ISMSC 2007 - Università degli Studi di Pavia

PSB 95
Photoresponsive Malachite Green Derivative and Photoinduced Vesicle
Fusion
Ryoko M. Uda a , Keiichi Kimura b
a Department of Chemical Engineering, Nara National College of Technology, Yata 22, Yamatokoriyama,
Nara 639-1080, Japan
b Department of Applied Chemistry, Faculty of Systems Engineering, Wakayama University,
Sakae-dani 930, Wakayama 640-8510, Japan
Amphiphiles contain hydrophilic and hydrophobic moieties and spontaneously form assemblies
in aqueous media. Control of molecular assembling can be achieved by shifting the balance of
hydrophobicity and hydrophilicity. Amphiphiles containing a photochromic moiety can undergo
conformational and electronic changes upon photoirradiation, offering an attractive modulation
of assemblies. We have designed a Malachite Green derivative carrying a long alkyl chain (Fig.
1). The Malachite Green derivative, when ionized photochemically, exhibits hydrophilicity by its
triphenylmethyl cation and hydrophobicity by its long alkyl chain. Consequently, the long-alkylchain
Malachite Green generates an amphiphilicity on the lipophilic compound by
photoirradiation. The photogenerated electrical charge on the head group is expected to provide
assemblies with a drastic effect. Actually, we have observed significant changes induced by the
long-alkyl-chain Malachite Green in the critical micelle concentration and the solubility of oily
substance into micelle solution 1,2 .
O
H3C CH3 N
Here we present the photoinduced structural change in vesicles containing the long-alkyl-chain
Malachite Green derivative. The Malachite Green derivative is embedded in the vesicle bilayer
consisting of cationic and anionic surfactants. Photoirradiation on the Malachite Green
derivative destabilizes the vesicle bilayer, resulting vesicle fusion (Fig. 2). We discuss the
photoinduced vesicle fusion by fluorescence analysis and transmission electron microscopy.
[1] R. M. Uda, M. Oue, K. Kimura, Chem. Lett., 2004, 33, 586-587.
[2] R. M. Uda, K. Kimura, Bull. Chem. Soc. Jpn., 2005, 78, 1862-1867.
C CN
N
H3C CH3
UV
Heat
Hydrophobic group
Hydrophiric group
H3C N CH3 O C+
+ CN -
N CH3 H3C Figure 1. Photo-generated amphiphilicity on the long-alkyl-chain Malachite Green derivative.
Malachite Green derivative
UV
Generated amphiphilicity
Bilayer destabilization Vesicle fusion
Figure 2. Conceptual represetion of photoinduced bilayer destabilization and subsequent vesicle fusion
Stable terbium probes highly luminescent in aqueous solutions :
macrocyclic ligands derived from N,C-pyrazolylpyridine
Isabelle Nasso, C. Galaup, B. Mestre, C. Picard
Laboratoire de Synthèse et Physicochimie de Molécules d’Intérêt Biologique, CNRS UMR 5068,
Université Paul Sabatier, 31062 Toulouse cedex 09, France
Some organic ligands can act as light collectors (antenna) transferring intra-molecularly the
excitation energy to the lanthanide ion (emitter), yielding highly luminescent lanthanide
complexes. [1] Eu(III) systems working in aqueous solutions are widely used for time-resolved
measurements in high throughput assays (clinical diagnostic assays or drug development) or
fluorescence microscopy. [2]
Recently, we reported the efficient sensitization of Tb(III) ion by an open chain polyaminocarboxylate
ligand based on the N,C-pyrazolylpyridine chromophore as antenna (compound
1). [3] Here we present the synthesis of new macrocyclic ligands based on this chromophoric unit
(compounds 2-4), and the luminescence properties of the corresponding Tb(III) complexes.
1
N
N
N
N
HO2C CO2H HO2C 2
HO 2C
N
N
N
N
N
N
CO 2H
N
CO 2H
CO 2H
R
N
N
N
HO 2C
N
N
3, R = H
N
N
4, R = COOH
CO 2H
CO 2H
PSB 96
These complexes are highly luminescent in aqueous solution: the decays of the Tb( 5 D4)
luminescence are long lived ( 1.70 ms) and high quantum yield ( 40 %) were obtained
following excitation of the -* state of the pyrazolylpyridine unit. The photophysical properties
of these complexes will be discussed with regard of the mechanism of the ligand-to-metal
energy transfer process and will be compared with those derived from 2,2’-bipyridine
analogues. Their kinetic stability in aqueous solutions will also be reported.
[1] P. G. Sammes and G. Yahogliou, Nat. Prod. Rep., 1996, 13, 1-28.
[2] I. Hemmila and V. Laitala, J. Fluorescence, 2005, 15, 529-542.
[3] C. Picard, N. Geum, I. Nasso, B. Mestre, P. Tisnès, S. Laurent, L. Vander Elst, Bioorg. Med.
Chem. Lett., 2006, 16, 5309-5312.