The crystal structures of tetrakis(μ-n-butyrato-κ2O:O′)bis[bromidorhenium(III)] and tetrakis(μ-n-butyrato-κ2O:O′)bis[chloridorhenium(III)] acetonitrile disolvate

Abstract

The title complexes, [Re2Br2(O2CC3H7)4], (1), and [Re2(O2CC3H7)4Cl2]·2CH3CN, (2), both exhibit paddlewheel structures with four carboxylate ligands bridging two ReIIIatoms. The Re—Re distances are 2.2325 (2) and 2.2299 (3) Å, indicating quadruple bonds between the ReIIIatoms in each complex. Both complexes contain an inversion center at the mid-point of the Re—Re bond. The Re—Br bond [2.6712 (3) Å] in (1) is 0.1656 (6) Å longer than the Re—Cl distance [2.5056 (5) Å] of (2). In (2), the N atom of each co-crystallized acetonitrile solvent molecule is nearly equidistant between and in close contact with two carboxylate C atoms.