Search results for "coordination complexes"
showing 10 items of 164 documents
Methylresorcinarene: a reaction vessel to control the coordination geometry of copper(II) in pyridine N-oxide copper(II) complexes
2015
Pyridine and 2-picolinic acid N-oxides form 2 : 2 and 2 : 1 ligand : metal (L : M) discrete L2M2 and polymeric complexes with CuCl2 and Cu(NO3)2, respectively, with copper(ii) salts. The N-oxides also form 1 : 1 host-guest complexes with methylresorcinarene. In combination, the three components form a unique 2 : 2 : 1 host-ligand-metal complex. The methylresorcinarene acts as a reaction vessel/protecting group to control the coordination of copper(ii) from cis-see-saw to trans-square planar, and from octahedral to square planar coordination geometry. These processes were studied in solution and in the solid state via(1)H NMR spectroscopy and single crystal X-ray diffraction.
Self-assembly and alterable relaxivity of an organic cation-encapsulated gadolinium-containing polyoxometalate
2012
A new amphiphilic molecule bearing poly(ethylene oxide) (PEO) and quaternary ammonium group, was designed and synthesized to encapsulate paramagnetic Gd(III)-containing polyoxometalate (Gd-POM) through electrostatic interaction for obtaining a water-soluble organic-inorganic hybrid building block based on POM. The yielding organic cation-encapsulated Gd-POM (OCEP-Gd) complex exhibited water-solubility and amphiphility, leading to the spontaneous self-assembly into a regular vesicular structure with PEO chains towards water phase and POM units locating at the middle. The vesicular aggregate which has a regular monolayer structure, was further studied by means of dynamic light scattering, tra…
m-Carboranylphosphinate as Versatile Building Blocks To Design all Inorganic Coordination Polymers
2017
The first examples of coordination polymers of manganese(II) and a nickel(II) complex with a purely inorganic carboranylphosphinate ligand are reported, together with its exhaustive characterization. X-ray analysis revealed 1D polymeric chains with carboranylphosphinate ligands bridging two manganese(II) centers. The reactivity of polymer 1 with water and Lewis bases has also been studied Thanks to MINECO (CTQ2015-66143-P, CTQ2010-16237 and SEV-2015-0496), Generalitat de Catalunya (2014/SGR/149), and COST CM1302. E.O. who is enrolled in the PhD program of the UAB thanks for FPU grant
Isomorphous replacement of MII ions in MII–GdIII dimers (MII = CuII, MnII, NiII, CoII, ZnII): magnetic studies of the products
2011
Complexes [M(II)Gd(III){pyCO(OEt)pyC(OH)(OEt)py}₃](ClO₄)₂·EtOH [M(II) = Cu(II) (1), Mn(II) (2), Ni(II) (3), Co(II) (4) and Zn(II) (5)] crystallize in the monoclinic Cc space group and contain one hexacoordinate M(II) ion and one enneacoordinate Gd(III) ion, bridged by three {pyCO(OEt)pyC(OH)(OEt)py}⁻ ligands. Magnetic susceptibility measurements indicate a ferromagnetic interaction for 1 and antiferromagnetic interactions for 2-4. Using the Ĥ = -JŜ(Gd(III))Ŝ(M(II)) spin Hamiltonian formalism, fits to the magnetic susceptibility data yielded J values of +0.32 cm⁻¹ for 1, -1.7 cm⁻¹ for 2, and -0.22 cm⁻¹ for 3. In complex 4, the orbital contributions of Co(II) precluded the determination of th…
Exploring the Specificity of Rationally Designed Peptides Reconstituted from the Cell-Free Extract of Deinococcus radiodurans toward Mn(II) and Cu(II)
2020
A series of five rationally designed decapeptides [DEHGTAVMLK (DP1), THMVLAKGED (DP2), GTAVMLKDEH (Term-DEH), TMVLDEHAKG (Mid-DEH), and DEHGGGGDEH (Bis-DEH)] have been studied for their interactions with Cu(II) and Mn(II) ions. The peptides, constructed including the most prevalent amino acid content found in the cell-free extract of Deinococcus radiodurans (DR), play a fundamental role in the antioxidant mechanism related to its exceptional radioresistance. Mn(II) ions, in complex with these peptides, are found to be an essential ingredient for the DR protection kit. In this work, a detailed characterization of Cu(II) systems was included, because Cu(II)–peptide complexes have also shown r…
Rational Design of Copper(II)-Uracil Nanoprocessed Coordination Polymers to Improve Their Cytotoxic Activity in Biological Media
2021
This work is focused on the rational structural design of two isostructural Cu(II) nano-coordination polymers (NCPs) with uracil-1-acetic acid (UAcOH) (CP1n) and 5-fluorouracil-1-acetic acid (CP2n). Suitable single crystals for ꭕ-ray diffraction studies of CP1 and CP2 were prepared under hydrothermal conditions, enabling their structural determination as 1D-CP ladder-like polymeric structures. The control of the synthetic parameters allows their processability into water colloids based on nanoplates (CP1n and CP2n). These NCPs are stable in water at physiological pHs for long periods. However, interestingly, CP1n is chemically altered in culture media. These transformations provoke the part…
A novel 2D coordination network built from hexacopper(i)-iodide clusters and cagelike aminophosphine blocks for reversible “turn-on” sensing of anili…
2018
A new copper(I) coordination polymer [Cu6(μ3-I)6(μ3-PTAO)2]n (1) was prepared from copper(I) iodide and 1,3,5-triaza-7-phosphaadamantane-7-oxide (PTAO). The crystal structure of 1 reveals an intricate 2D coordination network constructed from the hexacopper(I)-iodide [Cu6(μ3-I)6] cluster units with the 4M6-1 topology interlinked by the μ3-PTAO spacers. An overall 2D layer network can be simplified to a binodal 3,6-connected net with the kgd topology. A derived 1@paper material was prepared by impregnating compound 1 onto a filter paper. Detailed investigation of the luminescence properties for 1 and 1@paper in the solid state revealed a remarkable ability of both materials to sense aniline m…
Metal drugs and the anticancer immune response
2018
The immune system deploys a multitude of innate and adaptive mechanisms not only to ward off pathogens but also to prevent malignant transformation ("immune surveillance"). Hence, a clinically apparent tumor already reflects selection for those malignant cell clones capable of evading immune recognition ("immune evasion"). Metal drugs, besides their well-investigated cytotoxic anticancer effects, massively interact with the cancer-immune interface and can reverse important aspects of immune evasion. This topic has recently gained intense attention based on combination approaches with anticancer immunotherapy (e.g., immune checkpoint inhibitors), a strategy recently delivering first exciting…
Poly-Xaa Sequences in Proteins - Biological Role and Interactions with Metal Ions: Chemical and Medical Aspects
2016
Background: The understanding of the bioinorganic and coordination chemistry of metalloproteins containing unusual poly-Xaa sequences, in which a single amino acid is repeated consecutively, is crucial for describing their metal binding-structure-function relationship, and therefore also crucial for understanding their medicinal potential. To the best of our knowledge, this is the first systematic review on metal complexes with polyXaa sequences. Methods: We performed a thorough search of high quality peer reviewed literature on poly-Xaa type of sequences in proteins, focusing on their biological importance and on their interactions with metal ions. Results: 228 papers were included in the…
Intermolecular binding modes in a novel [1 + 1] condensation 1H-pyrazole azamacrocycle: a solution and solid state study with evidence for CO2 fixati…
2013
The synthesis of a novel cyclophane (L1) consisting of a 1H-pyrazole moiety linked through methylene groups to a 1,5,9,13-tetraazadecane chain is described. As far as we know, this is one of the first reported syntheses of a [1 + 1] condensation 1H-pyrazole azamacrocyclic ligand. The crystal structures of the complexes [Cu2(H(H(-1)L1))(H(-1)L1)](ClO4)3·3.75H2O (1) and ([Cu2(H(H(-1)L1))(0.5)(H(-1)L1)(1.5)]2(ClO4)3Br2·4.2H2O (2) show that Cu(2+) coordination leads to formation of 2:2 Cu(2+):L dinuclear dimeric complexes in which the 1H-pyrazole units lose a proton behaving as bis(monodentate) bridging ligands. Unlike previously reported complexes of [2 + 2] pyrazole azamacrocycles, the pyrazo…