Cecilia Rodríguez de Barbarín

Interaction between Glyglu and Ca2+, Pb2+, Cd2+ and Zn2+ in solid state and aqueous solution.: Crystal structures of poly[aqua-1,2-κ-O-di[lead(gly-gluH)]bis(perchlorate)] and poly[bisglycylglutamic-cadmium(II) tetrahydrate]

Abstract Glycylglutamic acid (GE H 2 ) is a peptide usually present in calcium binding sites. The interaction between the peptide and the cations Ca 2+ , Pb 2+ , Cd 2+ , and Zn 2+ in aqueous solution and in the solid state is described. Six compounds were isolated with different protonation states of the ligand. Potentiometric equilibrium studies, 13 C and 111 Cd solid state CP MAS NMR and IR spectroscopy were performed. Two crystal structures are reported: [Pb(GE H )(H 2 O) 1/2 ]ClO 4 and [Cd(GE H ) 2 ]·3H 2 O. Both constitute 3D polymers, where only carboxylate groups are coordinated to the cations. The crystalline lead compound shows a hemidirected coordination sphere due to its stereochemically active lone pair. In deprotonated derivatives, it is possible to assign a metal-amino interaction to a far IR signal (340–370 cm −1 ).

Complexation of lead(II) by l-aspartate: crystal structure of polymeric Pb(aspH)(NO3)

Abstract Two lead compounds containing the aspartate ligand are described, with compositions Pb(aspH)NO3 and Pb(asp). The crystal structure of the first shows it is a three-dimensional polymer in which each lead atom is coordinated to six oxygen atoms, five from carboxyl groups and one from a nitrate ion. For Pb(asp), spectroscopic data suggest the presence of Pb–NH2 interaction.

Crystal and molecular structure of o-methacryloylaminophenylarsonic acid

AbstractThe title compound, o-methacryloylaminophenylarsonic acid (o-MAPHA), C10H12AsNO4, is a monomer used to obtain water-soluble polyelectrolytes. It was obtained from the condensation reaction of o-arsanilic acid and methacryloyl chloride. Crystallization from aqueous ethanol solution yielded colorless prismatic crystals, and one was used for X-ray analysis. The crystal structure was solved using direct methods with a refined R1 = 0.0483. The crystal structure belongs to the triclinic system, space group

Zinc(II) complexes derived from potentially hexadentate(N4O2) acyclic ligands containing pyridinyl andphenolic groups

P\bar 1

Iridium–platinum perfluorobenzenethiolato trinuclear complexes: crystal structures of [Ir2Pt(C5Me5)2(µ-SRF)4Cl2](RF= C6F5 or C6F4H-p), syntheses and solution behaviour

, and the asymmetric unit comprises two molecules of the o-MAPHA acid and one water molecule. Both acid molecules are approximately planar and in both molecules the As atom presents common tetrahedral geometry with two long As–O bonds for hydroxyl groups and one short As–O bond for the oxo groups. The structure of o-arsanilic acid (o-ARSA), C6H8AsNO3, was also determinated using the same methods and compared with the o-arsanilic acid structure previously reported. The crystal structure of the o-arsanilic acid belongs to the monoclinic crystal system and to the P21 noncentrosymmetric space group with Z equals two.

Dinuclear zinc(II) complexes of a Robson macrocycle

A series of copper(II) complexes derived from tripodal ligands (HL) bearing pyridyl and phenolic arms have been synthesized and characterized. The molecular structures of complexes [CuL4(O2CMe)]·H2O and [CuL4(SCN)]·MeCO2Et {HL4= 2-bis[2-(2-pyridyl)ethyl]aminomethyl-4-nitrophenol} were determined by X-ray diffraction; the complexes exist as neutral, mononuclear species in the solid state. The co-ordination geometry around the copper atom in each is a distorted square-based pyramid (τ= 0.08 and 0.11) where one pyridyl nitrogen occupies the axial position (Cu–Npy 2.27 and 2.20 A). Three ligand donor atoms comprising the square plane are unchanged but the fourth ligand is an exogenous donor atom from MeCO2– or SCN– respectively. Reference is made to the relationship of the structures to that found at the copper(II) centre at the active site of galactose oxidase.

Ethyl 6-(4-ethoxy­phen­yl)-4-(furan-2-yl)-2-oxocyclo­hex-3-ene-1-carboxyl­ate

A group of zinc(II) complexes derived from potentially hexadentate (N 4 O 2 ) acyclic ligands derived from Schiff bases and bearing pyridinyl and phenolic arms have been prepared and characterized. The crystal structures of two of them show that hydrolysis of the corresponding pro-ligand has occurred to give mononuclear zinc complexes. The co-ordination geometries around the zinc are approximately trigonal biopyramidal.

Flat versus twisted rotamers of 2,4-­disubstituted thiazoles: the effect of intermolecular hydrogen bonds

Functionalisation of a mononuclear barium Complex of a 24-membered bibracchial tetraimine Schiff-base Macrocycle (L1) derived from the barium-templated cyclocondensation of 2,6-diacetylpyridine and tris(2-aminoethyl)amine was attempted using salicylaldehyde. The reaction leads to the isolation of the tripodal ligand tris[2-(salicylideneamino)ethyl]amine (L2) and the complex BaL22(ClO4)2. The crystal structures of the parent macrocyclic complex, [BaL1][ClO4]2[monoclinic, space group P21/c(no. 14), a= 11.755(7), b= 21.733(17), c= 15.621(15)A, β= 90.50(7)°, Z= 4], and BaL22(ClO4)2[monoclinic, space group P21/c(C2h5, no. 14), a= 12.299(15), b= 9.530(15), c= 25.798(32)A, β= 108.679(9)°, Z= 2] have been determined.