J. Catala, G. Clouet, J. Brossas
Oct 20, 1981
Citations
0
Influential Citations
7
Citations
Journal
Journal of Organometallic Chemistry
Abstract
Abstract Complexation of secondary-butyllithium (sec-BuLi) by N,N,N′,N′ -tetramethylethylenediamine (TMEDA) has been examined by NMR spectroscopy at various temperatures. The upfield chemical shift of the α-methine proton of the sec-BuLi has been determined as a function of the ratio R = TMEDA/sec-BuLi. The reversible variation of the chemical shift from −50°C to −20°C is explained in terms of an endothermic disproportionation of the 1 : 1 complex (1 sec-BuLi : 1 TMEDA) to the 1 : 2 complex (1 sec-BuLi : 2 TMEDA).