Cyclopentadienyl zincates:: Synthesis and x-ray studies of sodium and potassium salts of the [Zn(C5H5)3]- and [Zn2(C5H5)5]- ions
Cyclopentadienyl zincates:: Synthesis and x-ray studies of sodium and potassium salts of the [Zn(C5H5)3]- and [Zn2(C5H5)5]- ions
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DOI：
10.1002/anie.200603875
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发表时间：
2007-01-01
影响因子：
16.6
通讯作者：
Carmona, Ernesto
中科院分区：
文献类型：
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作者：
Alvarez, Eleuterio;Grirrane, Abdessamad;Carmona, Ernesto
母体锌茂[Zn（C5 H5）2]（1）首先由Fischer及其同事在1959年通过ZnCl 2和NaC 5 H5（约100克）的反应制备。1：2.4比率），在作为溶剂的Et 2 O中，通过在真空下高温升华不溶性固体以低收率分离。[1]随后开发了另一种高产率的方法，[2]包括[Zn {N（SiMe 3）2} 2]与新鲜蒸馏的C5 H6的反应，并且它通常用于1的大规模[3，4]合成。在固态下，[Zn（C5 H5）2]由无限长的锌原子链组成，这些锌原子链由两个基团桥接[3]，但1的自由分子具有η5/η1滑移三明治几何结构，如电子衍射研究所揭示的。[5] Zn（C5 H5）2的分子应该表现出刘易斯酸的特征，正如全甲基化[Zn（C5 Me 5）2]在其对N-杂环卡宾的反应性中所发现的那样。[6]考虑到这一点以及均配和杂配烃基锌酸盐在有机和有机金属合成中享有的突出地位，[7-9]令人惊讶的是，阴离子加合物，例如[Zn（C5 H5）2X]（X=单阴离子刘易斯碱，如H、烷基、酰胺基）尚未报道。在我们对锌茂的研究中[10]，我们发现均配型锌酸盐[Zn-（C5 H5）3]<$和二锌酸盐[Zn 2（C5 H5）5]<$通过对Fischer的原始方法[1]的微小修改，以良好的产率形成，并显示出碱金属盐Na [Zn（C5 H5）3]∑ 2 THF（2）的有趣的固态结构，K [Zn（C5H5）3]（3）和[Na（thf）6][Zn 2（C5H5）5]（4）。化合物2-4是在不成功的二锌并茂[Zn 2（η5-C5 H5）2]的尝试合成过程中作为意外产物首次获得的。虽然用NaH或KH [10 c]还原[Zn-（C5 H5）2]/ZnCl 2 1：1混合物未能得到
The parent zincocene [Zn (C5H5) 2](1), was first prepared by Fischer and co-workers in 1959, by the reaction of ZnCl2 and NaC5H5 (ca. 1: 2.4 ratio), in Et2O as the solvent, it was isolated in low yields by high-temperature sublimation of the insoluble solids under vacuum.[1] An alternative, higher-yield procedure was subsequently developed,[2] consisting in the reaction of [Zn {N (SiMe3) 2} 2] with freshly distilled C5H6, and it is routinely employed for the large-scale [3, 4] synthesis of 1. In the solid state,[Zn (C5H5) 2] consists of infinite chains of zinc atoms bridged by cyclopentadienyl groups,[3] but the free molecules of 1 have an η5/η1 slip-sandwich geometry, as revealed by electron diffraction studies.[5]The molecules of Zn (C5H5) 2 should exhibit Lewis acid character, as found for the permethylated [Zn (C5Me5) 2] in its reactivity toward N-heterocyclic carbenes.[6] Considering this and the prominent place that homo and heteroleptic hydrocarbyl zincates enjoy in organic and organometallic synthesis,[7–9] it is surprising that anionic adducts, for example,[Zn (C5H5) 2X]¿(X= monoanionic Lewis base, such as H¿, alkyl, amido) have not been reported. During our studies on zincocenes [10] we have found that homoleptic zincates [Zn-(C5H5) 3]¿, and dizincates [Zn2 (C5H5) 5]¿, form in good yields by minor modifications of Fischer s original procedure [1] and display interesting solid-state structures which have been determined for the alkali-metal salts Na [Zn (C5H5) 3]∑ 2 THF (2), K [Zn (C5H5) 3](3), and [Na (thf) 6][Zn2 (C5H5) 5](4). Compounds 2–4 were first obtained as unexpected products during the unsuccessful attempted synthesis of dizincocene [Zn2 (η5-C5H5) 2]. Although the reduction of [Zn-(C5H5) 2]/ZnCl2 1: 1 mixtures by NaH or KH [10c] failed to give