Synthesis and characterization of a binuclear rhenium nitropyrazole complex [Re2O3Cl2(PPh3)2(C3H2N3O2)2]

The binuclear nitropyrazole compound [Re2O3Cl2(PPh3)2(C3H2N3O2)2] (3) was synthesized by refluxing [ReOCl2(OEt)(PPh3)2] and 2-nitropyrazole in ethanol for 12 h. The octahedral {ReO2N2ClP} sites are linked by two bridging nitropyrazoles and an oxo group, with an Re–O–Re angle of 124.7(6)°. Compound 3 is electrochemically active, displaying a reversible one electron reduction at −0.55 V with respect to Ag/Ag+. Crystal data: C36H34Cl2N6O7P2Re2 (3), monoclinic C2/c, a=32.569(7), b=9.624(2), c=29.151(6) Å, β=109.33(3)°, V=8622(3) Å3, Z=8, Dcalc=1.799 g cm−3, structure solution and refinement based on 3364 reflections converged at R=0.056.