The evaluation of singlet-triplet separations for [W 2(μ-H)(μ-Cl)Cl 4(μ-dppm) 2] and [W 2(μ-H) 2 (μ-O 2CC 6H 5) 2(P(C 6H 5) 3) 2] based on 31P NMR and crystallographic data

Abstract

The singlet-triplet separations for the edge-sharing bioctahedral (ESBO) complex W 2(μ-H)(μ-Cl)(Cl 4(μ-dppm) 2 · (THF) 3 ( II) has been studied by 31P NMR spectroscopy. The structural characterization of [W 2(μ-H) 2(μ-O 2CC 6H 5) 2Cl 2(P(C 6H 5) 3) 2] ( I) by single-crystal X-ray crystallography has allowed the comparison of the energy of the HOMOLUMO separation determined using the Fenske-Hall method for a series of ESBO complexes with two hydride bridging atoms, two chloride bridging atoms and the mixed case with a chloride and hydride bridging atom. The complex representing the mixed case, [W 2(μ-H)(μ-Cl)Cl 4(μ-dppm) 2 · (THF) 3] ( II), has been synthesized and the value of −2 J determined from variable-temperature 31P NMR spectroscopy.