STRUCTURE OF SODIUM DINEOPENTYLDIOXORHENIUM(V)

Sodium dineopentyldioxorhenium(V), [Na(CH3CN)][ReO2(CH2CMe3)2], C12H25NNaO2Re, Mr = 424.53, triclinic, P 1 (No. 2), a = 14.209(3), b = 14.631(3), c = 11.144(2) Å, α = 97.80(1), β = 104.69(2), γ = 64.54(1)°, V = 2022.5(7) Å3, Z = 2, Dx = 1.39 g cm-3, λ(Mo-Kα) = 0.71073 Å, μ = 61.04 cm-1, F(000) = 796, T = 233(1) K, final R = 0699 for 3216 unique reflections with Fo > 6σ(Fo) and 308 variables. There are two independent molecules of [Na(CH3CN)][ReO2(CH2CMe3)2] in the asymmetric unit. In thesolid state the compound is polymeric having {[Na(CH3CN)][ReO2(CH2CMe3)2]}2 repeating units. The {[Na(CH3CN)][ReO2(CH2CMe3)2]}2 units are eight-membered rings of composition Re2O4Na2, which are connected via NaO bonds thereby forming the polymer. The [ReO2(CH2CMe3)2]- anions within the repeating units have distorted tetrahedral geometries with open OReO (av. 136°) and closed CReC (av. 83°) angles. The planes defined by OReO and CReC are perpendicular (90.6° and 90.0° for Re(1) and Re(2), respectively). Average ReO multiple bond and ReC single bond distances ae 1.72 and 2.11 Å, respectively. A comparison of the structures of related d0, d1 and d2 MO2R2 (R = alkyl and aryl) compounds is presented. The structural changes which occur as a function of electron count in these compounds are explained in the context of an earlier MO study. © 1990.