398136-44-2Relevant articles and documents
Bis(4-benzhydryl-benzoxazol-2-yl)methane – from a Bulky NacNac Alternative to a Trianion in Alkali Metal Complexes
Kretsch, Johannes,Kreyenschmidt, Anne-Kathrin,Schillm?ller, Timo,L?kov, M?rt,Herbst-Irmer, Regine,Leito, Ivo,Stalke, Dietmar
, p. 9858 - 9865 (2021)
A novel sterically demanding bis(4-benzhydryl-benzoxazol-2-yl)methane ligand 6 (4?BzhH2BoxCH2) was gained in a straightforward six-step synthesis. Starting from this ligand monomeric [M(4-BzhH2BoxCH)] (M=Na (7), K (81)) and dimeric [{M(4-BzhH2BoxCH)}2] (M=K (82), Rb (9), Cs (10)) alkali metal complexes were synthesised by deprotonation. Abstraction of the potassium ion of 8 by reaction with 18-crown-6 resulted in the solvent separated ion pair [{(THF)2K@(18-crown-6)}{bis(4-benzhydryl-benzoxazol-2-yl)methanide}] (11), including the energetically favoured monoanionic (E,E)-(4-BzhH2BoxCH) ligand. Further reaction of 4?BzhH2BoxCH2 with three equivalents KH and two equivalents 18-crown-6 yielded polymeric [{(THF)2K@(18-crown-6)}{K@(18-crown-6)K(4-BzhBoxCH)}]n (n→∞) (12) containing a trianionic ligand. The neutral ligand and herein reported alkali complexes were characterised by single X-ray analyses identifying the latter as a promising precursor for low-valent main group complexes.
