Density-Functional Theory Investigation of the Geometric, Energetic, and Optical Properties of the Cobalt(II)tris(2,2'-bipyridine) Complex in the High-Spin and the Jahn-Teller Active Low-Spin States
详细信息 查看全文
- 作者：Alfredo Vargas ; Mohamed Zerara ; Elmars Krausz ; Andreas Hauser ; Laté ; vi Max Lawson Daku
- 刊名：Journal of Chemical Theory and Computation
- 出版年：2006
- 出版时间：September 2006
- 年：2006
- 卷：2
- 期：5
- 页码：1342 - 1359
- 全文大小：794K
- 年卷期：v.2,no.5(September 2006)
- ISSN：1549-9626
文摘
State-of-the-art generalized gradient approximation (GGA) (PBE, OPBE, RPBE,OLYP, and HCTH), meta-GGA (VSXC and TPSS), and hybrid (B3LYP, B3LYP*, O3LYP, andPBE0) functionals are compared for the determination of the structure and the energetics of theD3 [Co(bpy)3]2+ complex in the 4A2 and 4E trigonal components of the high-spin 4T1g(
)state and in the low-spin 2E state of octahedral 2Eg(
) parentage. Their comparison extendsalso to the investigation of the Jahn-Teller instability of the 2E state through the characterizationof the extrema of C2 symmetry of this spin state's potential energy surface. The results obtainedfor [Co(bpy)3]2+ in either spin manifold are very consistent among the functionals used and arein good agreement with available experimental data. The functionals, however, perform verydifferently with respect to the spin-state energetics because the calculated values of the high-spin/low-spin energy difference 
vary between -3212 and 3919 cm-1. Semilocal functionals tend to give too large 
values and thus fail to correctly predict the high-spin state asthe ground state of the isolated complex, while hybrid functionals tend to overestimate the stabilityof the high-spin state with respect to the low-spin state. Reliable results are, however, obtainedwith the OLYP, HCTH, B3LYP*, and O3LYP functionals which perform best for the descriptionof the isolated complex. The optical properties of [Co(bpy)3]2+ in the two spin states are alsoanalyzed on the basis of electronic excitation calculations performed within time-dependentdensity functional response theory. The calculated absorption and circular dichroism spectraagree well with experimental results.
)state and in the low-spin 2E state of octahedral 2Eg( ) parentage. Their comparison extendsalso to the investigation of the Jahn-Teller instability of the 2E state through the characterizationof the extrema of C2 symmetry of this spin state's potential energy surface. The results obtainedfor [Co(bpy)3]2+ in either spin manifold are very consistent among the functionals used and arein good agreement with available experimental data. The functionals, however, perform verydifferently with respect to the spin-state energetics because the calculated values of the high-spin/low-spin energy difference vary between -3212 and 3919 cm-1. Semilocal functionals tend to give too large values and thus fail to correctly predict the high-spin state asthe ground state of the isolated complex, while hybrid functionals tend to overestimate the stabilityof the high-spin state with respect to the low-spin state. Reliable results are, however, obtainedwith the OLYP, HCTH, B3LYP*, and O3LYP functionals which perform best for the descriptionof the isolated complex. The optical properties of [Co(bpy)3]2+ in the two spin states are alsoanalyzed on the basis of electronic excitation calculations performed within time-dependentdensity functional response theory. The calculated absorption and circular dichroism spectraagree well with experimental results.