Two series of benzofuran and benzodifuran chelating chromophores with DR/NIR emission and anticancer activity

Benzofuran (BF) and benzodifuran (BDF) based compounds are known for their tunable optical and biological properties. Recently, their potential as chelating and anticancer agents has been examined and exploited. As dyes emissive in a physiological environment are in high demand for integrated therapeutic and imaging tools, BF and BDF scaffolds came up as possible theranostic probes. Here, we examined two series of BF and BDF based compounds with an extended conjugationpattern and a half-salen group producing a copper (II) ion-chelating O,N,O tridentate site. A combined experimental and theoretical approach was employed in the examination of spectroscopic and cytotoxic properties. The novel compounds are emissive according to an aggregation-induced emission mechanism and exhibit the DR/NIR (deep red/near-infrared) fluorescence required for penetration into living tissue. The results collected against HeLa, A431, and MCF7 human cells were discussed and compared, detecting in one case a very good performance against tumor cells as well as selectivity towards healthy HaCaT cells.