Qaiser Fatmi M, Hofer Thomas S, Randolf Bernhard R, Rode Bernd M
Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 52a, A-6020, Innsbruck, Austria.
Phys Chem Chem Phys. 2006 Apr 14;8(14):1675-81. doi: 10.1039/b518223a. Epub 2006 Mar 13.
A model complex of the hexahydrated zinc(ii) cation with one water substituted by ammonia in aqueous solution has been studied by hybrid ab initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) at the double-zeta Hartree-Fock (HF) quantum mechanical level. The first solvation shell, consisting of 5 + 1 ligand(s) at mean distances of 2.2 and 2.1 A, respectively, from the Zn(ii) ion, was found to remain stable with respect to exchange processes within the simulation time. The labile second shell consists on average of approximately 19 water molecules. For structural elucidation of the pentaaquozinc(ii) amine complex in aqueous solution several data sets such as radial distribution functions (RDF), coordination number distributions (CND) and different angular distributions (ADF, tilt and theta angle) were employed. Dynamics were characterised by the ligands' mean residence time (MRT), ion-ligand stretching frequencies and the vibrational and librational motions of water ligands. The labile second shell's MRT value decreases upon introduction of one NH(3) ligand to 7.2 ps from the 10.5 ps observed for the hexaaquozinc(ii) complex.
通过在双ζ哈特里 - 福克（HF）量子力学水平上的混合从头算量子力学/分子力学（QM/MM）分子动力学（MD），研究了水溶液中一个水分子被氨取代的六水合锌（II）阳离子的模型配合物。发现由分别距Zn（II）离子平均距离为2.2和2.1 Å的5 + 1个配体组成的第一溶剂化层在模拟时间内相对于交换过程保持稳定。不稳定的第二溶剂化层平均由大约19个水分子组成。为了阐明水溶液中五水合锌（II）胺配合物的结构，采用了几个数据集，如径向分布函数（RDF）、配位数分布（CND）和不同的角分布（ADF、倾斜角和θ角）。动力学通过配体的平均停留时间（MRT）、离子 - 配体伸缩频率以及水配体的振动和平动运动来表征。引入一个NH₃配体后，不稳定的第二溶剂化层的MRT值从六水合锌（II）配合物观察到的10.5 ps降至7.2 ps。
