| | 1 | Author
| C. P., R. S. Tu D, Wolfgang Baumann, Yuri Oprunenko, Harald Günther | Requires cookie* | | | Title
| D  | | | | Abstract
| y n a m ic B e h a v io u r o f T e tra m e th y le th y le n e D ia m in e (T M E D A) L ig a n d s in S o lid O r g a n o lith iu m C o m p o u n d s : A V a r ia b le T e m p e r a tu r e 13C a n d 15N Dedicated to Professor Dr. W . Müller-Warmuth on the occasion of his 65th birthday The dynamic behaviour of tetramethylethylene diamine (TMEDA) ligands in three organometallic complexes, dimeric phenyllithium, [Li(tmeda)/*-Ph]2 (1), lithium cyclopentadienide, [Li(tmeda)]C5H5 (2), and dilithium naphthalendiide, trans-[Li(tmeda)]2C10H8 (3), has been studied by CP/MAS 13C and 15N as well as 7Li MAS NMR spectroscopy of powdered samples. Two dynamic processes with free activation enthalpies of 40 and 68 kJ mol-1, respectively, were detected for 1. The first one can be assigned to ring inversion of the five-membered Li-TMEDA rings, while the second is caused by a complete rotation of the TMEDA ligands or a ring inversion of the central four-membered C-Li-C-Li metallacycle. Fast rotation of the ligands on the NMR time scale was found for 2, while 3 shows 180° ring flips of the Li-TMEDA groups, which are characterized by an energy barrier AG" (317) of 64 kJ mol-1. | | | |
Reference
| Z. Naturforsch. 50a, 429—438 (1995); received November 8 1994 | | | |
Published
| 1995 | | | |
Keywords
| CP/MAS NMR, 13C-NMR, 15N-NMR, 7Li NMR, dynamic processes, organometallics | | | |
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