Benzo[h]quinoline based Macrocyclic Copper(II), Cobalt(II) Complexes: Synthesis, Characterization and Light induced DNA Cleavage Studies

Cashew nutshell liquid catalyzed green chemistry approach for synthesis of a Schiff base and its divalent metal complexes: molecular docking and DNA reactivity

Cashew Nut Shell Liquid (CNSL) anacardic acid was used, for the first time, as a green and natural effective catalyst for the synthesis of a quinoline based amino acid Schiff base ligand from the condensation of 2-hydroxyquinoline-3-carbaldehyde with l-tryptophan via solvent-free simple physical grinding technique. The use of the nontoxic CNSL natural catalyst has many benefits over toxic reagents and the desired product was obtained in high yield in a short reaction time. The procedure employed is simple and does not involve column chromatography. Moreover, a series of metal(II) complexes (metal = iron(II), cobalt(II), nickel(II), and copper(II)) supported by the synthesized new quinoline based amino acid Schiff base ligand (L) has been designed and the compositions of the metal(II) complexes were examined by various analytical techniques. The findings imply that the 2-hydroxyquinoline-3-carbaldehyde amino acid Schiff base (L) serves as a dibasic tridentate ONO ligand and synchronizes with the metal(II) in octahedral geometry in accordance with the general formula [M(LH)₂]. Molecular docking study of the metal(II) complexes with B-DNA dodecamer has revealed good binding energy. The conductivity parameters in DMSO suggest the existence of nonelectrolyte species. The interaction of these metal complexes with CT-DNA has shown strong binding via an intercalative mode with a different pattern of DNA binding, while UV-visible photo-induced molecular cleavage analysis against plasmid DNA using agarose gel electrophoresis has revealed that the metal complexes exhibit photo induced nuclease activity.

Macrocyclic complexes: synthesis, characterization, antitumor and DNA binding studies

The present paper deals with the synthesis of novel macrocyclic complexes of the type [MLX]X, where [(M = Co(II) (1), and Ni(II) (2) X = (Cl₂)]. The complexes are synthesized by the reaction of ligand(L)diquinolineno[1,3,7,9]tetraazacyclododecine-7,15-ethane(14H,16H)-benzene with the corresponding metal salts. The synthesized complexes are thoroughly characterized by elemental analysis, FT-IR, ¹H-NMR, Mass and electronic spectra. The complexes (1) and (2) were evaluated for in vitro cytotoxicity against human breast adenocarcinoma cell (MCF-7). MTT cytotoxicity studies shows both the complexes are most effective. The binding properties of these complexes with calf thymus-DNA were studied by absorption, emission spectra, viscosity measurements, and thermal denaturation studies. On binding to CT-DNA, the absorption spectrum undergoes bathochromic and hypochromic shifts. The absorption spectral results indicate that the intrinsic binding constant (K_b) are 4.8 × 10⁵ M^-1 for (1) and 3.9 × 10⁵ M^-1 for (2) respectively, suggesting that complex (1) binds more strongly to CT-DNA than complex (2). The viscosity measurement results revealed the viscosity of sonicated rod like DNA fragments increased when the complex was added to the solution of CT-DNA. The synthesized ligand and its metal complexes are screened for antibacterial and antifungal activities.

Synthesis, DNA interactions and antibacterial PDT of Cu(II) complexes of phenanthroline based photosensitizers via singlet oxygen generation

Cu(II) complexes [Cu(mqt)(B)H2O]ClO4(1-3) of 2-thiol 4-methylquinoline and phenanthroline bases (B), viz 1,10-phenanthroline (phen in 1), Dipyrido[3,2-d:2',3'-f]quinoxaline (dpq in 2) and Dipyrido[3,2-a:2',3'-c]phenazine (dppz in 3) have been prepared and characterized by elemental analysis, IR, UV-Vis, magnetic moment values, EPR spectra and conductivity measurements. The spectral data reveal that all the complexes exhibit square-pyramidal geometry. The DNA-binding behaviors of the three complexes were investigated by absorption spectra, viscosity measurements and thermal denaturation studies. The DNA binding constants for complexes (1), (2) and (3) were determined to 2.2×10(3), 1.3×10(4) and 8.6×10(4)M(-1) respectively. The experimental results suggest that these complexes interact with DNA through groove-binding mode. The photo induced cleavage studies shows that the complexes possess photonuclease property against pUC19 DNA under UV-Visible irradiation via a mechanistic pathway involving formation of singlet oxygen as the reactive species. Antimicrobial photodynamic therapy was studied using photodynamic antimicrobial chemotherapy (PACT) assay against Escherichiacoli and all complexes exhibited significant reduction in bacterial growth on photoirradiation.

Synthesis, DNA binding, and photonuclease activity of new tetraaza macrocyclic constrained isoxazole rings as subunit in metal complexes

The DNA-binding and photonuclease activity of newly synthesized tetra-azamacrocyclic ligand L (C(32)H(32)N(8)O(4)) and its complexes of type [MLCl(2)] and [ML]Cl(2) (where M = Co(II), Fe(II) and Cu(II); L = N,N'-[3-(4-{5-[(2-amino-ethylamino)-methyl]-isoxazol-3yl}-phenyl)-isoxazol-5-yl methyl-ethane-1,2-diamine] are specified. An octahedral geometry has been proposed for Fe(II) and Co(II) complexes, while the Cu(II) complex has a square planar environment. The absorption spectral results indicate that the complexes bind with the base pairs of DNA, with an intrinsic binding constant K(b) of Fe(II), Co(II), and Cu(II) complexes found to be 3.2 × 10(4) M(-1), 5.3 × 10(4) M(-1), and 4.2 × 10(4) M(-1), respectively, in 5 mM Tris-HCl/50 mM NaCl buffer at pH 7.2. The large enhancement in the relative viscosity of DNA on binding to the complexes supports the proposed DNA binding modes. The viscosity and thermal denaturation studies sustain the effective intercalation with DNA. The DNA photocleavage studies demonstrated that compounds exhibit significant photonuclease activity by a concentration dependent on singlet oxygen mediated mechanism.

Synthesis, DNA-binding, DNA-photonuclease profiling and antimicrobial activity of novel tetra-aza macrocyclic Ni(II), Co(II) and Cu(II) complexes constrained by thiadiazole

A new tetra-aza macrocyclic ligand, L (C(24)H(16)N(12)O(2)S(4)) and its complexes of type, [MLCl(2)] and [CuL]Cl(2) (where M=Ni(II), Co(II); L=N,N'-(benzene-1,3-diyldi-1,3,4-thiadiazole-5,2-diyl)bis{2-[(5-benzene-1,3-diyl-1,3,4-thiadiazol-2-yl)amino]acetamide}) were synthesized and characterized by the spectral and analytical techniques. An octahedral geometry has been proposed for Ni(II) and Co(II) complexes while Cu(II) complex exhibit a square planar geometry. All the synthesized metal complexes were screened for their in vitro antimicrobial activity against selected species of pathogenic bacteria and fungi. The binding property of the complexes with CT-DNA was studied by absorption spectral analysis, followed by viscosity measurement and thermal denaturation studies. The photo induced cleavage studies revealed that the complexes possess photonuclease property against pUC19 DNA under UV-visible irradiation.