Search results for "coordination complex"
showing 10 items of 381 documents
The Influence of the Amide Linkage in the FeIII-Binding Properties of Catechol-Modified Rosamine Derivatives
2015
The two new fluorescent ligands RosCat1 and RosCat2 contain catechol receptors connected to rosamine platforms through an amide linkage and were synthesized by using microwave-assisted coupling reactions of carboxyl- or amine-substituted rosamines with the corresponding catechol units and subsequent deprotection. RosCat1 possesses a reverse amide, whereas RosCat2 has the usual oriented amide bond (HNCO vs. CONH, respectively). The ligands were characterized by means of NMR spectroscopy, mass-spectrometry, and DFT calculations and X-ray crystallography studies for RosCat1. The influence of the amide linkage on the photophysical properties of the fluorescent ligands was assessed in different …
Applications and stereoselective syntheses of P-chirogenic phosphorus compounds.
2016
International audience; Phosphorus compounds bearing chirality on the P-center are usually qualified as P-chirogenic or P-stereogenic. This chemical class concerns natural products, agrochemistry, molecular materials, biology and pharmacy, although it is certainly in coordination chemistry and in asymmetric catalysis using chiral transition metal complexes that P-chirogenic phosphorus compounds are the most used. The chiral phosphine ligands and their uses in asymmetric metal-catalyzed reactions have been widely reviewed in literature. However, an overview covering the applications as well as the stereoselective syntheses of all classes of phosphorus compounds has not yet been provided. Thi…
Double-CO32− Centered [CoII5] Wheel and Modeling of Its Magnetic Properties
2010
A high-spin Co(II) cluster with a rare pentagonal molecular structure and formula [Co(5)(CO(3))(2)(bpp)(5)]ClO(4) (1; Hbpp is 2,6-bis(phenyliminomethyl)-4-methylphenolate) has been synthesized and characterized by single-crystal X-ray diffraction. This topology arises from fusing five [Co(2)(bpp)] moieties in a cyclic manner around two CO(3)(2-) central ligands, resulting in propeller-like configuration. The irregular coordination of the carbonate ions to the metal centers results in a combination of coordination numbers (CNs) of the Co(II) ions of five and six. The bulk magnetization of this complicated magnetically exchanged system has been modeled successfully by employing a matrix diago…
Crystal structure of catena-poly[[[(2-ethoxypyrazine-κN)copper(I)]-di-μ2-cyanido] [copper(I)-μ2-cyanido]]
2019
The title compound, {[Cu(EtOpz)(CN)2][CuCN]}n, where EtOpz is 2-ethoxypyrazine, is a two-dimensional polymeric copper complex with different coordination environments of the two CuI ions. One Cu atom is coordinated to the 2-ethoxypyrazine molecule and two bridging cyanide ligands, equally disordered over two sites. The second Cu atom is coordinated by two disordered over two sites bridging cyanide groups. Two copper–cyanide chains are connected through Cu⋯Cu contact.
Crystal structure of a rare trigonal bipyramidal titanium(IV) coordination complex: trichlorido(3,3′-di-tert-butyl-2′-hydroxy-5,5′,6,6′-tetramethyl-1…
2017
The title compound, [Ti(C24H33O2)Cl3(C4H8O)], is a rare example of a trigonal–bipyramidal titanium coordination complex with three chloride and two oxygen donor ligands. The asymmetric unit contains two independent molecules having essentially the same conformation. The molecules feature the titanium(IV) metal cation complexed with three chloride ligands, a tetrahydrofuran molecule, and one oxygen atom from the resolved ligand precursor (R)-(+)-5,5′,6,6′-tetramethyl-3,3′-di-t-butyl-1,1′-biphenyl-2,2′-diol, where the remaining phenolic hydrogen atom engages in intermolecular O—H...Cl hydrogen bonding. In one molecule, the THF ligand is disordered over two orientations with refined site occup…
Crystal structure, spectroscopic characterization and Hirshfeld surface analysis of trans-diaqua[2,5-bis(pyridin-4-yl)-1,3,4-oxadiazole]dithioc…
2019
The NiII atom in the mononuclear title complex has an almost regular octahedral N4O2 coordination geometry. In the crystal, the complex molecules are linked in a three-dimensional network through strong O—H⋯N hydrogen bonds.
Oxidovanadium(v) complexes with l-proline-based amino acid phenolates
2019
Abstract l -proline was used to prepare chiral, tridentate amino acid phenol proligands H2L1–4. These proligands react with vanadium precursors VO(acac)2, VOSO4∙5H2O and VO(OPr)3 in methanol to form the corresponding oxidoalkoxidovanadium( v ) complexes 1–4. The complexes crystallize from methanol, and are octahedrally coordinated with a general formula [VO(L1–4)(OMe)(MeOH)]. In solution, however, they adopt several different conformations or isomeric structures depending on the solvent.
Simultaneous Endo- and Exo-Complex Formation of Pyridine[4]arene Dimer with Neutral and Anionic Guests
2017
The formation of complexes between hexafluorophosphate (PF6−) and tetraisobutyloctahydroxypyridine[4]arene has been thoroughly studied in the gas phase (ESI‐QTOF‐MS, IM‐MS, DFT calculations), in the solid state (X‐ray crystallography), and in chloroform solution (1H, 19F, and DOSY NMR spectroscopy). In all states of matter, simultaneous endo complexation of solvent molecules and exo complexation of a PF6− anion within a pyridine[4]arene dimer was observed. While similar ternary complexes are often observed in the solid state, this is a unique example of such behavior in the gas phase. peerReviewed
Comment on “Crystallographic Snapshot of an Arrested Intermediate in the Biomimetic Activation of CO2”
2015
Out of focus: A recent Communication published in this journal describes the synthesis of [nBu4 N]HCO3 . The authors performed a single-crystal X-ray study that revealed a putative species described as an incipient hydroxide ion engaging in a long, and presumably weak, interaction with CO2 . Our recent exploration of the coordination chemistry of CO2 with small ions leads us to believe that such an exceptional bonding situation is unlikely. Instead, we argue that the crystal structure is that of [nBu4 N]O2 CCH3 and therefore not representative of the bulk powder from the synthesis.
Synthesis, Characterization, and Cu(2+) Coordination Studies of a 3-Hydroxy-4-pyridinone Aza Scorpiand Derivative.
2016
The synthesis, acid-base behavior, and Cu(2+) coordination chemistry of a new ligand (L1) consisting of an azamacrocyclic core appended with a lateral chain containing a 3-hydroxy-2-methyl-4(1H)-pyridinone group have been studied by potentiometry, cyclic voltammetry, and NMR and UV-vis spectroscopy. UV-vis and NMR studies showed that phenolate group was protonated at the highest pH values [log K = 9.72(1)]. Potentiometric studies point out the formation of Cu(2+) complexes of 1:2, 2:2, 4:3, 1:1, and 2:1 Cu(2+)/L1 stoichiometries. UV-vis analysis and electrochemical studies evidence the implication of the pyridinone moieties in the metal coordination of the 1:2 Cu(2+)/L1 complexes. L1 shows …