Homoleptic optically active ditungsten and dimolybdenum alkoxides. The crystal structure of (+)[W2(OC10H19)6]
Abstract
Reaction of optically resolved methol (1R,2S,5R or 1S,2R,5S) with [M2(NMe2)6] or [M2(OBut)6](M = Mo or W) in hexane produces (+)- or (–)-[M2(OC10H19)6] respectively in high yield (86–98%). The [M2(OC10H19)6] compounds are air sensitive, extremely soluble in hydrocarbon solutions and have decomposition points of 174–177 °C. Characterization was achieved by 1H, 13C, 13C-{1H} NMR, IR, CD, ORD, UV and mass spectrometry. For (+)[W2(OC10H19)6] X-ray crystallography revealed two independent molecules in the unit cell, both d3–d3 ethane-like dimers: space group P1, a= 15.439(3), b= 15.883(3), c= 13.684(3)Å, α= 104.4(1), β= 99.10(1), γ= 94.27(1)°, Z= 2; WW 2.338 (average), W–O 1.88 Å(average). Reaction of [W2(NMe2)6] with neomenthol produces [W2(NMe2)(OC10H19)5] in high yield. Reaction of [W2(OC10H19)6] with MeCN produces [{WN(OC10H19)3}x] and [W(CMe)(OC10H19)3] and with hex-3-yne produces [W(CEt)(OC10H19)3] and polyhexyne. Reaction of (+)[W2(OC10H19)6] with 6 equivalents of L-HOC10H19 produces racemic [W2(OC10H19)6] in less than 5 min. Treatment of [{MoN(OBut)3}x] with menthol produces the optically active polymer [{MoN(OC10H19)3}x].