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Click Reaction Synthesis and Photophysical Studies of Dendritic Metalloporphyrins

Tran Nguyen, Nguyen; Hofkens, Johan; Scheblykin, Ivan LU ; Kruk, Mikalai and Dehaen, Wim (2014) In European Journal of Organic Chemistry 2014(8). p.1766-1777
Abstract
Several dendritic zinc(II)-porphyrins bearing carbazole units at the terminals have been prepared through click reaction of azide-substituted Zn-porphyrin precursors and carbazole-based alkynes under [Cu(NCCH3)(4)][PF6] catalysis. This family of new dendritic metalloporphyrins shows dual luminescence from both the upper S-2 and the lowest S-1 singlet states. The observed trends in the spectroscopic data and the photophysical properties of the dendrimers have been rationalized in terms of the type of meso-spacer between the macrocycle and dendritic shell. The key feature of the meso-spacer is proposed to be the degree of hindrance towards aryl ring rotation relative to the mean porphyrin plane. Based on the observed differences in the S1S0... (More)
Several dendritic zinc(II)-porphyrins bearing carbazole units at the terminals have been prepared through click reaction of azide-substituted Zn-porphyrin precursors and carbazole-based alkynes under [Cu(NCCH3)(4)][PF6] catalysis. This family of new dendritic metalloporphyrins shows dual luminescence from both the upper S-2 and the lowest S-1 singlet states. The observed trends in the spectroscopic data and the photophysical properties of the dendrimers have been rationalized in terms of the type of meso-spacer between the macrocycle and dendritic shell. The key feature of the meso-spacer is proposed to be the degree of hindrance towards aryl ring rotation relative to the mean porphyrin plane. Based on the observed differences in the S1S0 fluorescence quantum yield on going from four- to five-coordinate dendrimers, it was shown that dendrimer architectures with all four meso-aryl spacers sterically hindered, are most appropriate to monitor processes related to axial ligation of the dendrimer core, since they provide larger luminescence response differences between the four-coordinate and five-coordinate forms. The blue S2S0 fluorescence quantum yield has been measured and the observed trend has been rationalized in terms of the S2S1 energy gap law. No significant differences were observed between the compounds either with different rotational degree of freedom of the meso-spacers or with different ligation states of the dendrimer core. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Porphyrinoids, Dendrimers, Luminescence, Photochemistry, Fluorescence, Click chemistry
in
European Journal of Organic Chemistry
volume
2014
issue
8
pages
1766 - 1777
publisher
John Wiley & Sons
external identifiers
  • wos:000332161900022
  • scopus:84897658957
ISSN
1434-193X
DOI
10.1002/ejoc.201301158
language
English
LU publication?
yes
id
af334aa0-4dd6-4bd9-84e4-3a36ec08e182 (old id 4414302)
date added to LUP
2014-04-30 07:59:15
date last changed
2017-09-10 03:00:17
@article{af334aa0-4dd6-4bd9-84e4-3a36ec08e182,
  abstract     = {Several dendritic zinc(II)-porphyrins bearing carbazole units at the terminals have been prepared through click reaction of azide-substituted Zn-porphyrin precursors and carbazole-based alkynes under [Cu(NCCH3)(4)][PF6] catalysis. This family of new dendritic metalloporphyrins shows dual luminescence from both the upper S-2 and the lowest S-1 singlet states. The observed trends in the spectroscopic data and the photophysical properties of the dendrimers have been rationalized in terms of the type of meso-spacer between the macrocycle and dendritic shell. The key feature of the meso-spacer is proposed to be the degree of hindrance towards aryl ring rotation relative to the mean porphyrin plane. Based on the observed differences in the S1S0 fluorescence quantum yield on going from four- to five-coordinate dendrimers, it was shown that dendrimer architectures with all four meso-aryl spacers sterically hindered, are most appropriate to monitor processes related to axial ligation of the dendrimer core, since they provide larger luminescence response differences between the four-coordinate and five-coordinate forms. The blue S2S0 fluorescence quantum yield has been measured and the observed trend has been rationalized in terms of the S2S1 energy gap law. No significant differences were observed between the compounds either with different rotational degree of freedom of the meso-spacers or with different ligation states of the dendrimer core.},
  author       = {Tran Nguyen, Nguyen and Hofkens, Johan and Scheblykin, Ivan and Kruk, Mikalai and Dehaen, Wim},
  issn         = {1434-193X},
  keyword      = {Porphyrinoids,Dendrimers,Luminescence,Photochemistry,Fluorescence,Click chemistry},
  language     = {eng},
  number       = {8},
  pages        = {1766--1777},
  publisher    = {John Wiley & Sons},
  series       = {European Journal of Organic Chemistry},
  title        = {Click Reaction Synthesis and Photophysical Studies of Dendritic Metalloporphyrins},
  url          = {http://dx.doi.org/10.1002/ejoc.201301158},
  volume       = {2014},
  year         = {2014},
}