Photophysics and bonding in neutral gold(I) organometallic complexes with an extended aurophilic supramolecular structure
Photophysics and bonding in neutral gold(I) organometallic complexes with an extended aurophilic supramolecular structure
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DOI：
10.1021/om060524t
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发表时间：
2007-05-07
期刊：
影响因子：
2.8
通讯作者：
Omary, Mohammad A.
中科院分区：
文献类型：
--
作者：
Elbjeirami, Oussama;Yockel, Scott;Omary, Mohammad A.
本工作代表了协同实验/计算研究的分子光谱和键合在Au（CO）Cl在溶液和固体状态。结晶固体的发光行为与Au（CO）Cl和相关的（RNC）AuCl络合物相似，它们同样以无限链堆叠，并且都表现出具有极大斯托克斯位移（（15-20）x 10（3）cm（-1））的橙红色非结构化磷光带。长亲金距离计算的基态（类似于3.2埃）收缩的磷光激发态（类似于2.6埃），证明准分子金-金共价键。的光谱数据表明磷光物种中的准分子Au-Au键的扩展超出两个相邻的分子在固态。控制在冷冻溶液中的浓度达到磷光带由于二聚体的物种，其发射能量高于（在蓝色区域）比那些结晶固体，并通过从头计算再现。本文的光谱研究结果表明，有关的超分子结构的预测信息，可以得到的发光行为。这一点以（1，1，3，3-Me 4 BuNC）AuCl晶体为例，其橙红色发光预示着一种延伸链超分子结构，后来在晶体学上得到了验证，因为发现分子以锯齿形链包装，具有交替的短（3.418埃）和长（4.433埃）亲金距离。溶液的Au（CO）Cl表现出负偏离比尔定律，较高的能量单体带的外观较低的能量带在高浓度下，由于分子的二聚化。含时密度泛函理论（TD-DFT）计算的单体和二聚体模型显示出良好的协议与实验光谱和占的主要吸收带。从头计算（CCSD（T）/cc-pVTZ）显示络合后nu（C矩形O）频率的蓝移接近23 cm（-1），从而为Au（CO）Cl的这种实验已知的异常蓝移提供了第一个计算证据。
This work represents a synergistic experimental/computational study of the molecular spectroscopy and bonding in Au(CO)Cl in solution and the solid state. The luminescence behavior for crystalline solids is similar for Au(CO)Cl and related (RNC)AuCl complexes that likewise stack in infinite chains, and both exhibit orange-red unstructured phosphorescence bands with extremely large Stokes shifts ((15-20) x 10(3) cm(-1)). The long aurophilic distances computed for the ground state (similar to 3.2 angstrom) are contracted in the phosphorescent excited state (similar to 2.6 angstrom), demonstrating excimeric Au-Au covalent bonds. The spectral data suggest phosphorescent species in which the excimeric Au-Au bonding is extended beyond two adjacent molecules in the solid state. Controlling the concentration in frozen solutions attains phosphorescent bands due to dimeric species for which the emission energies are higher (in the blue region) than those for crystalline solids and are reproduced by ab initio calculations. The spectral findings herein suggest that predictive information about the supramolecular structure may be obtained by the luminescnce behavior. This is exemplified by crystals of (1,1,3,3-Me4BuNC)AuCl, whose red-orange luminsecence anticipated an extended-chain supramolecular structure, which was later verified crystallographically, as the molecules were found to pack in zigzag chains with alternating short (3.418 angstrom) and long (4.433 angstrom) aurophilic distances. Solutions of Au(CO)Cl exhibit negative deviation from Beer's law for, higher-energy monomer bands with the appearance of lower-energy bands at high concentrations due to the dimerization of molecules. Time-dependent density-functional theory (TD-DFT) calculations for monomer and dimer models show good agreement with the experimental spectra and account for the major absorption bands. Ab initio calculations (CCSD(T)/cc-pVTZ) show a blue shift of similar to 23 cm(-1) in the nu(C rectangle O) frequency upon complexation, thus providing the first computational evidence of this anomalous blue shift known experimentally for Au(CO)Cl.