Estudio de la Vegetación del Partido Judicial de Caldas de Reyes.

Sin resume

La situación jurídica del régimen de fuera de ordenación urbanística, con especial atención a la Comunidad Autónoma de Galicia

Traballo Fin de Mestrado (UDC.DER). Mestrado en Asesoramento Xurídico Empresaria

Efectos de las políticas de formación a desempleados

Mientras el gasto en políticas activas de empleo ha crecido significativamente durante los últimos años en España, la efectividad de estas políticas dista de ser suficientemente conocida. Esta investigación parte de la idea de que estas medidas no suponen beneficios indiscutibles, como se ha demostrado a través de diversos trabajos realizados en otros países, y analiza los efectos de una de las actividades más importantes, la formación a personas desempleadas. El artículo refleja los resultados de una investigación aplicada en una comunidad autónoma española, realizada a partir de una evaluación de los demandantes de un programa voluntario de formación. Los efectos estimados son positivos en el corto y el medio plazo, aunque modestos, en relación con el acceso al empleo y con el tiempo trabajado, mientras que no se observan efectos significativos sobre la situación laboral ni sobre los ingresos. Estos resultados son coincidentes con las investigaciones realizadas en otros países.desempleo, evaluación de políticas activas de mercado

Ditopic receptors containing urea groups for solvent extraction of Cu(II) salts

[Abstract] The ditopic receptor L3 [1-(2-((7-(4-(tert-butyl)benzyl)-1,4,7,10-tetraazacyclododecan-1-yl)methyl)phenyl)-3-(3-nitrophenyl)urea] containing a macrocyclic cyclen unit for Cu(II)-coordination and a urea moiety for anion binding was designed for recognition of metal salts. The X-ray structure of [CuL3(SO4)] shows that the sulfate anion is involved in cooperative binding via coordination to the metal ion and hydrogen-bonding to the urea unit. This behaviour is similar to that observed for the related receptor L1 [1-(2-((bis(pyridin-2-ylmethyl)amino)methyl)phenyl)-3-(3-nitrophenyl)urea], which forms a dimeric [CuL1(μ-SO4)]2 structure in the solid state. In contrast, the single crystal X-ray structure of [ZnL3(NO3)2] contains a 1 : 2 complex (metal : anion) where one anion coordinates to the metal and the other is hydrogen-bonded to the urea group. Spectrophotometric titrations performed for the [CuL3(OSMe2)]2+ complex indicate that this system is able to bind a wide range of anions with an affinity sequence: MeCO2− > Cl− > H2PO4− > Br− > NO2− > HSO4− > NO3−. Lipophilic analogues of L1 and L3 extract CuSO4 and CuCl2 from water into chloroform with high selectivity over the corresponding Co(II), Ni(II) and Zn(II) salts.Xunta de Galicia; EM 2012/088Xunta de Galicia; CN-2012/01

Binuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes with Schiff-bases derived from crown ether platforms: rare examples of ether oxygen atoms bridging metal centers

[Abstract] Bibracchial lariat ethers L3 and L4, derived from the condensation of N,N′-bis(2-aminobenzyl)-1,10-diaza-15-crown-5 or N,N′-bis(2-aminobenzyl)-4,13-diaza-18-crown-6 with salicylaldehyde, form binuclear complexes with Co(II), Ni(II), Cu(II) and Zn(II). Our studies show that the different denticity and crown moiety size of the two related receptors give rise to important differences on the structures of the corresponding complexes. Single crystal X-ray diffraction analysis shows that the [Ni2(L3)(H2O)2]2+ and [Cu2(L3)(NO3)]+ complexes constitute a rare example in which an oxygen atom of the crown moiety is bridging the two six coordinate metal ions. In contrast, none of the oxygen atoms of the crown moiety is acting as a bridging donor atom in the [Co2(L4)(CH3CN)2]2+, [Cu2(L4)]2+ and [Zn2(L4)]2+ complexes. This is attributed to the larger size the crown moiety and the higher denticity of L4 compared to L3. In [Co2(L4)(CH3CN)2]2+ the metal ions show a distorted octahedral coordination, while in the Cu(II) and Zn(II) analogues the metal ions are five-coordinated in a distorted trigonal bipyramidal environment. In [Cu2(L3)(NO3)]+ the coordinated nitrate anion acts as a bidentate bridging ligand, which results in the formation of a 1D coordination polymer.Xunta de Galicia; INCITE09E1R103013E

The effect of ring size variation on the structure and stability of lanthanide(III) complexes with crown ethers containing picolinate pendants

[Abstract] The coordination properties of the macrocyclic receptor N,N′-bis[(6-carboxy-2-pyridyl)methylene]-1,10-diaza-15-crown-5 (H2bp15c5) towards the lanthanide ions are reported. Thermodynamic stability constants were determined by pH-potentiometric titration at 25 °C in 0.1 M KCl. A smooth decrease in complexstability is observed upon decreasing the ionic radius of the LnIII ion from La [log KLaL = 12.52(2)] to Lu [log KLuL = 10.03(6)]. Luminescence lifetime measurements recorded on solutions of the EuIII and TbIII complexes confirm the absence of inner-sphere watermolecules in these complexes. 1H and 13C NMR spectra of the complexes formed with the diamagnetic LaIII metal ion were obtained in D2O solution and assigned with the aid of HSQC and HMBC 2D heteronuclear experiments, as well as standard 2D homonuclear COSY and NOESY spectra. The 1H NMR spectra of the paramagnetic CeIII, EuIII and YbIIIcomplex suggest nonadentate binding of the ligand to the metal ion. The syn conformation of the ligand in [Ln(bp15c5)]+ complexes implies the occurrence of two helicities, one associated with the layout of the picolinate pendant arms (absolute configuration Δ or Λ), and the other to the five fivemembered chelate rings formed by the binding of the crown moiety (absolute configuration δ or λ). A detailed conformational analysis performed with the aid of DFT calculations (B3LYP model) indicates that the complexes adopt a Λ(λδ)(δδλ) [or Δ(δλ)(λλδ)] conformation in aqueous solution. Our calculations show that the interaction between the LnIII ion and several donor atoms of the crown moiety is weakened as the ionic radius of the metal ion decreases, in line with the decrease of complex stability observed on proceeding to the right across the lanthanide series.Ministerio de Educación y Ciencia; CTQ2006-07875Ministerio de Educación y Ciencia; CTQ2009-10721Galicia. Consellería de Economía e Industria; INCITE09E1R103013E

Conformational study of lanthanide(III) complexes of N-(2-salicylaldiminatobenzyl)-1-aza-18-crown-6 by using X-ray and ab initio methods

[Abstract] A structural study of lanthanide complexes with the deprotonated form of the monobracchial lariat ether N-2-salicylaldiminatobenzyl-aza-18-crown-6 (L4) (Ln = La(III)–Tb(III)) is presented. Attempts to isolate complexes of the heaviest members of the lanthanide series were unsuccessful. The X-ray crystal structures of [Pr(L4)(H2O)](ClO4)2 · H2O · C3H8O and [Sm(L4)(H2O)](ClO4)2 · C3H8O show the metal ion being bound to the eight donor atoms of the ligand backbone. Coordination number nine is completed by the oxygen atom of an inner-sphere water molecule. Two different conformations of the crown moiety (labelled as A and B) are observed in the solid state structure of the Pr(III) complex, while for the Sm(III) complex only conformation A is observed. The complexes were also characterized by means of theoretical calculations performed in vacuo at the HF level, by using the 3-21G∗ basis set for the ligand atoms and a 46 + 4fn effective core potential for lanthanides. The optimized geometries of the Pr(III) and Sm(III) complexes show an excellent agreement with the experimental structures obtained from X-ray diffraction studies. The calculated relative energies of the A and B conformations for the different [Ln(L4)(H2O)]2+ complexes (Ln = La, Pr, Sm, Ho or Lu) indicate a progressive stabilization of the A conformation with respect to the B one upon decreasing the ionic radius of the Ln(III) ion. For the [Ln(L4)(H2O)]2+ systems, most of the calculated bond distances between the metal ion and the coordinated donor atoms decrease along the lanthanide series, as usually observed for Ln(III) complexes. However, our ab initio calculations provide geometries in which the Ln–O(5) bond distance [O(5) is an oxygen atom of the crown moiety] increases across the lanthanide series from Sm(III) to Lu(III).Ministerio de Educación y Ciencia; CTQ2006-0787

Recognition of AMP, ADP and ATP through cooperative binding by Cu(II) and Zn(II) complexes containing urea and/or phenylboronic acid moieties

[Abstract] We report a series of Cu(II) and Zn(II) complexes with different ligands containing a dipicolyl unit functionalized with urea groups that may contain or not a phenylboronic acid function. These complexes were designed for the recognition of phosphorylated anions through coordination to themetal ion reinforced by hydrogen bonds involving the anion and NHgroups of urea. The complexes were isolated and several adducts with pyrophosphate were characterized using X-ray diffraction measurements. Coordination of one of the urea nitrogen atoms to themetal ion promoted the hydrolysis of the ligands containing 1,3-diphenylurea units, while ligands bearing 1-ethyl-3-phenylurea groups did not hydrolyze significantly at room temperature. Spectrophotometric titrations, combined with 1H and 31P NMR studies, were used in investigating the binding of phosphate, pyrophosphate (PPi), and nucleoside 50-polyphosphates (AMP, ADP, ATP, CMP, and UMP). The association constants determined in aqueous solution (pH 7.0, 0.1MMOPS) point to a stronger association with PPi, ADP, and ATP as compared with the anions containing a single phosphate unit. The [CuL4]2+ complex shows important selectivity for pyrophosphate (PPi) over ADP and ATP.Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; EM 2012/08

Lead(II) complexes of lateral macrobicyclic receptors that incorporate a crown moiety and a pyridine head unit

[Abstract] The coordinative properties towards lead(II) of two lateral macrobicyclic receptors that incorporate either a 1,10‐diaza‐[15]crown‐5 (L7) or a 4,13‐diaza‐[18]crown‐6 (L8) fragment are reported. Spectrophotometric titrations performed in acetonitrile solution indicate only the formation of mononuclear complexes in solution. The X‐ray crystal structures of the two receptors show that the conformation adopted by the ligand is imposed by the presence of intramolecular hydrogen‐bonding interactions that involve the secondary amine groups and the pivotal nitrogen atoms. The solid‐state structure of [Pb(L7)(NCS)](SCN)·0.5H2O shows that the metal ion is asymmetrically coordinated inside the macrobicyclic cavity. The PbII ion is coordinated to the nitrogen atom of the pyridine unit, the two secondary amine atoms, two oxygen atoms of the crown moiety, and a nitrogen atom of an isothiocyanate group. The distances between the PbII ion and the two pivotal nitrogen atoms as well as one of the oxygen atoms of the crown moiety are too long (>2.92 Å) to be considered unequivocal bonds, and should be regarded only as weak interactions. The protonation constants of L7 and L8 as well as the stability constants of their PbII complexes were investigated by using potentiometric titrations in 95 % methanol (I = 0.1 M, nBu4NClO4, 25 °C). The two receptors undergo two protonation processes in the pH range investigated (2.0 < pH < 12.0), which correspond to the protonation of the nitrogen atoms of the oxa–aza moiety. The log KPbL value obtained for L7 [9.906(1)] is approximately 1.1 log K units higher than the one determined for L8 [8.75(1)].Xunta de Galicia; PGIDIT06TAM10301PRXunta de Galicia; INCITE09E1R103013E