The effect of the regioisomeric naphthalimide acetylide ligands on the photophysical properties of N^N Pt(ii) bisacetylide complexes.

Dalton transactions (Cambridge, England : 2003)

PubMedID: 25078493

Liu L, Zhang C, Zhao J. The effect of the regioisomeric naphthalimide acetylide ligands on the photophysical properties of N^N Pt(ii) bisacetylide complexes. Dalton Trans. 2014;.
Two N^N Pt(ii) bis(acetylide) complexes and with regioisomeric amino NI acetylide ligands ( and , = 5-amino-4-ethylnaphthaleneimide; = 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 ( and ) 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.