Communication
ChemComm
the photostability of silicon vs. oxygen fluorophores, focusing on Notes and references
the pair that has the most similar absorption: trimethine 7 and
‡
We classified structures with polymethine substituents pointed away
pentamethine 11 (Fig. 5C). We found that 11 began photobleaching
from each other as anti, while structures with polymethine substituents
rapidly, while 7 was unchanged over three hours (Fig. 5D). Upon pointed towards each other as syn.
calculation of the photobleaching rate constants, we quantified
1
L. D. Lavis and R. T. Raines, ACS Chem. Biol., 2008, 3, 142–155.
silicon-containing polymethine 7 to be six-fold more stable than 11
Fig. S11, ESI†). Photobleaching of pentamethine 10 under the
2 J. V. Frangioni, Curr. Opin. Chem. Biol., 2003, 7, 626–634.
3
4
R. Weissleder, Nat. Biotechnol., 2001, 19, 316–317.
M. Fu, Y. Xiao, X. Qian, D. Zhao and Y. Xu, Chem. Commun., 2008,
(
same conditions showed a similar decrease as 7, suggestive that
silicon incorporation plays an important role in increasing the
photostability. In comparison to other commercial fluorophores, 7
1780.
5 J. B. Grimm, T. A. Brown, A. N. Tkachuk and L. D. Lavis, ACS Cent.
Sci., 2017, 3, 975–985.
6 G. Lukinavic
ˇius, K. Umezawa, N. Olivier, A. Honigmann, G. Yang,
0
0
0
was more stable than HITCI (1,1 ,3,3,3 ,3 -hexamethylindotricarbo-
T. Plass, V. Mueller, L. Reymond, I. R. Corr ˆe a Jr, Z.-G. Luo, C. Schultz,
E. A. Lemke, P. Heppenstall, C. Eggeling, S. Manley and K. Johnsson,
Nat. Chem., 2013, 5, 132–139.
cyanine iodide) but less stable than rhodamine B (Fig. S11, ESI†).
We further explored the pathways of degradation for these
1
7 Y. Kushida, T. Nagano and K. Hanaoka, Analyst, 2015, 140, 685–695.
8
9
dyes. Photobleaching of cyanines are generally caused by O
2
A. Choi and S. C. Miller, Org. Lett., 2018, 20, 4482–4485.
T. Ikeno, T. Nagano and K. Hanaoka, Chem. – Asian J., 2017, 12,
1435–1446.
2
7
mediated photolysis of the polymethine chain. Thus, 10 and
1
1
2
1 were subjected to O and analysed for photodegradation
1
1
1
1
0 C. Li, T. Wang, N. Li, M. Li, Y. Li, Y. Sun, Y. Tian, J. Zhu, Y. Wu,
D. Zhang and X. Cui, Chem. Commun., 2019, 55, 11802.
1 J. L. Bricks, A. D. Kachkovskii, Y. L. Slominskii, A. O. Gerasov and
S. V. Popov, Dyes Pigm., 2015, 121, 238–255.
products via liquid chromatography mass spectrometry (LCMS,
Fig. S12, ESI†). We found that 11 degraded quickly (o1 hour)
0
28
and cleaved at C-1 of the polymethine chain as anticipated.
2 M. P. Shandura, Y. M. Poronik and Y. P. Kovtun, Dyes Pigm., 2005,
Surprisingly, 10 reacted slowly, only showing complete degradation
at 17 hours. Unlike its oxygen counterpart, 10 degraded into a
6
6, 171–177.
3 M. R. Detty and B. J. Murray, J. Org. Chem., 1982, 47, 5235–5239.
ˇebej, J. Medalov ´a , P. ˇS tacko and P. Kl ´a n, J. Org.
multitude of products suggesting that silicon incorporation 14 T. Pastierik, P. S
1
0
2
reactivity at C-1 . We compared this photo-
Chem., 2014, 79, 3374–3382.
deactivated the O
stability to acid and base stability of 7, 8, 10, and 11 where we found
1
1
5 L. M. Tolbert and X. Zhao, J. Am. Chem. Soc., 1997, 119, 3253–3258.
6 L. M. Tolbert, Acc. Chem. Res., 1992, 25, 561–568.
that the oxygen congeners (8, 11) were more stable to base and 17 S. V. Vasyluk, O. O. Viniychuk, Y. M. Poronik, Y. P. Kovtun, M. P.
Shandura, V. M. Yashchuk and O. D. Kachkovsky, J. Mol. Struct., 2011,
similarly stable to acid as compared to 7 and 10 (Fig. S13–S16, ESI†).
990, 6–13.
In summary, we have demonstrated that incorporation of
silicon into polymethine dyes is a valid approach to red shift
this class of fluorophores and is on par with vinylene chain
extension. We prepared tri- and pentamethines with xanthene-
1
8 H. Hu, O. V. Przhonska, F. Terenziani, A. Painelli, D. Fishman,
T. R. Ensley, M. Reichert, S. Webster, J. L. Bricks, A. D. Kachkovski,
D. J. Hagan and E. W. Van Stryland, Phys. Chem. Chem. Phys., 2013,
15, 7666.
1
9 Y. Zhao and D. G. Truhlar, Theor. Chem. Acc., 2008, 120, 215–241.
derived heterocycles which were 70–100 nm red-shifted and six 20 M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb,
J. R. Cheeseman, G. Scalmani, V. Barone, G. A. Petersson, H. Nakatsuji,
to ten-fold more photostable compared to oxygen analogues.
X. Li, M. Caricato, A. V. Marenich, J. Bloino, B. G. Janesko, R. Gomperts,
The xanthene-derived heterocycles, while providing an efficient
B. Mennucci, H. P. Hratchian, J. V. Ortiz, A. F. Izmaylov, J. L. Sonnenberg,
avenue for the synthesis of silicon polymethine dyes, also
promoted ground state desymmetrization, which resulted in a
broad, bimodal absorption spectrum and a decreased presence
of the emissive species. Looking forward, the implementation
of silicon into polymethine heterocycles that do not promote
desymmetrization should provide avenues for the creation of deeply
red-shifted (4900 nm) fluorophores with high photostability.
We acknowledge research funding from Sloan Research
Award (FG-2018-10855 to E. M. S.), NIH (1R01EB027172-01 to
E. M. S.), NSF (1940307 to S. A. L.), DOE BES (DE-SC0019245 to
J. R. C.), Ms C. Shapazian (to P. N.) and instrumentation funding
through the NSF MRI (CHE-1048804), NIH (1S10OD016387-01)
and computing resources provided by the Massachusetts Green
High-Performance Computing Center (MGHPCC). We thank
I. Lim, Dr J. Li, Dr J. Cox, and the Northeastern Research
Computing Team for discussions.
D. Williams-Young, F. Ding, F. Lipparini, F. Egidi, J. Goings, B. Peng,
A. Petrone, T. Henderson, D. Ranasinghe, V. G. Zakrzewski, J. Gao,
N. Rega, G. Zheng, W. Liang, M. Hada, M. Ehara, K. Toyota, R. Fukuda,
J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai,
T. Vreven, K. Throssell, J. A. Montgomery, Jr., J. E. Peralta, F. Ogliaro,
M. J. Bearpark, J. J. Heyd, E. N. Brothers, K. N. Kudin, V. N. Staroverov,
T. A. Keith, R. Kobayashi, J. Normand, K. Raghavachari, A. P. Rendell,
J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, J. M. Millam, M. Klene,
C. Adamo, R. Cammi, J. W. Ochterski, R. L. Martin, K. Morokuma,
O. Farkas, J. B. Foresman and D. J. Fox, Gaussian 16, Revision A.03, 2016.
1 M. Head-Gordon, R. J. Rico, M. Oumi and T. J. Lee, Chem. Phys. Lett.,
2
2
1994, 219, 21–29.
2 M. Head-Gordon, D. Maurice and M. Oumi, Chem. Phys. Lett., 1995,
246, 114–121.
23 F. Neese, Wiley Interdiscip. Rev.: Comput. Mol. Sci., 2018, 8, 1327.
24 F. Neese, Wiley Interdiscip. Rev.: Comput. Mol. Sci., 2012, 2, 73–78.
25 E. Thimsen, B. Sadtler and M. Y. Berezin, Nanophotonics, 2017, 6,
1043–1054.
2
6 F. Terenziani, O. V. Przhonska, S. Webster, L. A. Padilha,
Y. L. Slominsky, I. G. Davydenko, A. O. Gerasov, Y. P. Kovtun,
M. P. Shandura, A. D. Kachkovski, D. J. Hagan, E. W. Van Stryland
and A. Painelli, J. Phys. Chem. Lett., 2010, 1, 1800–1804.
7 S. Yamaguchi and K. Tamao, J. Chem. Soc., Dalton Trans., 1998,
2
2
Conflicts of interest
3693–3702.
8 R. Nani, J. A. Kelley, J. Ivanic and M. J. Schnermann, Chem. Sci.,
2015, 6, 6556–6563.
There are no conflicts to declare.
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