The Fabrication of Multicomponent Oxide Films by Computer- Controlled Dual Ion Beam Sputter Deposition

这项有机和大分子化学项目的拨款为普林斯顿大学Robert Pascal博士的研究提供了支持。这项工作的重点是分子的结构，其中两个相对不活泼的分子实体被迫非常接近在一起。以这种方式被迫占据有限空间的原子群，在化学反应性和物理性质方面都表现出不寻常的行为。在一类靶分子中，甲基、胺基和铵基将被压在芳香环π电子云的外围附近；在第二类中，这些相同的基团将被投射到环的中心。在第一种情况下，“目标”苯基上的取代基将发生变化，从而产生相对富电子或缺电子的芳香环。官能团与环的相互作用程度应随这种电子取代而变化。在第二类化合物中，增加的相互作用不是通过改变芳香环取代基来实现的，而是通过合成一系列功能基团和环之间的距离被系统地缩短的化合物来实现的。通过平衡这些化合物的分子内应变力与环的亲核或亲电性，可以观察到这些基团之间存在部分键合的结构。这种结构可以解释为芳香化合物亲核和亲电取代反应中过渡态的类似物（它们本身是不可观察到的）。

This grant in the Organic and Macromolecular Chemistry Program provides support for the research of Dr. Robert Pascal, Jr., Princeton University. The work is focused on the structures of molecules in which two relatively unreactive molecular entities are forced to be very close together. Groups of atoms which are forced in this way to occupy a limited space have unusual behavior, both in terms of their chemical reactivity and their physical properties. In one class of target molecules, methine, amine, and ammonium groups will be pressed near the periphery of the pi electron clouds of aromatic rings; in a second class these same groups will be projected toward the center of the rings. In the first case, the substituents on the "target" phenyl groups will be varied to produce aromatic rings which are relatively electron-rich or electron-deficient. The extent of interaction of the functional groups with the ring should vary with this electronic substitution. In the second class of compounds, increased interactions will be achieved not by the variation of aromatic ring substituents, but by synthesizing a series of compounds in which the distance between the functional group and ring is systematically reduced. By balancing the forces due to intramolecular strain in these compounds with the degree of nucleophilicity or electrophilicity of the ring, structures may be observed with partial bonding between these groups. Such structures should be interpretable as analogs of transition states (which are not themselves observable) in the nucleophilic and electrophilic substitution reactions of aromatic compounds.