Phosphine oxide-based tricarbonylrhenium(i) complexes from phosphine/phosphine oxide and dihydroxybenzoquinones

Abstract

Neutral phosphine oxide (PO) donor-based organometallic complexes [{Re(CO)₃OPCy₃}{μ-DHBQ}{Re(CO)₃OPCy₃}] (1), [{Re(CO)₃OPPh₃}{μ-DHBQ}{Re(CO)₃OPPh₃}] (2), [{Re(CO)₃OPCy₃}{μ-THQ}{Re(CO)₃OPCy₃}] (3), [{Re(CO)₃OPPh₃}{μ-THQ}{Re(CO)₃OPPh₃}] (4), [{Re(CO)₃OPCy₃}{μ-CA}{Re(CO)₃OPCy₃}] (5), and [{Re(CO)₃OPPh₃}{μ-CA}{Re(CO)₃OPPh₃}] (6) were assembled from phosphine/phosphine oxide, a dihydroxybenzoquinone donor and Re₂(CO)₁₀via a one-pot solvothermal approach. The soft phosphine donor was transformed into a hard phosphine oxide donor during the formation of 1, 3, 4, 5, and 6. The complexes 1–6 were air and moisture stable and were soluble in polar organic solvents. The complexes were characterized by elemental analysis, FT-IR, and NMR spectroscopic methods. The molecular structures of 1, 2, 4, and 6 were analyzed by single-crystal X-ray diffraction analysis. The UV-Visible absorption studies indicated that 1–6 in THF display strong visible light absorption in the range of ∼350–700 nm.