Search results for "complex"
showing 10 items of 5889 documents
Protonation, coordination chemistry, cyanometallate "supercomplex" formation and fluorescence chemosensing properties of a bis(2,2'-bipyridino)cyclop…
2013
A new polyazamacrocycle (L) containing two 2,2'-bipyridino (bpy) units, where the heteroaromatic nitrogen atoms point outwards from the macrocyclic cavity, was synthesized and characterized by elemental analysis, ESI-MS, (1)H and (13)C NMR, FTIR and TGA. Five protonation constants involving aliphatic nitrogens with log K in the range 9.39-3.07 were determined by potentiometry and NMR and a sixth protonation (log K = 2.2) involving a bipyridine moiety could be detected by UV-Vis and NMR titrations. The interaction of L with the cyanometallate anions [Pt(CN)4](2-) and [Co(CN)6](3-) was studied by potentiometry yielding respectively log K values in the ranges 4.0-6.4 and 5.2-10.5, covering pro…
Spin crossover FeII complexes as templates for bimetallic oxalate-based 3D magnets
2007
Abstract We present the synthesis and structural characterization of the salt [Fe(bpp)2][MnCr(ox)3]2 · bpp · CH3OH. It crystallizes in the monoclinic space group. This material contains an anionic [MnCr(ox)3]− 3D 10-gon ferromagnetic network, that orders below 3.0 K. The channels created by this architecture are filled by the spin crossover cations [Fe(bpp)2]2+ (bpp = 2,6(bispyrazol-3-yl)pyridine), free ligand and solvent molecules. No spin transition has been observed at ambient pressure.
Experimental and theoretical investigations of the redox behavior of the heterodichalcogenido ligands [(EP(i)Pr2)(TeP(i)Pr2)N](-) (E = S, Se): cyclic…
2008
The two-electron oxidation of the lithium salts of the heterodichalcogenidoimidodiphosphinate anions [(EP (i)Pr 2)(TeP (i)Pr 2)N] (-) ( 1a, E = S; 1b, E = Se) with iodine yields cyclic cations [(EP (i)Pr 2)(TeP (i)Pr 2)N] (+) as their iodide salts [(SP (i)Pr 2)(TeP (i)Pr 2)N]I ( 2a) and [(SeP (i)Pr 2)(TeP (i)Pr 2)N]I ( 2b). The five-membered rings in 2a and 2b both display an elongated E-Te bond as a consequence of an interaction between tellurium and the iodide anion. One-electron reduction of 2a and 2b with cobaltocene produces the neutral dimers (EP (i)Pr 2NP (i)Pr 2Te-) 2 ( 3a, E = S; 3b, E = Se), which are connected exclusively through a Te-Te bond. Two-electron reduction of 2a and 2b …
A novel mixed valent Cu(II)-Cu(I) 2D framework made of a hydrazone and μ-SCN bridged metallacyclic loops cross-linked by μ3-SCN chains.
2012
A mixed valent copper complex [Cu(II)Cu(I)(L)(μ-SCN)(μ(3)-SCN)](n) (LH = N'-((pyridin-2-yl)methylene)acetohydrazide) has been synthesized and characterized. It is a unique example of a 2D mixed valent Cu(II)-Cu(I) interlinked molecular assembly with a very unusual bridging property of the hydrazone ligand. An extraordinary in situ partial Cu(II)→ Cu(I) reduction is observed in this system at room temperature.
Coordination ability of pentapeptides with two dehydro-amino acid residues inserted into their sequences.
2004
The study on the binding ability of tested ligands have shown that insertion of two dehydro-amino acid residues into peptide sequences makes them more effective in metal ion binding than ligands with one dehydro-amino acid residue. The ligand with two Z(Delta)Phe residue form more stable complexes than his analogues with one Z(Delta)Phe residue. Interesting is this that position of Z(Delta)Phe residue in peptide chain have impact on Cu(II)-complexes formation.
An Unlockable-Relockable Iron Cage by Subcomponent Self-Assembly
2008
Anion coordination chemistry in aqueous solution of polyammonium receptors
2006
The behavior of polyamines as receptors of selected families of anions in water is explored. First metallocyanide interaction with saturated polyammonium hosts is analyzed both in solution and in the solid state. The utility of potentiometry, multinuclear NMR, microcalorimetry and cyclic voltammetry to describe solution features of this chemistry is described for selected systems. Sulfate, phosphate, polyphosphate and nucleotide interactions with large polyammonium receptors are then reviewed. Hydrogen bond formation is discussed from a thermodynamic point of view. The influence of the presence of aromatic fragments within the structure on the binding strength is discussed. Factors affectin…
Synthèse de chalcones à base de tétrathiafulvalène: RC(O)CHC(CH3)TTF, TTFC(O)CHC(CH3)R (R TTF: C6H3S4; Bct: C6H5Cr(CO)3; Fc: C5H4FeC5H5). Propr…
1992
Abstract Novel chalcones that contain tetrathiafulvalene (TTF) and/or metallocene (ferrocenyl or benchrotrenyl) moieties: RC(O)CHC(CH 3 )R′ (R and/or R′ TTF: C 6 H 3 S 4 ; Fc: C 5 H 4 FeC 5 H 5 ; Bct: C 6 H 5 Cr(CO) 3 ) were prepared using TiCl 3 /Et 3 N as the condensation reagent. The 1-1 charge transfer complex with TCNQ (tetracyanoquinodimethane was obtained for the ditetrathiafulvalenic derivative (R R′ TTF). This complex exhibits the semiconducting behaviour.
Stereospecific CC-bond formation with rabbit muscle aldolase - A chemoenzymatic synthesis of (+)-exo-brevicomin
1990
Abstract (+)-(1S,5R,7S)-Exo-brevicomin 9, a sex pheromone of the western pine bark beetle, is synthesized using an aldol reaction catalyzed by fructose-1,6-diphosphate aldolase (EC 4.1.2.13) from rabbit muscle as the key step by which the absolute configuration of the target is established.
Sublimable Single Ion Magnets Based on Lanthanoid Quinolinate Complexes: The Role of Intermolecular Interactions on Their Thermal Stability
2018
We report the design, preparation, and characterization of two families of thermally robust coordination complexes based on lanthanoid quinolinate compounds: [Ln(5,7-Br2q)4]− and [Ln(5,7-ClIq)4]−, where q = 8-hydroquinolinate anion and Ln = DyIII, TbIII, ErIII, and HoIII. The sodium salt of [Dy(5,7-Br2q)4]− decomposes upon sublimation, whereas the sodium salt of [Dy(5,7- ClIq)4]−, which displays subtly different crystalline interactions, is sublimable under gentle conditions. The resulting film presents low roughness with high coverage, and the molecular integrity of the coordination complex is verified through AFM, MALDI-TOF, FT-IR, and microanalysis. Crucially, the single-molecule magnet …