Synthesis, spectral and X-ray diffraction of two new 2D lead(II) coordination polymers formed by nicotinic acid N -oxide linkers

Synthesis and crystal structures of two new lead(II) complexes with the pincer-type ligand 4′-(4-chlorophenyl)-2,2′:6′,2″-terpyridine (Cl-Ph-tpy): subtle interplay of weak intermolecular interactions

A dinuclear and a tetranuclear complex of lead(II) with the pincer-type ligand 4′-(4-chlorophenyl)-2,2′:6′,2″-terpyridine (Cl-Ph-tpy), [Pb2(Cl-Ph-tpy)2(μ-I)2I2] (1) and [Pb4(Cl-Ph-tpy)4(μ-Br)4(μ-OH2)Br4]·2CH3OH (2), have been synthesized and characterized by elemental analysis, FT-IR and 1H NMR spectroscopy, and by single-crystal X-ray diffraction. In the binuclear structure of 1, the Pb atom has a hemidirected PbN3I3 environment with a Pb(μ-I)2Pb central unit. In the tetranuclear structure of 2, two crystallographically independent Pb(II) centres having hemidirected PbN3Br3 and PbN3OBr2 environments are connected to Pb(μ-Br)Pb(μ-Br)2(μ-OH2)Pb(μ-Br)Pb chains. The supramolecular features in 1 and 2 are supported through weak but directional C–H···Cl, C–H···I and C–H···Br, C–H···O, O–H···Br, and O···Br interactions and aromatic π-π stacking.

2D-Coordination polymer containing lead(II) in a hemidirected PbO4S3 environment formed by molecular breaking of the 1,3-oxathiolane ligand

A new 1,3-oxathiolane-based ligand, 2-(1,3-oxathiolan-2-yl)pyridine, was prepared and its coordination to lead(II) was investigated. Experiments revealed a ligand-breaking reaction during the complexation process, which leads to the formation of a 2D-coordination polymer of lead(II), [Pb(μ 3-HME)(μ-OAc)] n ; H2ME: 2-mercaptoethanol. The compounds have been characterized by elemental analysis, FT-IR, 1H NMR spectroscopy and single-crystal X-ray diffraction. X-ray analysis revealed a 2D-coordination polymer extending via acetato bridges. The lead(II) center adopts a rare PbO4S3-distorted pentagonal bipyramidal geometry with a hemidirected arrangement. Upon coordination, the thiol group of the H2ME ligand is deprotonated to coordinate as an anionic ligand. The network extends in sheets in the crystallographic ab plane via Pb–S–Pb and Pb–O–Pb bridges, aided by O–H⋯O hydrogen bonds.

Spectral, structural and theoretical study of the effects of thiocyanato and dicyanamido ligands on the geometry of PbII complexes containing a triazinic ligand

Two lead(II) complexes of 5,6-bis(furan-2-yl)-3-(pyridin-2-yl)-1,2,4-triazine (DFPT), namely one-dimensional (1D) catena-poly[[bis[5,6-bis(furan-2-yl)-3-(pyridin-2-yl-κN)-1,2,4-triazine-κN²]lead(II)]-di-μ-thiocyanato-κ²N:S;κ²S:N], [Pb(NCS)₂(C₁₆H₁₀N₄O₂)₂]_n, 1, and binuclear di-μ-dicyanamido-κ²N¹:N⁵;κ²N⁵:N¹-bis{[5,6-bis(furan-2-yl)-3-(pyridin-2-yl-κN)-1,2,4-triazine-κN²](nitrato-κ²O,O')lead(II)}, [Pb₂(C₂N₃)₂(NO₃)₂(C₁₆H₁₀N₄O₂)₄], 2, as well as DFPT itself, were prepared and identified by elemental analysis, FT-IR, ¹H NMR spectroscopy and single-crystal X-ray structural analyses. In the double-chain 1D coordination polymer of 1 and the binuclear structure of 2, the Pb atom has a hemidirected-PbN₆S₂ and a rare holodirected-PbN₆O₂ environment, respectively, with a distorted cubic geometry. All the coordination modes of dicyanamide ligands within lead complexes were studied using the Cambridge Structural Database (CSD) to compare them with the structures of 1 and 2. In addition to hydrogen bonds, the crystal networks are stabilized by π-π stacking interactions between the triazine, furyl and pyridine aromatic rings. The most stable theoretical structures of the title compounds predicted by density functional theory (DFT) calculations were compared with the solid-state results.

Reaction of 2-[(2-aminoethyl)amino]ethanol with pyridine-2-carbaldehyde and complexation of the products with CuII and CdII along with docking studies

The reaction between 2-[2-(aminoethyl)amino]ethanol and pyridine-2-carbaldehyde in a 1:2 molar ratio affords a mixture containing 2-({2-[(pyridin-2-ylmethylidene)amino]ethyl}amino)ethanol (PMAE) and 2-[2-(pyridin-2-yl)oxazolidin-3-yl]-N-(pyridin-2-ylmethylidene)ethanamine (POPME). Treatment of this mixture with copper(II) chloride or cadmium(II) chloride gave trichlorido[(2-hydroxyethyl)({2-[(pyridin-2-ylmethylidene)amino]ethyl})azanium]copper(II) monohydrate, [Cu(C10H16N3O)Cl3]·H2O or [Cu(HPMAE)Cl3]·H2O, 1, and dichlorido{2-[2-(pyridin-2-yl)oxazolidin-3-yl]-N-(pyridin-2-ylmethylidene)ethanamine}cadmium(II), [CdCl2(C16H18N4O)] or [CdCl2(POPME)], 2, which were characterized by elemental analysis, FT–IR, Raman and 1H NMR spectroscopy and single-crystal X-ray diffraction. PMAE is potentially a tetradentate N3O-donor ligand but coordinates to copper here as an N2 donor. In the structure of 1, the geometry around the Cu atom is distorted square pyramidal. In 2, the Cd atom has a distorted octahedral geometry. In addition to the hydrogen bonds, there are π–π stacking interactions between the pyridine rings in the crystal packing of 1 and 2. The ability of PMAE, POPME and 1 to interact with ten selected biomolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS, Top II and B-DNA) was investigated by docking studies and compared with doxorubicin.

Structural, spectral and docking studies of a coordination polymer of zinc(II) formed by a pyridine-derived linker

A mixed ligand zinc coordination polymer, {Zn(μ-DPE)(DBM)2} n (1) (HDBM: dibenzoylmethane and DPE: (E)-1,2-di(pyridin-4-yl)ethene), was prepared and identified by elemental analysis, FT-IR, 1H NMR spectroscopy and single-crystal X-ray diffraction. In the 1D linear coordination polymer of 1, the zinc atom has a ZnN2O4 environment with octahedral geometry. These complex units are linked by the bridging of the planar N2 donor DPE ligands. In the coordination network of complex 1, in addition to the hydrogen bonds, the network is more stabilized by π–π stacking interactions between pyridine and β-diketone moieties of the ligands. These interactions increase the ability of the compound to interact with biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS and Top II) as investigated by docking calculations.

Sonochemical synthesis of two novel Pb(II) 2D metal coordination polymer complexes: New precursor for facile fabrication of lead(II) oxide/bromide micro-nanostructures

Two new lead(II) coordination polymer complexes (CSCs) (2D), [Pb₂(L)₂(Br)₂]_n·H₂O (1), [Pb₂(HL^/)(L^/)(H₂O)₂]_n·H₂O (2), where L = C₆H₅NO₂ (2-pyridinecarboxylic acid) and L^/ = C₉H₆O₆ (1,3,5-tricarboxylic acid), have been synthesized under different experimental conditions. Micrometric crystals (bulk) or microsized materials have been obtained depending on using the branch tube method or sonochemical irradiation. All materials have been characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD) and FT-IR spectroscopy. Single crystal X-ray analyses on complexes 1 and 2 shows that Pb²⁺ ions are 8-coordinated, 7 and 9-coordinated, respectively. Topological analysis shows that the compound 1 and 2 are 4,6L26 and bnn net, respectively. However, neither the shape nor the morphology is maintained, showing the role of sonochemistry to modulate both morphology and dimensions of the resulting crystalline material, independently of whether we have a 2D coordination polymer (CP). Finally, micro structuration of lead(II) bromide oxide and lead(II) oxide have been prepared by calcination of two different lead (II) CPs at 700 °C that were characterized by SEM and XRD.

Theoretical and experimental investigation of anticancer activities of an acyclic and symmetrical compartmental Schiff base ligand and its Co(ii), Cu(ii) and Zn(ii) complexes

A compartmental Schiff base ligand, 2,2′-((((((2-hydroxypropane-1,3-diyl)bis(oxy))bis(2,1-phenylene))bis(methylene))bis(azanylylidene))bis(methanylylidene))bis(4-bromophenol) (H₃L^Br) and its complexes with cobalt(ii), copper(ii) and zinc(ii) including, [Co(HL^Br)] (1), [Cu₂(L^Br)(μ-1,3-OAc)]·MeOH (2) and [Zn(HL^Br)] (3) were prepared using template synthesis and characterised by elemental analysis, FT-IR and ¹H NMR spectroscopies and single-crystal X-ray diffraction. In the structure of complexes 1 and 3 the metal atom has a MN₂O₂ environment with tetrahedral geometry while complex 2 has a binuclear structure with a MNO₄ environment and square planar geometry around the copper atom. The ability of all compounds to interact with the nine biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS and Top II) are investigated by docking calculations. For examination of the docking results, the in vitro activities of eight compounds against the human leukemia cell line K562 was investigated by evaluation of IC₅₀ values and mode of cell death (apoptosis).

A compartmental Schiff base ligand and its copper, cobalt and zinc complexes were prepared. The in vitro activities of all compounds against the human leukemia cell line K562 were investigated along with docking and DFT studies.