Facile and rapid synthesis of crystalline quadruply bonded Cr(ii) acetate coordinated with axial ligands.

A quadruple bond formed between d-block or f-block atoms is an interesting research topic due to its unique nature including a supershort bonding distance and narrow energy gap between δ and δ*. Among various multiply bonded complexes, quadruply bonded Cr(ii) acetates are considered useful to control the δ-δ* energy gap by the Lewis basicity of additional ligands. However, the synthesis and preparation of the high-quality, large-sized crystals of Cr(ii) acetates coordinated with axial ligands (Cr(OAc)L) have been difficult due to their vulnerability to O, a representative oxidizing agent under aerobic conditions.