DEPARTAMENTO DE QUÍMICA ORGÁNICA

A homologous series of bisIJ1-isoquinolinecarboxamide)alkane derivatives (3a–f) with two to seven carbon atoms in the alkyl bridge and their AgIJI) complexes (4a–f) have been synthesized. Four ligand and five AgIJI) complex crystal structures were obtained by single crystal X-ray diffraction and analyzed in terms of: a) their structural patterns based on intra-and intermolecular hydrogen bonds which were compared to those of bisIJ2-quinolinecarboxamide)alkanes (1n) and bisIJ6-quinolinecarboxamide)alkanes (2n) attending to specific geometrical parameters and b) the AgIJI) coordinate bond effect on these patterns and the amide

Six new compounds of the homologous series of N,N9-bis(2-quinolinecarboxamide)alkane (4a-c) and N,N9-bis(6-quinolinecarboxamide)alkane (5a-c) derivatives having two, four and six carbon atoms in the alkyl spacer were synthesized and their crystal structures were determined by single crystal X-ray diffraction. These solid-state structures have been analyzed finding that the two series exhibit interesting differences between them. The remarkable preference of the bis(6-quinolinecarboxamide)alkanes to form one-or two-dimensional networks via N-H … O intermolecular hydrogen bonds appears total or partially disrupted by the intramolecular N-H … N quinoline hydrogen bond in bis(2-quinolinecarboxamide)alkanes.

Two novel hydroxyethyl pyrazolones were obtained by condensation of 2-hydroxyethylhydrazine with ethyl acetoacetate or ethyl benzoylacetate, later nitrosation of the C4 carbon atom in the heterocyclic moiety, afforded two novel oxime-derivatives. The 1 H and 13 C NMR data show that 1-(2-hydroxyethyl)-3-methyl-5pyrazolone (1) is largely present together with a very small amount of the 5-one tautomer in DMSO-d 6 ; in contrast, 1-(2-hydroxyethyl)-3-phenyl-5-pyrazolone (2) is found as a single tautomer in CDCl 3 . Two diastereomers occur in DMSO-d 6 in 1-(2-hydroxyethyl)-3-methyl-4-hydroxyimino-5-pyrazolone (3) while in 1-(2hydroxyethyl)-3-phenyl-4-hydroxyimino-5-pyrazolone (4), a single species is present in CDCl 3 . Despite the polarity differences in the solvents used, remarkably the oxime tautomers proved to be more stable in both cases and DMSO-d 6 only allows the equilibrium between E/Z diastereomers. Single crystal X-ray diffraction data of 1, 3 and 4 are presented, they show that 1 occurs as a keto-enamine tautomer, in clear contrast with the situation in solution; in the case of 3 and 4, the tautomeric equilibrium remains shifted to the oximes in the solid phase as the Z-diastereomer, exclusively. This finding is the opposite of what was described in a previous report for 1-alkyl-3-methyl-4-hydroximino-5-pyrazolone, where the E-diastereomer was present.

The syntheses and crystal structures of two novel trisamides, the ethyl-(2) and propyl-substituted (3) N,N 0 ,N 00trialkylbenzene-1,3,5-carboxamides, are reported. The compounds are prepared in good yields by aminolysis of the trimethyl-1,3,5benzenecarboxylate and the respective primary amine. Compound 2 crystallizes in the P2 1 2 1 2 1 space group with a complete molecule in the asymmetric unit and four molecules per unit cell, whereas 3 does it in the R3c space group with one-third of the molecule in the asymmetric unit and six molecules per unit cell. Their solid-state structures show that the N;H 3 3 3 OdC hydrogen bond plays the most important role in the supramolecular framework of both cases, despite considerable differences in crystal packing. Supramolecular sheets are formed in 2, whereas molecules of 3 are packed in a H-bonded primitive cubic [4 6 ] three-dimensional network. The main difference in the molecular conformation is the tilting of the carboxamide group with respect to the aryl, which in the case of 3 occurs in the same direction, leading to the formation of "solid-state" chiral molecules.

DSC/TGA thermal analysis. FT-IR spectra of the compounds indicates the nature of the metal-ligand coordination environment. Presence of ν(O-H) shifted to lower energy indicated H-bonded carboxylic acid, while ν as (COO −) and ν s (COO −) splitting show both monodentate and bidentate carboxylate coordination [2]. Monodentate SO 4 2− (C 3v) and bidentate bridging SO 4 2− (C 2v) modes can also be inferred from infrared spectral analysis.