Neutral dodecanuclear supramolecular complexes containing dimetal units linked by the trimesate anion

Two compounds having six metal-metal bonded Mo-2(4+) and Rh-2(4+) units, the midpoints of which occupy the vertexes of an octahedron, are described here. Each of the M-2(4+) units is also bridged by two mutually cis formamidinate groups of the type DAniF = N,N'-di-p-anisylformamidinate. These units are linked to each other by four tricarboxylate anions from trimesic acid, the centers of which form a tetrahedron that is encapsulated by the octahedron of dimetal units. Each of the neutral cages has a clathrated solvent molecule, CH2Cl2 when the metal M is Mo and CH3CN when it is Rh. For the latter, there are CH3CN molecules occupying 2/3 of the axial sites on the Rh-2 units in a way that reduces the symmetry. These symmetrical structures appear to persist in solution as shown by the H-1 NMR spectra. The compounds [M-2(cis-DAniF)(2)](6)[1,3,5-C6H3(CO2)(3)](4), 1 for M = Mo and 2 for M = Rh, were crystallized as 1(.)22.1CH(3)CN(.)2.3CH(2)Cl(2) and 2(.)13.9CH(3)CN, respectively. In 1 there are four crystallographically independent quadruply bonded Mo-Mo distances in the narrow range 2.098-2.104 For 2, the six independent singly bonded Rh-Rh distances are in the range 2.428-2.438 Angstrom.