Synthesis of a 1-Hydrosilene Stable in Solution and Its Unique Properties

An overcrowded 1-hydrosilene bearing a 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (denoted as Tbt) group and a xanthenyl moiety was synthesized as a compound stable in solution by dehydrofluorination reaction of the corresponding fluorosilane. The newly generated 1-hydrosilene was characterized by NMR spectroscopy to reveal its 1JSiH coupling constant between the sp2-silicon atom and the attached hydrogen atom in the 1-hydrosilene skeleton. The 1-hydrosilene was found to undergo an unexpected [6+6]-dimerization during its recrystallization. In addition, the thermolysis of the isolated [6+6]-dimer in C6D6 at 70 °C afforded the 1-hydrosilene via retro [6+6]-cycloaddition.