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.

当代灯笼化学的最令人兴奋，最具挑战性的领域之一（灯笼是元素周期表底部的14个元素）是孤立的灯笼烷基乙烯（具有碳原子的化合物，具有碳原子均匀粘结到lanthanide，ln = C），只有非常有限的数量。因此，仍然存在有关灯笼烷基德烯的稳定性，结构，粘合和反应性的持续基本问题。这样的物种很少，因为它们缺乏足够的良好的轨道相互作用，无法以多种过渡金属的方式稳定LN = C双键。但是，如果将杂原子（磷或硅）添加到烷基烷基，则可以帮助稳定电子在LN = C双键中。这笔赠款将基于申请人获得的初步结果，该结果利用了烷基烷基杂原稳定，并利用他在灯笼化学方面的专业知识来实现该领域的显着而快速扩张，以解决灯笼烷基烷基乙烯的新化学。新的灯笼烷基德烯将接受详细的结构和光谱审查，将其与理论计算计算相结合，以全面建立其稳定性，结构和键合。这些复合物的反应性模式将在平行的转变金属烷基烷基反应（Cycloaditions，Wittig-type）的反应中进行筛选。重要的是，申请人的初步结果包括一个系统，该系统不仅表现出正式的LN = C双键，还表现出反应性LN-C单键。这将两个非常反应性的碎片近在咫尺，并在同一金属中心附近，并提供了一个独特的机会，可以利用它们的协同作用，从而利用它们在一起。我们将使用这种协同作用来尝试访问以前未知的结构基序，例如第一个末端灯笼酰胺（LN = N双键）和第一个灯笼元素四烯烯（LN = SI和LN = GE Double Bonds）。这些将是非常有趣的无机版本的不饱和有机烯烃和艾伦（C = C，C = C = C），并且鉴于学术界和行业广泛使用过渡金属烷基德烯和酰亚胺，以合成精细的化学物质，药物和商品药物的塑料组合，他们承诺新型化学药品，药物和商品塑料聚合物。