Effects of Heteroatoms on Aromatic π-π Interactions: Benzene-Pyridine and Pyridine Dimer
Effects of Heteroatoms on Aromatic π-π Interactions: Benzene-Pyridine and Pyridine Dimer
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DOI：
10.1021/jp809062x
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发表时间：
2009-02-05
影响因子：
2.9
通讯作者：
Sherrill, C. David
中科院分区：
文献类型：
--
作者：
Hohenstein, Edward G.;Sherrill, C. David
杂原子存在于许多具有重要生物学意义的非共价化合物中。杂原子对pi-pi的影响。相互作用是通过高精度的量子化学计算来评估的，这两个最简单的例子是含有杂原子的芳香分子之间的相互作用，即苯-吡啶和吡啶二聚体。基准质量通过微扰三重态[CCSD(T)]估计的耦合团簇结合能在完整的基组极限附近计算。将其与苯晚餐进行比较，以确定杂原子的贡献。与苯相比，杂原子的存在降低了pi电子云的空间范围和吡啶的极化率。因此，与苯二聚体相比，苯-吡啶和吡啶二聚体中的分散、交换和诱导相互作用的大小通常较小。在几种构型中，苯-吡啶和吡啶的结合比苯抖动更强，与苯抖动相反，平行置换构型比T形构型更受欢迎。与杂原子平行的氢原子是更有效的“pi-氢键”供体，但含杂原子的芳环是较差的“pi-氢键”受体。
Heteroatoms are found in many noncovalent complexes which are of biological importance. The effect of heteroatoms on pi-pi. interactions is assessed via highly accurate quantum chemical computations for the two simplest cases of interactions between aromatic molecules containing heteroatoms, namely, benzene-pyridine and pyridine dimer. Benchmark quality estimated coupled-cluster through perturbative triples [CCSD(T)] binding energies are computed near the complete basis set limit. Comparisons to the benzene dinner are made to determine the contributions from heteroatoms. The presence of a heteroatom reduces the spatial extent of the pi-electron cloud and polarizability of pyridine as compared to benzene. As a result, the magnitude of the dispersion, exchange, and induction interactions in benzene-pyridine and pyridine dimer is generally reduced as compared to those for the benzene dimer. Benzene-pyridine and pyridine dinner bind more strongly than the benzene dither in several configurations, and in contrast to the benzene dither, parallel-displaced configurations can be significantly preferred over T-shaped configurations. Hydrogens para to a heteroatom are more effective "pi-hydrogen bond" donors, but aromatic rings with heteroatoms are worse "pi-hydrogen bond" acceptors.