Synthesis and characterization of ReV, ReVI and ReVII complexes of the [α2-P2W17O61]10– isomer

Abstract

Rhenium-(V), -(VI) and -(VII) complexes of the [α₂-P₂W₁₇O₆₁]^10– isomer, a mono-lacunary derivative of the [α-P₂W₁₈O₆₂]^6– (Wells–Dawson) ion have been prepared and characterized by multinuclear NMR spectroscopy, electrospray mass spectrometry and electron paramagnetic resonance spectroscopy, among other techniques. The molecules have the formulation [α₂-ReOP₂W₁₇O₆₁]^n–, where n = 7,6,5 for Re^V, Re^VI and Re^VII, respectively. ¹⁸³W NMR spectroscopy for the Re^V and Re^VII analogs shows that the molecules have C_s symmetry, as expected for substitution in the α₂ site. Simulations of the X-band and Q-band EPR spectra of the Re^VI analog, using C_s symmetry, allow determination of the g, hyperfine and quadrupole coupling tensors. X-Band, Q-band and W-band EPR spectroscopy show extreme variations in linewidths due to random strains or distortions of the complex.