields (ФT) ranged from 0.77 to 0.95 in DMF and from 0.77 to 0.94) in DMSO. The tetra substituted photosensitizers do not differ in their inactivation of bacteria with over 8 log reduction of viable bacteria when compared with the mono substituted photosensitizer which could only manage a 1 log reduction.
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  • Date Issued: 2015

Photodegradation of tetracycline by asymmetrical zinc (II) phthalocyanines conjugated to cobalt tungstate nanoparticles

  • Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/300233 , vital:57908 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.132938"
  • Description: This work focused on syntheses of novel asymmetrically tetra substituted Zn phthalocyanines (ZnPc) each containing a single carboxyl group, with the other substituents bearing alkynyl (complex 1) and fluorine containing groups (complexes 2 and 3). The complexes were conjugated to cobalt tungstate nanoparticles and employed as efficient photocatalysts for degradation of tetracycline in water. ZnPc complexes and their conjugates showed good photophysical and photochemical properties behaviour with complex 1 giving higher triplet and singlet oxygen quantum yields compared to 2 and 3. Complex 1 showed higher activity towards the photodegradation of tetracycline compared to complexes 2 and 3, with higher kobs and initial rates for the former. The photocatalysis obeyed the Langmuir-Hinshelwood kinetic model.
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  • Date Issued: 2022

Fluorescence behaviour of supramolecular hybrids containing graphene quantum dots and pyrene-derivatized phthalocyanines and porphyrins

  • Authors: Achadu, Ojodomo John , Managa, Muthumuni , Nyokong, Tebello
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/188953 , vital:44801 , xlink:href="https://doi.org/10.1016/j.jphotochem.2016.10.029"
  • Description: Novel pyrene-derivatized zinc and cobalt phthalocyanines (Pcs) and porphyrins (Ps) were immobilized on graphene quantum dots (GQDs) to form GQDs-Pcs and GQDs-Ps supramolecular hybrids via the π–π stacking interaction method. Spectroscopic evidence shows that the resultant hybrids were stable owing to the strong π–π stacking interaction between the GQDs and the respective Pcs and Ps, thus leading to the fabrication of interesting and functional supramolecular hybrids by taking advantage of the delocalized π electron systems of GQDs and the macrocycles. The conjugates showed increased fluorescence quantum yields for the Pcs/Ps, but decreased values for the GQDs in the conjugates. These novel hybrid materials could potentially be deployed for studies in both fundamental and applied perspectives due to the synergistic contributions resulting from the combination of their excellent electronic and optical properties.
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  • Date Issued: 2017
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