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 (1)J(siH) coupling constant between the SP(2)-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 C(6)D(6) at 70 degrees C afforded the 1-hydrosilene via retro [6+6]-cycloaddition.