A Periodic Walk through a Series of First-Row, Oxido-Bridged, Heterodimetallic Molecules: Synthesis and Structure

A series of heterodimetallic molecules, centered around an LTi=O→M2+L′ (M = Mn, Fe, Co, Ni, Cu, Zn) core, are described. Each of these complexes are structurally similar, with L = tmtaa and L′ = Py5Me2. The Ti=O→M linkage is slightly bent, varying from 157° (Mn) to 170° (Zn), with bond lengths typical of a dative bond between the Ti=O group and the M2+ center. The relative strength of the heterodimetallic linkage is correlated with the Lewis acidity of the M2+ precursor, with Mn2+ showing the strongest interaction and Ni2+ the weakest. By varying the metal identity the electrochemical properties of the molecules can be tuned, along with the M3+/2+ redox couple. This series of complexes provide a platform for studying structure/function relationships in heterodimetallic molecules linked through a single atom. For instance, spectroscopic features such as IR stretching frequencies can be roughly correlated with structural features such as bond lengths and angles. By using a Lewis‐basic Ti=O group, a series of oxido‐bridged heterodimetallic molecules comprised of earth‐abundant first‐row elements is described. By varying the metal identity of the Lewis‐acidic center, molecular properties such as bridge stability and redox potentials can be tuned.