Metallomacrocycles as anion receptors: combining hydrogen bonding and ion pair based hosts formed from Ag(I) salts and flexible bis- and tris-pyrimidine ligands.

Two self-assembled hosts are formed from Ag(I) salts and bis-pyrimidyl ligands and X-ray characterized. Both are able to incorporate two anions into the structure combining hydrogen bonding and electrostatic interactions.

Cytokinin activity of disubstituted aminopurines in Amaranthus.

Cytokinin (CK) receptors have different affinities for certain ligands, and consequently, studies of the plant's response to CK analogues constitute a good approach to identify active compounds that trigger specific plant responses. In this study, N(6) and N(6),N(6)-substituted CK analogues were synthesized and their CK-like activity was examined in the Amaranthus betacyanin and the bacterial receptor assay. The compounds showed CK-like activities that were not always associated with their binding affinity to the Arabidopsis receptors AHK3 and CRE1/AHK4.

Anion-pi interactions in bisadenine derivatives: a combined crystallographic and theoretical study.

In this manuscript we report a high-level ab initio study of anion-pi interactions involving N9-methyl-adenine, N6-methyl-adenine, N9-methyl-hypoxanthine, a dimer of N9-methyl-adenine, and N9,N9'-trimethylene-bisadenine. DNA bases like adenine are electron-deficient arenes that are well suited for interacting favorably with anions. We demonstrate that these compounds are able to interact favorably with anions.

Ag(I) complexes with alkylidene-bis(2-aminopyrimidines) as building units for discrete metallomacrocyclic frames. A structural and solution study.

Alkylidene-bis(2-aminopyrimidines) (pyr2Cx, x = 2-5) are useful ligands to interact with Ag(I) yielding discrete metallocycles. Crystal structures of the [(pyr2C2)Ag(NO3)]2 and [(H-pyr2C4)Ag(NO3)2]2 have been isolated where each macrocyclic moiety interacts with their surroundings through weak interactions, yielding 3D discrete structures, On the other hand, the solution study shows that the equilibrium constants for the formation of Ag(pyr2Cx)+ complexes are higher than the literature values for Ag(I) complexes with single pyrimidines, although the differences could be explained by invoking the solid-state structures of the Ag(I)-pyr2Cx complexes.

Synthesis, equilibrium studies and structural characterisation of the Zn(II) complexes with trimethylene-N6,N6'-bisadenine.

The new compound trimethylene-N(6),N(6')-bisadenine (L), in which two adenine molecules are linked together by a trimethylene bridge that connects the N(6) atoms, has been prepared. Reaction of L with HgCl(2) and ZnCl(2) in concentrated HCl solution leads to crystalline solids. The X-ray characterisation of the Hg(II) complex (H(2)L)[HgCl(4)].