Juan J. Fiol

Synthesis, structure and nuclease properties of several ternary copper(II) peptide complexes with 1,10-phenanthroline.

Three new ternary peptide-Cu(II)-1,10-phenanthroline (phen) complexes, [Cu(L-ala-gly)(phen)].3.5H(2)O 1, [Cu(L-val-gly)(phen)] 2 and [Cu(gly-L-trp)(phen)].2H(2)O 3, have been prepared and structurally characterised. These compounds exist as distorted square pyramidal complexes with the five co-ordination sites occupied by the tridentate peptide dianion and the two heterocyclic nitrogens of the phenanthroline ligand. The bulk of the lateral chain in the peptide moiety determines the relative disposition of the phen ligand. Thus, in [Cu(L-val-gly)(phen)] 2, the phenanthroline plane is deviated towards the opposite side of the isopropyl group of the L-valine moiety. On the other hand, in [Cu(gly-L-trp)(phen)].2H(2)O 3 the absence of stacking interactions between phen and indole rings and the presence of an intramolecular CH...pi interaction should be pointed out. These complexes exhibit significant differences in their nuclease activity which depends on the nature of the peptidic moiety, the complex [Cu(gly-L-trp) (phen)].2H(2)O 3 being the most active.

Coordination behaviour of sulfanilamide derivatives.: Crystal structures of [Hg(sulfamethoxypyridazinato)2], [Cd(sulfadimidinato)2(H2O)]·2H2O and [Zn(sulfamethoxazolato)2-(pyridine)2(H2O)2]

Abstract Hg(II), Cd(II) and Zn(II) complexes with the ligands sulfadimethoxine, sulfamethoxypyridazine, sulfadiazine, sulfamerazine, sulfadimidine and sulfamethoxazole have been prepared and characterised by spectral data. 1H and 13C NMR have been used to interpret the structural characteristics of the complexes in solution. The X-ray crystal structures of [Hg(sulfamethoxypyridazinato)2] (2a), [Cd(sulfadimidinato)2(H2O)]·2H2O (4b) and [Zn(sulfamethoxazolato)2(py)2(H2O)2] (6d) have been determined. In complex 2a the Hg(II) ion lies on an inversion centre and exhibits linear coordination by two sulfonamidic nitrogen atoms [Hg–N(1)=2.071(4) A] of the two deprotonated sulfamethoxypyridazinato ligands. The polymeric Cd(II) complex (4b) exhibits a high distorted-octahedral geometry, involving the sulfonamidic nitrogen [Cd–N(1)=2.328(6); Cd–N(1′)=2.326(6) A] and the heterocyclic N(3)/N(2′) [Cd–N(3)=2.307(6) A; Cd–N(2′)=2.426(6) A] of two bidentate sulfadimidine ligands, the terminal amino N(4′b) [Cd–N(4′b)=2.379(7) A] of a third sulfadimidine which is bonded to an adjacent Cd(II), and the O(3) atom of a coordinated water molecule [Cd–O(3)=2.334(6) A]. In complex 6d the geometry around the Zn(II) ion can be described as a slightly distorted compressed octahedron. Two pyridine [Zn–N(16)=2.1841(17) A] and two isoxazole N atoms [Zn–N(2)=2.1736(15) A] are located in the equatorial plane and two oxygen atoms of two water molecules [Zn–O(4)=2.0984(14) A] are placed in the apical positions. IR and NMR spectral studies suggest a similar behaviour of the Cd(II) and Zn(II) complexes, both in solid state and solution, and different to the corresponding Hg(II) complexes. Thus 1H and 13C NMR spectra, in DMSO-d6, of Cd(II) and Zn(II) compounds show coordination mainly through the heterocyclic nitrogen while the corresponding Hg(II) derivatives seem to be coordinated through the sulfonamidic nitrogen.

CRYSTAL STRUCTURES OF THE N-SALICYLIDENE-L-SERINATOAQUACOPPER(II) MONOHYDRATE AND ITS TERNARY DERIVATIVE WITH 2-AMINOPYRIDINE

Abstract The complexes [Cu(Sal–( L -Ser))H2O]⋅H2O 1 and [Cu(Sal–Ser)(2-amino pyridine)] 2 have been prepared and their crystal structures determined. In 1 the copper(II) has a square-pyramidal geometry, being coordinated to the tridentate Sal–( L -Ser) Schiff base ligand and the oxygen atom (O(16)) of one water molecule occupying the corners of a square. The coordination sphere about the copper is completed by an axial O(12) atom of an hydroxyl group belonging to an adjacent complex unit. In the racemic ternary complex 2 the metal atom has a square-planar coordination with O,N,O atoms of the tridentate Sal–Ser dianion and the heterocyclic N atom of the 2-aminopyridine. Spectroscopic data are discussed.

X-ray diffraction structures of two N-salicylidene tryptophananato diaquocopper(II) complexes: erythro and threo isomers

Abstract X-ray crystal structures are reported for two novel N-salicylidene tryptophanato diaquocopper(II) isomers, [Cu(Sal-Trp)(h2O)2, erythro (1) and hreo (2). The coordination geometry about the copper in both complexes is approximately square-pyramidal with the tridentate Sal-Trp Schiff base ligand and the oxygen atom O(W1) of one water molecule occupying the corners of a square. The coordination sphere about the copper is completed by an axial OW(2) water molecule. In 1, O(W2) [CuO(W2) distance 2.25(1) A] is at the same side of the indole ring (syn disposition—“erythro” isomer), whereas in 2 the O(W2) and the α-amino acid chain are disposed anti (“threo” isomer), with a longer CuO(W2) distance, 2.485 A. IR, ESR, electronic spectral data and magnetic properties are discussed and related to the copper binding mode derived from the crystal structure determination.

Synthesis of Zn N-salicylidene-l-aminoacidatos: X-ray structure of [(N-salicylidene-l-alaninato)(aqua)zinc(II)]·0.25H2O and [(N-salicylidene-l-valinato)(aqua)zinc(II)]

Abstract The synthesis in aqueous ethanol solution of eight Zn(II) compounds of salicylaldehyde-amino acid Schiff bases together with their spectral characterisation is reported. Two of the complexes, [( N -salicylidene- l -alaninato)(aqua)zinc(II)]·0.25H 2 O ( 1 ) and [( N -salicylidene- l -valinato)(aqua)zinc(II)] ( 2 ), have been obtained in the form of crystals suitable for X-ray crystallography. The coordination geometry about the zinc in both structures is between distorted trigonal bipyramidal and distorted square pyramidal with the iminic nitrogen N(4) ( 1 =2.020(3) and 2 =2.015(7) A), the phenolic O(8) ( 1 =1.991(2) and 2 =1.997(6) A) and the carboxylic O(1) ( 1 =2.160(2) and 2 =2.156(5) A) of the N -salicylidene-aminoacidato base ligand. Another carboxylic O(1)* of an adjacent unit ( 1 =2.033(2) and 2 =2.033(5) A), curiously shorter than the bond from the ligand itself, and a water molecule ( 1 =2.006(3) and 2 =1.999(6) A) comprise the fourth and fifth coordination positions. The crystals are constituted by polymeric [( N -salicylidene- l -aminoacidato)zinc(II)] moieties forming helical arrays about three-fold screw axes. To our knowledge these are the first two structures of binary complexes of the type [( N -salicylidene- l -aminoacidato)Zn(II)]. The NMR studies, in DMSO, agree with a general endo disposition between the side chain of the amino acid and the aromatic ring of the salicylidene moiety.

Crystal structures of two copper(II) ternary complexes of N-salicylidene-tryptophanato with 2-aminopyridine and 2-aminopyrimidine

Two ternary copper(II) complexes of a tridentate Schiff base of the N -salicylidene-tryptophanato type: [Cu(Sal-Trp)(2-aminopyrimidine)] ( 1 ) and [Cu(Sal-Trp)(2-aminopyridine)]·methanol ( 2b ) have been synthesized and structurally characterized. Single crystal X-ray diffraction analyses show that the copper atom exhibits in 1 a distorted square-pyramidal geometry and in 2b a square-planar geometry, with the tridentate Sal-Trp and one heterocyclic nitrogen of the ligand in the basal plane. In 1 , a weakly bonded nitrogen atom of a second 2-aminopyrimidine molecule is located in the apical position. This second ligand connects to an adjacent unit through the basal plane yielding polymeric chains. In both structures a CH⋯π interaction between the heterocyclic ligand and the indole moiety is present but stacking interactions are not observed.

Crystal structure of the copper(II) ternary complex of N-salicylidene-l-serinato with 2,6-diaminopyridine.: Toxicity studies against Drosophila melanogaster

Abstract The ternary [Cu(Sal-( l -Ser))(2,6-diaminopyridine)H2O] (1b) complex has been prepared and the crystal structure determined. The copper(II) cation has a square pyramidal geometry, being coordinated to the tridentate Sal-( l -Ser) Schiff base ligand and the heterocyclic nitrogen atom N(11) of the 2,6-diaminopyridine molecule which occupying the corners of the square base. The coordination sphere about the copper is completed by an axial O(W) atom of a water molecule. Spectroscopic data are discussed. Preliminary toxicity studies [larva-to-adult viability (V) and developmental time (in days) (DT)] of several copper(II) compounds including complex 1 and other related previously described complexes [Cu(Sal-( l -Ser))H2O]·H2O (2) and [Cu(Sal-Ser)(2-aminopyridine)] (3) against Drosophila melanogaster (Or-R) show that these copper(II) complexes display less toxicity than simple copper(II) salts.

Some new derivatives of Co(III) with uracil, uridine and pyrimidine nucleotides

Abstract This paper describes the synthesis of compounds of Co(III) with uracil, uridine and the nucleotides 5′UMP, 5′CMP and their characterization, carried out by elemental analysis, by studying the infrared spectra, diffuse reflectance, 13 C NMR and conductivity measurements. The compounds were obtained by reaction of the starting complexes trans -[Co(en) 2 Cl 2 ]Cl and [Co(NH 3 ) 5 Cl]Cl 2 with the base, nucleoside and nucleotides. In the case of uracil (URA) and uridine (URD) compounds, indirect bonding of Co(III) to the pyrimidine ring seems to occur through the C 4 O and -NH 3 (-NH 2 ) groups of starting complexes. In the complexes of Co-nucleotide, bonding is inferred through the heterocyclic ring (for the Co(en) 2 (5′CMP)(5′CMPH)·6H 2 O complex) and through the phosphate group in the other cases.

SYNTHESIS AND CHARACTERIZATION OF A NOVEL COPPER(II)-CYTOSINE COMPLEX : TETRAKIS(CYTOSINE)COPPER(II) CHLORIDE BIS(DIMETHYLACETAMIDE) SOLVATE

Abstract The compound [Cu(C4H5N3O)4]Cl2·2DMA (DMA = N,N-dimethyl-acetamide) has been prepared in DMA-water solution from the parent compound Cu(cyt)2Cl2 (cyst = cytosine), already described, and characterized by X-ray diffraction. The cytosine compound was obtained in an attempt to synthesize the ternary cytosine-creatinine (creat) complex. In the first stage of the reaction in methanol, the yellow Cu(creat)2Cl2 complex is obtained which reacts finally with cytosine yielding the 1:4 Cu-cyt complex, the creatinine being completely displaced by cytosine. The [Cu(cyt)4]Cl2·2DMA complex has been characterized by X-ray crystallography. IR and electronic spectral data of the compound are discussed and related to the copper binding mode derived from the crystal structure determination.

Metallation of 2-sulfanilamidopyrimidine (sulfadiazine). X-ray diffraction structure and solution behaviour of bis(sulfadiazinato) mercury(II) bis(dimethylsulfoxide)

Abstract The X-ray crystal structure of Hg(Sulfa) 2 · 2DMSO ( 1 ) was determined. Compound 1 was obtained from the reaction of sulfadiazine (2-sulfanilamidopyrimidine (Sulfa-H)) with mercury(II) acetate in methanol and crystallization in DMSO/methanol. The coordination geometry about the mercury atom is approximately linear [N-Hg : 2087(4)A˚; N-Hg-N: 175.0(2)°]. Two secondary DMSO molecules are loosely bound to the mercury atom, [Hg-O(DMSO): 2.769(7)A˚]. No π-aryl stacking interaction was observed in either the solid or solution state. The IR, electronic and 1 H and 13 C NMR spectral data for 1 suggest binding of mercury to the sulfonamide nitrogen, in agreement with the crystal structure determination.