Jaume Casabó

Copper complexes with a pyrazole derivative ligand. Crystal structure of tetrakis{[(3,5-bis(pyridin-2-yl)pyrazolate)-(aqua)copper(II) nitrate monohydrate}

Abstract Reaction of the pyrazole-derived ligand 3,5-bis(pyridin-2-yl)pyrazole (bpypz) with Cu(NO3)2, CuCl2 and CuBr2 yields polynuclear copper(II) compounds with remarkable structural and magnetic properties. The magnetic behaviour was studied by fitting the experimental data with a dimer and tetramer magnetic model. Strong antiferromagnetic exchange interactions were found in all cases. The molecular structure of the nitrate compound was solved by X-ray diffraction methods. The compound is tetranuclear, orthorhombic, space group Fddd, a = 18.572(4), b = 23.816(8), c = 27.337(9) A, V= 12092 A3, Z = 8.

Dinuclear μ-pyrazole nickel(II), cobalt(II), cadmium(II) and zinc(II) complexes with dinucleating pyrazole-derived ligands

Abstract New pyrazole-derived ligands, 3,5-bis(2-pyridyl)pyrazole (HL), 2-(6-methyl) pyridyl-2-pyridyl-3,5-pyrazole (HL1) and 3,5-bis-2-(6-methyl)pyridyl-3,5-pyrazole (HL2), are reported. Complexes of formulae [ML(NO3)]·xH2O (M = CoII, NiII, ZnII and CdII), [ML(NCS)]·H2O (M = CoII, NiII, ZnII and CdII), [ML1(NO3)]·H2O (M = NiII and CoII), [M2L2(NO3)2(OH)]·H2O (M = NiII and CoII), [M2L1Cl2(OH)] (M = CoII and NiII) were synthesized and characterized by IR and UV-vis spectroscopies and magnetic susceptibility measurements. Dinuclear compounds containing a di-μ-pyrazole bridge are found in nitrate and thiocyanate complexes with the first two ligands, while mixed μ-hydroxo, μ-pyrazole-bridged structures are found in chloride complexes with the second ligand and nitrate complexes with the last ligand.

Silver-selective membrane electrodes using acyclic dithia benzene derivative neutral carriers. Comparison with related macrocyclic compounds

Abstract Four new acyclic dithia benzene derivatives have been synthesized: 1,3-bis[(ethylthio)methyl]benzene; 1,3-bis-[(pentylthio)methyl]benzene; 1,3-bis[(octylthio)methyl]benzene, 1,3-bis[(dodecylthio)methyl]benzene. All compounds have been tested as silver(I) ion sensors in membrane-based ion-selective electrodes, exhibiting good sensitivity, detection limits, reproducibility and selectivity. The chemical recognition of silver(I) by these receptors is compared to the behaviour presented by closely related macrocyclic and acyclic polythia compounds.

Cobalt(II) complexes with pyrazole-derived ligands: crystal structure of {bis[3-phenyl-5-(2-pyridyl) pyrazole]aquachlorocobalt(II)}chloride monohydrate

Abstract The synthesis of the new pyrazole-derived ligands 3-phenyl-5-(2-pyridyl) pyrazole (HL0) and 3-phenyl-5-(6-methyl-(2-pyridyl))pyrazole (HL1) and their Co(II) complexes is reported. Elemental analyses, conductivity measurements and IR and UV–Vis spectroscopies defined all complexes. 1H and 13C NMR spectroscopies were also used in the characterization of ligands. The crystal and molecular structures of [Co(HL0)2Cl(H2O)]Cl·H2O, consisting of discrete ions and water molecules linked by hydrogen bonds, are also reported. The hexacoordinated metal atom is bonded to two pyridinic nitrogens, two pyrazolic nitrogens (one of each nitrogen belonging to two different ligands), one chlorine atom and one water molecule, forming a distorted octahedral environment. The ligands are not exactly planar and the arrangement of ligands is cis, with a dihedral angle between the two mean planes of ligands of 89.21(6)°. The degree of distortion from regular octahedral geometry is compared to that of closely related structures.

Application of a new phosphadithiamacrocycle to ClO−4-selective CHEMFET and ion-selective electrode devices

Abstract A new dithiamacrocycle incorporating a phosphine donor group (I) has been synthesized and tested as neutral carrier in PVC membranes. ClO−4-selective CHEMFET and ISE devices based on these plasticized membranes have been developed. Both devices have shown Nernstian response and a wide working pH range. Most common anions, except BF−4, do not cause interferences. The response properties and selectivity found for perchlorate ions compare favourably with the commercial and conventional ClO−4 electrodes based on quaternary ammonium ion-exchange sites. This is probably the first example of perchlorate selective CHEMFETs.

Notes. A planar, binucleating, pyrazole derivative ligand. Crystal structure of bis[µ-3,5-bis(2′-pyridyl)pyrazolato-N1N′:N2N″]-bis[dimethanolnickel(II)] dichloride dihydrate

The co-ordinating properties of the ligand 3,5-bis(2-pyridyl)pyrazole (Hbpypz) are reported and complexes of general formulae [M(bpypz)]NO3·xH2O (M = CoII, NiII, CuII, ZnII, or CdII), [M(bpypz)] Cl·xH2O (M = MnII, CoII, NiII, or ZnII), and [M(bpypz)]Br·xH2O (M = CoII NiII or ZnII) are described. The crystal and molecular structure of [Ni2(bpypz)2(MeOH)4]Cl2·2H2O is also reported. The crystals are triclinic, space group P with a= 8.934(3), b= 8.958(6), c= 12.040(5)Aα= 72.02(3), β= 77.66(3), and γ= 68.58(3)°.

Silver(I) ion-selective electrodes based on polythiamacrocycles

Some polythiamacrocycles having aromatic rings as macrocyclic components have been synthesised and tested as sensors in solid-state electrodes. High selectivity for Ag+, even over that for Hg2+, and excellent electrode properties have been found.

Mixed bridged, dinuclear copper(II) complexes with dinucleating, pyrazole derived ligands

Abstract Mixed μ-OH or μ-halide, μ-pyrazolato dinuclear copper(II) complexes of 3,5-bis(pyridin-2-yl)pyrazole (HL), 3-(6-methylpyridin-2-yl)-5-(pyridin-2-yl)pyrazole (HL1) and 3,5-bis(6-methylpyridin-2-yl)pyrazole (HL2) have been synthesized and characterized. Their spectral and magnetic behaviour are also reported. The μ-OH compounds behave as a Curie-Weiss paramagnet, while the μ-halide complexes exhibit strong antiferromagnetic interactions.

Synthesis and structural characterisation of new binuclear Pd(II) complexes with both bridging and terminal pyrazolate ligands

Abstract Dinuclear pyrazolato-bridged Pd(II) complexes Pd2L40 and Pd2L41 have been prepared by reacting Pd(Ac)2 and one equivalent of HL0 (3-phenyl-5-(2-pyridyl)pyrazole) or HL1 (3-phenyl-5-(6-methyl-(2-pyridyl))pyrazole. The new complexes have been characterised by elemental analyses, IR, 1H NMR and in the case of PdL14 by single crystal X-ray diffraction methods. This structure shows two palladium atoms bridged by two L1 ligands. The square-planar geometry of each Pd atom is completed by a bidentate chelating L1 ligand. The six-membered dipalladacycle formed by the two Pd atoms and the two bridging pyrazolato ligands adopts a distorted boat-like conformation.

Macrocycles incorporating closo- and nido-carbaborane cages: molecular structure of 1,2-(3′-oxapentane-1′,5′-dithiolato-SS′)-1′,2′-dicarba-closo-dodecaborane

Reaction of 1,2-dimercapto-1,2-dicarba-closo-dodecaborane under basic conditions with appropriate dihalogenated organic compounds results in the formation of macrocycles incorporating 7,8-dicarbaundecaborate or 1,2-dicarba-closo-dodecaborane units. Polymers are obviated by using high dilution. The crystal structure of 1,2-(3′-oxapentane-1′,5′-dithiolato-SS′)-1′,2′-dicarba-closo-dodecaborane has been determined. It crystallizes in space group P21/a with four formula units in a cell of dimensions a= 11.708(2), b= 10.209(3), c= 12.613(3)A, and β= 109.04(2)°.