Search results for "Ordination"
showing 10 items of 1367 documents
Imidazoporphyrins as supramolecular tectons: synthesis and self-assembly of zinc 2-(4-pyridyl)-1H-imidazo[4,5-b]porphyrinate
2019
International audience; 5,10,15,20-Tetramesityl-2-(4-pyridyl)-1H-imidazo[4,5-b]porphyrin (PyPor) bearing a pyridine donor site connected to the tetrapyrrolic macrocycle by a rigid imidazole linker was prepared in high yield by the condensation of the corresponding 2,3-dioxochlorin and 4-formylpyridine in the presence of ammonium acetate. After the insertion of a metal ion capable of metal–ligand axial coordination, namely Zn(II), this compound afforded self-complementary porphyrin PyPorZn which was suitable for self-assembly. In the crystals, this complex exists as a zigzag coordination polymer formed through the axial coordination of the pyridine nitrogen atom to the zinc ion of the neighb…
Magnetostructural correlations in parallel square-planar halo-bridged copper(II) dimers. Part II: Structure and magnetic properties of [Cu2(terpy)2Br…
1987
Abstract The crystal and molecular structure of bis-μ- bromo-bis [(2,2′:6′,2″ - terpyridyl) copper (II) ] bis (hexafluorophosphate) has been determined from three dimensional single-crystal X-ray diffraction data, collected by counter techniques. The blue crystals belong to the monoclinic system, space group P21/a, with four formula units in a unit cell of dimensions a=20.40(2), b=13.35(2), c=6.453(8) A and β=97.74(9)°. The structure was solved using a refinement procedure and starting with the atomic positions of the isostructural complex [Cu(terpy)- Cl]2(PF6)2, to final agreement factors R=0.071 (Rw=0.077). The structure consists of dimeric molecules bridged by two bromine atoms. The coor…
Unprecedented heptacopper(ii) cluster with body-centred anti-prismatic topology. Structure, magnetism and density functional study
2011
Using a (2-pyridyl)ethylamine-appended carboxylate ligand a new cluster [Cu(II)(7)(L)(4)(μ(3)-OH)(2)(H(2)O)(2)(DMF)(2)][ClO(4)](4)·4H(2)O (1) [L(2-): N-{CH(2)CH(2)(2-pyridyl)}(CH(2)CH(2)CO(2))(2)] is synthesized, as a result of 'coordination-driven self-assembly'. The structure of 1 is unique and consists of a centrosymmetric carboxylato- and hydroxo-bridged heptanuclear copper(II) cation, with body-centred anti-prismatic topology. The four crystallographically independent copper(II) centres differ markedly in their coordination geometry. In addition to establishing cluster authenticity, the structural analysis of 1 discloses two notable features. The existence of {Cu(II)(3)(μ(3)-OH)}(5+) c…
Synthesis and mössbauer studies of some aquo complexes of tin(IV) with crown ethers
1984
Abstract The preparation, characterization, and 119Sn Mossbauer spectra of a number of tin(IV) complexes with cyclic polyethers are presented. With tin(IV) chloride and methyltin(IV) trichloride, 1:1 and 2:1 metal-to-crown-ether complexes are formed, while dimethyltin(IV) dichloride forms only 2:1 complexes; in every case, two water molecules are present in the solid state structure. An octahedral coordination geometry around the tin(IV) center is proposed on the basis of Mossbauer and IR spectra.
Impact of the synergistic collaboration of oligothiophene bridges and ruthenium complexes on the optical properties of dumbbell-shaped compounds.
2012
The linear and non-linear optical properties of a family of dumbbell-shaped dinuclear complexes, in which an oligothiophene chain with various numbers of rings (1, 3, and 6) acts as a bridge between two homoleptic tris(2,2'-bipyridine)ruthenium(II) complexes, have been fully investigated by using a range of spectroscopic techniques (absorption and luminescence, transient absorption, Raman, and non-linear absorption), together with density functional theory calculations. Our results shed light on the impact of the synergistic collaboration between the electronic structures of the two chemical moieties on the optical properties of these materials. Experiments on the linear optical properties …
Enhanced porosity in a new 3D Hofmann-like network exhibiting humidity sensitive cooperative spin transitions at room temperature
2011
The porous coordination polymers (PCPs) of general formula {Fe(bpac)[M(CN)4]}·guest (M = Pt, Pd) exhibit larger channels than previously synthesised 3D-Hofmann-like PCP. The channels are partially occupied by uncoordinated guest bpac ligands and labile H2O molecules. These PCPs exhibit very scarce cooperative spin crossover behaviour around room temperature with a large hysteresis loop (up to 49 K) and also display sensitivity to humidity and guest molecules. The inclusion of bpac molecules in the 3D network can be avoided by adding competitive volatile molecules during the crystallization process, affording the guest-free material. The spin crossover behavior of different guest and guest-f…
Crystal structure and spectroscopic study of [Cu(BPCA)(OH2)(O2CCH3)·H2O complex; BPC = N-2-pyridinylcarbonyl-2-pyridinecarboximidate anion
1989
Abstract The crystal and molecular structure of the [Cu(BPCA)(OH2)(O 2CCH3]·H2O complex (BPCA = N-2-pyridinylcarbonyl-2-pyridinecarboximidate anion) has been determined by X-ray diffraction methods. It crystallizes in the triclinic space group P l with two formula units in a cell of dimensions: a = 7.416(2), b = 8.632(4), c = 13.034(3) A, α = 74.55(3), β = 84.84(3), γ = 81.04(5)°. Least-squares refinement of 2534 reflections with I > 2.5σ(I) and 218 parameters gave a final R = 0.047 and Rw = 0.049. The structure consists of discrete [Cu(BPCA)(OH2)(O2CCH3)] neutral units linked through hydrogen bonding. The coordination geometry around copper ions can be described as tetragonal square pyrami…
One-dimensional oxalato-bridged copper(II) complexes with 3-hydroxypyridine and 2-amino-4-methylpyridine
2001
Two new one-dimensional oxalato-bridged copper(II) compounds of formula [Cu(ox)L2]n (1) and {[Cu2(ox)2L%3]·L%}n (2) [ox oxalate dianion, L3-hydroxypyridine (pyOH) and L% 2-amino-4-methylpyridine (ampy)] have been synthesized and characterized by FT-IR spectroscopy, variable-temperature magnetic measurements and single-crystal X-ray diffraction. The crystal structure of 1 comprises chains of copper atoms in which cis-[Cu(pyOH)2] 2 units are sequentially bridged by asymmetric bis-bidentate oxalato ligands with an intrachain copper‐copper separation of 5.548(1) A, . Each copper atom is six-coordinated: four oxygen atoms belonging to two bridging oxalato ligands and two nitrogen atoms from two …
Coordination self-assembly through weak interactions in meso-dialkoxyphosphoryl-substituted zinc porphyrinates.
2019
International audience; The self-assembly of seven zinc 10-(dialkoxyphosphoryl)-5,15-diarylporphyrinates Zn5-Zn11 containing different substituents at the phosphonate and aryl groups was investigated. Single crystals of Zn5-Zn9 complexes were grown under the same conditions and analyzed by X-ray structural analysis. A supramolecular self-assembly is observed in all crystals through weak coordinative bonding of the phosphoryl group of one porphyrin molecule to the zinc(II) ion of a second porphyrin molecule. The geometry of the porphyrin macrocycle is similar in all of the studied crystals and the central zinc atom in each case adopts a distorted tetragonal pyramidal environment. However, th…
Biological Evaluation of the NIR-Emissive Ruby Analogue [Cr(ddpd) 2 ][BF 4 ] 3 as a Photodynamic Therapy Photosensitizer
2018
International audience; Photodynamic therapy relies on the bioavailability of photosensitizers with suitable photophysical, chemical and biochemical properties. Although the photophysical properties, stability and high water solubility of the chromium(III) complex [Cr(ddpd)2][BF4]3 (ddpd = N,N'-dimethyl-N,N'-dipyridin-2-ylpyridine-2,6-diamine) are very favorable, its photocytotoxicity against cancerous and non-cancerous cell lines has not yet been elucidated. We now report the cytotoxicity and photocytotoxicity of the complex [Cr(ddpd)2][BF4]3 against human cervical cancer cells, human primary glioblastoma cells, human glioblastoma astrocytoma cells and non-cancerous retinal pigment epithel…