A dimolybdenum paddlewheel as a building block for heteromultimetallic structures

Diphenylphosphine functionalized propionic acid was applied for the synthesis of heteromultimetallic dimolybdenum(ii) complexes. The ligand features both carboxylic acid and phosphine functionalities, allowing the selective synthesis of a tetracarboxylate bridged Mo2(ii)-paddlewheel structure in a first step. Due to the symmetrically arranged phosphine functionalities, the dimolybdenum(ii) complex was utilized as a metalloligand. Subsequent coordination of late transition metal ions, such as gold(i), rhodium(i), iridium(i) or ruthenium(ii) to the phosphine moieties allowed the formation of heteromultimetallic structures. The flexibility of the diphenylphosphino propionate ligand system enabled intermolecular aurophilic interactions in the Au(i) functionalized dimolybdenum(ii) complexes. Depending on the Au(i) species applied, either a dimeric structure or a 1D coordination polymer was formed in the solid state. These structures represent the first examples of heterometallic dimolybdenum(ii) complexes, forming supramolecular structures via aurophilic interactions.