A boron imidazolate framework with mechanochromic and electrocatalytic properties

Abstract

A new alkaline-stable anionic boron imidazolate framework, CdB(im)₄(btec)_0.5·H₂O (BIF-89, im = imidazolate, btec = benzene-1,2,4,5-tetracarboxylate), was designed and synthesized. The resulting BIF-89 with a three-dimensional molecular structure exhibits a unique mechanochromic behavior with a maximum emission blue shift of about 23 nm in the blue emitting range. Additionally, the uncoordinated carboxylic groups in the BIF-89 framework can stabilize incorporation of Fe(III) at the atomic level to form Fe-immobilized BIF-89 (Fe@BIF-89), which can serve as an effective electrocatalyst for the oxygen evolution reaction in strongly alkaline media. The new BIF-89 expands the field of MOFs to luminescence mechanochromism and electrocatalytic applications without involving precious metals.