Synthesis and crystal structures of boratranes with methyl substituents on the atrane cage

Three monomeric boratranes B[(OCH2CH2)nN(CH2CMe2O)3−n] (n = 0, 1; n = 1, 2; n = 2, 3) have been synthesized by the reaction of B(OMe)3 with a series of triethanolateamines such as [(OCH2CH2)nN(CH2CMe2O)3−n]3− (n = 0, L1; n = 1, L2; n = 2, L3), where the number of CMe2 groups adjacent to the OH functionality varied from 3 (L1H3) to 2 (L2H3) to 1 (L3H3). These boratranes 1–3 have been characterized by solution 1H, 13C{1H} and 11B NMR, and the crystal structures of 1 and 2 have been determined by single crystal X-ray diffraction.

Graphical abstractNovel boratranes complexes with methyl substituents in the atrane cage were prepared. X-ray analysis revealed that the coordination around boron was a distorted tetrahedral geometry and three five-membered rings adopt an envelope conformation.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Trialkanolamine ligands (HOCH2CH2)nN(CH2CMe2OH)3−n (n = 0–2) were used as ligands. ► B(OMe)3 was used as metal precursors. ► Monomeric boratrane complexes were prepared. ► X-ray analysis revealed that three five-membered rings adopt an envelope conformation.