Syntheses and Structural Characterizations of a Novel Bowl-Type Germanol and Its Derivatives

A novel bowl-type triarylgermyl group, tris(2,2",6,6"-tetramethyl[1,1ʹ:3ʹ,1"-terphenyl]-5ʹ-yl)germyl (denoted as TRMG), was designed, and a germanol and its derivatives bearing this framework were synthesized. X-ray crystallographic analysis of TRMG-OH (5) revealed that there is no OH···O hydrogen bonding between adjacent molecules, although the possible presence of a weak intermolecular OH···(pi) interaction was suggested. In sharp contrast to organogermanols known so far, 5 is extremely resistant to self-condensation; no digermoxane was obtained when 5 was subjected to the conditions under which Ph3GeOH (8) affords the corresponding digermoxane. On the other hand, germanol 5 was readily converted to various derivatives. The crystal structure of TRMG-SH (12) was also determined.