Al-Yasari Ahmed, El Moll Hani, Purdy Ryan, Vincent Kevin B, Spence Philip, Malval Jean-Pierre, Fielden John
School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
Phys Chem Chem Phys. 2021 May 28;23(20):11807-11817. doi: 10.1039/d0cp06610a. Epub 2021 May 14.
A family comprising seven arylimido-polyoxometalate (POM) hybrid chromophores (three of which are new), with linear dipolar, C and linear centrosymmetric geometries have been synthesised and studied by electronic absorption spectroscopy, electrochemistry, Z-scans (two photon absorption, TPA) and computation (DFT/TD-DFT). These reveal that POM acceptor units are an effective basis for TPA materials: the centrosymmetric bis-POM chromophores produce significant cross sections (δ up to 82 GM) from a single aryl bridge, a similar performance to larger dipolar π-systems combining carbazole or diphenylamino donors with the imido-POM acceptor. DFT/TD-DFT calculations indicate strong communication between POM and organic components is responsible for the linear and non-linear optical behaviour of these compounds, while electrochemical measurements reveal class II mixed valence behaviour resulting from an interplay of through-bond and through-space effects.
合成了一个由七个芳基亚胺基多金属氧酸盐（POM）杂化发色团组成的家族（其中三个是新的），其具有线性偶极、C型和线性中心对称几何结构，并通过电子吸收光谱、电化学、Z扫描（双光子吸收，TPA）和计算（DFT/TD-DFT）进行了研究。这些结果表明，POM受体单元是TPA材料的有效基础：中心对称的双POM发色团从单个芳基桥产生显著的截面（δ高达82 GM），其性能与将咔唑或二苯胺供体与亚胺基-POM受体结合的较大偶极π体系相似。DFT/TD-DFT计算表明，POM与有机成分之间的强相互作用是这些化合物线性和非线性光学行为的原因，而电化学测量揭示了由键间和空间效应相互作用导致的II类混合价行为。
