25th Croatian meeting of chemists and chemical engineers, Poreč, 2017.
Phenanthridine-pyrene conjugates as fluorescent probes with peculiar kinetic
behaviour
Konjugati fenantridina i pirena kao fluorescentne probe s neobičnom
kinetikom
Josipa Matić,1 Lidija-Marija Tumir,1 Marijana Radić Stojković, Filip Šupljika,2 Ivo Piantanida1
1
2
Ruđer Bošković Institute, Zagreb, Croatia
Faculty of Food Technology and Biotechnology, Zagreb, Croatia
E-mail: [email protected]
Phenanthridine derivatives are promising fluorescent probes whose properties can be
modified by different substituents attached to the aromatic core. On the other hand, pyrene
derivatives are one of the earliest known fluorescent probes for biomolecules. Also, it is known
that two or more pyrenes form an excimer [1], where fluorescence band of single pyrene
molecule is significantly shifted to longer wavelengths upon inter- or intramolecular stacking
of pyrene moieties. Some of the compounds from both described classes show intriguing
biological activity. It has been reported recently that some pyrene-guanidiniocarbonyl pyrrole
derivatives exhibit strong pH-dependent affinity towards ds-DNA which can be modified by
the flexibility of the linker connecting those two units [2]. Also, one of them binds to human
dipeptidyl peptidase III enzyme with a micromolar affinity which can be monitored by
significant changes in fluorescence spectra of the compound [3]. Moreover, previous studies
have shown that two phenanthridine units can also form an excimer, characterized by specific
fluorescence band [4].
Two phenanthridine-pyrene conjugates, differing only in linker connecting them, have been
prepared. New conjugates exhibit excimer formation: 1 and 2 show new fluorescence
emission bands at 495 nm and 485 nm, respectively, which are significantly red-shifted
compared to fluorescence of single phenanthridine or pyrene molecule. To the best of our
knowledge, it is the first reported phenanthridine-pyrene excimer. Further on, excimer band
is not kinetically stabile and shows strong fluorescence decrease upon consecutive excitations.
Figure 1: Two novel pyrene-phenanthridine conjugates
References
[1] JR Lakowicz, Principles of Fluorescence Spectroscopy, Kluwer Academic/Plenum: New York, 1999.
[2] M. Radić Stojković et al., Org. Biomol. Chem. 13 (2015) 1629-1633.
[3] J. Matić et al., RSC Adv. 6 (2016) 83044–83052
[4] a) M. Dukši et al., Eur. J. Med. Chem. 45 (2010) 2671–2676; b) M. Dukši et. al., Acta Chim. Slov. 59
(2012) 464–472.