Furanyl bis(indolyl)methane as a palladium ion-selective chromogenic agent

The colorless solution of furan-2-yl bis(indolyl)methane (BIM) is newly revealed to work as a palladium (Pd2+) ion-selective chromogenic agent by turning orange. 5-(N-Methyl-N-phenyl-aminomethyl)-furan-2-yl BIM could be synthesized from 5-chloromethylfurfural as a biorenewable feedstock via one-pot and double functionalization, and a mixture of its solution and Pd2+ ions showed the highest absorbance at 465 nm in UV-Vis analysis. On the other hand, other metal ions (Cu2+, Cr2+, Cr3+, Fe2+, Fe3+, Ni2+, Zn2+, In2+, Pt2+, or Ce3+) exhibited no response. 5-(N-Methyl-N-phenyl-aminomethyl)-furan-2-yl bis(indolyl)methane, synthesized from 5-CMF as a biorenewable feedstock, serves as a Pd2+ ion-selective sensor.