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DNA and BSA-Binding Studies of Dinuclear Palladium(II) Complexes with 1,5-Naphtiridine Bridging Ligands

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22 juin 2021
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Figure 1.

Structural formulas of 1,5-naphthyridine (1,5-nphe), ethylenediamine (en) and 1,3-propylenediamine (1,3-pd), and dinuclear palladium(II) complexes Pd1 and Pd2.
Structural formulas of 1,5-naphthyridine (1,5-nphe), ethylenediamine (en) and 1,3-propylenediamine (1,3-pd), and dinuclear palladium(II) complexes Pd1 and Pd2.

Figure 2.

1H and 13C NMR spectra of [{Pd(en)Cl}2(μ-1,5-nphe)](NO3)2 (Pd1) and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)](NO3)2 (Pd2) complexes.
1H and 13C NMR spectra of [{Pd(en)Cl}2(μ-1,5-nphe)](NO3)2 (Pd1) and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)](NO3)2 (Pd2) complexes.

Figure 3.

UV-Vis spectra of dinuclear [{Pd(en)Cl}2 (μ-1,5-nphe)]2+ and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)]2+ complexes and free 1,5-nphe ligand.
UV-Vis spectra of dinuclear [{Pd(en)Cl}2 (μ-1,5-nphe)]2+ and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)]2+ complexes and free 1,5-nphe ligand.

Figure 4.

IR spectra of Pd1 and Pd2 complexes, KBr, 4000-450 cm−1.
IR spectra of Pd1 and Pd2 complexes, KBr, 4000-450 cm−1.

Figure 5.

Absorption spectra of [{Pd(en)Cl}2(μ-1,5-nphe)]2+ and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)]2+ complexes in 0.01 M phosphate buffer before and after addition of CT-DNA. [Pd(II) complex] = 4.51 · 10−5 M, [DNA] = (0 – 2.00) · 10−4 M.
Absorption spectra of [{Pd(en)Cl}2(μ-1,5-nphe)]2+ and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)]2+ complexes in 0.01 M phosphate buffer before and after addition of CT-DNA. [Pd(II) complex] = 4.51 · 10−5 M, [DNA] = (0 – 2.00) · 10−4 M.

Figure 6.

EtBr/CT-DNA emission spectra in the presence of [{Pd(en)Cl}2(μ-1,5-nphe)]2+ and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)]2+ complex. [EtBr] = 1.28 · 10−5 M, [DNA] = 1.28 · 10−5 M, [Pd(II) complex] = (0 – 1.28) · 10−5 M. Inserted graph: Dependence of I0/I from concentration [Q].
EtBr/CT-DNA emission spectra in the presence of [{Pd(en)Cl}2(μ-1,5-nphe)]2+ and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)]2+ complex. [EtBr] = 1.28 · 10−5 M, [DNA] = 1.28 · 10−5 M, [Pd(II) complex] = (0 – 1.28) · 10−5 M. Inserted graph: Dependence of I0/I from concentration [Q].

Figure 7.

BSA emission spectra in the presence of [{Pd(en)Cl}2(μ-1,5-nphe)]2+ and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)]2+ complexes. [BSA] = 1.60 · 10−6 M, [Pd(II) complex] = (0 – 4.00) · 10−5 M; λex = 295 nm. Inserted graph: Dependence of Io/I from concentration [Q].
BSA emission spectra in the presence of [{Pd(en)Cl}2(μ-1,5-nphe)]2+ and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)]2+ complexes. [BSA] = 1.60 · 10−6 M, [Pd(II) complex] = (0 – 4.00) · 10−5 M; λex = 295 nm. Inserted graph: Dependence of Io/I from concentration [Q].

Stern-Volmer constant (Ksv), quenching constant (kq), binding constant (Ka) and number of binding sites (n) for interactions between BSA and dinuclear Pd1 and Pd2 complexes_

complex Ksv · 105 (M1) kq · 1012 (M1s1) Ka · 109 (M1) n
[{Pd(en)Cl}2 (μ-1,5-nphe)]2+ (2.80 ± 0.03) (28 ± 2) (1.20 ± 0.05) 1.8
[{Pd(1,3-pd)Cl}2 (μ-1,5-nphe)]2+ (3.90 ± 0.04) (39 ± 1) (1.20 ± 0.02) 1.8

Stern-Volmer constant (Ksv), stability constant (Ka) and number of binding sites (n) of the investigated dinuclear palladium(II) complexes with CT-DNA

complex Ksv · 105 (M1) Ka · 105 (M1) n
[{Pd(en)Cl}2 (μ-1,5-nphe)]2+ (4.50 ± 0.04) (8.80 ± 0.02) 1.7
[{Pd(1,3-pd)Cl}2 (μ-1,5-nphe)]2+ (2.80 ± 0.06) (2.50 ± 0.05) 1.1

1H and 13C NMR chemical shifts (δ, ppm) for 1,5-naphthyridine (1,5-nphe), ethylenediamine (en), 1,3-propylenediamine (1,3-pd) and the corresponding dinuclear palladium(II) complexes

ligand/complex NMR shifts
1H 13C
H2, H6 H4, H8 H3, H7 alifatic protons C2, C6 C4, C8 C3, C7 C4a, C8a L
1,5-nphe 8.57 dd 7.89 d 7.48 dd 154 139 128 144
en 2.64 s (CH2) 45 (CH2)
Pd1 10.21 d 9.58 d 8.14 m 2.76 m (CH2) 160 147 130 143 50 (CH2)
1,3-pd 1.60 m (H2, CH2) 2.47 m (H1,H3,CH2) 29 (C2, CH2) 39 (C1,C3, H2)
Pd2 10.17 d 9.55 d 8.23 m 1.85 m (H2,CH2) 2.76 m (H1,H3,CH2) 160 146 131 143 30 (C2, CH2) 43,44 (C1,C3, CH2)

Internal binding constants (Kb), changes in Gibbs energy (ΔG) and hypochromism (H) of the investigated dinuclear palladium(II) complexes, Pd1 and Pd2, with CT-DNA

complex Kb · 104 (M−1) ΔG (kJ/mol) H
[{Pd(en)Cl}2 (μ-1,5-nphe)]2+ (7.50 ± 0.05) −28.93 22.42
[{Pd(1,3-pd)Cl}2 (μ-1,5-nphe)]2+ (4.00 ± 0.03) −27.31 25.77
Langue:
Anglais
Périodicité:
4 fois par an
Sujets de la revue:
Médecine, Médecine clinique, Médecine clinique, autres