Construction of Diiron Diamond-Core Complexes Influenced by a Fluoroalkoxide Ligand

The FenXn scaffold (X= p-block elements) occurs commonly in multimetallic metalloproteins and metalloenzymes. In particular, the synthon Fe2X2 is of great interest for biomimetic studies. Here is presented the use of α,α-bis(trifluoromethyl)benzyloxide as a ligand to support the assembly of two heteroleptic iron complexes featuring a diamond-core structure of the type Fe2X2 (X = N(SiMe3)2, HMDS; O-2,6-(2’,4’,6’-Me3-C6H2)2-C6H3, HMTO). The relatively low Lewis basicity of the fluoroalkoxide ligand cause it to selectively occupy the terminal position at the iron centers, while the more basic amido or alcoxo donors X are bridging the iron atoms and thus force them to take part in the diamond-core scaffold Fe2X2. In solution, even at room temperature, the amide-bridged diamond-core compound features a stable dimeric structure, exhibiting low-coordinate iron centers and a strong intermetallic antiferromagnetic interaction, as supported by experimental data and theoretical calculations.