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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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DYNAMIC BEHAVIOR OF TETRAMETHYLETHYLENE DIAMINE (TMEDA) LIGANDS IN SOLID ORGANOLITHIUM COMPOUNDS - A VARIABLE-TEMPERATURE C-13 AND N-15 CP/MAS NMR-STUDYстатья
Информация о цитировании статьи получена из
Web of Science
Дата последнего поиска статьи во внешних источниках: 27 мая 2015 г.
- Авторы: BAUMANN W., OPRUNENKO Y., GUNTHER H.
- Журнал: ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES
- Том: 50
- Номер: 4-5
- Год издания: 1995
- Первая страница: 429
- Последняя страница: 438
- Аннотация: The dynamic behaviour of tetramethylethylene diamine (TMEDA) ligands in three organometallic complexes, dimeric phenyllithium, [Li(tmeda)mu-Ph](2) (1), lithium cyclopentadienide, [Li(tmeda)]C5H5 (2), and dilithium naphthalendiide, trans-[Li(tmeda)]2C10H8 (3), has been studied by CP/MAS C-13 and N-15 as well as Li-7 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 degrees ring flips of the Li-TMEDA groups, which are characterized by an energy barrier Delta G(not equal)(317) of 64 kJ mol(-1).
- Добавил в систему: Опруненко Юрий Федорович