Effect of the organometallic fragment R = -CCHCo2(CO)(6) on the properties of M-2{OOCR}(4) clusters (M = Mo, Cu)

Abstract

Three structures of novel cluster carboxylates of molybdenum(II) (la-c) and copper(II) (2) with the OOC-CCHCo2(CO)(6) ligand are presented. The solvent topology plays an important role in the formation of the crystal lattice of the molybdenum(II) cluster, which shows a pillared structure for 1, with stacked 1,4-xylene (1a,b) and toluene (1c). The nature of the cluster(...)solvent interaction has been investigated by means of B3LYP density functional theory calculations using double-zeta basis functions. These DFT calculations together with polarizable continuum media and effective fragment potentials allow us to explain the nature of the arene(...)Mo(2) arrangement (ca. 3.10 angstrom) found in the pillared cluster 1b. The copper(II) dimer 2 displays an unexpected weak intramolecular magnetic coupling for a copper tetracarboxylate, which can also be ascribed to the electronic nature of the ligand. The weak coupling within the copper(II) syn,syn-carboxylate cluster was investigated with DFT calculations. In the solvated species the copper(II) cluster 2 presents an oxo ligand at the axial positions, while the molybdenum(II) cluster 1 stacks between the aromatic ligands.