How trimethyl(trifluoromethyl)silane reacts with itself in the presence of naked fluoride--a one-pot synthesis of bis([15]crown-5)cesium 1,1,1,3,5,5,5-heptafluoro-2,4-bis(trifluoromethyl)pentenide.
Reactions of trimethyl(trifluoromethyl)silane in the presence of "naked" fluoride proceed up to a temperature of +5 degrees C mainly with formation of [Me3Si(CF3)2]-. A further rise of temperature up to about 20 degrees C gives evidence for the formation of a salt with the 1,1,1,2,3,6,6,6-octafluoro-2,4,4,5,5-pentakis(trifluoromethyl)hexan-3-ide anion. This intermediate decomposes at room temperature into the 1,1,1,3,5,5,5-heptafluoro-2,4-bis(trifluoromethyl)pentenide anion. The bis([15]crown-5)cesium salt, [Cs([15]crown-5)2][(CF3)2CCFC(CF3)2] has been characterized unambiguously as the stable final product of this reaction sequence. Thermal decomposition of this salt opens a convenient nontoxic route to obtain 1,1,3,3-tetrakis(trifluoromethyl)allene, (F3C)2C=C=C(CF3)2.
Tyrra
Wieland
W
Institut für Anorganische Chemie, Universität zu Köln, Greinstr. 6, 50939 Köln, Germany. tyrra@uni-koeln.de
Kremlev
Mikhail M
MM
Naumann
Dieter
D
Scherer
Harald
H
Schmidt
Harald
H
Hoge
Berthold
B
Pantenburg
Ingo
I
Yagupolskii
Yurii L
YL
D002586:Cesium; D018360:Crystallography, X-Ray; D005459:Fluorides / Q000737:chemistry*; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D015394:Molecular Structure; D012680:Sensitivity and Specificity; D012821:Silanes / Q000138:chemical synthesis* / Q000737:chemistry; D013696:Temperature; D005466:Fluorocarbons
D002586:Cesium; D005459:Fluorides; D006845:Hydrocarbons, Fluorinated; D012821:Silanes; C509467:bis((15)crown-5)cesium 1,1,1,3,5,5,5-heptafluoro-2,4-bis(trifluoromethyl)pentenide; D005466:Fluorocarbons; C509472:trimethyl(trifluoromethyl)silane