Synthesis, Characterization, and Reactivity of [Li(N6,N9-Me2Ade-H)]: A Structurally Characterized Lithiated Adenine

Anion–Cation Recognition Pattern, Thermal Stability and DFT-Calculations in the Crystal Structure of H2dap[Cd(HEDTA)(H2O)] Salt (H2dap = H2(N3,N7)-2,6-Diaminopurinium Cation)

The proton transfer between equimolar amounts of [Cd(H2EDTA)(H2O)] and 2,6-diaminopurine (Hdap) yielded crystals of the out-of-sphere metal complex H2(N3,N7)dap[Cd(HEDTA)(H2O)]·H2O (1) that was studied by single-crystal X-ray diffraction, thermogravimetry, FT-IR spectroscopy, density functional theory (DFT) and quantum theory of “atoms-in-molecules” (QTAIM) methods. The crystal was mainly dominated by H-bonds, favored by the observed tautomer of the 2,6-diaminopurinium(1+) cation. Each chelate anion was H-bonded to three neighboring cations; two of them were also connected by a symmetry-related anti-parallel π,π-staking interaction. Our results are in clear contrast with that previously reported for H2(N1,N9)ade [Cu(HEDTA)(H2O)]·2H2O (EGOWIG in Cambridge Structural Database (CSD), Hade = adenine), in which H-bonds and π,π-stacking played relevant roles in the anion–cation interaction and the recognition between two pairs of ions, respectively. Factors contributing in such remarkable differences are discussed on the basis of the additional presence of the exocyclic 2-amino group in 2,6-diaminopurinium(1+) ion.

The chameleonic reactivity of dilithio bis(alkylamido)cyclodiphosph(iii)azanes with chlorophosphines

Analogous reactions do not necessarily give analogous products.

Semiconductive and magnetic one-dimensional coordination polymers of Cu(II) with modified nucleobases

Four new copper(II) coordination complexes, obtained by reaction of CuX2 (X = acetate or chloride) with thymine-1-acetic acid and uracil-1-propionic acid as ligands, of formulas [Cu(TAcO)2(H2O)4]·4H2O (1), [Cu(TAcO)2(H2O)2]n (2), [Cu3(TAcO)4(H2O)2(OH)2]n·4H2O (3), and [Cu3(UPrO)2Cl2(OH)2(H2O)2]n (4) (TAcOH = thymine-1-acetic acid, UPrOH = uracil-1-propionic acid) are described. While 1 is a discrete complex, 2-4 are one-dimensional coordination polymers. Complexes 2-4 present dc conductivity values between 10(-6) and 10(-9) S/cm(-1). The magnetic behavior of complex 2 is typical for almost isolated Cu(II) metal centers. Moderate-weak antiferromagnetic interactions have been found in complex 3, whereas a combination of strong and weak antiferromagnetic interactions have been found in complex 4. Quantum computational calculations have been done to estimate the individual "J" magnetic coupling constant for each superexchange pathway in complexes 3 and 4. Compounds 2-4 are the first known examples of semiconductor and magnetic coordination polymers containing nucleobases.