Europium confined cyclen dendrimers with photophysically active triazoles

Antoni, Per, Malkoch, Michael, Vamvounis, George, Nyström, Daniel, Nyström, Andreas, Lindgren, Mikael and Hult, Anders (2008) Europium confined cyclen dendrimers with photophysically active triazoles. Journal of Materials Chemistry, 18 22: 2545-2554. doi:10.1039/b802197j


Author Antoni, Per
Malkoch, Michael
Vamvounis, George
Nyström, Daniel
Nyström, Andreas
Lindgren, Mikael
Hult, Anders
Title Europium confined cyclen dendrimers with photophysically active triazoles
Journal name Journal of Materials Chemistry   Check publisher's open access policy
ISSN 0959-9428
1364-5501
Publication date 2008-06-14
Sub-type Article (original research)
DOI 10.1039/b802197j
Open Access Status Not Open Access
Volume 18
Issue 22
Start page 2545
End page 2554
Total pages 10
Place of publication Cambridge, U.K.
Publisher Royal Society of Chemistry
Language eng
Subject 0306 Physical Chemistry (incl. Structural)
0912 Materials Engineering
Formatted abstract
Dendrimers up to the fourth generation (G1–G4) were successfully synthesized via the efficient copper catalyzed 1,3-dipolar cycloaddition between primary alkynes and azides (CuAAC), also referred to as a click reaction. The synthetic protocol involved the preparation of presynthesized dendron wedges that subsequently were attached to a tetra-valent alkyne functional cyclen core. These constructed structures integrated stable triazole groups intra-locked between the cyclen and dendron wedges. The incorporation of a lanthanide metal ion, europium, into the interior of all cyclen dendrimers was monitored by FT-IR. Interestingly, the photophysical results showed that the proximate triazole not only acts as a stable linker but also as a sensitizers, transferring its singlet–singlet excitation in the ultraviolet region (270–290 nm) to the partially filled luminescent lanthanide 4f shell. An increase of luminescence decay time from the lanthanide 5D07F2 emission was observed with increasing dendrimer size, indicating that the shielding effect of the dendron wedges is important for the relaxation of the photo-excitation and energy transfer. To the best of our knowledge, this is the first time a set of dendron wedges have successfully been attached to a cyclen metal ion cage via the versatile click reaction. Furthermore, the produced triazoles intra-locked in close proximity to the macrocycle core elucidated an interesting photophysical function. © The Royal Society of Chemistry 2008
Keyword Click chemistry
Organometallic compounds
Photoexcitation
Size effect
Luminescence decay
Singlet state
Dendrimer
Europium
Q-Index Code C1
Q-Index Status Provisional Code

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Chemistry and Molecular Biosciences
 
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Created: Thu, 07 Jan 2010, 14:18:27 EST by Jon Swabey on behalf of Faculty of Science