Remarkable fluorescence enhancement versus complex formation of cationic porphyrins on the surface of ZnO nanoparticles

Handle URI:
http://hdl.handle.net/10754/563597
Title:
Remarkable fluorescence enhancement versus complex formation of cationic porphyrins on the surface of ZnO nanoparticles
Authors:
Aly, Shawkat Mohammede ( 0000-0002-0455-1892 ) ; Eita, Mohamed Samir; Khan, Jafar Iqbal; Alarousu, Erkki; Mohammed, Omar F. ( 0000-0001-8500-1130 )
Abstract:
Fluorescence enhancement of organic fluorophores shows tremendous potential to improve image contrast in fluorescence-based bioimaging. Here, we present an experimental study of the interaction of two cationic porphyrins, meso-tetrakis(1-methylpyridinium-4-yl)porphyrin chloride (TMPyP) and meso-tetrakis(4-N,N,N-trimethylanilinium)porphyrin chloride (TMAP), with cationic surfactant-stabilized zinc oxide nanoparticles (ZnO NPs) based on several steady-state and time-resolved techniques. We show the first experimental measurements demonstrating a clear transition from pronounced fluorescence enhancement to charge transfer (CT) complex formation by simply changing the nature and location of the positive charge of the meso substituent of the cationic porphyrins. For TMPyP, we observe a sixfold increase in the fluorescence intensity of TMPyP upon addition of ZnO NPs. Our experimental results indicate that the electrostatic binding of TMPyP with the surface of ZnO NPs increases the symmetry of the porphyrin macrocycle. This electronic communication hinders the rotational relaxation of the meso unit and/or decreases the intramolecular CT character between the cavity and the meso substituent of the porphyrin, resulting in the enhancement of the intensity of the fluorescence. For TMAP, on the other hand, the different type and nature of the positive charge resulting in the development of the CT band arise from the interaction with the surface of ZnO NPs. This observation is confirmed by the femtosecond transient absorption spectroscopy, which provides clear spectroscopic signatures of photoinduced electron transfer from TMAP to ZnO NPs. © 2014 American Chemical Society.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Solar and Photovoltaic Engineering Research Center (SPERC); Chemical Science Program
Publisher:
American Chemical Society (ACS)
Journal:
The Journal of Physical Chemistry C
Issue Date:
12-Jun-2014
DOI:
10.1021/jp5030075
Type:
Article
ISSN:
19327447
Sponsors:
S.M.B.A. is grateful for the postdoctoral fellowship provided by Saudi Basic Industries Corporation (SABIC). The research reported in this publication was supported by the King Abdullah University of Science and Technology.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; KAUST Solar Center (KSC)

Full metadata record

DC FieldValue Language
dc.contributor.authorAly, Shawkat Mohammedeen
dc.contributor.authorEita, Mohamed Samiren
dc.contributor.authorKhan, Jafar Iqbalen
dc.contributor.authorAlarousu, Erkkien
dc.contributor.authorMohammed, Omar F.en
dc.date.accessioned2015-08-03T11:55:19Zen
dc.date.available2015-08-03T11:55:19Zen
dc.date.issued2014-06-12en
dc.identifier.issn19327447en
dc.identifier.doi10.1021/jp5030075en
dc.identifier.urihttp://hdl.handle.net/10754/563597en
dc.description.abstractFluorescence enhancement of organic fluorophores shows tremendous potential to improve image contrast in fluorescence-based bioimaging. Here, we present an experimental study of the interaction of two cationic porphyrins, meso-tetrakis(1-methylpyridinium-4-yl)porphyrin chloride (TMPyP) and meso-tetrakis(4-N,N,N-trimethylanilinium)porphyrin chloride (TMAP), with cationic surfactant-stabilized zinc oxide nanoparticles (ZnO NPs) based on several steady-state and time-resolved techniques. We show the first experimental measurements demonstrating a clear transition from pronounced fluorescence enhancement to charge transfer (CT) complex formation by simply changing the nature and location of the positive charge of the meso substituent of the cationic porphyrins. For TMPyP, we observe a sixfold increase in the fluorescence intensity of TMPyP upon addition of ZnO NPs. Our experimental results indicate that the electrostatic binding of TMPyP with the surface of ZnO NPs increases the symmetry of the porphyrin macrocycle. This electronic communication hinders the rotational relaxation of the meso unit and/or decreases the intramolecular CT character between the cavity and the meso substituent of the porphyrin, resulting in the enhancement of the intensity of the fluorescence. For TMAP, on the other hand, the different type and nature of the positive charge resulting in the development of the CT band arise from the interaction with the surface of ZnO NPs. This observation is confirmed by the femtosecond transient absorption spectroscopy, which provides clear spectroscopic signatures of photoinduced electron transfer from TMAP to ZnO NPs. © 2014 American Chemical Society.en
dc.description.sponsorshipS.M.B.A. is grateful for the postdoctoral fellowship provided by Saudi Basic Industries Corporation (SABIC). The research reported in this publication was supported by the King Abdullah University of Science and Technology.en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleRemarkable fluorescence enhancement versus complex formation of cationic porphyrins on the surface of ZnO nanoparticlesen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentSolar and Photovoltaic Engineering Research Center (SPERC)en
dc.contributor.departmentChemical Science Programen
dc.identifier.journalThe Journal of Physical Chemistry Cen
kaust.authorAly, Shawkat Mohammedeen
kaust.authorEita, Mohamed Samiren
kaust.authorKhan, Jafar Iqbalen
kaust.authorAlarousu, Erkkien
kaust.authorMohammed, Omar F.en
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