Supramolecular Assemblies of Nucleobase Derivative 1-Mecyt with Mg(II) and Ni(II) and Solid-State Transformation of Ni(II) Phase:  A Comprehensive Evidence of Their Different Reactivity toward 1-Mecyt [1-Mecyt = 1-Methylcytosine]

The synthesis and crystal structure of the compounds [Mg(H₂O)₆(1-Mecyt)₂]Cl₂ (1), [Ni(H₂O)₆(1-Mecyt)₂]Cl₂ (2), and [Ni(1-Mecyt)₂Cl₂] (3) (where 1-Mecyt = 1-Methylcytosine) are reported. Compounds 1 and 2 consist of hexaaquo ions, 1-Mecyt molecules, and chloride ions self-assembled through an extended network of hydrogen-bonding interactions. Compound 3 is made of [Ni(1-Mecyt)₂Cl₂] units, with the 1-Mecyt molecules directly coordinated to the metal centers through the N(3) and O(2) atoms. When crystals of compound 2 are allowed to stand in air for 1 week, a solid transformation occurs. The results of our investigation clearly suggest that a solid-state reaction takes place in 2, leading to 3.