A Biphenol-Based Chemosensor for Zn(II) and Cd(II) Metal Ions: Synthesis, Potentiometric Studies, and Crystal Structures

• Published in: Inorganic chemistry 2016-08, Vol.55 (15), p.7676-7687
• Main Authors: Ambrosi, Gianluca, Formica, Mauro, Fusi, Vieri, Giorgi, Luca, Macedi, Eleonora, Micheloni, Mauro, Paoli, Paola, Rossi, Patrizia
• Format: Article
• Language: English
• ISSN: 1520-510X
• DOI: 10.1021/acs.inorgchem.6b01145

We synthesized and characterized the ligand N,N'-bis[(2,2'-dihydroxybiphen-3-yl)methyl]-N,N'-dimethylethylenediamine (L), which contains two biphenol moieties linked as side arms to an N,N'-dimethylethylenediamine scaffold. The ligand is highly soluble in a 50/50 (v/v) water/ethanol mixture and, in its deprotonated form H-2L(2-), is able to coordinate transition-metal ions such as Ni(II), Zn(II), Cu(II), Cd(II), and Pd(II). The crystal structures of [Ni(H-2L)·2n-BuOH], [Ni(H-2L)·2MeOH], [Cd(H-2L)·2DMF], [Cu(H-2L)(DMF)], and [Pd(H-2L)(DMF)] were also determined and described. Potentiometric titrations were carried out in a mixed solvent with Zn(II), Cu(II), and Ni(II) metal ions to determine the acid-base and stability constants. L was highly fluorescent in the visible range (400 nm). Moreover, its emission intensity increased upon the addition of Zn(II) or Cd(II) ions in an ethanol/water solution and behaved as a chemosensor for the presence of these ions in the solution.