Unusual Structure and Bonding in Strained Aromatic Molecules

将研究两个相对不活泼的官能团被迫彼此靠近的分子的合成和性质。特别强调的是，在环双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲双亲。其他富电子基团，如烯烃、胺、氧化膦和氟硅烷也将进行研究。通过平衡这些化合物的分子内张力与亲核性或亲电性，就有可能获得基团之间存在部分键合的结构。这种结构可以作为普通芳香族反应过渡态结构的模型。该项目的第二部分将涉及富勒烯碎片的物理性质的合成和研究。这些碎片中的每一个都是巴克敏斯特富勒烯（球形C60）的不同片段。这项来自有机动力学项目的资助支持了普林斯顿大学罗伯特·帕斯卡教授的继续工作。该项目的主要重点是合成和研究高度紧张的有机分子，即分子中的一些原子由于空间约束而被迫占据位置，从而导致与其他原子的不自然相互作用以及不寻常的键距和角度。特别令人感兴趣的是分子的结构和反应性，其中两个相对不反应的官能团被迫非常接近。预计强制的接近将导致所涉及的基团的不寻常的反应性，以及不寻常的物理性质。在该项目的另一部分，将制备最近发现的球形碳的C60同素异形体的碎片（碳的其他同素异形体是金刚石和石墨），以了解如何从碳碎片形成C60。

The synthesis and properties of molecules in which two relatively unreactive functional groups are forced into close proximity to each other will be studied. Particular emphasis will be placed on in-cyclophanes bearing phosphine lone-pair electrons brought into close proximity with aromatic rings. Other electron-rich groups, such as olefins, amines, phosphine oxides, and silyl fluorides will also be examined. By balancing the forces due to intramolecular strain in these compounds with the nucleophilicity or electrophilicity of the aromatic ring, it may be possible to obtain structures in which there is partial bonding between the groups in question. Such structures may serve as models for transition state structures in ordinary aromatic reactions. A second part of the project will involve the synthesis and study of the physical properties of fullerene fragments. Each of these fragments will be a different segment of buckminsterfullerene (spherical C60). %%% This grant from the Organic Dynamics Program supports the continuing work of Professor Robert Pascal at Princeton University. the main focus of the project is the synthesis and study of highly strained organic molecules, i.e., molecules in which some atoms are forced by steric constraints to occupy positions which lead to unnatural interactions with other atoms and to unusual bond distances and angles. Of particular interest are the structure and reactivity of molecules in which two relatively unreactive functional groups are forced to be very close together. It is expected that the enforced proximity will lead to unusual reactivity for the groups involved,and to unusual physical properties as well. In another part of this project, fragments of a recently discovered spherical C60 allotrope of carbon (other allotropes of carbon are diamond and graphite) will be prepared in order to understand how C60 may be formed from carbon fragments.