STRUCTURAL CHARACTERIZATION OF 1,3-CYCLODISILOXANES

Four single-crystal X-ray analyses are presented for 1,3-cyclodisiloxa nes: tetramesitylcyclodisiloxane-benzene (1), two crystalline forms of tetramesitylcyclodisiloxane-toluene (2a and 2b), and -1,3-bis(1-adama ntyl)-1,3-dimesitylcyclodisiloxane (3). For all of these crystals the cross-ring silicon-silicon distances are 238-239 pm, and the Si-O dist ances are 167-168 pm. These crystal structures are compared with those of four previously reported cyclodisiloxanes, and the implications fo r chemical bonding in cyclodisiloxanes are discussed.