title: The effect of the regioisomeric naphthalimide acetylide ligands on the photophysical properties of N^N Pt(II) bisacetylide complexes.
abstract: Two N^N Pt(II) bis(acetylide) complexes Pt-1 and Pt-2 with regioisomeric amino NI acetylide ligands (L-1 and L-2, L-1 = 5-amino-4-ethylnaphthaleneimide; L-2 = 3-amino-4-ethylnaphthaleneimide) were prepared. The photophysical properties of the complexes were studied by steady state and time-resolved spectroscopy. The two complexes with regioisomeric ligands (Pt-1 and Pt-2) show different photophysical properties such as maximal absorption wavelength (485 nm vs. 465 nm), triplet excited state lifetimes (23.7 μs vs. 0.9 μs), and different solvent-polarity dependences of the emission properties. The absorption of the complexes is red-shifted as compared with the previously reported Pt(II) complex containing the 4-ethylnaphthaleneimide ligand. The two complexes with regioisomeric NI ligands were used as triplet photosensitizers for triplet-triplet annihilation (TTA) upconversion; drastically different upconversion quantum yields (15.0% vs. 1.1%) were observed. Our results are useful for designing new visible light-harvesting Pt(II) bisacetylide complexes as triplet photosensitizers which can be used in areas such as photocatalysis, photodynamic therapy and TTA upconversion.
authors: State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, E 208 Western Campus, 2 Ling-Gong Road, Dalian 116012, P.R. China. zhaojzh@dlut.edu.cn.
authors: Lianlian
authors: L
authors: Liu
authors: Caishun
authors: C
authors: Zhang
authors: Jianzhang
authors: J
authors: Zhao