Synthesis of bis(pyrylium salt)s monomer M
Scheme S1: Synthesis route for the bis(pyrylium salt)s monomer M .
Synthesis of 3,30-(1,4-Phenylene)bis(1,5-diphen-yl-1,5-pentadione) (1)
Compound 1 was synthesized according to a procedure described in the literature.
1
The synthesis of the phenyl tetraketone was carried out in a round bottom flask to which a mixture of acetophenone (5.43 g, 45 mmol) and terephthaldehyde
(1.00 g, 7.5 mmol) were added in a 6 to 1 mole ratio. The mixture was then stirred in
25 mL of 95% ethanol and heated to 65

C until completely dissolved. Once the starting materials were dissolved, a solution of potassium hydroxide (1.05 g, 190 mmol in 1 mL of distilled water) was added dropwise to the reaction mixture with vigorous stirring over a thirty minutes time period. A yellow precipitate formed immediately and the heterogeneous reaction mixture was then heated at reflux until it
1

turned pink, which occurred over a 4-5 hours. During this time, the p-bischalcone redissolved and reacted with additional equivalents of acetophenone to form the phenyl tetraketone, which precipitated. The reaction mixture was then filtered hot, and the tan solid materials was collected by vacuum filtration to afford 4.10 g of crude product. The crude produce was then purified by recrystallization from toluene to yield 3.50 g (81% yield) of off-white crystals, which was collected by vacuum filtration and dried in a vacuum oven before the final analysis. m.p. 205–206

C.
1
H
NMR (400 MHz, d
6
-DMSO, ppm): 7.96 (d, J = 7.6 Hz, 8H, ortho Ar–C=O),
7.38–7.56 (m, 12H, meta and para Ar–C=O), 7.19 (s, 2H, center Ar–H), 4.02 (t, 2H,
Ar–CH), 3.23–3.51 (m, 8H, CH
2
–C=O).
Synthesis of 4,40-(1,4-phenylene)bis(2,6-diphen-yl-pyrylium) ditosylate (M)
Compound M was synthesized according to a procedure described in the literature.
1
In a round bottom flask, triphenylmethanol (7.8 g, 0.030 mol) and p-toluenesulfonic acid monohydrate (5.8 g, 0.030 mol) were added to 100 mL of acetic anhydride. These reactants were stirred at room temperature for 3 hours. Once this process was completed, the solid phenyl tetraketone 1 (7.2 g, 0.012 mol) was added to the reaction mixture, and the reaction mixture was heated to 100

C for 1 hour. The heterogeneous mixture became clear, and upon cooling, yellow crystals appeared and were collected by vacuum filtration. These crystals were carefully washed with acetic anhydride and ethanol respectively. The material was then air dried to give the crude product. The crude product was then purified by recrystallization in acetic acid, and dried in a vacuum oven to afford 7.9 (75% yield)
2

of orange powder. 1 H NMR (400 MHz, d
6
-DMSO, ppm): 9.35 (s, 4H, aromatic meta to O
+
), 9.21 (s, 4H, 1,4-phenylene), 7.58–8.93 (m, 20H, phenyl), 7.46–7.47 (d, J = 6.7
Hz, 4H, tosylate), 7.09–7.10 (d, J = 7.7 Hz, 4H, tosylate), 2.27 (s, 6H, CH
3
). Anal. calcd for C
54
H
42
O
8
S
2
: C, 73.45; H, 4.79. Found: C, 73.15; H, 4.71%.
Figure S1
1
H NMR spectrum of poly(pyridinium salt)s P1 .
3

Figure S2 FT-IR spectrum of poly(pyridinium salt)s P1 .
Figure S3 GPC trace of poly(pyridinium salt)s P1 .
4

Figure S4 Job's plot. A
0 is the initial absorbance of the free P1 , A i
is the recorded absorbance of complexes at different ctDNA concentrations in tris-HCl buffer solution, and X i
is the molar fraction of ctDNA.
Reference:
1. (a) P. K. Bhowmik, R. A. Burchett, H. Han and J. J. Cebe, Macromolecules , 2001,
34 , 7579; (b) F. W. Harris, K. C. Chuang, S. A. X. Huang, J. J. Janimak and S. Z. D.
Cheng, Polymer , 1994, 35 , 4940; (c) S. A. X. Huang, K. C. Chuang, S. Z. D. Cheng and F. W. Harris, Polymer , 2000, 41 , 5001; (d) P. K. Bhowmik, H. Han, A. K.
Nedeltchev, H. D. Mandal, J. A. Jimenez-Hernandez and P. M. McGannon, Polymer ,
2009, 50 , 3128.
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