Mechanochromic Cu(I) boron imidazolate frameworks with low-dimensional structures and reducing function

Two low-dimensional Cu(I) boron imidazolate frameworks (BIFs), [CuBH(bim)₃]_n (BIF-40; bim = benzimidazolate) and [CuBH(im)₃]_n (BIF-6, im = imidazolate), have been synthesized and both of them display unique mechanochromism. In addition, BIF-40 showed reducing activity due to the rich B–H bonds in the structure, and it was employed to load AuPd bimetal nanoparticles through a one-step process for further catalysis. The corresponding mechanism involving a grinding process between chains or layers is discussed in detail. This work not only provides compelling evidence for designing and applying coordination polymers as mechanochromic materials, but also develops an eco-friendly strategy for loading bimetallic NPs into BIFs.