Pnicogen Bonds between X = PH3 (X = O, S, NH, CH2) and Phosphorus and Nitrogen Bases
Pnicogen Bonds between X = PH3 (X = O, S, NH, CH2) and Phosphorus and Nitrogen Bases
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DOI：
10.1021/jp411623h
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发表时间：
2014-02-27
影响因子：
2.9
通讯作者：
Del Bene, Janet E.
中科院分区：
文献类型：
--
作者：
Alkorta, Ibon;Sanchez-Sanz, Goar;Del Bene, Janet E.
已进行从头算 MP2/aug'-cc-pVTZ 计算，以研究酸 O=PH3、S= PH3、HN=PH3 和 H2C=PH3 与碱 NH3、NCH、N-2、PH3 和 PCH 之间形成的 pnicogen 键合络合物。所有氮和磷碱基形成络合物，其中碱基是孤对电子供体。涉及较强碱 NH3、NCH 和 PH3 的络合物的结合能在酸之间有所不同，但与较弱碱的络合物的结合能则不然。这些络合物通过从 N 或 P 的孤对电子轨道到 X=PH3 的 sigma*P=A 轨道的电荷转移而稳定，其中 A 是直接与 P 键合的 X 原子。PCH 还与作为 sigma*P=A 轨道的 pi 电子供体的 X=PH3 酸形成络合物。 pi配合物的结合能和电荷转移能大于PCH为孤对供体的配合物。无论 P 上的正电荷在复合物形成时增加、减少还是保持不变，复合物中 P-31 的化学屏蔽相对于相应的单体都会减少。 (1P)J(P-P) 值与相应的 P N 和 P P 距离作为碱基性质的函数最相关。 'AP A) 值与 P-A 距离无关。相反，(1)J(P-O)、(1)J(P-S) 和 (1)J(P-N) 的绝对值在络合时减小。 (1)J(P-A) 值的降低与复合结合能的增加呈线性相关。相反，(1)J(P-C) 值在络合时增加，并与结合能的增加线性相关。
Ab initio MP2/aug'-cc-pVTZ calculations have been carried out to investigate the pnicogen bonded complexes formed between the acids O=PH3, S= PH3, HN=PH3, and H2C=PH3 and the bases NH3, NCH, N-2, PH3, and PCH. All nitrogen and phosphorus bases form complexes in which the bases are lone pair electron donors. The binding energies of complexes involving the stronger bases NH3, NCH, and PH3 differentiate among the acids, but the binding energies of complexes with the weaker bases do not. These complexes are stabilized by charge transfer from the lone pair orbital of N or P to the sigma*P=A orbital of X=PH3, where A is the atom of X directly bonded to P. PCH also forms complexes with the X=PH3 acids as a pi electron donor to the sigma*P=A orbital. The binding energies and the charge-transfer energies of the pi complexes are greater than those of the complexes in which PCH is a lone pair donor. Whether the positive charge on P increases, decreases, or remains the same upon complex formation, the chemical shieldings of P-31 decrease in the complexes relative to the corresponding monomers. and (1P)J(P-P) values correlate best with the corresponding P N and P P distances as a function of the nature of the base. 'AP A) values do not correlate with P-A distances. Rather, the absolute values of (1)J(P-O), (1)J(P-S), and (1)J(P-N) decrease upon complexation. Decreasing (1)J(P-A) values correlate linearly with increasing complex binding energies. In contrast, (1)J(P-C) values increase upon complexation and correlate linearly with increasing binding energies.