Homobimetallic zinc(II) dithiocarbamates: synthesis,characterization and in vivo antihyperglycemic activity

This article presents structural characteristic and in vivo antihyperglycemic activities of three new homobimetallic Zn(II) dithiocarbamates (1–3) with general formula [ZnL₂]₂, where L is 4-(3-methoxyphenyl)piperazine-1-carbodithioate (1), 4-(4-methoxyphenyl)piperazine-1-carbodithioate (2) and 4-benzhydrylpiperazine-1-carbodithiaoate (3). These complexes have been characterized by elemental analysis, FT-IR, multinuclear NMR (¹H and ¹³C), and X-ray single crystal analysis. The latter technique has confirmed the homobimetallic nature of 1 and 2 in which Zn ions are linked via sulfurs to form a four-membered ring Zn₂S₂. Non-covalent intermolecular interactions give a supramolecular ladder-like zigzag chain (1) and layered structure (2). The antihyperglycemic activities revealed that the blood glucose lowering ability follows the trend: glibenclamide (83.0 mg dL^?1) > 3 (97.6 mg dL^?1) > 2 (100.4 mg dL^?1) > 1 (141.4 mg dL^?1).     

Heteroleptic Pd(II) dithiocarbamates: synthesis,characterization, packing and in vitro anticancer activity against HeLa cell line

Two new heteroleptic Pd(II) dithiocarbamates (1 and 2) have been synthesized by reaction of equimolar quantities of palladium(II) chloride, sodium 4-(3-methoxyphenyl)piperazine-1-carbodithioate, and appropriate substituted triphenylphosphines. The synthesized complexes have been characterized by their physical, spectral (IR, ¹H, ¹³C, and ³¹P NMR), and X-ray crystallographic data. Complexes 1 and 2 showed square-planar geometry both in solution and solid states. The crystal packing of both complexes revealed similar 3-D-supramolecular networks comprised of 1-D chains. However, the nature and strength of various non-covalent interactions of these networks were slightly different. The DNA interaction studies of the complexes have been carried out by UV–visible spectroscopy to evaluate their anticancer potential. The study suggested intercalative interaction with 2.402 × 10⁴ and 2.713 × 10³ M^?1 binding constants, respectively. The complexes have also been evaluated for their anticancer activity against HeLa cell line. Both complexes showed higher activity with IC₅₀ values much lower (22.176 and 26.166 μM for 1 and 2, respectively) than the standard cisplatin (78.075 μM). Furthermore, the complexes induced stronger DNA fragmentation as investigated by DNA ladder assay for apoptosis. Our findings suggested that the anticancer action of these compounds stems from their interaction with DNA leading to DNA damage and apoptosis. The excellent activity of 1 and 2 deserves to be a focus for further research and in vivo studies.     

New 3D and 2D supramolecular heteroleptic palladium(II) dithiocarbamates as potent anticancer agents

Three new heteroleptic palladium(II) dithiocarbamates with better in vitro anticancer activity than cisplatin were synthesized and characterized by different analytical techniques, elemental analysis, FTIR, NMR, and single crystal X-ray diffraction analysis. The Pd center is chelated by dithiocarbamate ligand {4-benzylpiperazine-1-carbodithioate (1) and (3) or (4-(2-methoxyphenyl)piperazine-1-carbodithioate (2)}, triorganophosphine {tris-(4-flourophenyl)-phosphine (1) and (2) or tris-(4-chlorophenyl)phosphine (3)}, and a chloro-group, resulting in a square planar geometry. The packing diagram reveals a 3D network (1 and 2) and a 2D network (3) composed of various 1D chains in which the molecules are linked via hydrogen bonds (1–3) and halide?π (1, 3) interactions. The anticancer activities of complexes against HeLa cell line varies in the sequence 2 (23.438 μM) > 1 (38.293 μM) > 3 (47.554 μM) > cisplatin (78.075 μM). The cytotoxicity of these complexes is due to their strong induction of oxidative stress and DNA-damage ability leading to apoptosis.     

Humidity-sensing and DNA-binding ability of bis(4-benzylpiperazine-1-carbodithioato-k2 S,S′)nickel(II)

Bis(4-benzylpiperazine-1-carbodithioato-k² S,S?)nickel(II), 1, was prepared by metathesis of sodium salt of 4-benzylpiperazine-1-carbodithioate with nickel(II) chloride in 2?:?1 ratio. Complex 1 was characterized by analytical techniques including elemental analysis, FT-IR, UV–visible spectroscopy, and X-ray single-crystal analysis. The latter technique confirmed square-planar geometry around Ni with the formation of NiS₄ core with two shorter and two longer Ni–S bonds. The packing diagram revealed a supramolecular chain structure mediated by unconventional H?H dihydrogen bonds that resulted in a chair and a ladder-like structure when viewed along the a-axis and c-axis, respectively. The thin-film coating resulted in a microporous film with a band gap of 1.69 eV. Complex 1-based sensor was fabricated to check the humidity-sensing properties of the material. Resistance of the device decreased by two orders of magnitude and capacitance was enhanced with the increase of relative humidity. The DNA binding study proved 1 to be a good DNA binder with binding constant value of 1.4 × 10⁴ M^?1.     

Ternary paddlewheel copper(II) complexes: synthesis,structural elucidation,DNA-binding,anti-oxidant and conductance studies

ABSTRACT

Two new binuclear Cu(II) complexes Cu₂L₄(DMS)₂ (1) and Cu₂L₄(3BrPy)₂ (2) where L = para-chlorophenyl acetate, DMS = dimethylsulfoxide and 3BrPy = 3-bromopyridine have been synthesised and characterised using FT-IR, single crystal XRD analysis, absorption and conductance studies. In both the complexes copper(II) ion lies in distorted square pyramidal geometry where the apical position is occupied by pyridine in monodentate fashion while the equatorial positions are occupied by four carboxylate ligands in bidentate coordination mode. The supramolecular structures of the complexes arise primarily as a result of C–H…O and H–C…H types of interactions and are different owing to the different apical ligands. The DNA-binding activity of the complexes has been studied through absorption spectroscopy, viscometry and competitive ethidium bromide displacement techniques. These techniques indicated a mixed electrostatic and intercalative mode of interaction with DNA-binding constant values K_b of 1.98 × 10⁴ M^?1 and 2.86 × 10⁴ M^?1 for complexes 1 and 2, respectively. These activities represent the preliminary biological relevance of the synthesised complexes.     

A new quinoline-based chemosensor in ratiometric sensing of Hg2+ ions

A new quinoline-based chemosensor 1 has been designed and synthesised. Its metal ion-binding properties have been documented in organic and aqueous organic solvents. While chemosensor 1 recognises Hg²⁺ ions (K _a = 2.15 × 10⁴ M^? 1) by exhibiting ratiometric change in emission in CHCl₃/CH₃OH (1:1, v/v), under similar condition both Zn²⁺ and Cd²⁺ ions are sensed by significant non-ratiometric increase in emission with measurable red shift. In DMSO/H₂O (5:95, v/v), the sensor 1 exhibits a greater selectivity towards Hg²⁺ ions (K _a = 9.20 × 10³ M^? 1) over the other metal ions examined.     

Synthesis,characterization, crystal structure,and DNA binding of two copper(II)–hydrazone complexes

Two new Cu(II)–hydrazone complexes, [Cu(L)(Hbpe)ClO₄]·ClO₄·[Cu(L)Cl] (1) and [Cu(HL)₂]·1.5ClO₄·0.5OH (2) (where HL?=?(E)-N′-(1-(pyridine-2-yl)ethylidene)benzohydrazide and bpe = trans-1-(2-pyridyl)-2-(4-pyridyl)ethylene), have been synthesized and characterized by physicochemical methods. The structures of the complexes have been established by single-crystal X-ray diffraction direct methods, which reveal that the metal ions have distorted square-pyramidal and square-planar geometries in 1, and a distorted octahedral geometry in 2. DNA binding of HL, 1, and 2, performed by UV–vis titration in tris-buffer medium, yielded binding constants, which are 9.5 × 10³, 1.88 × 10⁴, and 4.66 × 10⁴ M^?1, respectively. Viscosity measurements suggest a surface or groove-binding mode of interaction between CT-DNA with HL, 1, and 2.     

New β-orcinol depsides from Hypotrachyna caraccensis,a lichen from the páramo ecosystem and their free radical scavenging activity

The new hypotrachynin A (1) and B (2) along with the known (+)-(9b-R)-usnic (3) and methylstictic acids (4) were isolated for the first time from Hypotrachyna caraccensis. Additionally, their potency and reactivity as DPPH? scavengers was determined by a kinetic study calculating their EC₅₀ and second-order rate constants (k₂). Considering 1–4 could be dermatological agents, their n-octanol-water partition coefficients and standard molar Gibbs free energies of transfer were calculated as estimation of their lipophilicity and skin penetration. Compounds 1, 3 and 4 were less potent than 2 (EC₅₀ = 3.3014; 1.7540; 2.6652 vs 0.7376) as DPPH? scavengers, in turn 4, was the most reactive with a comparable k₂ to the antioxidant BHT (k₂ = (232 ± 24) × 10^?2 vs (564 ± 12) × 10^?2 M^?1 s^?1, respectively). Since 2 and 4 had an optimal lipophilicity and permeability for skin penetration, they might be developed as topical ingredients to prevent oxidative damage.     

Effect of cucurbit[n]urils on tropicamide and potential application in ocular drug delivery

The supramolecular interactions of the ocular drug tropicamide (TR) with cucurbit[7]uril (CB7) and cucurbit[8]uril (CB8) were investigated in aqueous solutions by using ¹H NMR, ESI-MS and UV–vis spectroscopic techniques. The results indicate a 1:1 binding stoichiometry of TR with CB7 and CB8. The binding constants of TR in its protonated form were higher (e.g. K = 4 × 10⁶ M^? 1 with CB8) than in its neutral form (e.g. K = 1.4 × 10⁴ M^? 1 with CB8), which led to a complexation-induced increase in its pK _a value of ca. 0.5 and 2 units with CB7 and CB8, respectively. In the presence of about 1% (w/v) CB8, the ionisation degree of 0.1% (w/v) TR was increased from 2% to 62% at neutral pH. The increase in the pK _a value and thus stabilisation of the protonated TR species at neutral pH is discussed in the context of supramolecular drug delivery of ophthalmologic drugs.     

Ag(I) and Zn(II) isonicotinate complexes: design,characterization, antimicrobial effect,and CT-DNA binding studies

Trinuclear Ag(I) (1) and dinuclear and mononuclear Zn(II) isonicotinate (2 and 3) complexes were prepared and characterized by X-ray crystallography, elemental analysis, IR spectroscopy, and thermal analysis. Single-crystal analysis of the Ag(I) complex reveals two different monodentate carboxylate coordination modes, protonated and deprotonated, respectively. IR spectra showed correlations between isonicotinate coordination modes and Δ(ν_as???ν_s)_IR values. In addition, the hydrogen bonds significantly influence a position of carboxylate absorption bands. Moreover, IC₅₀ and MIC data for bacteria, yeasts, and filamentous fungi were determined and the binding of Ag(I) and Zn(II) complexes to calf thymus DNA was investigated using electronic absorption, fluorescence, and CD measurements. Biological tests showed that the Ag(I) complex is more active than commercially used Ag(I) sulfadiazine against Escherichia coli. The fluorescence spectral results indicate that the complexes can bind to DNA through an intercalative mode. The Stern–Volmer quenching constants for investigated complexes obtained from the linear quenching plot are in the range of 1.67 × 10⁴–3.42 × 10⁴ M^?1.     

Octahedral copper(II) carboxylate complex: synthesis,structural description,DNA-binding and anti-bacterial studies

Self-assembly of CuSO₄, para-methyl-2-phenyl acetate and 1,10-phenanthroline afforded good-quality crystalline complex in quantitative yield. The complex was characterized by FTIR and UV-visible spectroscopy, electrochemistry, and powder and single-crystal XRD studies. Its structure was found to possess axially elongated octahedral symmetry with CuO₄N₂ chromophore. Its purity was assessed by powder XRD spectrum. Absorption study yielded a broad band corresponding to ²E_g→²T_2 g transition. Electrochemical solution study indicated diffusion-controlled irreversible electron transfer process corresponding to Cu(II)/Cu(I) redox couple with diffusion coefficient = 7.89(±0.1)×10^?9 cm²s^?1. Results of spectroscopic techniques support each other. Complex exhibited excellent DNA-binding ability through UV-visible spectroscopy and cyclic voltammetry yielding K_b values 1.399 × 10⁴ M^?1 and 5.81 × 10³ M^?1, respectively. The complex exhibited significant activity against bacterial strains Escherichia coli, Micrococcus luteus and Staphylococcus aureus and good activity against Bacillus subtilis. These preliminary studies impart good biological relevance on the synthesized complex.     

DNA-binding,antioxidant activity and in vitro cytotoxicity induced by ruthenium(II) complexes containing polypyridyl ligands

Two new ruthenium(II) polypyridyl complexes, [Ru(dmp)₂(maip)](ClO₄)₂ 1 (maip = 2-(3-aminophenyl)imizado[4,5-f][1,10]phenanthroline and [Ru(dmp)₂(paip)](ClO₄)₂ 2 (paip = 2-(4-aminophenyl)imidazo[4,5-f][1,10]phenanthroline, dmp = 2, 9-dimethyl-1,10-phenanthroline) have been synthesized and characterized. The DNA-binding behaviors of complexes 1 and 2 were studied by viscosity measurements, thermal denaturation, and absorption titration. The results show that the two complexes intercalate between the base pairs of DNA. The DNA-binding constants K _b for complexes 1 and 2 were determined to be 3.23 ± 0.16 × 10⁴ M⁻¹ (s = 0.97) and 4.34 ± 0.65 × 10⁴ M⁻¹ (s = 1.13). The cytotoxicity of these complexes has been evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The IC₅₀ values are 35.70, 41.04, 55.25 and 37.50 for complex 1 and 37.02, 103.08, 130.07 and 37.80 for complex 2 against BEL-7402, C-6, HepG-2 and MCF-7 cell lines, respectively. The antioxidant activity against hydroxyl radical (OH•) was also investigated.     

Iron(II) complexes containing the 2,6-bis-iminopyridyl moiety. Synthesis,characterization, reactivity,and DNA binding

Two iron(II) complexes, [Fe^II(py^tBuN₃)₂](FeCl₄) (1) and [Fe^II(py^tBuMe₂N₃)Cl₂] (2), with sterically constrained py^tBuN₃ and py^tBuMe₂N₃ chelate ligands (py^tBuN₃ = 2,6-bis-(aldiimino)pyridyl; py^tBuMe₂N₃ = 2,6-bis-(ketimino)pyridyl), have been synthesized and characterized by elemental analysis, IR, UV–vis spectra, and preliminary X-ray single-crystal diffraction. The latter revealed that Fe(II) in 1 is six-coordinate by six nitrogen donors from two bisiminopyridines in a distorted octahedron. Complex 2 reacts with thiourea with a second-order rate constant k₂ = (2.50 ± 0.05) × 10^?3 M^?1 s^?1 at 296 K, and the reaction seemed to be slow. In a similar way, the interaction of 2 and DNA was studied by fluorescence and absorption spectroscopy. The results revealed that 2 caused fluorescence quenching of DNA through a dynamic quenching procedure. The binding constants K_A, K_app, and K_SV as well as the number of binding sites between 2 and DNA were determined.     

Nuclease activity of redox/non-redox active binuclear transition metal mixed-polypyridine complexes: [M2(1,4-tpbd)(diimine)2(H2O)2]4+, M = Zn,Co, Ni,Cd, diimine = phen,bpy, dafo

Seven new transition metal complexes formulated as [M₂(1,4-tpbd)(diimine)₂(H₂O)₂]⁴⁺ [M = Zn, Co, Ni, Cd; 1,4-tpbd = N,N,N′,N′-tetrakis(2-pyridylmethyl)benzene-1,4-diamine; diimine is a N,N-donor heterocyclic base like 1,10-phenanthroline (phen), 2,2′-bipyridine (bpy), 4,5-diazafluoren-9-one (dafo)] have been synthesized and structurally characterized by X-ray crystallography: [Zn₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (1), [Zn₂(1,4-tpbd)(bpy)₂(H₂O)₂]⁴⁺ (2), [Co₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (3), [Ni₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (4), [Ni₂(1,4-tpbd)(bpy)₂(H₂O)₂]⁴⁺ (5), [Ni₂(1,4-tpbd)(dafo)₂(H₂O)₂]⁴⁺ (6) and [Cd₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (7). Single crystal diffraction reveals that the metals in the complexes are all in a distorted octahedral geometry. The interactions of the seven complexes with calf thymus DNA (CT-DNA) have been investigated by UV absorption, fluorescence, circular dichroism spectroscopy and viscosity measurements. The apparent binding constants (K_app) are calculated to be 5.2?×?10⁵ M^?1 for 1, 1.05?×?10⁵ M^?1 for 2, 5.76?×?10⁵ M^?1 for 3, 4.57?×?10⁵ M^?1 for 4, 1.29?×?10⁵ M^?1 for 5, 1.7?×?10⁵ M^?1 for 6, 2.53?×?10⁵ M^?1 for 7, the binding propensity to the calf thymus DNA in the order: 3 (Co-phen) > 1 (Zn-phen) > 4 (Ni-phen) > 7 (Cd-phen) > 6 (Ni-dafo) > 5 (Ni-bpy) > 2 (Zn-bpy). Furthermore, these complexes display efficient oxidative cleavage of supercoiled DNA; the Zn(II)/H₂O₂ and Cd(II)/H₂O₂ systems efficiently cleave DNA attributed to the peroxide ion coordinated to the Zn(II) and Cd(II), which enhanced their nucleophilicity, this is rare.     

Synthesis, characterization, DNA-binding, photocleavage, cytotoxicity and docking studies of Co(III) mixed ligand complexes

A new ligand, (2-ethoxy-6-(1H imadazo[4,5-f][1,10]phenanthroline-2-yl)phenol) (HEPIP) and its three Co(III) complexes [Co(phen)₂(HEPIP)](ClO₄)₃ (1), [Co(bpy)₂(HEPIP)](ClO₄)₃ (2) and [Co(dmb)₂(HEPIP)](ClO₄)₃ (3) have been synthesized and characterized. All three Co(III) complexes exhibited antitumor activity against four human tumor cell lines. The interaction of these complexes with calf thymus DNA was studied by absorption and emission spectroscopy, viscosity measurements and DNA cleavage assays. The DNA-binding constants of complexes 1, 2 and 3 were determined as 6.13 × 10⁵, 4.46 × 10⁵ and 3.72 × 10⁵ M^?1, respectively. The complexes appear to interact with DNA through intercalation. Studies on the mechanism of photocleavage indicated that both superoxide anion radical and singlet oxygen may play an important role.     

Experimental and computational investigations on the high binding-selectivity of pyrimidine derivatives by a pillar[5]arene

The binding selectivity of an adenine-monofunctionalized pillar[5]arene (H) with a series of pyrimidine derivatives were investigated through ¹H NMR experiments and density functional theory (DFT) study. High binding-selectivity was demonstrated. Typically, H displayed very strong binding strength with 6-(2,4-dioxo-3, 4-dihydropyrimidin-1 (2H)-yl)hexanenitrile (G1) [K_a >10⁵ M^?1], up to about 3000-fold as compared with 1-hexylpyrimidine-2,4(1H, 3H)-dione (G5) [K_a = 31 M^?1]. The strong binding ability of H with G1 was due to the cooperative multiple hydrogen bond, dipole-dipole, C-H···π and π···π interactions. The high binding-selectivity was also verified by calculation results. The calculated interaction energy (ΔE_i) of G1?H was ?12.92 Kcal·mol^?1 while that of G5?H was ?2.85 Kcal·mol^?1.     

DNA-binding and photocleavage, cytotoxicity, apoptosis and antioxidant activity studies of ruthenium(II) complexes

Two ruthenium(II) polypyridyl complexes, namely [Ru(phen)₂(DMDPPZ)](ClO₄)₂ 1 (phen = 1,10-phenanthroline, DMDPPZ = 3,6-dimethyldipyrido[3,2-a:2′,3′-c]phenazine) and [Ru(dmp)₂(DMDPPZ)](ClO₄)₂ 2 (dmp = 2,9-dimethyl-1,10-phenanthroline), have been synthesized and characterized. The DNA-binding properties of the complexes were investigated by spectrophotometric methods, viscosity measurements, and photoactivated cleavage studies. The DNA-binding constants for complexes 1 and 2 have been determined as 8.78 (±0.94) × 10⁵ M⁻¹ (s = 3.02) and 1.26 (±0.35) × 10⁵ M⁻¹ (s = 1.69), respectively. The results suggest that these complexes bind to calf thymus DNA through intercalation. When irradiated at 365 nm, the complexes promote the photocleavage of pBR322 DNA, and complex 1 cleaves DNA more effectively than complex 2 under comparable experimental conditions. The cytotoxicities of complexes 1 and 2 have been evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) method. Complex 2 shows higher anticancer potency than complex 1 against four tumor cell lines. The apoptosis-inducing activity was assessed by acridine orange/ethidium bromide staining assay, and the antioxidant activities of these complexes against hydroxyl radical were also explored.     

Synthesis,crystal structure,and third-order non-linear optical properties of a new Cd(II) polymer constructed from pyrazine-2-carboxylic acid

A new cadmium(II) pyrazine-2-carboxylate coordination polymer, {[Cd(L)(H₂O)₂(SO₄)_0.5]₂·H₂O}_n (1) (HL = pyrazine-2-carboxylic acid), has been synthesized by low-temperature solid-state reaction. Single-crystal X-ray analyses reveal that 1 possesses a 3-D framework structure. The polymer 1 was characterized by elemental analyses, thermogravimetric analyses, X-ray powder diffraction analyses, IR spectra, and UV–visible spectra. The third-order non-linear optical properties were also investigated and they exhibit nice non-linear absorption and self-defocusing performance with modulus of the hyperpolarizability (γ) 1.30 × 10^?30 esu for 1 in a 2.01 × 10^?4 M?dm^?3 DMF solution.     

Synthesis,structure, and thermal decomposition of two copper coordination compounds [Cu(DAT)2(PA)2] and [Cu(DAT)2(HTNR)2] with nitrogen rich 1,5-diaminotetrazole (DAT)

Both [Cu(DAT)₂(PA)₂] (1) and [Cu(DAT)₂(HTNR)₂] (2) were prepared from 1,5-diaminotetrazole (DAT) and copper trinitrophenol, 1 for picrate (PA) and 2 for styphnate acid (2,4,6-trinitro resorcinol, TNR), and were characterized by elemental analysis, FT-IR spectroscopy, and single crystal X-ray diffraction. The space group of these compounds is P2₁/c (monoclinic). The lattice parameters are similar [a = 11.405(3) Å, b = 14.867(3) Å, c = 8.099(2) Å for 1 and a = 12.262(3) Å, b = 14.900(3) Å, c = 7.243(2) Å for 2], except the β = 106.257(3)° in 1 and β = 92.989(4)° in 2. Both have extended structures due to hydrogen bonds, but there are some differences because of the ligands induced effect. Differential scanning calorimetry analysis shows that two exothermic processes take place in both complexes, the first peak temperatures are 488.2 K for 1 and 519.2 K for 2. The kinetic parameters of the first exothermic process were studied by using Kissinger’s method and Ozawa’s method, in which the enthalpy of formation (?7346 and ?5706 kJ M^?1), critical temperature of thermal explosion (475.0 and 515.8 K), entropy of activation (ΔS^≠), enthalpy of activation (ΔH^≠), and free energy of activation (ΔG^≠) were calculated and obtained as ?117.25 J K^?1 M^?1, 140.64 kJ M^?1, 196.44 kJ M^?1 and ?219.1 J K^?1 M^?1, 383.56 kJ M^?1, 495.34 kJ M^?1 for 1 and 2, respectively. The sensitivity test results showed that both compounds were sensitive to impact (<5 J) and flame (>20 cm) rather than friction.     

The DNA-binding behavior and DFT calculation of ruthenium(II) complexes [Ru(phen)2L](ClO4)2 (L = HMOPIP and MOHPIP)

Two ruthenium(II) complexes, [Ru(phen)₂HMPIP]²⁺ (1) and [Ru(phen)₂MHPIP]²⁺ (2), have been synthesized and characterized by elemental analysis, ESI-MS, and ¹H NMR spectroscopy. The DNA-binding properties of 1 and 2 have been investigated by electronic and emission spectra and viscosity experiments. The results show that both 1 and 2 can bind to DNA in intercalating mode, with 1 exhibiting stronger binding affinity. These were confirmed by the strong hypochromism at IL and MLCT absorption bands in both complexes when DNA was added into solution, and the increase in relative viscosity of CT-DNA in the presence of both complexes. Moreover, the calculated intrinsic binding constant for 1 and 2 from the decay of electronic spectra is 3.82 × 10⁵ and 2.06 × 10⁵ M^?1, respectively. Finally, the effects of the substituent groups on the DNA-binding behavior of ruthenium(II) complexes have also been rationally discussed by computer calculation of density functional theory (DFT) methods.