Toward Accurate Theoretical Thermochemistry of First Row Transition Metal Complexes

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• 作者：Wanyi Jiang ; Nathan J. DeYonker ; John J. Determan ; Angela K. Wilson
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：January 19, 2012
• 年：2012
• 卷：116
• 期：2
• 页码：870-885
• 全文大小：1117K
• 年卷期：v.116,no.2(January 19, 2012)
• ISSN：1520-5215

文摘

The recently developed correlation consistent Composite Approach for transition metals (ccCA-TM) was utilized to compute the thermochemical properties for a collection of 225 inorganic molecules containing first row (3d) transition metals, ranging from the monohydrides to larger organometallics such as Sc(C₅H₅)₃ and clusters such as (CrO₃)₃. Ostentatiously large deviations of ccCA-TM predictions stem mainly from aging and unreliable experimental data. For a subset of 70 molecules with reported experimental uncertainties less than or equal to 2.0 kcal mol^鈥?, regardless of the presence of moderate multireference character in some molecules, ccCA-TM achieves transition metal chemical accuracy of 卤3.0 kcal mol^鈥? as defined in our earlier work [J. Phys. Chem. A2007, 111, 11269鈥?1277] by giving a mean absolute deviation of 2.90 kcal mol^鈥? and a root-mean-square deviation of 3.91 kcal mol^鈥?. As subsets are constructed with decreasing upper limits of reported experimental uncertainties (5.0, 4.0, 3.0, 2.0, and 1.0 kcal mol^鈥?), the ccCA-TM mean absolute deviations were observed to monotonically drop off from 4.35 to 2.37 kcal mol^鈥?. In contrast, such a trend is missing for DFT methods as exemplified by B3LYP and M06 with mean absolute deviations in the range 12.9鈥?4.1 and 10.5鈥?1.0 kcal mol^鈥?, respectively. Salient multireference character, as demonstrated by the T₁/D₁ diagnostics and the weights (C₀²) of leading electron configuration in the complete active self-consistent field wave function, was found in a significant amount of molecules, which can still be accurately described by the single reference ccCA-TM. The ccCA-TM algorithm has been demonstrated as an accurate, robust, and widely applicable model chemistry for 3d transition metal-containing species with versatile bonding features.