A new 3D nickel(II) framework composed of large rings: Ionothermal synthesis and crystal structure

Ionothermal reaction between Ni2+ and 1,3,5-benzentricarboxylic acid (H3BTC) with [AMI]Cl (AMI=1-amyl-3-methylimidazolium) as the reaction medium produced a novel 3D mixed-ligand metal-organic framework [AMI][Ni3(BTC)2(OAc)(MI)3] (1) (MI=1-methylimidazole) with [AMI]+ incorporated in the framework. The framework is formed by connecting 2D planes, made up of 32- and 48-membered rings, through 1D chains composed of 32-membered rings. The two BTC3− ligands in 1 show the same connectivity mode with two bidentate and one μ2 bridging carboxylic groups. This is a new connectivity mode to the already existing 17 in the Ni-BTC system. The role of MI and [AMI]Cl in the structure formation is discussed.