C3-symmetric, dendritic structured, chiral chromophores: synthesis and linear and nonlinear optical properties

新型多功能分子材料的合成是当前合成化学领域的挑战之一。这个建议正好应对了挑战。一边是C3对称的、偶极的、树突状结构的发色团，它们具有配位的介质和顺磁性金属原子，它们的第一超极化率将被测定。另一方面，为了研究二次谐波产生（SHG-CD）和磁化诱导倍频（MSHG）以及磁手性二色性，这些化合物必须是手性的。此外，作为另一种磁诱导效应，这些配合物的法拉第旋转将被研究。金属原子通过螯合配位固定了NLO发色团的螺旋手性排列，顺磁性增强了磁效应。对于螯合配位，偶极单链NLO发色团由2,2'-联吡啶（bipy）和2-苯基吡啶（ppy）修饰。在5′和5′位置上用给电子和接受电子的功能取代螯合配体对于保证供体和受体之间的通信和保证偶极性是特别重要的。第一个超极化率beta将由我们自己的超瑞利散射来确定，这是DFG为另一个项目提供的。HRS装置配备了Nd:YAG激光器和OPO，可以调整刺激波长（1064 - 1500 nm）。关于SHG-CD和磁感应效应的测量将与比利时鲁汶大学的Verbiest小组密切合作进行。

The synthesis of new multifunctional molecular materials is one of the current challenges in synthetic chemistry. This proposal just meets the challenge. On the one side C3 symmetric, dipolar, dendritic structured chromophores with coordinated dia- and paramagnetic metal atoms will be synthesized and their first hyperpolarizability beta will be determined. On the other side these compounds should be chiral in order to study the circulardichroism depending on the second harmonic generation (SHG-CD) and magnetization induced frequency doubling (MSHG) as well as magnetochiral dichroism. Additionally, as another magnetically induced effect, the Faraday rotation of these complexes will be investigated. The metal atoms fix a helical chiral arrangement of the NLO chromophores through chelating coordination and the paramagnetism is believed to enhance the magnetic effects. For the chelating coordination the dipolar single strand NLO chromophore is decorated with 2,2'-bipyridine (bipy) and 2-phenylpyridine (ppy). The substitution of the chelating ligands with electron donating and electron accepting functions in 5 and 5'-position is of particular importance to warrant the communication between the donor and acceptor, and to warrant the dipolar character. The first hyperpolarizability beta will be determined by hyper-Rayleigh scattering with our own set-up, which was provided from the DFG for another project. The HRS set-up is equipped with a Nd:YAG laser and an OPO, which allows to tune the stimulating wavelength (1064 - 1500 nm). Measurements concerning the SHG-CD and the magnetically induced effects will be performed in close collaboration with Verbiest's group at the University of Leuven (Belgium).