Abstract
The solution and solid-state characterization of the tetraorganozincates [(TMEDA)2Li2ZnMe(NMe2)3] (2) and [(TMEDA)2Li2ZnMe4] (4) and the all-amido triorganozincate [{(TMEDA)LiZn(NMe2)3}2] (3) are reported. X-ray crystallographic studies reveal that 2 and 4 exhibit similar structural motifs, namely trinuclear Li···Zn···Li chain arrangements held together by a methyl and three amido ligands in the former and exclusively by methyl groups in the latter, whereas 3 adopts a longer tetranuclear Li···Zn···Zn···Li chain arrangement with all NMe2 ligands. The zinc coordination in all these structures is distorted tetrahedral. DFT calculations revealed that the formation of tetraorganozincate 4 by cocomplexation of 2 equiv of MeLi and Me2Zn is thermodynamically preferred over the parent triorganozincate [(TMEDA)LiZnMe3]. Preliminary studies show that the tris(amido)alkyl zincate 2 is a poor Brønsted base for metalation (zincation) of functionalized aromatic substrates such as anisole, N,N-diisopropylbenzamide, and benzonitrile.
Original language | English |
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Pages (from-to) | 6063-6070 |
Number of pages | 7 |
Journal | Organometallics |
Volume | 27 |
Issue number | 23 |
DOIs | |
Publication status | Published - 8 Dec 2008 |
Keywords
- synthesis
- structural elucidation
- alkyl
- amido
- mixed alkyl−amido
- "highly-coordinated” zincates