Chiral organometallic triangles with Rh-Rh bonds. 1. Compounds prepared from racemic cis-Rh2(C6H4PPh2)2(OAc)2

Reaction of racemic cis-Rh(2)(C(6)H(4)PPh(2))(2)(OAc)(2)(HOAc)(2) with excess Me(3)OBF(4) in CH(3)CN results in the formation of racemic cis-Rh(2)(C(6)H(4)PPh(2))(2)(CH(3)CN)(6)](BF(4))(2).0.5H(2)O (1.0.5H(2)O), an ionic dirhodium complex which has two cisoid nonlabile orthometalated phosphine bridging anions and six labile CH(3)CN ligands in equatorial and axial positions. Reactions of 1 with tetraethylammonium salts of the linear dicarboxylates, oxalate, terephthalate, and 4,4'-biphenyl-dicarboxylate, in organic solvents, produced racemic crystals of the triangular compounds Rh(2)(C(6)H(4)PPh(2))(2)](3)(C(2)O(4))(3)(py)(6).6MeOH.H(2)O (2.6MeOH.H(2)O), Rh(2)(C(6)H(4)PPh(2))(2)](3)(O(2)CC(6)H(4)CO(2))(3)(DMF)(6).6.5DMF.0.5H(2)O (3.6.5DMF.0.5H(2)O), and Rh(2)(C(6)H(4)PPh(2))(2)](3)(O(2)CC(6)H(4)C(6)H(4)CO(2))(3)(py)(6).4.5CH(3)OH.0.75H(2)O (4.4.5CH(3)OH.0.75H(2)O), respectively. All compounds are electrochemically active. The relative chiralities of the dirhodium units in each triangle have been established using a combination of data from X-ray crystallography and (31)P NMR spectroscopy.