Supporting Information
Investigation on the Interaction of a Cyanine Dye with
Transferrin Based on Spectroscopic Methods
Xiu-feng Zhanga*, Ling Lana, Lei Chena, Hong-bo Chena, Qian-fan Yangb, Qian Lib,
Qi-long Lia, Xiao-ran Suna, Ya-lin Tangb*
a. College of Chemical Engineering, North China University of Science and
Technology, Tangshan, Hebei, 063009, China
b. Beijing National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese
Academy of Sciences, Beijing 100190, China
Identification of Cyanine Dye ETC
The structure and purification of cyanine dye ETC were identified by MS-ESI,
elemental analysis, NMR and absorption spectroscopy.
a) MS-ESI
From the mass spectrum, the measured molecular weight of ETC is 679, which is
consistent with the calculated value, 680.
b) Elemental Analysis
ETC molecular formula: C39H47N3O6S4·3H2O
Table 1. Elemental analysis of cyanine dye ETC
Element
N
C
H
S
Calculated Value (%)
5.03
56.02
6.39
15.34
Experimental Value (%)
5.09
56.13
6.27
15.10
c) NMR spectrum
Figure 1. The numbering scheme of molecular structure of ETC
Figure 2. The 1H-NMR spectrum of cyanine dye ETC in DMSO-d6
Table 2. The full assignments of the proton peaks of ETC
Proton
Proton
Proton
Proton
1
1
H peak
number
kind
1
Aromatic
2
H peak
number
kind
8.127-8.106, d
13
Aromatic
7.663, t
Aromatic
7.788, t
14
Aromatic
7.788, t
3
Aromatic
7.663, t
15
Aromatic
8.127-8.106, d
4
Aromatic
7.956-7.934, d
16
Secondary
4.97, s
5
Aromatic
8.258-8.224, d
17
Secondary
--*
6
Aromatic
8.614-8.592, d
18
Secondary
3.002-2.928,
m
7
Tertiary
8
Secondary
6.653, s
19
Secondary
4.97, s
20
Secondary
--*
21
Secondary
3.002-2.928,
m
3.002-2.928,
9
Tertiary
6.653, s
m
*
10
Aromatic
8.614-8.592, d
22
Secondary
3.125-3.070, q
11
Aromatic
8.258-8.224, d
23
Primary
1.17, t
12
Aromatic
7.956-7.934, d
24
Primary
1.374, t
The peaks of these secondary protons are covered by the peak of the solvent DMSO-d6