Lin Jian, Wu Kechen, Zhang Mingxin
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Graduate School of Chinese Academy of Sciences, Fujian 350002, China.
J Comput Chem. 2009 Oct;30(13):2056-63. doi: 10.1002/jcc.21200.
The electronic excitations and the static first hyperpolarizability of three typical transition metal (TM) aromatic carbonyl complexes, two tungsten pentacarbonyl derivatives (W(CO)5L, L = Py and PyCHO) and one chromium tricarbonyl arene derivative (Cr(CO)3Bz, Bz = benzene), have been theoretically studied by a variety of density functional methods. The assessments reveal that most of the conventional DFT methods including local density approximation, generalized gradient approximation (GGA), and the various kinds of hybrid exchange-correlation (xc) methods present the first hyperpolarizabilities of these TM-containing molecules with large deviations from the experiments. A one-parameter hybrid xc functional is introduced by using the Perdew-Wang 1991 gradient-corrected correlation functional (PW91) and the Barone's-modified PW91 exchange functional (mPW). The ratio between the exact and the density functional exchange is determined to be 0.40 by the adiabatic connection method. The application of the new hybrid functional to the three organometallic carbonyl molecules results in the satisfactory agreement between the calculated first hyperpolarizabilities and the experimental ones. The second-order nonlinear optical properties of the three organometallic complexes are addressed to the metal-to-ligand charge transfers, and the extended pi-delocalization ligands benefit the enhancement of the first hyperpolarizability.
采用多种密度泛函方法对三种典型的过渡金属（TM）芳香羰基配合物、两种五羰基钨衍生物（W(CO)5L，L = 吡啶和吡啶甲醛）以及一种三羰基铬芳烃衍生物（Cr(CO)3Bz，Bz = 苯）的电子激发和静态第一超极化率进行了理论研究。评估结果表明，包括局域密度近似、广义梯度近似（GGA）以及各种杂化交换相关（xc）方法在内的大多数传统密度泛函方法给出的这些含TM分子的第一超极化率与实验值存在较大偏差。通过使用Perdew-Wang 1991梯度校正相关泛函（PW91）和Barone修正的PW91交换泛函（mPW）引入了一种单参数杂化xc泛函。通过绝热连接方法确定精确交换与密度泛函交换的比例为0.40。将新的杂化泛函应用于这三种有机金属羰基分子，计算得到的第一超极化率与实验值之间取得了令人满意的一致性。这三种有机金属配合物的二阶非线性光学性质归因于金属到配体的电荷转移，并且扩展的π离域配体有利于第一超极化率的增强。
