Author: Norma Ortega-villar

Electronic Structure Modulation in an Exceptionally Stable Non-Heme Nitrosyl Iron(II) Spin-Crossover Complex

2016

The highly stable nitrosyl iron(II) mononuclear complex [Fe(bztpen)(NO)](PF6)(2) (bztpen=N-benzyl-N,N',N'-tris(2-pyridylmethyl)ethylenediamine) displays an S=1/2 S=3/2 spin crossover (SCO) behavior (T-1/2=370 K, Delta H= 12.48 kJmol(-1), Delta S=33 JK(-1) mol(-1)) stemming from strong magnetic coupling between the NO radical (S=1/2) and thermally interconverted (S=0 S=2) ferrous spin states. The crystal structure of this robust complex has been investigated in the temperature range 120-420 K affording a detailed picture of how the electronic distribution of the t(2g)-e(g) orbitals modulates the structure of the {FeNO}(7) bond, providing valuable magneto-structural and spectroscopic correlat…

Spin statesIronInorganic chemistryAntiferromagnetic couplingEthylenediamineCrystal structureElectronic structure010402 general chemistry01 natural sciencesCatalysisFerrouschemistry.chemical_compoundAtomic orbitalSpin crossover[CHIM.COOR]Chemical Sciences/Coordination chemistryMolecular structures010405 organic chemistryEstructura molecularOrganic ChemistryNitric oxideGeneral ChemistryAtmospheric temperature rangeSpin crossoverÒxid nítric0104 chemical sciences3. Good healthCrystallographychemistryFISICA APLICADANitrosyl complexesMolecular structureFerroChemistry - A European Journal

researchProduct

A new N6 hexadentate ligand and a novel heptacoordinated N6O-type Fe(III) compounds: Synthesis, characterization and structure of [Fe(dimpyen)(OH)](A…

2011

Abstract In this contribution, we report the syntheses of a novel N6 donor set ligand, dimpyen = N1,N2-di[(1-methyl-1H-2-imidazolyl) methyl]-N1,N2-di(2-pyridilmethyl)-1,2-ethanediamine. This type of ligand was designed to modulate the properties of the metal ions bound to it. The reaction with Fe(II) gives off a new heptacoordinated iron(III) complex. We study the spectroscopic (UV–Vis), magnetic and electrochemical behavior and also made the structural determination with X-ray diffraction at 134 K and a heptacoordinated N6O-type derivative of Fe(III) is reported as well. This complex crystallize as perchlorate or hexafluorophosphate and the formula of these derivatives are [Fe(dimpyen)(OH)…

LigandMetal ions in aqueous solutionInorganic chemistryCrystal structureElectrochemistryInorganic Chemistrychemistry.chemical_compoundPerchlorateCrystallographyPentagonal bipyramidal molecular geometrychemistryOctahedronHexafluorophosphateMaterials ChemistryPhysical and Theoretical ChemistryInorganica Chimica Acta

researchProduct

Spin crossover behavior in a series of iron(III) alkoxide complexes.

2015

The synthesis, crystal structures, magnetic behavior, and electron paramagnetic resonance studies of five new FeIII spin crossover (SCO) complexes are reported. The [FeIIIN5O] coordination core is constituted of the pentadentate ligand bztpen (N5) and a series of alkoxide anions (ethoxide, propoxide, n-butoxide, isobutoxide, and ethylene glycoxide). The methoxide derivative previously reported by us is also reinvestigated. The six complexes crystallize in the orthorhombic Pbca space group and show similar molecular structures and crystal packing. The coordination octahedron is strongly distorted in both the high- and low-temperature structures. The structural changes upon spin conversion ar…

FE(3-OET-SALAPA)2>(CLO4).SInorganic chemistryFERRIC COMPLEXESCrystal structureMethoxideLIGAND; SYSTEMMAGNETIC-SUSCEPTIBILITYlaw.inventionInorganic Chemistrychemistry.chemical_compoundlawSpin crossoverPhysical and Theoretical ChemistryElectron paramagnetic resonanceSchiff baseLigandIRONCrystallographySOLID-STATEchemistryFISICA APLICADAAlkoxideMOSSBAUEROrthorhombic crystal systemPHASE-TRANSITIONSLIGANDSYSTEMSOLVATEInorganic chemistry

researchProduct

Enhanced porosity in a new 3D Hofmann-like network exhibiting humidity sensitive cooperative spin transitions at room temperature

2011

The porous coordination polymers (PCPs) of general formula {Fe(bpac)[M(CN)4]}·guest (M = Pt, Pd) exhibit larger channels than previously synthesised 3D-Hofmann-like PCP. The channels are partially occupied by uncoordinated guest bpac ligands and labile H2O molecules. These PCPs exhibit very scarce cooperative spin crossover behaviour around room temperature with a large hysteresis loop (up to 49 K) and also display sensitivity to humidity and guest molecules. The inclusion of bpac molecules in the 3D network can be avoided by adding competitive volatile molecules during the crystallization process, affording the guest-free material. The spin crossover behavior of different guest and guest-f…

ChemistryPorous Coordination PolymersHumidityNanotechnologyGeneral Chemistrylaw.inventionCrystallographylawSpin crossoverMaterials ChemistryMoleculeCrystallizationSpin (physics)PorosityJournal of Materials Chemistry

researchProduct

Solid- and solution-state studies of the novel mu-dicyanamide-bridged dinuclear spin-crossover system {[(Fe(bztpen)]2[mu-N(CN)2]}(PF6)3 x n H2O.

2005

The mononuclear diamagnetic compound {Fe(bztpen)[N(CN)2]} (PF6)CH3OH (1) (bztpen = N-benzyl-N,N′,N′- tris(2-pyridylmethyl)ethylenediamine) has been synthesized and its crystal structure studied. Complex 1 can be considered to be the formal pre-cursor of two new dinuclear, dicyanamide-bridged iron(II) complexes with the generic formula {[(Fe(bztpen)]2[μN(CN)2]}(PF6) 3·nH2O (n = 1 (2) or 0 (3)), which have been characterized in the solid state and in solution. In all three complexes, the iron atoms have a distorted [FeN6] octahedral coordination defined by a bztpen ligand and a terminal (1) or a bridging dicyanamide ligand (2 and 3). In the solid state, 2 and 3 can be considered to be molecu …

Organic ChemistrySpin transitionEthylenediamineGeneral ChemistryCrystal structureCatalysischemistry.chemical_compoundCrystallographyParamagnetismOctahedronchemistrySpin crossoverX-ray crystallographyDicyanamideChemistry (Weinheim an der Bergstrasse, Germany)

researchProduct

Spin‐Crossover 2D Metal–Organic Frameworks with a Redox‐Active Ligand: [Fe(ttf‐adpy) 2 M(CN) 4 ]· n H 2 O (ttf‐adpy = 4‐Tetrathiafulvalenylcarboxamid…

2008

A new ttf (tetrathiofulvalene) ligand containing an amidopyridine moiety was synthesized and characterized. The electrochemical study of the 4-tetrathiofulvalenylcarboxamidopyridine (ttf–adpy) ligand showed two reversible oxidation processes at EI′1/2 = 0.08 V/Fc+–Fc and EII′1/2 = 0.26 V/Fc+–Fc. The crystal structure of [(ttf–adpyH)2Pt(CN)4] (1) was solved at 293 K, where 1 displays the triclinic space group P. The ttf–adpyH+ molecule is planar, and the bond lengths within the ttf core are in the usual range for neutral ttf moieties. The ttf–adpyH+ molecules and the [Pt(CN)4]2– anions organize in a three-dimensional network by means of hydrogen bonds and short S···S contacts. In the network…

Inorganic ChemistryCrystallographyChemistryHydrogen bondLigandSpin crossoverInorganic chemistrySpin transitionMoleculeMetal-organic frameworkCrystal structureAcceptorEuropean Journal of Inorganic Chemistry

researchProduct

Synergetic effect of host-guest chemistry and spin crossover in 3D Hofmann-like metal-organic frameworks [Fe(bpac)M(CN)4] (M=Pt, Pd, Ni).

2012

The synthesis and characterization of a series of three-dimensional (3D) Hofmann-like clathrate porous metal-organic framework (MOF) materials [Fe(bpac)M(CN) 4] (M=Pt, Pd, and Ni; bpac=bis(4-pyridyl)acetylene) that exhibit spin-crossover behavior is reported. The rigid bpac ligand is longer than the previously used azopyridine and pyrazine and has been selected with the aim to improve both the spin-crossover properties and the porosity of the corresponding porous coordination polymers (PCPs). The 3D network is composed of successive {Fe[M(CN) 4]} n planar layers bridged by the bis-monodentate bpac ligand linked in the apical positions of the iron center. The large void between the layers, w…

Pyrazine010405 organic chemistryChemistryStereochemistrymicroporous materialsTransition temperatureOrganic Chemistryhost–guest systemsStackingSpin transitionGeneral Chemistry010402 general chemistry01 natural sciencesCatalysis0104 chemical scienceschemistry.chemical_compoundCrystallographymetal–organic frameworksspin crossoverSpin crossoveradsorptionMoleculeMetal-organic framework[CHIM.COOR]Chemical Sciences/Coordination chemistryHost–guest chemistryChemistry (Weinheim an der Bergstrasse, Germany)

researchProduct

[Fe III (bztpen)(OCH 3 )](PF 6 ) 2 : Stable Methoxide–Iron(III) Complex Exhibiting Spin Crossover Behavior in the Solid State

2010

Complex [Fe III (bztpen)(OCH 3 )](PF 6 ) 2 (1) crystallizes as the major yellow-brown product from spontaneous oxidation of its corresponding iron(II) counterpart in methanol solution. Magnetic measurements and EPR spectra demonstrate that 1 undergoes a poorly cooperative 6 A 1 ↔ 2 T 2 spin conversion in the temperature range 300-50 K, with characteristic thermodynamic parameters ΔH = 6.15 kJ mol -1 , ΔS = 39.88 J K -1 mol -1 , and T 1/2 = 154 K. The crystal structure of 1 has been investigated at 100 and 293 K.

StereochemistryCrystal structureAtmospheric temperature rangeMethoxideSpectral linelaw.inventionInorganic Chemistrychemistry.chemical_compoundCrystallographychemistrylawSpin crossoverMethanolElectron paramagnetic resonanceSpin (physics)European Journal of Inorganic Chemistry

researchProduct