Synthesis and X-ray diffraction analysis/crystal structure of new germatranes containing methyl substituents in three five-membered chelating rings

Abstract

Three monomeric germatranes, 1-isopropoxy-3,3,7,7,10,10-hexamethyl-2,8,9-trioxa-5-aza-1-germatricyclo[3.3.3.0(1.5)]undecane (1), 1-isopropoxy-3,3,7,7-tetramethyl-2,8,9-trioxa-5-aza-1-germatricyclo[3.33.0(1.5)]undecane (2), and 1-isopropoxy-3,3-dimethyl-2,8,9-trioxa-5-aza-1-germatricyclo[3.3.3.0(1.5)]undecane (3) have been synthesized by the reaction of Ge(O-i-Pr)(4) in refluxing toluene with corresponding triethanolamines, (HOCH(2)CH(2))(n)N(CH(2)CMe(2)OH)(3-n) (n = 0, L1H(3); n = 1, L2H(3); n = 2, L3H(3)), where the number of CMe(2) groups adjacent to a OH functionality varied from 3 (L1H(3)) to 2 (L2H(3)), and to 1 (L3H(3)). These germatranes 1-3 have been characterized by solution (1)H and (13)C{(1)H) NMR and the solid state structure of 2 has been determined by single crystal X-ray diffraction. (C) 2011 Elsevier Ltd. All rights reserved.