Synthesis, Characterization and DNA Binding Investigations of a New Binuclear Ag(I) Complex and Evaluation of Its Anticancer Property

Figures & data

Figure 1 Synthesis of ligand 5-fluorouracil-1-yl acetic acid (L1).

Table 1 Data Collection and Refinement Parameters for A₃

Compound	A3
Identification code	p
Empirical formula	C102H83Ag2F2N4O8P5
Formula weight	1901.31
Temperature	296(2) K
Wavelength	0.71073 Å
Crystal system, space group	Triclinic, P-1
Unit cell dimensions	a = 13.806(3) Å alpha = 75.622(4) deg.
	b = 14.652(3) Å beta = 79.104(4) deg.
	c = 27.796(5) Å gamma = 62.666(3) deg.
Volume	4820.1(17) Å^3
Z, Calculated density	2, 1.310 Mg/m^3
Absorption coefficient	0.549 mm^−1
F(000)	1948
Crystal size	0.310 x 0.230 x 0.120 mm
Theta range for data collection	0.759 to 28.440 deg.
Limiting indices	−17≤h≤18, −10≤k≤19, −36≤l≤37
Reflections collected/unique	42,714/23,856 [R(int) = 0.0412]
Completeness to theta = 25.242	98.4%
Absorption correction	None
Refinement method	Full-matrix least-squares on F^2
Data/restraints/parameters	23,856/120/1108
Goodness-of-fit on F^2	0.953
Final R indices [I>2sigma(I)]	R1 = 0.0723, wR2 = 0.2139
R indices (all data)	R1 = 0.1345, wR2 = 0.2737
Extinction coefficient	n/a
Largest diff. peak and hole	1.147 and −1.396 e. Å^3

Figure 2 Molecular diagram of [(PPh₃)₃Ag(L1)].[(PPh₃)₂Ag(L1)] (A₃).

Figure 3 Electronic absorption spectra of the A₃ (10 μM) in the absence and presence of amounts of CT-DNA (0, 0.005, 0.01, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045 mg mL⁻¹) in KH₂PO₄/NaOH buffer ((A) pH = 6.2, (B) pH = 7.2, (C) pH = 8.2). Inset: Plot of A₀/A-A₀ vs.1/[DNA] for the titration of the A₃ with CT-DNA. The binding constants (K_b) of A₃ are 36.03 mg mL⁻¹ (A), 50.40 mg mL⁻¹ (B) and 41.1 mg mL⁻¹ (C), respectively.

Figure 4 Emission spectra of EtBr (0.05 mM) connected to CT-DNA (0.12 mg mL⁻¹) in the absence and presence of A₃ (0.00, 0.02, 0.04, 0.06, 0.08, 0.10 mM) in KH₂PO₄/NaOH buffer (pH = 7.2). Inset: Stern–Volmer quenching curve. The K_SV value is 2.789 × 10³ M⁻¹.

Figure 5 Cyclic voltammograms of Fe(CN)₆ ^3－/4－ in pH 7.2 KH₂PO₄/NaOH buffer solution at a bare Au electrode (a), CT-DNA/Au (b). The scan rate is 0.1 V s ⁻¹ and the concentrations of Fe(CN)6^3－/4－ and KCl are 5 mM.

Figure 6 The relationship between anodic peak current and the scanning rate (0.01–-0.13 V s ⁻¹) for CT-DNA/Au.

Figure 7 Cyclic voltammograms of Fe(CN)₆^3-/4- in KH₂PO₄/NaOH buffer solution (pH 7.2) containing different concentrations of drugs. The scan rate is 0.1 V s ⁻¹ and the concentrations of Fe(CN)₆ ^3-/4- and KCl are 5 mM.

Figure 8 Adsorption isotherm of drug A₃ on CT-DNA/Au. The solid line corresponds to the Langmuir model. Inset: The relationship between 1/[DRUG] and 1/ΔI_P.

Figure 9 Cell viability of A₃+NIR, A₃ and 5-Fu in HCT 116 cell line. Significant differences are indicated as ***P<0.001, **P<0.01, *P<0.05, n=3.

Figure 10 Cell viability of A₃+NIR, A₃ and 5-Fu in MDA-`MB-231 cell line. Significant differences are illustrated as **P<0.01, *P<0.05, n=3.

Table 2 IC₅₀s of A₃+NIR, A₃ and 5-Fu (µm). IC₅₀s Were Calculated Based on CCK-8 Results by IBM SPSS Statistics Software

Group	HCT116	MDA-MB-231
A3+NIR	4.51 ± 0.25	3.34 ± 0.51
A3	4.93 ± 0.22	4.15 ± 0.21
5-FUAA	9.61 ± 1.06	9.91 ± 0.81