An interesting luminescent mechanochromic 9-anthryl gold(I) isocyanide complex has been reported. Its polymorphs perform different luminescent properties and their luminescence spectra are both bathochromically shifted upon grinding. This curious phenomenon arouses our interest to disclose how intermolecular weak interactions tune the luminescent properties from a theoretical perspective. The QM/MM approach was employed through all the calculations to consider the sensitive dependence of geometric and electronic structures on intermolecular interactions. The results show that the monomer is enough to describe the fluorescence of α phase crystal and its almost perpendicular dihedral angle between anthracene unit and phenyl ring leads to the forbidden emission from the first excited state which breaks Kasha’s rule. While the larger spin orbital coupling between excited singlet and triplet states of dimer makes key contribution to the phosphorescence emission of β phase crystal which is related with its near planar structure and stronger intermolecular interactions. Moreover, multiple intermolecular interactions including strong aurophilic interaction were found to be responsible for the red-shifted luminescence of the γ phase crystal. Therefore, the distinct molecular structures and intermolecular interactions codetermine the different photophysical processes in these crystal phases.

已经报道了一种有趣的发光的机械变色9-蒽金（I）异氰化物配合物。它的多晶型物具有不同的发光特性，并且它们的发光光谱在研磨时都发生了红移。这种奇怪的现象引起了我们的兴趣，即从理论的角度揭示分子间的弱相互作用如何调节发光性质。所有计算均采用QM / MM方法，以考虑几何和电子结构对分子间相互作用的敏感依赖性。结果表明，该单体足以描述α的荧光相晶体及其在蒽单元与苯环之间几乎垂直的二面角导致从第一激发态的禁发光，这打破了卡沙法则。虽然二聚体的激发单重态和三重态之间更大的自旋轨道耦合对β相晶体的磷光发射起关键作用，这与β相晶体的近平面结构和更强的分子间相互作用有关。此外，发现多种分子间相互作用，包括强亲液相互作用，是造成γ相晶体红移发光的原因。因此，不同的分子结构和分子间的相互作用共同决定了这些晶相中不同的光物理过程。