Kim Joonghan, Kim Tae Kyu, Kim Jangbae, Lee Yoon Sup, Ihee Hyotcherl
Department of Chemistry and School of Molecular Science (BK21), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Republic of Korea.
J Phys Chem A. 2007 May 31;111(21):4697-710. doi: 10.1021/jp066081o. Epub 2007 May 9.
Cr(CO)n (n = 1-6) systems were studied for all possible spin states using density functional and high-level ab initio methods to provide a more complete theoretical understanding of the structure of species that may form during ligand dissociation of Cr(CO)6. We carried out geometry optimizations for each system and obtained vibrational frequencies, sequential bond dissociation energies (BDE), and total CO binding energies. We also compared the performance of various DFT functionals. Generally, the ground states of Cr(CO)6, Cr(CO)5, and Cr(CO)4, whose spin multiplicity is a singlet, are in good agreement with both previous theoretical results and currently available experimental data. Calculations on Cr(CO)3, Cr(CO)2, and CrCO provide new findings that the ground state of Cr(CO)3 might be a quintet with C2v symmetry instead of a singlet with C3v symmetry, and the ground state of Cr(CO)2 is not a linear quintet, as suggested by previous DFT calculations, but rather a linear septet. We also found that nonet states of Cr(CO)2 and CrCO display partial C-O bond breakage.
使用密度泛函和高水平从头算方法研究了Cr(CO)n（n = 1 - 6）体系的所有可能自旋态，以便更全面地从理论上理解在Cr(CO)6配体解离过程中可能形成的物种结构。我们对每个体系进行了几何优化，并获得了振动频率、顺序键解离能（BDE）和总CO结合能。我们还比较了各种DFT泛函的性能。一般来说，自旋多重度为单重态的Cr(CO)6、Cr(CO)5和Cr(CO)4的基态与先前的理论结果和目前可得的实验数据都吻合得很好。对Cr(CO)3、Cr(CO)2和CrCO的计算提供了新的发现，即Cr(CO)3的基态可能是具有C2v对称性的五重态，而不是具有C3v对称性的单重态，并且Cr(CO)2的基态不是如先前DFT计算所暗示的线性五重态，而是线性七重态。我们还发现Cr(CO)2和CrCO的九重态显示出部分C - O键断裂。
