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Lanthanide Heteroatom-Stabilised Alkylidenes: A New Approach to Multiply Bonded Lanthanide Chemistry

稀土杂原子稳定的亚烷基：多重键合稀土化学的新方法

基本信息

批准号：
EP/F030517/1
负责人：
Stephen Liddle
金额：
$ 38.22万
依托单位：
University of Nottingham
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FF030517%2F1
关键词：
Lanthanide Heteroatom Stabilised Alkylidenes New

项目摘要

One of the most exciting and challenging areas of contemporary lanthanide chemistry (lanthanides are the 14 elements at the bottom of the periodic table) is the isolation of lanthanide alkylidenes (compounds which feature a carbon atom doubly bonded to a lanthanide, Ln=C), and only a very limited number are known. Therefore, enduring fundamental questions regarding the stability, structure, bonding, and reactivity of lanthanide alkylidenes remain. Such species are scarce because they lack sufficiently good orbital interactions to stabilise the Ln=C double bond in the way numerous transition metals can. However, if heteroatoms (phosphorus or silicon) are appended to the alkylidene they can help stabilise the electrons in the Ln=C double bond. This First Grant will build on preliminary results the applicant has obtained, which exploits alkylidene heteroatom stabilisation, and utilises his expertise in lanthanide chemistry, to effect a significant and rapid expansion of this field to address the new chemistry of lanthanide alkylidenes. New lanthanide alkylidenes will be subjected to a detailed structural and spectroscopic interrogation, which will be combined with theoretical computational calculations to comprehensively establish their stability, structure and bonding. The reactivity patterns of these complexes will be screened in reactions which parallel transition metal alkylidene reactions (cycloadditions, Wittig-type). Importantly, the applicants preliminary results include a system which exhibits not only a formal Ln=C double bond, but also a reactive Ln-C single bond. This places two very reactive fragments in close proximity at the same metal centre, and presents a unique opportunity to exploit the synergy resulting from them being harnessed together. We will use this synergy to attempt access to previously unknown structural motifs, such as the first terminal lanthanide imides (Ln=N double bond) and the first lanthanide tetrylenes (Ln=Si and Ln=Ge double bonds). These will be highly interesting inorganic versions of unsaturated organic olefins and allenes (C=C, C=C=C), and given the extensive use of transition metal alkylidenes and imides by academia and industry for the synthesis of fine chemicals, pharmaceutical drugs, and commodity plastic polymers, they promise novel new reactivities.

当代镧系元素化学（镧系元素是周期表底部的14种元素）中最令人兴奋和最具挑战性的领域之一是镧系元素亚烷基（具有与镧系元素双键连接的碳原子的化合物，Ln=C）的分离，并且只有非常有限的数量是已知的。因此，关于镧系亚烷基的稳定性、结构、成键和反应性的持久的基本问题仍然存在。这类物种是稀缺的，因为它们缺乏足够好的轨道相互作用来稳定Ln=C双键的方式，许多过渡金属可以。然而，如果杂原子（磷或硅）附加到亚烷基上，它们可以帮助稳定Ln=C双键中的电子。该第一笔资助将建立在申请人已经获得的初步结果的基础上，该结果利用了亚烷基杂原子的稳定性，并利用他在镧系元素化学方面的专业知识，以实现该领域的显着和快速扩展，以解决镧系元素亚烷基的新化学。新的镧系亚烷基将进行详细的结构和光谱询问，这将与理论计算相结合，以全面建立其稳定性，结构和键合。这些配合物的反应模式将被筛选在平行的过渡金属亚烷基反应（环加成，维蒂希型）的反应。重要的是，申请人的初步结果包括不仅表现出形式Ln=C双键，而且表现出反应性Ln-C单键的体系。这将两个非常活跃的碎片放在同一个金属中心，并提供了一个独特的机会来利用它们一起使用所产生的协同作用。我们将利用这种协同作用来尝试获得先前未知的结构基序，例如第一末端镧系元素酰亚胺（Ln=N双键）和第一镧系元素四亚苯基（Ln=Si和Ln=Ge双键）。这些将是非常有趣的不饱和有机烯烃和联烯（C=C，C=C=C）的无机版本，并且考虑到学术界和工业界广泛使用过渡金属亚烷基和酰亚胺合成精细化学品，药物和商品塑料聚合物，它们承诺新颖的新反应性。