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In this manuscript we report the preparation of three N 6 -aminoacid-adenine-derivatives: N-(7H-purin-6-yl)glycine·0.5H 2 O (N 6 -GlyAde), N-(7H-purin-6-yl)-β-alanine·1.5H 2 O (N 6 -β-AlaAde) and N-(7H-purin-6-yl)-γ-aminobutyric·2H 2 O (N 6 -GabaAde) and the synthesis and X-ray characterization of three Ir(III) NAMI-A derivatives (NAMI-A is [imidazoleH][trans-Ru III Cl 4 (DMSO-κS)(imidazole)]) [trans-Ir III Cl 4 (DMSO-κS)(N 3 -H)-(7H-purin-6-yl)glycine-κN 9 ] (1), [trans-Ir III Cl 4 (DMSO-κS)(N 3 -H)-(7H-purin-6-yl)-β-alanine-κN 9 ] hydrate (2) and [trans-Ir III Cl 4 (DMSO-κS)(N 3 -H)-(7H-purin-6-yl)-γ-aminobutyryl-κN 9 ] (3). In all complexes the metal center shows octahedral geometry with coordination to four chlorido ligands and one S coordinated dimethylsulfoxide (DMSO-κS). The coordination sphere of the metal is completed by the modified adenine molecule which is bound via N(9) and protonated at N(3). In two complexes the importance of lone pair (lp)-π interactions involving the adenine ring have been studied using density functional theory (DFT) calculations and the Bader's theory of atoms in molecules. Furthermore, the ability of complexes (1-3) to affect the cell viability was evaluated against three different cancer cell lines: human lung carcinoma cells (A549), human cervical carcinoma cells (HeLa) and human breast cancer cells (MCF7). We have also analyzed their ability to cleave the DNA experimentally and their affinity for two models of DNA has been studied using molecular docking simulations., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The reaction of adenine with 2-chloropyrimidine yields as a major product the unexpected N 7 -(2-pyrimidyl)-adenine (1) and as a minor one N 9 -(2-pyrimidyl)-adenine (2). Both compounds have been characterized by X-ray diffraction analysis. Moreover, we report the formation of a 1:1 co-crystal (3) composed by compound (1) and adenine that was formed serendipitously during the synthesis of (1). Unexpectedly, the treatment of (1) with Brönsted acids like HCl or HNO 3 causes the opening of the imidazole ring of the N 7 -substituted adenine, yielding N 5 -(pyrimidin-2-yl)pyrimidine-4,5,6-triamine (4-7) which we have X-ray characterized in its neutral, (4), monoprotonated [nitrate salt (6)] and diprotonated forms [hydrochloride salt (5) and, also, a tetrachlorozincate salt (7)]. Finally, we have used compound (5) as ligand to synthesize and X-ray characterize its complexes with Ir(III) and Ag(I) (compounds (8) and (9), respectively), where the latter is a 2D coordination polymer and the former is a discrete mononuclear complex. We have studied the supramolecular assemblies formed in the solid state by using density functional theory (DFT) calculations. Finally, DNA-docking studies of several compounds have been carried out in order to analyze their ability to interact with the DNA., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest., (Copyright © 2019 Elsevier Inc. All rights reserved.)

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)].3H(2)O reveals that it is an outer-sphere complex in which the ligand is protonated at N(1) and N(1'). In contrast, the structure of the complex [H(2)L(ZnCl(3))(2)].2H(2)O shows the ligand co-ordinated to two different Zn(II) ions through the N(7) of both adenine fragments, the protons being located on the N(1) atoms. The latter compound constitutes the first crystallographic evidence of an inner sphere complex with bis-adenines and, for this reason, an equilibrium study was carried out on the Zn(II)-L-H(+) system. Potentiometric studies indicate that L is protonated in aqueous solution to form HL(+) and H(2)L(2+) with logK(H) values of 4.42 and 3.35 (25 degrees C, 0.10 M KNO(3)). The data from potentiometric titrations in the presence of Zn(2+) can be analysed considering the formation of the species LZn(2+), HLZn(3+), LZn(2)(4+) and HLZn(2)(5+), whose stability constants exceed the value expected for a monodentate interaction of the metal ion with adenine and suggest the possibility of a polydentate behaviour of L in the pH range 2.5-5.0. In contrast, spectrophotometric titrations carried out under conditions similar to those used in the synthetic work (1 M HCl) can be fitted with a model involving exclusively the H(2)LZn(4+) and H(2)LZn(2)(6+) species with logK(M) values reasonable for the interaction of Zn(II) with the N(7) of the protonated adenine fragments. Despite the H(2)LZn(2)(6+) species has a low stability, the spectrophotometric results are in agreement with its formation under the conditions in which the solid complex was prepared.