Bis(benzimidazole-triazolyl)benzenes as chemosensors in metal ion coordination

Triazoli su peteročlani heterociklički prsteni koji sadrže tri dušikova atoma. Benzimidazoli su biciklički prsteni koji u strukturi posjeduju dva dušikova atoma. Obje molekule su zbog svojih spektralnih svojstava i mogućnosti da koordiniraju različite metalne ione, česte funkcionalne jedinice u kemosenzorskim molekulama. Cilj ovog rada bio je ispitati potencijalnu primjenu novih derivata 1,3- i 1,4-bis(1,2,3-triazolil-benzimidazolil)benzena kao potencijalnih kemijskih optičkih senzora za metalne ione istraživanjem njihovih spektroskopskih svojstava u otopinama. UV-vidljivom apsorpcijskom i fluorescencijskom spektrofotometrijom ispitana su svojstva spojeva u etanolnim otopinama u prisutnosti različitih metalnih kationa pri koncentraciji spoja 1 × 10^–5 M. Oba spoja pokazuju smanjenje intenziteta fluorescencije u prisutnosti Fe3+ i Cu2+ iona, a u prisutnosti Zn2+ povećanje intenziteta i batokromni pomak u emisijskom spektru, što ukazuje na njihovu potencijalnu primjenu kao senzora za određivanje navedenih kationa u otopinama. Provedene su fluorescencijske titracije spojeva s navedenim kationima, te je 1,3-bis(1,2,3-triazolil-benzimidazolil)benzen 1 detaljnije ispitan kao potencijalni senzor za Fe(III) ione. Rezultati su pokazali da spoj 1 može brzo i uspješno određivati Fe(III) ione u etanolu i univerzalnom puferu pH=7 i selektivan je za Fe(III) u prisutnosti ostalih ispitivanih kationa.Triazoles and benzimidazoles are heterocyclic molecules with nitrogen atoms which allow them the ability to coordinate different metal cations. Because of their spectroscopic properties, they are often used as functional moieties in design of chemosensing probes. The aim of this work was spectroscopic characterisation of novel 1,3- and 1,4-bis(benzimidazole-1,2,3-triazolyl)benzenes as potential chemosensing molecules for metal ions. In order to determine the sensing possibility of studied compounds, the changes of their spectroscopic properties were studied by UV-visible and fluorescence spectroscopy in the presence of different metal cations in ethanol solution, by compound concentration of 1 × 10^–5 M. The presence of Fe3+ and Cu2+ causes fluorescence quenching in both spectrum of studied compounds, while in the presence of Zn2+, fluorescence intensity of compound 2 is notably increased, followed by bathochromic shift, implying their possible chemosensing ability to determine Fe(III), Cu(II) and Zn(II) ions in ethanol solutions. In addition, detailed spectroscopic titration eksperiments of compounds with Fe3+, Cu2+ and Zn2+ were carried out. Results showed that 1,3,-bis(benzimidazole-1,2,3-triazolyl)benzene 1 shows pronounced fluorescence quenching in the presence of Fe3+ compared with 1,4-bis-derivative 2