Deciphering anion–π-acceptor interactions and detecting fluoride using a naphthalenediimide-based Pd(ii) coordination polymer

Abstract

Unequivocal structural evidence of noncovalent interactions between π-acidic naphthalenediimides (NDIs) and anions has been elicited by X-ray crystallographic analysis of a zigzag coordination polymer involving Pd(II) ions and linear N,N′-di(4-pyridyl)NDI (DPNDI) ligands. Electrochemical studies show that the DPNDI/TfO⁻ interactions suppress DPNDI's π-acidity, whereas Pd(II)-coordination of DPNDI enhances its π-acidity. The ability of DPNDI to participate in F⁻-induced electron transfer leading to colorimetric sensing of F⁻ remains intact in the [Pd(II)/DPNDI]_n coordination polymer.