Rhenium(V) Dioxo Complexes with Dihydrobis(pyrazolyl)borates:  Synthesis and Reactivity toward Electrophilic Substrates

Abstract

The compounds trans, trans -[ReO 2 (py) 4 ][ReO 2 {H 2 B(pz*) 2 } 2 ] (pz* = pz ( 1 ), 3,5-Me 2 pz ( 2 )) have been prepared by reacting trans -[ReO 2 (py) 4 ]Cl with the corresponding dihydrobis(pyrazolyl)borate. Compounds 1 and 2 react with electrophilic substrates, such as ClXMe 3 (X = Si, Sn), leading to the neutral monoxo derivatives [ReO(OSiMe 3 ){H 2 B(pz*) 2 } 2 ] (pz* = pz ( 3 ), 3,5-Me 2 pz ( 4 )) and [ReO(OSnMe 3 ){H 2 B(pz) 2 } 2 ] ( 5 ) and regenerating trans -[ReO 2 (py) 4 ]Cl. Compounds 1 and 3 crystallize from dichloromethane/ n -hexane as yellow crystals, with one molecule of solvated CH 2 Cl 2 in the case of 1 . Crystallographic data: 1, triclinic space group P 1̄, a = 9.419(1) Å, b = 9.584(1) Å, c = 12.652(1) Å, α = 89.03(1)°, β = 82.41(1)°, γ = 72.75(1)°, V = 1080.9(2) Å 3, Z = 2; 3, monoclinic space group P 2 1 / n, a = 10.785(2) Å, b = 17.680(2) Å, c = 11.971(2) Å, β = 98.67(1)°, V = 2256.5(6) Å 3, Z = 4.