Wei Yuanxin, Li Qingzhong, Li Wenzuo, Cheng Jianbo, McDowell Sean A C
The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, People's Republic of China.
Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill Campus, Barbados.
Phys Chem Chem Phys. 2016 Apr 28;18(16):11348-56. doi: 10.1039/c6cp00551a.
Ab initio MP2/aug-cc-pVTZ calculations were performed to investigate the pnicogen-bonded complexes of PyZX2 (Py = pyridine, Z = P and As, X = H and F) and their protonated analogues. The selected Lewis bases include H2S, PH3, H2O, NH3, and H2CO. The relative stability of pnicogen-bonded complexes is related to the nature of PyZX2 and bases. When the nitrogen atom of the pyridine ring in PyZX2 is protonated, the protonated complexes are more stabilized than their neutral counterparts, with the interaction energies increased by 8.5-34.6 kJ mol(-1) and the binding distances shortened by 0.050-0.574 Å. Protonation strengthens the pnicogen bond, from a weak interaction to one of moderate strength. In the neutral complexes of PyZX2 and H2O, the formation of a N···H-O hydrogen bond is favorable compared to the pnicogen bond. Such inclination is more prominent in the complexes of protonated PyZX2 and NH3. In H2O···PyZX2···H2O, pnicogen bonding is strengthened by hydrogen bonding due to positive synergistic effects; however, in NH3···H(+)-PyZX2···NH3, pnicogen bonding is weakened by hydrogen bonding due to negative synergistic effects.
进行了从头算MP2/aug-cc-pVTZ计算，以研究PyZX2（Py = 吡啶，Z = P和As，X = H和F）及其质子化类似物的氮族元素键合配合物。所选的路易斯碱包括H2S、PH3、H2O、NH3和H2CO。氮族元素键合配合物的相对稳定性与PyZX2和碱的性质有关。当PyZX2中吡啶环的氮原子被质子化时，质子化配合物比其中性对应物更稳定，相互作用能增加8.5 - 34.6 kJ mol(-1)，结合距离缩短0.050 - 0.574 Å。质子化增强了氮族元素键，从弱相互作用增强为中等强度的相互作用。在PyZX2与H2O的中性配合物中，与氮族元素键相比，形成N···H - O氢键更有利。这种倾向在质子化的PyZX2与NH3的配合物中更为突出。在H2O···PyZX2···H2O中，由于正协同效应，氢键增强了氮族元素键；然而，在NH3···H(+)-PyZX2···NH3中，由于负协同效应，氢键削弱了氮族元素键。
