Search results for "Ferro"
showing 10 items of 2451 documents
Syntheses, structures and magnetic properties of cyano-bridged one-dimensional Ln3+–Fe3+ (Ln = La, Dy, Ho and Yb) coordination polymers
2019
Four new heterometallic one-dimensional coordination polymers with formulae trans-[La(o-phen)3(H2O)(μ-CN)2Fe(CN)4]·7H2O (1) and trans-[Ln(H2O)2(phen)2(μ-CN)2Fe(CN)4]·nH2O [Ln/n = Dy/8 (2), Ho/7 (3) and Yb/7 (4), (o-phen = 1,10-phenanthroline)] have been synthesized by reacting Ln(NO3)3·xH2O with K3[Fe(CN)6] and 1,10-phenanthroline. The structures of 1–4 have been established by single crystal X-ray diffraction. Polymer 1 presents a chain structure with three o-phen ligands coordinated to La3+ and [Fe(CN)6]3− complexes connecting them through two trans CN− ligands to form a linear chain. Compounds 2–4 are solvates and contain Ln3+ ions coordinated to two o-phen ligands and also bridged by [F…
“Tail–Tail Dimerization” of Ferrocene Amino Acid Derivatives
2010
Acid anhydrides of N-protected 1'-aminoferrocene-1-carboxylic acid (Fca) have been prepared and spectroscopically characterized (protection group Boc, Fmoc, Ac; 4a―4c). The structure of the Boc-derivative 4a has been determined by single-crystal X-ray crystallography. An intramolecular N― H···O hydrogen bond involving the carbamate units results in a ring structure containing the two ferrocene units, the anhydride moiety, and the hydrogen bond. In the crystal, the individual molecules are connected by intermolecular N-H···O hydrogen bonds of the carbamate unit. Experimental and theoretical studies suggest that the ring motif is also a dominant species in solution. Electronic communication a…
Ferrocenyl-Labeled Sugar Amino Acids: Conformation and Properties
2012
Novel organometallic sugar amino acid conjugates 1–5 have been prepared by amide coupling of O-protected N-acetylmuramic acid and iso-muramic acid (2-[3-amino-2, 5-dihydroxy-6-(hydroxymethyl)oxan-4-yl]oxypropanoic acid) with 1-aminoferrocene, 1-aminoferrocene-1′-carboxylic acid (H-Fca-OH), or 1, 1′-diaminoferrocene, respectively. The influence of the ferrocenyl moiety and presence of additional remote potential hydrogen atom acceptors and donors at the ferrocenyl core on the conformation and lipophilicity is investigated by TLC, IR, NMR, and CD spectroscopic methods augmented by density functional calculations. Furthermore, the redox potential of the ferrocene/ferrocenium couple is tuned by…
Conformational stability of oligoferrocene oligoamide foldamers
2016
Abstract Organometallic oligoamides built from three to four ferrocene amino acid units ( H-Fca-OH , 1-amino-1′-ferrocene carboxylic acid) fold into hydrogen bonded secondary structures featuring eight-membered rings by cooperative hydrogen bonds. NMR studies and DFT calculations (CAM-B3LYP, LANL2DZ, IEFPCM (THF)) reveal that the organometallic zigzag foldamer structures are highly resistant toward denaturation by hydrogen bond acceptors such as dimethyl sulfoxide and 2,4-lutidine. Replacing one ferrocene amino acid unit by the organic α -amino acid glycine at the C -terminal end (Fca → Gly) significantly destabilizes the secondary zigzag structure facilitating denaturation by DMSO. Highly …
Electroactive linear-hyperbranched block copolymers based on linear poly(ferrocenylsilane)s and hyperbranched poly(carbosilane)s.
2009
A convenient two-step protocol is presented for synthesis of linear-hyperbranched diblock copolymers consisting of a linear, organometallic poly(ferrocenylsilane) (PFS) block and hyperbranched poly(carbosilane) (hbPCS) segments. Linear PFS diblock copolymers were synthesized through photolytic ring-opening polymerization of dimethyl[1]silaferrocenophane as the first block and methylvinyl[1]sila-ferrocenophane as the second. These block copolymers served as polyfunctional cores in a subsequent hydrosilylation polyaddition of different silane-based AB 2 monomers. Three AB 2 monomers (methyldiallylsilane; methyldiundecenylsilane, and ferrocenyldiallylsilane) were investigated; they introduced …
Oxalate‐Based 3D Chiral Magnets: The Series [Z II (bpy) 3 ][ClO 4 ][M II Fe III (ox) 3 ] (Z II = Fe, Ru; M II = Mn, Fe; bpy = 2,2'‐Bipyridine; ox = O…
2005
The synthesis, structure, and physical properties of the oxalate-based molecular magnets with the formula [ZII(bpy)3][ClO4][MIIFeIII(ox)3] (ZII = Fe, Ru; MII = Mn, Fe; bpy = 2,2'-bipyridine; ox = oxalate dianion) are presented here. All compounds are isostructural and crystallize in the chiral cubic space group P4132, and contain three-dimensional dimetallic networks formed by alternating MII and MIII ions that are connected by oxalate anions. These compounds exhibit strong antiferromagnetic interactions that give rise to magnetic ordering as ferrimagnets or weak ferromagnets, with critical temperatures of up to 20 K, which is twice as high as those found for the isostructural magnets based…
2D Bimetallic Oxalate‐Based Ferromagnets with Inserted [Fe(4‐Br‐sal 2 ‐trien)] + and [Fe(3‐R‐sal 2 ‐trien)] + (R = Br, Cl and CH 3 O) Fe III Spin‐Cro…
2012
The syntheses, structures and magnetic properties of the compounds of formula [FeIII(4-Br-sal2-trien)][MnIICrIII(ox)3]0.67Cl0.33·CH3OH_solvate (1), [FeIII(3-Br-sal2-trien)][MnIICrIII(ox)3]·(CH3CN)2 (2), [FeIII(3-Cl-sal2-trien)][MnIICrIII(ox)3]·(CH3OH)2·(CH3CN)2 (3) and [FeIII(3-CH3O-sal2-trien)][MnIICrIII(ox)3]·(CH3OH)·(H2O)1.5·(CH2Cl2)0.5 (4) are reported. The four structures present a 2D honeycomb anionic layer formed by MnII and CrIII ions linked through oxalate ligands and a cationic layer of the FeIII complexes intercalated between the 2D oxalate network. The main differences compared with previous 2D oxalate-based structures are the presence of double layers of cations in compounds 1,…
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.
New hexanuclear FeIII clusters with the gem-diol hydrated form of di(2-pyridyl)ketone and carboxylato ligands: Crystal structures and magnetic proper…
2019
Abstract The hexanuclear compounds [Fe6O2Cl2{(py)2CO2}2(pyOH)2(pyCOO)2(ButCOO)6] (1) and [Fe6O2{(py)2CO2}2(pyCOO)4(ButCOO)6] (2) were obtained by condensation of the trinuclear μ3-oxo-centered iron(III) pivalate [Fe3O(ButCOO)6(H2O)3]+ in the presence of di(2-pyridyl)ketone [(py)2CO] in MeCN at ambient temperature. Both complexes contain an analogous core which can be described as two {Fe3O}7+ units joined by gem-diolato (py)2CO22− bridges. Variable-temperature magnetic susceptibility measurements in polycrystalline samples of 1 and 2 reveal strong antiferromagnetic couplings between the iron(III) ions leading to S = 0 ground states.
Structural and magnetic properties of polynuclear oximate copper complexes with different topologies
2017
Abstract Two new copper(II) complexes containing the methyl(2-pyridyl)ketone oxime ligand (mpkoH) [Cu3(OH)(ClO4)2(mpko)3]·CH3OH (1) and [Cu(ClO4)(mpko)(mpkoH)]n (2) have been prepared from Cu(ClO4)2 and mpkoH in different metal-to-ligand molar ratios. In addition, the compound [Cu{(mpko)2BF2}(H2O)](BF4) (3) [(mpko)2BF2 is the fluoroboration product of the oxime] has been obtained when replacing Cu(ClO4)2 by Cu(BF4)2. Compound 1 is an isolated triangle with a {Cu3(µ3-OH)}5+ core, whereas 2 is a chain of CuII ions linked by anionic mpko− bridges. 1 exhibits strong antiferromagnetic competing interactions, as well as antisymmetric exchange. On the other hand, very weak ferromagnetic interactio…