Naphthalimide Phosphorescence Finally Exposed in a Platinum(II) Diimine Complex
journal contributionposted on 02.08.2010, 00:00 by Huimin Guo, Maria L. Muro-Small, Shaomin Ji, Jianzhang Zhao, Felix N. Castellano
Room temperature (RT) phosphorescence is observed from a naphthalimide species for the first time in the square-planar chromophore Pt(dbbpy)(CCNI)2, where NI = N-butyl-4-ethynylnaphthalimide and dbbpy = 4,4′-di-tert-butyl-2,2′-bipyridine. The combination of static and time-resolved absorption and photoluminescence data is uniformly consistent with triplet-state photophysics localized on an appended CCNI unit following excitation into the low-energy absorption bands. This molecule features rather impressive long-lifetime, high-quantum-efficiency NI-based RT phosphorescence (τ = 124 μs; Φ = 0.215) centered at 621 nm, exemplifying how the platinum acetylide linkage strongly promotes intersystem crossing in the NI subunit, representative of a class of molecules whose excited states are typically dominated by singlet fluorescence.