0000000001310676
AUTHOR
José-vicente Folgado
Alternating Ferro/Antiferromagnetic Copper(II) Chain Containing an Unprecedented Triple Formato/Hydroxido/Sulfato Bridge.
The first example of a triple formato/hydroxido/sulfato (FHS) bridge for any metal is reported in compound [Cu2(bpym)(OH)(HCO2)(SO4)(H2O)2]·3H2O (1). Its structure shows the presence of alternating triple FHS bridges and 2,2'-bipyrimidine (bpym) ones. Although in the initial synthesis the sulfate anions were introduced accidentally, here we report the rational synthesis and the magnetic properties of this compound. The magnetic properties show that 1 is an alternating ferro/antiferromagnetic (F/AF) chain compound with predominant antiferromagnetic interactions and were fit to an alternating F/AF S = (1)/2 chain with g = 2.103, JAF = -139 cm(-1), and JF = 116 cm(-1) (α = JF/|JAF| = 0.83). Th…
Coordinating behaviour of a new pyridylhydrazone; tris-complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) with 2-pyridylcarbaldehyde-N,N-dimethylhydrazone
The preparation and characterization oftris-complexes of MnII, CoII, NiII, CuII and ZnII with a new pyridylhydrazone, 2-pyridylcarbaldehyde-N,N-dimethylhydrazone (pch), are described. In all the complexes pch behaves as a bidentate ligand binding through the pyridine and azomethyne nitrogen atoms. The complexes appear to be monomeric, high spin six-coordinate, and a distorted octahedral stereochemistry around the metal is suggested. The e.p.r. results for both CuII compounds indicate a mainly dx2−y2 ground state with a static Jahn-Teller distortion, whilst for the MnII complex the e.p.r. data indicates a very low symmetry for the MnN6 polyhedron.
Cooperative H-bonds, π⋯π and anion⋯π interactions as driving forces in the construction of novel Cu(II) bis(imidazol-2-yl) supramolecular 3D frameworks
Abstract Two new Cu(II) complexes with bis(2-imidazolyl) based ligands, with the formula [Cu(BIM)2(SCN)2]·2H2O (BIM = bis(2-imidazol-2-yl)methane) and [Cu(HBIMAM)2(OH2)2](BF4)4·2H2O (BIMAM = bis(2-imidazol-2-yl)methylaminomethane) have been synthesized and characterized. Both compounds contain mononuclear entities as molecular building blocks (MBBs); neutral [Cu(BIM)2(SCN)2] in compound 1 and cationic [Cu(HBIMAM)2(OH2)2]4+ in compound 2. The coordination around the metal atoms shows a tetragonally-elongated octahedral geometry (CuN4S2 and CuN4O2 chromophores). The Q-band EPR spectra of both compounds are indicative of an essentially d x 2 - y 2 ground state for copper(II) ions. The analysis…
X-ray crystal structure and electronic properties of chlorobis(mepirizole)copper(II) tetrafluoroborate (mepirizole = 4-methoxy-2-(5-methoxy-3-methyl-1H-pyrazol-1-yl)-6-methylpyrimidine)
Abstract The crystal structure of [Cu(mep)2Cl](BF4)[mep = 4-methoxy-2-(5-methoxy-3-methyl-1H-pyrazol-1-yl)-6-methylpyrimidine] has been determined by X-ray diffraction. The crystal structure is built up of [Cu(mep)2Cl]+ cations and BF4− anions. The structure of the cation involves a five-coordinated CuN4Cl chromophore, with a stereochemistry near to a compressed trigonal bypyramid (TBP) but with a significant degree of distortion towards the square pyramidal (SP) topology. The EPR spectrum is indicative of a mixed dz2/dx2 − y2 ground state for the copper(II) ions, in agreement with the structural data.
An Unusual Geometry of Five-Coordinate Copper(II): The Structure of Cu(terpy)I2 and Spectroscopic Investigations of Complexes Cu(terpy)X2 (X: I, NCS)
The structure of the compound Cu(terpy)I2 (terpy 2,2′: 6′, 2″ terpyridine) was determined at room temperature. It is monoclinic, space group I2/c with a = 13.689(3), b = 9.510(2), c = 11.605(3) Å, β = 97.59(4)° and Ζ = 4. The copper(II) ions are five-coordinated by the three nitrogen atoms from the terpy ligand and the two iodine atoms. The CuN3I2 polyhedron exhibits the same unusual “reverse” geometry as is observed for Cu(terpy)(NCS)2. Single crystal EPR measurements of the iodide and the isothio-cyanate complexes confirmed the structural results, excluding the possibility of a dynamically averaged geometry.
Synthesis and characterization of molybdenum(VI)-dioxo complexes containing both coordinated thiolate and carboxylate groups. Reactions with their own free ligands
Abstract The synthesis, characterization and spectroscopic properties of a group of Mo(VI) complexes having thiocarboxylate ligands of type [MoVIO2(O2CC(S)MePh-X)2]2 have been reported (X = H, p-Me, p-Cl). The peak potential for the Mo(VI) reduction increasing according to the electron-donor ability of X (Me > H > Cl). Reaction of these Mo(VI) complexes with their own free ligands has been studied by ESR and UV-Vis spectroscopy, yielding the monomeric [MoVO(O2CC(S)MePh-X)2]− as unique complex products. The kinetic study of this oxidation reaction has also been investigated.
Structural effects of Co and Cr substitution in LaMnO3 + δ
Series of perovskite oxides with the composition LaMn1 − xMxO3 + δ (M = Cr, Co; 0 ≤ x ≤ 1) have been synthesized by thermal treatment of precursors obtained by freeze-drying of acetic acid solutions. The oxides have been characterized by X-ray diffraction, and the Mn4+ content and, thus, the oxygen excess, δ, has been determined by redox back-titration. LaMnO3.14 and LaCrO3 phases have the rhombohedral-LaAlO3 and the orthorhombic-GdFeO3 structures, respectively. The LaMn1 − xCrxO3 + δ phases have the rhombohedral structure for x ≤ 0.3, and the orthorhombic structure for x ≥ 0.5. LaCoO3 has, as LaMnO3.14, the rhombohedral structure. However, the LaMn1 − xCoxO3 + δ phases have orthorhombic st…
Study of the thermal behaviour of ordered bimetallic EDTA complexes
Abstract The study of the thermal behaviour of a family of isostructural ordered bimetallic MM'(EDTA)·6H 2 O complexes has been performed using TG and DTA. Formal kinetic analysis of the dehydration step has been approached using non-isothermal procedures. The resulting correlation among the calculated E a values and the cationic sizes implies a common dehydration mechanism. Copper-containing complexes show distinctive behaviour during the ligand pyrolysis processes. A mechanistic interpretation involving formation of Cu(I) and Cu(0) intermediates is furnished. The evolution of the inorganic residues in systems containing both Co and Ni is especially considered given the interest in the (Co…
A novel dinuclear manganese(II) compound incorporating two bis(imidazolyl) based ligands with single μ2-η1:η1-carboxylato bridges. Molecular and crystal structure and magnetic properties of [Mn2Cl(BIP)(HBIMAM)(H2O)5]Cl3·4H2O (BIP=3,3-di(2-1H-2-imidazolyl)propanoate; BIMAM=N-methyldi(1H-2-imidazolyl)methanamine)
Abstract This paper reports the synthesis, X-ray structure and magnetic characterization of [Mn 2 Cl(BIP) (HBIMAM)(H 2 O) 5 ]Cl 3 ·4H 2 O a novel dinuclear manganese(II) incorporating two related bis(imidazolyl)-based ligands, BIP (3,3-di(2-1 H -2-imidazolyl)propanoate) and BIMAM ( N -methyldi(1 H -2-imidazolyl)methanamine). The metal atoms in the dinuclear entity are bridged by a μ 2 -η 1 :η 1 carboxylate group (from the propionate arm of the BIP ligand) acting in an anti – anti coordination bridging mode, with an intramolecular Mn⋯Mn distance of 6.47 A. The coordination around the Mn(II) ions shows a distorted octahedral geometry for both MnClN 2 O 3 and MnN 2 O 4 chromophores. Between th…
Exchange interactions through hydrogen-bond bridges. Crystal structure, spectroscopic characterisation and magnetic properties of the complex [{Cu(en)}2(μ-egta)]·4H2O (H4egta = 3,12-bis(carboxymethyl)-6,9-dioxa-3,12-diazatetradecanedionic acid)
Abstract The structure and spectroscopic and magnetic properties of [{Cu(en)}2(μ-egta)]·4H2O (H4egta = 3,12-bis(carboxymethyl)-6–9-dio 3,12-diazatetradecanedioic acid) are described. The compound is built of centrosymmetric neutral dimeric {[Cu(en)}2(μ-egta)] entities linked through hydrogen bonds involving water molecules. -NH2 groups and -CO2 groups, affording a three-dimensional framework. The egta anion displays an opened-up structure acting as a bridging ligand between two copper atoms. The coordination geometry about the metal atoms can be viewed as 4 + 1 + 1 (CuN3OO′O″ chromophores). The EPR spectra are indicative of an essentially dv−v ground state for the copper(II) ions. Magnetic …
Synthesis, Crystal Structure, and Magnetic Properties of Oxalato-Copper(II) Complexes with 3,3-Bis(2-imidazolyl)propionic Acid, an Imidazole-Carboxylate Polyfunctional Ligand: From Mononuclear Entities to Ladder-Like Chains.
The synthesis of five new Cu(II) compounds of formula [Cu(HBIP)(C(2)O(4))].H(2)O (1), [Cu(HBIP)(C(2)O(4))(OH(2))].2H(2)O (2), [{Cu(HBIP)Cl}(2)(mgr;-C(2)O(4))].2H(2)O (3), [{Cu(BIP)}(2)(mgr;-C(2)O(4))].2H(2)O (4) and [{Cu(BIP)}(2)(mgr;-C(2)O(4))].6H(2)O (5), together with their spectral and magnetic characterization, is reported. Crystal structures of compounds 2, 3 and 5 have been solved. All these compounds crystallize in the triclinic system, space group Ponemacr;, with a = 7.3322(3) Å, b = 10.014(1) Å, c = 11.541(1) Å, alpha = 113.22(1) degrees, beta = 91.37(1) degrees, gamma = 94.51(1) degrees, Z = 2 for compound 2; a = 7.444(2) Å, b = 8.518(2) Å, c = 11.231(2) Å, alpha = 97.45(2) degre…
ESR study of thianthrenium radical cation within acid zeolites
Abstract Thianthrene (E ox = 1.47 V vs NHE) has been adsorbed into a series of zeolites beta (s) and ZSM-5 in the NH 4 + or H + forms, having different particle size and Si/Al ratio. The resulting population of generated thianthrenium radical cation was determined by a combination of diffuse reflectance and ESR spectroscopies. From the results obtained it can be concluded: i) the process takes predominantly place in the interior of the voids (XPS measurements and lack of influence of the particle size); ii) ZSM-5 is more efficient than zeolite s; iii) no strong acid sites are required (both NH 4 + and H + forms produced very similar spin concentrations); iv) the zeolite framework acts isola…
Crystal structure, magnetic and spectroscopic properties of the bis(dimethyl sulfoxide) adduct of tetra-μ-formato-dicopper(II), a new tetracarboxylato-bridged copper(II) dimer
The crystal and molecular structure of a new tetracarboxylato-bridged copper(II) dimer, the bis(dimethyl sulfoxide)tetrakis(μ-formato)dicopper(II) has been determined by X-ray diffraction methods. It crystatlizes in the tetragonal space group I41/a, with Z=8 in a cell of dimensions a=17.688(2), c=10.408(1) Å. The structure is built up of centrosymmetric neutral dimers [Cu2(HCOO)4(dmso)2], where four bidentate carboxylate anions form syn-syn bridges between the metal atoms which are in a 4 + 1 environment. Magnetic susceptibility data show that the copper atoms are strongly antiferromagnetically coupled with J=-434 cm-1. The obtained triplet-singlet energy gap is compared with those reported…
Synthesis and structural, spectroscopic and magnetic characterization of iron(II) and iron(III) complexes of N-2-pyridinylcarbonyl-2-pyridinecarboximidate
Abstract One iron(II) complex of N -2-pyridinylcarbonyl-2-pyridinecarboximidate monoanion (bpca), [Fe(bpca) 2 ]·H 2 O ( 1 ), and three iron(III) complexes, [Fe(bpca)Cl 2 (H 2 O)]·(CH 3 ) 2 CO ( 2 ), [Fe(bpca) 2 ](NO 3 )·1.67H 2 O ( 3 ), [Fe(bpca) 2 ](ClO 4 ) ( 4 ), have been prepared and characterized by means of IR, UV-Vis and EPR spectroscopy and magnetic susceptibility measurements, where appropriate. The crystal structures of 1 – 3 have been determined from single crystal X-ray data, showing that the metallic ions are surrounded in all cases by distorted octahedral coordination spheres. From magnetic measurements it is evident that compounds 1 and 3 are practically in the low-spin state…
A new approach to the synthesis of intermetallic compounds: mild synthesis of submicrometric CoxMy (M = Mo, W; x∶y = 3∶1 and 7∶6) particles by direct reduction of freeze-dried precursors
A simple processing route to cobalt–molybdenum and cobalt–tungsten intermetallics (CoxMy, where M = Mo and W, and x∶y = 3∶1 and 7∶6) has been developed, on the basis of the use of precursors resulting from freeze-drying of aqueous solutions of the appropriate common metal salts. The influence of the preparative variables on the outcomes of this procedure is examined. These compounds are prepared as single phases by thermal reduction of amorphous freeze-dried powders under a hydrogen–argon atmosphere (8% H2), followed by slow cooling of the samples. The materials have been characterised by X-ray powder diffraction, metal analysis, scanning electron microscopy and thermogravimetry under an ox…
Magneto-Structural Correlations in μ-Halo Bridged Copper(II) Chains
To design synthetic pathways to systems of desired properties is a growing challenge for inorganic chemist. Our current interest in this area is focused on copper(II) chemistry. Besides to advance in the understanding of the factors determining the conformation around copper(II) in the solid state, we intend to gain insight into the chemical and structural effects that govern exchange coupling interactions in condensed species. In this context, we have approached the synthesis and characterization of a wide set of pentacoordinated Cu(LIII)XY complexes (LIII=tridentate ligand, X=coordinating anion, Y=coordinating or non-coordinating anion) showing a great structural diversity (including mono…
Spectroscopic studies and crystal structure of bis(N-2-pyridinylcarbonyl-2-pyridinecarboximidato) manganese(II) monohydrate: Zero-field splitting param
Abstract The X-ray crystal structure of bis(N-2-pyridinylcarbonyl-2-pyridinecarboximidato)manganese(II) monohydrate, Mn(BPCA)2·H2O, has been determine
Pseudohalide derivatives of manganese(II) and copper(II) complexes with mepirizole, a biologically active pyrimidyl-pyrazole ligand
Abstract The synthesis and characterization of thiocyanate and azide derivatives of mepirizole(4-methoxy-2-(5-methoxy-3-methyl-pyrazol-1-yl)-6-methylpyrimidine, hereinafter L) with manganese(II) and copper(II) is reported. The compounds were characterized by IR, electronic and EPR spectra and analytical data. Spectroscopic results suggest the existence of dimeric neutral entities [L2Cu2(μ-X)2(X)2] (X = NCS or N3) with unsymmetrical end-to-end bridges and five-coordination geometry around the copper(II) ion. Magnetic susceptibility data show that in the azide derivative the copper atoms are antiferromagnetically coupled (J = −18 cm−1), but no magnetic exchange interaction could be detected i…
Crystal and molecular structure and electronic properties of [Cu(phen)2(HL)] · (phen)0.5 · 7H2O (H3L = 1,3,5-triazine-2,4,6(1H,3H,5H)-trione), a novel N-cyanurate(2-) derivative
Abstract The crystal and molecular structure of [Cu(phen)2(HL) · (phen)0.5 · 7H2O (H2L = 1,3,5-triazine-2,4,6(1H,3H,5H)-trione) has been determined by X-ray diffraction methods. The structure is built up of neutral [Cu(phen)2(HL)] entities (which are associated to form dinuclear units through hydrogen bonds involving the cyanurate ions), uncoordinated phenanthroline and crystallisation water molecules. The copper atom is involved in a CuN5 chromophore, with an stereochemistry near to a compressed trigonal bipyramid (TBP) but with a significant degree of distortion towards the square pyramidal (SP) topology. The EPR spectrum is indicative of a mixed d z 2 d x 2 −y 2 ground state for the copp…
New dinuclear copper complexes incorporating bis(imidazolyl) based ligands and bidentate–monodentate oxalate bridges. Crystal structure and magnetic properties of [Cu2(BIM)2(C2O4)2]·4H2O and [Cu2(BIK)2(C2O4)2] (BIM=bis(2-imidazolyl)methane), BIK=bis(2-imidazolyl)ketone). Exploring magneto-structural correlations
Abstract This paper reports the synthesis, X-ray crystal structure and magnetic characterization of two novel copper(II) dinuclear compounds including bis(imidazolyl) ligands and oxalate anions, [Cu2(BIM)2(C2O4)2]·4H2O (1) (BIM = bis(2-imidazolyl)methane) and [Cu2(BIK)2(C2O4)2] (2) (BIK = bis(2-imidazolyl)ketone). The oxalate anion acts as bidentate–monodentate in both cases, although it exhibits different coordination bridging modes: whereas in compound 1 a μ1,1,2-oxalato is observed, a μ1,2,3-oxalato is found in compound 2. In both cases, the 3D framework is held together by a combination of H-bonding and aromatic-aromatic interactions provided by the convenient structural features of BIM…
Crystal and molecular structure, and electronic properties of hexakis(imidazole)copper(II) formate
The crystal and molecular structure of [Cu(Im)6] (HCOO)2 (Im = imidazole) has been determined by X-ray diffraction methods. The compound is built of centrosymmetric Cu(Im) inf6 sup2− cations and non-coordinated HCO2 − anions, linked through H-bonds giving a layered structure in the ac plane. The coordination polyhedron around the Cu atoms can be described as a rhombically-distorted octahedron (CuN2N′2N′'2 chromophores). Both electronic and e.p.r. spectra are indicative of an essentially d x2− y2 ground state for the CuII ions. No exchange coupling has been detected down to 4.2 K by means of magnetic susceptibility measurements. This feature is discussed on the basis of the structural data.
CCDC 1439890: Experimental Crystal Structure Determination
Related Article: Emilio Escrivà, José-Vicente Folgado, Guillermo Mínguez Espallargas, Lucia Soto, Amparo Sancho, Lourdes Perelló, Rosa Ortíz|2016|Polyhedron|112|137|doi:10.1016/j.poly.2016.03.041
CCDC 1469282: Experimental Crystal Structure Determination
Related Article: Carlos J. Gómez-García, Emilio Escrivà, Samia Benmansour, Juan J. Borràs-Almenar, José-Vicente Folgado, and Carmen Ramírez de Arellano|2016|Inorg.Chem.|55|2664|doi:10.1021/acs.inorgchem.6b00105
CCDC 1469281: Experimental Crystal Structure Determination
Related Article: Carlos J. Gómez-García, Emilio Escrivà, Samia Benmansour, Juan J. Borràs-Almenar, José-Vicente Folgado, and Carmen Ramírez de Arellano|2016|Inorg.Chem.|55|2664|doi:10.1021/acs.inorgchem.6b00105
CCDC 1439889: Experimental Crystal Structure Determination
Related Article: Emilio Escrivà, José-Vicente Folgado, Guillermo Mínguez Espallargas, Lucia Soto, Amparo Sancho, Lourdes Perelló, Rosa Ortíz|2016|Polyhedron|112|137|doi:10.1016/j.poly.2016.03.041
CCDC 1910411: Experimental Crystal Structure Determination
Related Article: Emilio Escrivà, José-Vicente Folgado, Amparo Sancho, Rosa Ortíz, Lourdes Perelló, Carmen Ramírez de Arellano|2019|Polyhedron|171|137|doi:10.1016/j.poly.2019.06.054
CCDC 1910410: Experimental Crystal Structure Determination
Related Article: Emilio Escrivà, José-Vicente Folgado, Amparo Sancho, Rosa Ortíz, Lourdes Perelló, Carmen Ramírez de Arellano|2019|Polyhedron|171|137|doi:10.1016/j.poly.2019.06.054