A Theoretical Study of Compounds Containing Heavier Main Group 14 and 15 Atoms

我们已经进行了从头计算的化合物的骨架是由较重的主族14（Si，Ge，Sn，和Pb）和14族（P，As，Sb，和Bi）原子的碳化合物不具有的新性能的期望。一个主要的关注点是表征与碳骨架相比更重的原子骨架，并预测在新材料设计中有用的一般规则。第14族中的原子不能形成双键，因为它们变得更重，因为形成杂化轨道的倾向较低。相反，较重的第15族原子在形成双键方面并不是特别不利。芳香族和反芳香族化合物。碳化学中建立的芳香性和反芳香性等概念，在应用于苯和环丁二烯的较重类似物时，价值有限。取代基在芳香族或反芳香族化合物的设计中起着重要的作用。当骨架碳被较重的原子取代时，多环碳化合物的应变能大大降低。这一性质值得注意，因为它有助于设计张力较小的多环笼化合物。一些有趣的性质，较重的原子之间的键建议，这是没有看到在碳化学。

We have carried out ab initio calculations of the compounds whose skeletons are made of the heavier main group 14 (Si, Ge, Sn, and Pb) and group 14 (P, As, Sb, and Bi) atoms in the expectation of novel properties which carbon compounds do not have. A primary concern is to characterize the heavier atom skeletons compared with carbon skeletons and predict a general rule which is useful in the design of new material.Doubly Bonded Compounds. The atoms in group 14 are incapable of forming double bonds as they become heavier because of a lower tendency to form hybrid orbitals. In contrast, the tendency of the heavier group 15 atoms is not especially unfavorable in forming double bonds.Aromatic and Antiaromatic Compounds. Concepts such as aromaticity and antiaromaticity established in carbon chemistry are of limited value when they are applied to the heavier analogues of benzene and cyclobutadiene. Substituents play a important role in designing aromatic or antiaromatic compounds.Polycyclic Compounds. The strain energies of polycyclic carbon compounds are greatly decreased when the skeletal carbons are replaced by the heavier atoms. This property is noteworthy since it is useful for designing less strained polycyclic cage compounds.Unusually Short Phantom Bonds. Several interesting properties of bonding between the heavier atoms are suggested which is not seen in carbon chemistry.