Supporting information

Electrochemiluminescent chemodosimeter based on iridium(III) complex for

point-of-care detection of homocysteine levels

Hoon Jun Kim,†§ Kyung-Sik Lee,†§ Yong-Jun Jeon,† Ik-Soo Shin,‡* and Jong-In Hong†*

†Department of Chemistry, College of Natural Science, Seoul National University, Seoul 151-

747, Republic of Korea

‡Department of Chemistry, College of Natural Science, Soongsil University, Seoul 156-743,

Republic of Korea

* Prof. Dr. J.-I. Hong, Department of Chemistry, Seoul National University, Seoul 151-747

(Rep. Korea), Fax: (+82) 2-889-1568, E-mail: jihong@snu.ac.kr

* Prof. Dr. I.-S. Shin, Department of Chemistry, Soongsil University, Seoul 156-743, (Rep.

Korea), E-mail: extant@ssu.ac.kr

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Table S1. Electrochemical properties of Ir(III)-based Hcy probes

Compounda

(V vs SCE)

b *

(V vs SCE)

E0−0 *

(eV)

3 0.40 -1.66 2.06

3-Hcy 0.37 -1.99 2.36

3-Cys 0.38 -1.98 2.36

1 0.77 -1.04 1.81

1-Hcy 0.74 -1.28 2.02

1-Cys 0.70 -1.32 2.02

aThe oxidation potentials were measured using cyclic voltammetry at the scan rate of

0.1 V/s in acetonitrile (CH3CN) solutions with 0.1 M tetra-n-butylammonium

perchlorate as the supporting electrolyte and then the values were calibrated against the

oxidation of 1 mM ferrocene (Fc/Fc+) as a standard and then referenced to SCE. bThe

reduction potential values were calculated from the excitation energies (E0−0 ) and the

oxidation potentials ( ).

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Figure S1. Partial 1H NMR spectra of 1 (a), 1 + Hcy (10 equiv.) (b), and 1 + Hcy (50 equiv.) (c)

in DMSO-d6. The aldehyde proton at 9.61 ppm disappeared and new peak at 4.82 ppm appeared.

The new peak at 4.82 ppm was assigned as the methine protons in the six-memebered thiazinane

after the ring formation with Hcy.

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Figure S2. ECL spectra of (piq)2Ir(acac) and Ru(bpy)32+ (10 M, each) in CH3CN solution. (10

mM TPA as a coreactant and 0.1M NaClO4 as the supporting electrolyte)

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Figure S3. Normalized absorption and emission spectra of probe 1 (10 M) in the absence (red

line) and presence (black line) of Hcy (1 mM) (λex: 500 nm).

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Figure S4. (a) Phosphorescence spectra of probe 1 (10 M) in the absence and presence (1 mM

and 2 mM, each) of Hcy. (b) Phosphorescence titration curve of probe 1 (10 M) upon addition

of Hcy (HEPES buffer/CH3CN, 1:1 v/v, pH 7.4) (λex: 500 nm).

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Figure S5. (a) Phosphorescence spectra of probe 1 (10 M) in the absence and presence of 0.1-

5.0 mM of Hcy in DMSO solution (λex: 500 nm).

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Figure S6. DFT calculated HOMO and LUMO energy levels of probe 1 and reaction adducts of

1 + 1 equiv. Hcy (or Cys) and 1 + 2 equiv. Hcy (or Cys).

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 Figure S7. DFT calculations of 1 and 1-Hcy: (a) three-dimensional optimized geometries (b)

electron density contour maps of the calculated HOMO, and (c) LUMO.

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Figure S8. PL competition assays performed by addition of 5 mM Hcy to 50 µM 1 in the

presence of 10 mM of various amino acids. (HEPES buffer/CH3CN, 1:1 v/v, pH 7.4)

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Figure S9. (a) Phosphorescence spectra of probe 2 (50 M) in the absence and presence (5 mM)

of Hcy. (HEPES buffer/CH3CN, 1:1 v/v, pH 7.4)

400 450 500 550 600 650 700

0

100

200

300

400

PL In

tens

ity (a

.u.)

Wavelength (nm)

2 2-Hcy

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Figure S10. (a) ECL spectra of 2 (50 M) in the absence and presence (1, 5 and 10 mM, each) of

Hcy. (b) ECL titration curve of 2 (50 M) upon addition of Hcy (HEPES buffer/CH3CN, 1:1 v/v,

pH 7.4).

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Figure S11. ECL spectra of 3 (10 M) in the absence and presence (5 mM) of Hcy. (Inset)

Relative ECL intensity of 3, 3-Hcy, 1, and 1-Hcy. (1, 3: 10 M, Hcy: 5 mM, each, HEPES

buffer/CH3CN, 1:1 v/v, pH 7.4).

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Figure S12. PL & ECL images of probes 1 & 2 (10 each) in the absence and presence of

Hcy (1 mM) (HEPES buffer/CH3CN, 1:1 v/v, pH 7.4). PL images were taken under UV light

irradiation using a UV hand lamp (4W, 365 nm). ECL images were taken during CV between 0.5

and 1.5V vs. Ag/AgCl at 0.1V/s.

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