Pan Qing-Jiang, Zhou Xin, Guo Yuan-Ru, Fu Hong-Gang, Zhang Hong-Xing
Laboratory of Physical Chemistry, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China.
Inorg Chem. 2009 Apr 6;48(7):2844-54. doi: 10.1021/ic801687w.
To understand their photocatalytic activity and application in luminescent materials, a series of gold and rhodium phosphine complexes (mononuclear Au(I)(PH(3))(2) (1) and Rh(I)(CNH)(2)(PH(3))(2) (2); homobinuclear Au(I)(2)(PH(2)CH(2)PH(2))(2) (3) and Rh(I)(2)(CNH)(4)(PH(2)CH(2)PH(2))(2) (4); heterobinuclear Au(I)Rh(I)(CNH)(2)(PH(2)CH(2)PH(2))(2) (5), [Au(I)Rh(I)(CNH)(2)(PH(2)NHPH(2))(2)Cl(2)] (6), and Au(I)Rh(I)(CNH)(2)(PH(2)NHPH(2))(2) (7); and oxidized derivatives Au(II)Rh(II)(CNH)(2)(PH(2)CH(2)PH(2))(2) (8), Au(II)Rh(II)(CNH)(2)(PH(2)NHPH(2))(2)Cl(3) (9), and Au(II)Rh(II)(CNH)(2)(PH(2)NHPH(2))(2) (10)) were investigated using ab initio methods and density functional theory. With the use of the MP2 method, the M-M' distances in 3-7 were estimated to be in the range of 2.76-3.02 A, implying the existence of weak metal-metal interaction. This is further evident in the stretching frequencies and bond orders of M-M'. The two-electron oxidation from 5-7 to their respective partners 8-10 was shown to mainly occur in the gold-rhodium centers. Experimental absorption spectra were well reproduced by our time-dependent density functional theory calculations. The metal-metal interaction results in a large shift of d(z(2)) --> p(z) transition absorptions in binuclear complexes relative to mononuclear analogues and concomitantly produces a low-lying excited state that is responsible for increasing visible-light photocatalytic activities. Upon excitation, the metal-centered transition and the metal-to-metal charge transfer strengthen the metal-metal interaction in triplet excited states for 3-6, while the promotion of electrons into the sigma*(d(z(2))) orbital weakens the interaction in 9.
为了解它们在发光材料中的光催化活性及应用，使用从头算方法和密度泛函理论对一系列金和铑膦配合物（单核Au(I)(PH(3))(2) (1) 和 Rh(I)(CNH)(2)(PH(3))(2) (2)；同双核Au(I)(2)(PH(2)CH(2)PH(2))(2) (3) 和 Rh(I)(2)(CNH)(4)(PH(2)CH(2)PH(2))(2) (4)；异双核Au(I)Rh(I)(CNH)(2)(PH(2)CH(2)PH(2))(2) (5)，[Au(I)Rh(I)(CNH)(2)(PH(2)NHPH(2))(2)Cl(2)] (6)，以及 Au(I)Rh(I)(CNH)(2)(PH(2)NHPH(2))(2) (7)；和氧化衍生物Au(II)Rh(II)(CNH)(2)(PH(2)CH(2)PH(2))(2) (8)，Au(II)Rh(II)(CNH)(2)(PH(2)NHPH(2))(2)Cl(3) (9)，以及 Au(II)Rh(II)(CNH)(2)(PH(2)NHPH(2))(2) (10)）进行了研究。使用MP2方法，估计3 - 7中的M - M'距离在2.76 - 3.02 Å范围内，这意味着存在弱的金属 - 金属相互作用。这在M - M'的伸缩频率和键级中更加明显。从5 - 7到它们各自对应的8 - 10的双电子氧化显示主要发生在金 - 铑中心。我们的含时密度泛函理论计算很好地再现了实验吸收光谱。金属 - 金属相互作用导致双核配合物中相对于单核类似物，d(z(2)) --> p(z)跃迁吸收发生大的位移，并随之产生一个低激发态，该激发态负责增加可见光光催化活性。激发后，金属中心跃迁和金属 - 金属电荷转移增强了3 - 6在三重激发态下的金属 -金属相互作用，而电子跃迁到σ*(d(z(2)))轨道则削弱了9中的相互作用。
