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Macroayclic complexes of Ni(II), Cu(II) and Co(II) were synthesized via the reaction of 1,4-bis(o-aminobenzyl)-1,4-diazacycloheptane (L) with the respective metal salts. The polyamine ligand and the corresponding complexes were characterized by mass spectrometry, elemental analysis and FT-IR and for [CuL](ClO 4 ) 2 (2) , by a single crystal X-ray structural analysis which revealed the copper was in a square planar environment. The interaction of the ligand and its complexes with calf thymus DNA (ct-DNA) at pH 7.4 was investigated by UV–Vis, competitive fluorescence spectroscopic methods and dynamic viscosity measurements. These results of these experiments supported intercalative mode of binding. The competitive fluorescence studies in the presence of methylene blue (MB) as an intercalator probe showed that the ligand and its complexes were able to release MB from DNA helix. Viscosity measurements were in good agreement with the results of the competitive fluorescence, indicating that all compounds are intercalating species.

To synthesize new symmetrical macroacyclic Schiff base ligands (L1 and L2), polyamine (A) was condensed with 2-formylpyridine and salicylaldehyde. Furthermore, Ni(ClO4)2.6H2O and Zn(ClO4)2.6H2O in methanol were reacted with the ligands to prepare corresponding metal complexes. The cytotoxicity of the synthesized complexes against MCF-7 and A549 adenocarcinoma cells was evaluated, where Zn-complexes displayed greater cytotoxic effects than Ni-complexes. Conductivity measurements, ESI-MS, UV-Vis, molar conductivity, IR, 1H, and 13C NMR spectra were used to characterize the products. Furthermore, molecular docking was performed to assess the biological activity of the complexes, and it was observed that Zn-complexes exhibited the highest inhibition effect against cytotoxic receptors.

This study discusses the determination of thyroxine hormone in blood serum samples by a novel MOF composite electrode. The used MOF was Zn(BTC)-(MOF) which was constructed from 1,3,5-benzenetricarboxylic acid ligand (BTC) and zinc ions in DMF solvent. Using cysteine as the linker, the MOF was plated on the surface of a gold electrode, formerly covered by a layer of gold nanoparticles immersed in conductive polymer polypyrrole (PPy). Different analytical methods, such as FTIR, XRD, SEM, EIS, CV, and BET, were utilized to investigate the morphology and performance of the prepared materials. The modified electrode exhibited excellent electrocatalytic ability to reduce thyroxine without interference from common coexisting substances such as different salts. The fabricated electrode has been successfully used to determine thyroxine in a linear concentration range of 10–210 nM with a detection limit of 8 nM. Graphical abstract

Two potentially heptadentate (N4O3) tripodal Schiff-base ligands: tris(3-(salicylideneimino)propyl)amine (H3L1) and tris(3-(4’-hydroxysalicylideneimino)-propyl)amine (H3L2) have been prepared and characterized by various spectroscopic methods (IR, FAB-MS, NMR). They are derived from the condensation reactions of tris(3-aminopropyl)amine (tpt), with 3 equivalents of either salicylaldehyde or the ringsubstituted salicylaldehyde, 4-hydroxysalicylaldehyde. The nickel(II) and copper(II) complexes of H3L1 were obtained from the its reactions Ni(II) and Cu(II) salts in absolute methanol. These complexes were studied by IR and FAB-Mass spectrometry.

To synthesize new symmetrical macroacyclic Schiff base ligands (L[sub.1] and L[sub.2]), polyamine (A) was condensed with 2-formylpyridine and salicylaldehyde. Furthermore, Ni(ClO[sub.4])[sub.2].6H[sub.2]O and Zn(ClO[sub.4])[sub.2].6H[sub.2]O in methanol were reacted with the ligands to prepare corresponding metal complexes. The cytotoxicity of the synthesized complexes against MCF-7 and A549 adenocarcinoma cells was evaluated, where Zn-complexes displayed greater cytotoxic effects than Ni-complexes. Conductivity measurements, ESI-MS, UV-Vis, molar conductivity, IR, [sup.1]H, and [sup.13]C NMR spectra were used to characterize the products. Furthermore, molecular docking was performed to assess the biological activity of the complexes, and it was observed that Zn-complexes exhibited the highest inhibition effect against cytotoxic receptors.

A simple, clean, and highly efficient green protocol has been developed for synthesis of bis(indolyl), di(bis-indolyl), and tris-indolyl methanes by the reaction of indole with aldehydes and ketones irn the presence of oxalic acid dihydrate [(CO₂H)₂·2H₂O] and N-cetyl-N, N, N-trimethylammonium bromide (CTAB) in water. Also, tri(bis-indolyl) and tetra(bis-indolyl)methanes as new bis(indolyl)methanes were prepared under thermal conditions.

A potentially hexadentate N 4 O 2 Schiff base ligand, L, has been synthesized by condensation of an aromatic diamine with 2-pyridinecarbaldehyde. The complexes [MLNO 3 ]NO 3 (M=Cu, Ni, Cd or Zn) and [MlCl 2 ] (M=Co or Mn) were synthesized by the reactions of L with metal salts in methanol. Both free L and its complexes were characterized by physicochemical and spectroscopic methods. In addition, the crystal structures of [CuLNO 3 ]NO 3 and [ZnLNO 3 ]NO 3 have been determined by single-crystal X-ray diffraction. In both complexes, the ligand L is coordinated via pyridine and azomethine nitrogen atoms to give a distorted octahedral geometry. These complexes have antibacterial activities against three Gram-positive and three Gram-negative bacteria, which in most cases exceed those of tobramycin and tetracycline as standards.

A new potentially octadentate N 2 O 6 Schiff base ligand, H 2 L derived from the condensation of 2,2′-(1,1′-binaphthyl-2,2′-diylbis(oxy))dianiline and o-vanillin, along with its copper(II) and zinc(II) complexes, is synthesized and has been characterized by elemental analyses, IR, UV–vis, 1 H and 13 C NMR spectra, as well as conductivity measurements. H 2 L forms mononuclear complexes of 1:1 (metal:ligand) stoichiometry with Cu(II) and Zn(II), and conductivity data confirm the non-electrolyte nature of these complexes. The [ZnL] and [CuL] complexes display very different solid-state structures, as determined by X-ray crystallography. While the [ZnL] complex has a distorted octahedral geometry about the metal, the [CuL] complex displays a distorted square planar geometry about the copper, with long Cu–O(ether) distances of 2.667 Å.

The asymmetrical tripodal tetraamine ligand N[(CH2)3NH2]2[(CH2)2NH2] (ppe) was condensed with 2-acetylpyridine in the presence of nickel(II) ion. In ethanolwater solution the reaction stops after the first stage of condensation, and a new nickel(II) complex of an acyclic pentadentate (N5) mono Schiff base ligand was obtained. X-ray structure analysis of the resulting complex, [Ni(ppe-py)(H2O)](ClO4)2, indicates that condensation with 2-acetylpyridine is at the propylene chain of ppe. The geometry around the nickel ion is distorted octahedral in which the sixth co-ordination group is a solvent molecule.

Three new Mn(II) bis(pendant arm)-macrocyclic Schiff base complexes, [MnL n ] 2+ ( n  = 1, 2, 3), have been prepared via cyclocondensation of 2,6-diacetylpyridine with three different branched hexadentate amines (3,6-bis(2-pyridylmethyl)-3,6-diazaoctane-1,8-diamine ( 1 ), 3,7-bis(2-pyridylmethyl)-3,7-diazanonane-1,9-diamine ( 2 ) and 3,8-bis(2-pyridylmethyl)-3,8-diazadecane-1,10-diamine ( 3 )) in the presence of MnCl 2 in methanol. The ligands, L, are 15-, 16- and 17-membered pentaaza macrocycles having two 2-pyridylmethyl pendant arms [L 1 ; 2,13-dimethyl-6,9-bis(2-pyridylmethyl)-3,6,9,12,18-pentaazabicyclo[12.3.1]octadeca-1(18), 2, 12, 14, 16-pentaene, L 2 ; 2,14-dimethyl-6,10- bis(2-pyridylmethyl)-3,6,10,13,19-pentaazabicyclo[13.3.1]nonadeca-1(19), 2, 13, 15, 17-pentaene and L 3 ; 2,15-dimethyl-6,11-bis(2-pyridylmethyl)-3,6,11,14,20-pentaazabicyclo[14.3.1]eicosa-1(20),2,14,16,18-pentaene]. All the complexes have been characterized by physicochemical and spectroscopic methods. The crystal structure of [MnL 1 ](ClO 4 ) 2 ·CH 3 CN has been determined and indicates that in the solid state, the complex adopts a slightly distorted pentagonal bipyramidal geometry with the Mn(II) centre located within a pentaaza macrocycle with two 2-pyridylmethyl pendants coordinating in the axial positions.