α-Methyl-benzylcalcium complexes:: syntheses, structures and reactivity

被引：63

作者：

Feil, F ^{[1
]}

Müller, C ^{[1
]}

Harder, S ^{[1
]}

机构：

[1] Univ Konstanz, D-78457 Constance, Germany

来源：

JOURNAL OF ORGANOMETALLIC CHEMISTRY | 2003年 / 683卷 / 01期

关键词：

calcium; carbanion; polystyrene; C-H activation;

D O I：

10.1016/S0022-328X(03)00405-4

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

alpha-Methyl-benzylcalcium complexes were prepared analogue to alpha-Me3Si-benzylcalcium complexes for which procedures were reported earlier. The crystal structures of homoleptic bis(2-Me2N-alpha-Me-benzyl)calcium.(THF)(2) and heteroleptic (9-Me-3-Si-fluorenyl)(2-Me2N-alpha-Me-benzyl)calcium.(THF) were determined. For both compounds only one of the two diastereomers crystallized. Barriers for inversion of the chiral benzylic carbon were estimated by variable temperature NMR spectroscopy. The alpha-methyl-benzylcalcium compounds are less stable and show a higher reactivity and faster initiation of styrene polymerization than the analogue alpha-Me3Si-benzylcalcium complexes. Intramolecular C-H activation in a heteroleptic a-methyl-benzylcalcium complex was observed and the product, a calcium complex with a dianionic alkyl/fluorenyl ansa-ligand, was characterized by crystal structure determination. (C) 2003 Elsevier Science B.V. All rights reserved.

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页码：56 / 63

页数：8

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