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

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

EABR. Experimental and Applied Biomedical Research
Volume 25 (2024): Issue 2 (June 2024)
By: ,  ,   and    
Open Access
|Jun 2021
Figures & tables

Figures & Tables

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.

Table 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/complexNMR shifts
1H13C
H2, H6H4, H8H3, H7alifatic protonsC2, C6C4, C8C3, C7C4a, C8aL
1,5-nphe8.57 dd7.89 d7.48 dd154139128144
en2.64 s (CH2)45 (CH2)
Pd110.21 d9.58 d8.14 m2.76 m (CH2)16014713014350 (CH2)
1,3-pd1.60 m (H2, CH2)
2.47 m (H1,H3,CH2)		29 (C2, CH2)
39 (C1,C3, H2)
Pd210.17 d9.55 d8.23 m1.85 m (H2,CH2)
2.76 m (H1,H3,CH2)		16014613114330 (C2, CH2)
43,44 (C1,C3, CH2)

[i] In the 1H NMR spectrum of free 1,5-naphthyridine, two multiplets (doublet-doublets, dd) occur at 7.48 (H3, H7) and 8.57 (H2, H6) ppm, derive from the equivalent protons of the two condensed pyridine rings. The doublet at 7.89 ppm originates from the H4 and H8 protons of 1,5-nphe.

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.

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.

Figure 4.

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.

Table 2.

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

complexKb · 104 (M−1)ΔG (kJ/mol)H
[{Pd(en)Cl}2 (μ-1,5-nphe)]2+(7.50 ± 0.05)−28.9322.42
[{Pd(1,3-pd)Cl}2 (μ-1,5-nphe)]2+(4.00 ± 0.03)−27.3125.77
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].

Table 3.

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

complexKsv · 105 (M−1)Ka · 105 (M−1)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
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].

Table 4.

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.

complexKsv · 105 (M−1)kq · 1012 (M−1s−1)Ka · 109 (M−1)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
DOI: https://doi.org/10.2478/sjecr-2021-0030 | Journal eISSN: 2956-2090 (formerly 2335-075X, 2956-0454) | Journal ISSN: 2956-0454 (formerly 1820-8665)
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Language: English
Page range: 113 - 126
Submitted on: Jan 22, 2021
Accepted on: Feb 24, 2021
Published on: Jun 22, 2021
Published by: University of Kragujevac, Faculty of Medical Sciences
In partnership with: Paradigm Publishing Services
Keywords:
Dinuclear palladium(II) complexes,
1,5-naphthyridine,
DNA,
bovine serum albumin (BSA)
Related subjects:
Medicine,
Clinical medicine,
Clinical medicine, other

© 2021 Snezana Rajkovic, Andjela A. Franich, Vojislav Cupurdija, Marija D. Zivkovic, published by University of Kragujevac, Faculty of Medical Sciences
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

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