Search results for "Bridging"
showing 10 items of 155 documents
Exchange Coupling in Cyano-Bridged Homodinuclear Cu(II) and Ni(II) Complexes: Synthesis, Structure, Magnetism, and Density Functional Theoretical St…
2001
The synthesis and structural characterization of several new cyano-bridged copper(II) and nickel(II) homodinuclear complexes is presented. The measure of magnetic properties for these complexes is complemented with a computational study of the exchange coupling for several model structures representing this family of compounds. The influence of several factors on the coupling constant has been examined, coordination position occupied by the bridging ligand, distortions of the coordination environment, and relative disposition of the cyanide ion with respect to the M-M vector. Comparison of experimental and calculated coupling constants allows for the rationalization of the most relevant fea…
Mixed spin-state [HS-LS] pairs in a dinuclear spin-transition complex: confirmation by variable-temperature 57Fe Mössbauer spectroscopy.
2008
Exquisite sensitivity of Mossbauer spectroscopy for tiny local molecular distortion is demonstrated in [FeII2(pmat)2](BF4)4?DMF: high-spin (HS) iron(II) in [HS-HS] and in [LS-HS] (low-spin–high-spin) pairs is clearly distinguished (see picture) for the first time without the need to apply a magnetic field. This dinuclear complex clearly shows that spin crossover via a [LS-HS] species is promoted by the use of a highly constrained bridging ligand (the bis-terdentate pmat).
Syntheses, crystal structures and magnetic properties of dinuclear copper(II) complexes with pyrazino[2,3-f ][4,7]phenanthroline (pap) as bridging l…
2000
Three dinuclear copper(II) complexes with pyrazino[2,3-f][4,7]phenanthroline (pap) as bridging ligand have been prepared; [Cu2(pap)(C2O4)2]·5H2O 1, [Cu2(pap)(H2O)7(SO4)]SO4·3H2O 2 and [Cu2(pap)(H2O)3(NO3)3]NO33. These are the first metal complexes of pap which have been characterized by X-ray crystallography and magnetic susceptibility measurements. In 1 the dinuclear complex is intercepted by a mirror plane; the bridging pap and the terminal oxalate ligands are bidentate in the equatorial plane of copper. In addition copper has weak axial interactions to oxygen atoms of oxalate in two neighbouring molecules. In 2 the two crystallograpically independent copper atoms are both six-co-ordinate…
Bridging between the metal community and the church: Entextualization of the Bible in Christian metal discourse
2012
Abstract For many metal music groups, the music and sounds play a more important role than language and the lyrics do. In the Christian metal (CM) genre, however, the verbal dimension has a significant status. Drawing on the concept of entextualization, the process of producing texts through extraction and relocation, this paper describes how CM groups craft their discourse (song lyrics plus textual contents on their websites) by drawing on pre-existing biblical texts while connecting them with the resources provided by the metal music culture. Entextualization is a fruitful way of looking into how the Bible is used on CM band websites for mediating between Christianity and metal music cult…
Photoinduced HS state in the first spin-crossover chain containing a cyanocarbanion as bridging ligand
2009
A new polymeric approach, based on cyanocarbanion ligands, for the design of spin crossover (SCO) compounds led us to the compound [Fe(abpt)2(tcpd)] (1) (tcpd^2 = (C[C(CN)2|3)^2 , abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) which has been characterised as the first SCO molecular chain involving a cyanocarbanion as bridging ligand. Gomez Garcia, Carlos Jose, Carlos.Gomez@uv.es
Preparation and crystal structure of the oxalato-bridged CrIII–AgItwo-dimensional compound {Ag3(H2O)[Cr(dpa)(ox)2]3}n·2nH2O (dpa = 2,2′-dipyridylamin…
2004
The reaction of the mononuclear complex [Cr(dpa)(ox)2]− (dpa = 2,2-dipyridylamine) with Ag+ in aqueous solution affords the two-dimensional compound {Ag3(H2O)[Cr(dpa)(ox)2]3}n·2nH2O (1) whose structure has been determined by single-crystal X-ray diffraction. Six crystallographically independent metal atoms (three chromium and three silver atoms) occur in 1. The three [Cr(dpa)(ox)2]− units in 1 act as ligands towards the silver atoms through the two oxalate groups. Each oxalate group acts as bridging ligand adopting five coordination modes: bis-bidentate, bis-bidentate/monodentate (outer), bis-bidentate/monodentate (inner), bidentate/bis-monodentate (outer) and bidentate/monodentate (outer).…
Zinc complexation to N-substituted sulfonamide ligands. Preparation, properties and crystal structure of copper(II) doped ?[Zn(sulfamethizolate)2(py)…
2003
Abstract The single crystal structure and spectroscopic properties of the copper(II) doped {[Zn(sulfamethizolate) 2 (py)]·H 2 O} ∞ are reported. The complex is a polymer where the Zn(II) ions are coordinated by four N atoms in a very distorted tetrahedral environment. The sulfamethizolate anion acts as a monodentate ligand through the thiadiazole N atom and as a bridging ligand via the amino and thiadiazole N atoms. The compound is studied by EPR, by 13 C NMR in solid state and by 1 H and 13 C NMR in DMSO-d 6 solution. The similarity between the 13 C NMR spectrum in solution and the solid 13 C NMR spectrum indicates that the structure of the compound remains in solution. The EPR spectrum sh…
High-dimensional mixed-valence copper cyanide complexes: Syntheses, structural characterizations and magnetism
2009
International audience; Reactions of CuCl 2 with different CN complexes in presence of a neutral ancillary ligand lead to two novel mixed-valence Cu complexes [Cu II (bpy)Cu I (CN) 3 ] n , 1 (bpy=2,2′-bipyridine) and {[Cu II (tn) 2 ][Cu I 4 (CN) 6 ]} n 2 (tn=1,3-diaminopropane). For compound 1, the asymmetric unit involves two Cu ions Cu1 and Cu2 (Cu I and Cu II centres, respectively) which strongly differ in their environments. The Cu1 ion presents a CuC 4 pseudo-tetrahedral geometry, while the Cu2 ion presents a CuN 5 slightly distorted square-pyramidal geometry. The extended structure of 1 is generated by three cyano ligands which differ in their coordination modes. One CN group has a μ …
Syntheses, crystal structures and magnetic properties of copper(ii) dicyanamide complexes; dinuclear, chain and ladder compounds
2002
The preparation, crystal structures and magnetic properties of three heteroleptic copper(II) complexes with dicyanamide (dca) bridges, [Cu(bpca)(H2O)(dca)]2 (1) (bpca = bis(2-pyridylcarbonyl)amidate), [Cu(bpy)(dca)2]n (2) (bpy = 2,2′-bipyridine), [Cu2(bpm)(dca)4]n (3) (bpm = 2,2′-bipyrimidine) are reported. In addition, magnetic susceptibility measurements of the sheetlike polymer [Cu(phen)(dca)2] (4) (phen = 1,10-phenanthroline), structurally characterized previously, have been performed. In complex 1 pairs of mononuclear structural building blocks, [Cu(bpca)(dca)(H2O)], are loosely connected through a 1,3-dca bridge in which nitrile is equatorially bound and the amide is semi-coordinated …
4,2-Ribbon like ferromagnetic cyano-bridged FeIII2NiII chains: a magneto-structural study
2007
The low-spin iron(III) complex AsPh(4)[Fe(III)(bpy)(CN)(4)].CH(3)CN (1) [AsPh(4) = tetraphenylarsonium cation] and the heterobimetallic chains [{Fe(III)(L)(CN)(4)}(2)Ni(II)(H(2)O)(2)].4H(2)O with L = bpy (2) and phen (3) [bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline] have been prepared and their structures determined by X-ray diffraction methods. The structure of 1 consists of mononuclear [Fe(bpy)(CN)(4)](-) anions, tetraphenylarsonium cations and acetonitrile molecules of crystallization. The iron(III) is hexacoordinated with two nitrogen atoms of the bidentate bpy and four carbon atoms of four terminal cyanide groups building a distorted octahedral surrounding around the metal ato…