Crystal and molecular structure of 2,2,4,4,6,6-hexamethyl-1,3,5-tris-(trimethylsilyl)cyclotrisilazane, C15H45N3Si6, a compound containing a six-membered ring in the ‘boat’ form

Abstract

The structure of 2,2,4,4,6,6-hexamethyl-1,3,5-tris(trimethylsilyl)cyclotrisilazane, C₁₅H₄₅N₃Si₆ has been determined by single-crystal X-ray diffraction methods. The crystals are orthorhombic, space group Pnma with Z= 4 in a unit cell of dimensions a= 13·486, b= 18·016, c= 11·286 Å. The final R factor for 1872 diffractometer data is 0·059. The six-membered cyclotrisilazane ring is almost in the ‘boat’ form with an average silicon–nitrogen bond length of 1·744(4)Å. The silicon–nitrogen bond lengths outside the ring are slightly longer, mean 1·758(4)Å. It is suggested that the ‘boat’ form is favoured because the three valences on each nitrogen atom adopt a planar configuration.