Molecular and crystal structure of 9,9,10,10-tetramethyl-9,10-disiladihydroanthracene

Synthesis, Structures, and Isomerization of 9,10-Di-tert-butyl-9,10-dihydro-9,10-disilaanthracenes

“…The Si−C−C bond angles of the disilacyclohexadiene rings (average 124.1°) are larger than those of trans - 3 (average 122.8°), 4 (average 122°),2e and 5 (average 123°) 2c2c. These structural features of cis - 3 seem to be favorable for reducing the steric repulsion among the tert -butyl groups…”

“…The tert -butyl groups occupy less crowded flagpole positions. The Si−C(phenyl) bond lengths (average 1.870 Å) are longer than those of trans - 3 (average 1.861 Å), 4 (average 1.85 Å),2e and 5 (average 1.86 Å) 2c2e and 5 (average 123°) 2c…”

“…Structures of trans -3 and cis -3. There have been some reports on X-ray crystal structures of 9,10-dihydro-9,10-disilaanthracene derivatives. 2b-e, 9,10-Dihydro-9,10-disilaanthracene ( 4 ), 2b,e 9,9,10,10-tetramethyl-9,10-dihydro-9,10-disilaanthracene ( 5 ), 2b,c and the 9,10-dimethyl-9,10-disilaanthracene dimer 4 have folded structures along the silicon atoms at the 9- and 10-positions…”

“…Since the first 9,10-dihydro-9,10-disilaanthracene was synthesized by Gilman and co-workers, studies on the syntheses, structures, properties, and reactions have been developed. − One of the most interesting features of the 9,10-dihydro-9,10-disilaanthracene derivatives is their utility as potential precursors of organosilicon reactive intermediates. For example, Ando and co-workers have recently reported the formation of 9,10-dilithio- and 9,10-dipotassio-9,10-dimethyl-9,10-disilaanthracene from the 9,10-dimethyl-9,10-disilaanthracene dimer …”

Synthesis, Structure, and Properties of an Intramolecularly Coordinated Diindacycle: 9,10-Dihydro-9,10-bis[2,6-bis((dimethylamino)methyl)- phenyl]-9,10-diindaanthracene

“…However, the observed In−C(phenylene) bonds (2.160(8) and 2.161(8) Å), and especially the In−C(aryl) bonds (2.191(8) Å), are longer than those in (C 6 H 5 ) 3 In (2.111(14)−2.155(14) Å) B, Si, Ge, As, Te 16 ) are planar or have a boat conformation; to our knowledge, there is only one other example of a sterically hindered 9,10-dihydro-9,10-dimetallaanthracene with a chairlike puckering of the central six-membered ring (M = Si) …”