Buda Corneliu, Kazi Abul B, Dinescu Adriana, Cundari Thomas R
Department of Chemistry, University of North Texas, Denton, Texas 76203, USA.
J Chem Inf Model. 2005 Jul-Aug;45(4):965-70. doi: 10.1021/ci050050t.
Several hypotheses to elucidate the linkage isomer preference of the thiocyanate (SCN(-)) ion have been offered. For complexes with small coordination numbers (i.e., 1 and 2) and groups 11 (Cu-triad) and 12 (Zn-triad) metals, different levels of theory and a variety of basis sets have been employed to study linkage isomerism. Similar results are obtained for all density functionals tested, pure and hybrid. Overall, good agreement, vis-à-vis experimentally identified linkage isomers, is achieved for ab initio techniques, whereas semiempirical quantum mechanical methods show a bias toward S-ligated isomers. Despite the seeming ease for the a priori prediction of the most stable thiocyanate isomers using acid/base principles, this research highlights the sensitivity of quantitative calculations of transition-metal linkage isomerism to the choice of basis set and electron correlation, particularly with post-Hartree-Fock treatments.
为解释硫氰酸根离子（SCN⁻）的键连异构体偏好，人们提出了几种假说。对于配位数较小（即1和2）且与第11族（铜族）和第12族（锌族）金属形成的配合物，已采用不同层次的理论和多种基组来研究键连异构现象。对于所测试的所有密度泛函（纯泛函和杂化泛函），都得到了相似的结果。总体而言，与实验鉴定的键连异构体相比，从头算技术取得了良好的一致性，而半经验量子力学方法则表现出偏向于硫配位异构体的倾向。尽管使用酸碱原理似乎可以很容易地先验预测最稳定的硫氰酸根异构体，但这项研究突出了过渡金属键连异构定量计算对基组选择和电子相关的敏感性，特别是在进行后哈特里 - 福克处理时。
