Rhenium(V) dioxo complexes with dihydrobis(pyrazolyl)borates: Synthesis and reactivity toward electrophilic substrates

The compounds trans,trans-[ReO2(py)(4)][ReO2{H2B(pz*)(2)}(2)] (pz* = pz (1) , 3,5-Me(2)pz (2)) have been prepared by reacting trans-[ReO2(py)(4)]Cl wit h the corresponding dihydrobis(pyrazolyl)borate. Compounds 1 and 2 react wi th electrophilic substrates, such as ClXMe3 (X = Si, Sn), leading to the ne utral monoxo derivatives [ReO(OSiMe3){H2B(pz*)(2)}(2)] (pz* = pz (3), 3,5-M e(2)pz (4)) and [ReO(OSnMe3){H2B(pz)(2)}(2)] (5) and regenerating trans-[Re O2(py)(4)]Cl. Compounds 1 and 3 crystallize from dicbloromethane/n-hexane a s yellow crystals, with one molecule of solvated CH2Cl2 in the case of 1. C rystallographic data: 1, triclinic space group P (1) over bar, a = 9.419(1) Angstrom, b = 9.584(1) Angstrom, c = 12.652(1) Angstrom, alpha = 89.03(1)d egrees, beta = 82.41(1)degrees, gamma = 72.75(1)degrees, V = 1080.9(2) Angs trom(3), Z = 2; 3, monoclinic space group P2(1)/n, a = 10.785(2) Angstrom, b = 17.680(2) Angstrom, c = 11.971(2) Angstrom, beta = 98.67(1)degrees, V = 2256.5(6) Angstrom(3), Z = 4.