Tetrakis(trimethylsilyl)cyclodisilthiane and -selenane

Reactions of 2,2-dichlorohexamethyltrisilane (1) with lithium sulfide or selenide furnishes (Me3Si)2Si(E)2Si(SiMe3)2 (E=S (2), Se (3)). Both compounds were characterized by multinuclear NMR spectroscopy (1H, 13C, 29Si, 77Se). The molecular structure of 2 is reported. 2 crystallizes in monoclinic space group P21/n (Z=2). The four membered ring Si2S2 is planar with an angle Si–S–Si of 83.32° resulting in a transannular Si–Si distance of 2.886 Å.