Photophysical Properties of Cyclometalated Platinum(II) Diphosphine Compounds in the Solid State and in PMMA Films

Abstract

Platinum­(II) compounds were synthesized with both chelate cyclometalated ligands and chelate diphosphine ligands. The cyclometalated ligands include phenylpyridine and a benzothiophene-containing ligand. The three new benzothiophene compounds were characterized by nuclear magnetic resonance (NMR) spectroscopy, high-resolution mass spectrometry (HR-MS), and photophysical measurements. In the case of one compound, L1-DPPM, the structure was determined by single crystal X-ray diffraction. The structural coherence of the noncrystalline emissive solid state was measured by X-ray total scattering real space pair distribution function analysis. Quantum yield values of all of the platinum compounds measured in the solid state and in PMMA films were much greater than in solution.

Luminescent Anionic Cyclometalated Organoplatinum (II) Complexes with Terminal and Bridging Cyanide Ligand: Structural and Photophysical Properties

“…The complexes are not emissive in fluid solution at room temperature, probably due to an easy quenching process of the excited states caused by (a) molecular motions in the solution, (b) collisional interactions with solvent molecules, (c) energy transfer to triplet 3 O 2 facilitated by the long lifetimes, or (d) thermally activated deactivation through the 3 MC excited state . However, all complexes exhibit strong luminescence in the rigid matrix (glassy solution and PS) and in the solid state with lifetimes in the range of microsecond (μs) regime, confirming the involvement of the triplet excited state in the emission. , The potassium ( 1 – 3 ) and tetrabutylammonium derivatives ( 4 – 6 ) exhibit similar structured emission bands in glassy solution and PS film, the latter being slightly red-shifted, suggesting some interactions between relatively well-separated ions. The emissions in glassy solutions do not reveal any systematic dependence on the solvent (Figure S19 for 6 and 9 ).…”

“…In 7 and 8, the HOMOs are delocalized on both Pt-cyclometalating units with contribution of the cyanide (C^N/Pt/CN − : 55/39/5% bzq/ Pt/CN − 7; 46/47/6% ppy/Pt/CN − 8), while in 9, the HOMO 73 However, all complexes exhibit strong luminescence in the rigid matrix (glassy solution and PS) and in the solid state with lifetimes in the range of microsecond (μs) regime, confirming the involvement of the triplet excited state in the emission. 74,75 The potassium (1−3) and tetrabutylammonium derivatives (4−6) exhibit similar structured emission bands in glassy solution and PS film, the latter being slightly red-shifted, suggesting some interactions between relatively well-separated ions. The emissions in glassy solutions do not reveal any systematic dependence on the solvent (Figure S19 for 6 and 9).…”

Design Strategies for Luminescent Titanocenes: Improving the Photoluminescence and Photostability of Arylethynyltitanocenes

“…For Ru­(bpy) 3 2+ , one of the deactivation mechanisms involves thermal access of the highly distorted 3 MC state; rigidification renders such states thermally inaccessible . Likewise, a range of phosphors that undergo nonradiative deactivation through 3 MC states have substantially longer lifetimes and larger photoluminescent quantum yields upon immobilization in PMMA films, ,− or viscous media . Thus, we have investigated the effect of rigidification in a PMMA film on the photophysical characteristics of Ph [Ti] and Ph [Ti]­CuBr .…”

Two luminescent film sensors constructed from new lanthanide coordination polymers for ratiometric detection of Zn2+ and NH3 in water and their white emission properties

“…Presumably, the nonradiative transitions in EuL / TbL decreased owing to the restriction of their molecular vibration upon doping them in the hydrophobic PMMA matrix. 40 Furthermore, the quenching effect induced by concentration and solvent molecules could be greatly reduced by the formation of PMMA films upon heating. 41 The water resistance capability of the spin-coated EuL / TbL and EuL / TbL @PMMA were further evaluated by recording their emission spectra upon immersion in water for five minutes.…”