Two bisthienylethene–Ir(iii) complexes showing acid/base-induced structural transformation and on–off luminescence switching in solution

Abstract

Complexes [Ir(dfppy)2(pbdtiH)](PF6)·2CHCl3 (1-H) and [Ir(dfppy)2(pbdti)] (1) were synthesized by the reaction of bisthienylethene pbdtiH and an [Ir(dfppy)2Cl]2 dimer under neutral and basic conditions, respectively. Thus, the {Ir(dfppy)2}(+) unit is coordinated by pbdtiH in 1-H, and by pbdti(-) in 1, which are confirmed by their crystal structures. The structures of 1-H and 1 could be interconverted in solution, upon alternately adding NEt3 and TFA, thus resulting in reversible luminescence switching between the on-state of 1-H and the off-state of 1 at room temperature. In addition, both 1-H and 1 show solid-state luminescence, with a broad emission at 534 nm and 525 nm, respectively. The free pbdtiH ligand shows photochromic behavior in CH2Cl2 solution. However, no photochromism has been observed in 1-H and 1, indicating that the coordination of the pbdtiH/pbdti(-) ligand to the {Ir(dfppy)2}(+) unit could suppress their photochromic behaviors.

Coordination Polymer Gels with Modular Nanomorphologies, Tunable Emissions, and Stimuli-Responsive Behavior Based on an Amphiphilic Tripodal Gelator

“…Emission spectrum of the sol shows a broad emission at 440 nm, attributed to the free L (Figure b). Diffusion of TFA vapor in the CPG2 gel matrix results in the protonation of the N tpy atoms. , The protonated terpyridine (tpyH + ) shows a lower affinity for the Ln III ions due to increased electrostatic repulsion. Hence Ln–N tpy coordination bonds break, and gel converts to sol.…”

Light‐Controllable Ionic Conductivity in a Polymeric Ionic Liquid

“…[25][26][27][28] Moreover,the photoinduced rearrangement of the p bond in the bridging imidazolium ring can be used to control the electronic properties and chemistry of the imidazolium ring. Photochromic diarylethenes bearing an imidazolium ring have found applications in different areas such as photoswitchable organocatalysts, [29][30][31] chemical sensors, [32] and as anew type of Lewis acid. [33] Forexample,the Bielawski group used aD AE-based organocatalyst with photoswitchable electron density at the C2 position of the imidazole ring in N-heterocyclic carbene adducts to regulate the rate of transesterification reactions.…”

Light‐Controllable Ionic Conductivity in a Polymeric Ionic Liquid

“…Moreover, the photoinduced rearrangement of the π bond in the bridging imidazolium ring can be used to control the electronic properties and chemistry of the imidazolium ring. Photochromic diarylethenes bearing an imidazolium ring have found applications in different areas such as photoswitchable organocatalysts, chemical sensors, and as a new type of Lewis acid . For example, the Bielawski group used a DAE‐based organocatalyst with photoswitchable electron density at the C2 position of the imidazole ring in N ‐heterocyclic carbene adducts to regulate the rate of transesterification reactions .…”