Sulfate Donor Based Dinuclear Heteroleptic Triple-Stranded Helicates from Sulfite and Ditopic Nitrogen Donor Ligands and Their Transformation to Dinuclear Homoleptic Double-Stranded Mesocates.

Sulfate donor based supramolecular coordination complexes [{ fac-Re(CO)3}(μ-SO4)(L n)2{ fac-Re(CO)3}] (1-3) were obtained using ditopic N donors (L n; n = 1-3), NaHSO3, and Re2(CO)10 in a one-pot, multicomponent, coordination-driven self-assembly approach, in which SO32- becomes oxidized to SO42- during the reaction and acts as a building framework. Complexes 1-3 were characterized using IR, ESI-TOF-MS, and 1H NMR spectroscopy. The structures of complexes 1-3 were confirmed using single-crystal X-ray diffraction analysis. The transformation of the dinuclear heteroleptic triple-stranded helicate to the dinuclear homoleptic double-stranded mesocate [{Re(CO)3Cl}2(L n)2] (L n = L1, L2, L3; 4a-6a) was achieved by the addition of BaCl2. The direct treatment of Re(CO)5X (X = Cl, Br) with L1/L2/L3 yielded the dinuclear homoleptic double-stranded helicates [{Re(CO)3X}2 (L n)2] (4b-6b and 7-9).