Yutaka Tomona, Mori Ichiro, Kurihara Masato, Mizutani Jun, Tamai Naoto, Kawai Tsuyoshi, Irie Masahiro, Nishihara Hiroshi
Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Japan.
Inorg Chem. 2002 Dec 30;41(26):7143-50. doi: 10.1021/ic0260116.
Pt(II) complexes with a terpyridylazobenzene ligand (tpyAB) were newly synthesized, and their photoluminescence properties by trans-cis isomerization of the azo moiety were investigated. In these complexes, upon excitation with 366-nm light in polar solvents such as DMF, DMSO, and propylene carbonate, trans-to-cis isomerization with significant UV-vis spectral changes occurred almost completely. Cis-to-trans isomerization was observed both by irradiation with visible light and by heat. The reduction peaks due to the terpyridine and the azo group in the cyclic voltammograms of the Pt complexes were shifted in the positive direction by trans-to-cis isomerization. Emission spectral changes due to trans-cis isomerization were observed for both the tpyAB and the Pt complexes. The significant differences in the emission properties of the complex compared to tpyAB include the observation that both the excitation and emission wavelengths were shifted to lower energy, located in the visible region. Moreover, the change in emission intensity between the trans and cis forms was more significant upon excitation with UV light, because the trans form of the complexes showed absolutely no emission. Accordingly, the azobenzene-conjugated Pt(II) terpyridine complexes promise to be doubly photofunctional materials, showing complete off-on switching of emission linked to the trans-cis conformation change.
新合成了带有三联吡啶偶氮苯配体（tpyAB）的铂（II）配合物，并研究了其通过偶氮部分的反式-顺式异构化产生的光致发光特性。在这些配合物中，在诸如N，N-二甲基甲酰胺、二甲基亚砜和碳酸亚丙酯等极性溶剂中用366 nm光激发时，会发生几乎完全的伴有显著紫外-可见光谱变化的反式到顺式异构化。通过可见光照射和加热都观察到了顺式到反式异构化。铂配合物的循环伏安图中由于三联吡啶和偶氮基团产生的还原峰通过反式到顺式异构化向正方向移动。对于tpyAB和铂配合物都观察到了由于反式-顺式异构化引起的发射光谱变化。与tpyAB相比，该配合物发射特性的显著差异包括观察到激发波长和发射波长都移至较低能量，位于可见光区域。此外，在用紫外光激发时，反式和顺式形式之间的发射强度变化更为显著，因为配合物的反式形式完全不发射。因此，偶氮苯共轭的铂（II）三联吡啶配合物有望成为双光功能材料，显示出与反式-顺式构象变化相关的发射的完全关-开切换。
