Aggregation-caused quenching versus crystallization induced emission in thiazolo[5,4-b]thieno[3,2-e]pyridine (TTP) derivatives: theoretical insights

Abstract

Combining adequate theoretical strategies enables rationalization of the different photophysical processes at the origin of the ACQ/CIE effects.

Understanding the Driving Mechanisms of Enhanced Luminescence Emission of Oligo(styryl)benzenes and Tri(styryl)‐s‐triazine

“…Three significant Huang–Rhys (HF) factors values (>1.5) involved in the nonradiative internal conversion decay have been predicted for this compound in aqueous solution (see Figure and Figure S14 in the Supporting Information for additional information in both aqueous solution and dichloromethane). These HF factor values are associated with low vibrational frequencies of 15, 22, and 25 cm −1 ; this implies a wide wagging of the molecule as a whole, which could be blocked by stacking aggregation (see Figure S15 in the Supporting Information) . Both RIVs and the blocking of E / Z photoisomerization upon aggregation are mechanisms consistent with the increase of the fluorescence lifetime reported for compound 1 upon going from f w =0 to 30 % in mixtures of water/acetonitrile due to a reduction of the nonradiative rate constant.…”

“…[43] (see Figure S15 in the Supporting Information). [66] Both RIVs and the blocking of E/Z photoisomerization upon aggregation are mechanismsc onsistentw ith the increase of the fluorescence lifetimer eported for compound 1 upon going from f w = 0t o3 0% in mixtures of water/acetonitrile due to ar eduction of the nonradiative rate constant.…”

[Cu(POP)(N^S)][PF6] and [Cu(xantphos)(N^S)][PF6] compounds with 2-(thiophen-2-yl)pyridines

“…With the exception of [Cu(xantphos)(1)][PF 6 ] and [Cu(xantphos)(3)][PF 6 ], the PLQY values for the powder samples of the compounds are lower than in solution and this may be indicative of aggregation-caused quenching (ACQ) in the solid state, although this is typically associated with p-stacking of planar molecular species. 58,59 The most promising solid-state emitter, [Cu(xantphos)(1)] [PF 6 ], was also tested in a thin lm with ionic liquid but the PL signal was below the detection limit and no PLQY could be measured. In a LEC conguration, [Cu(xantphos)(1)][PF 6 ] exhibited no electroluminescence, even when the LEC was driven under a high bias (18 V).…”

Intense Red‐Blue Luminescence Based on Superfine Control of Metal–Metal Interactions for Self‐Assembled Platinum(II) Complexes

“…When appropriate aromatic ligands are introduced into such systems,t hey often exhibit characteristic light absorption/ emission based on ac harge transfer transition between the ds*o rbital and the p*o rbital of the ligand, the so-called metal-metal-to-ligand charge transfer (MMLCT) transition ( Figure S1). [8] Theassembly-induced luminescent systems are fascinating because an intense emission can occur even if the monomeric unit is non-emissive.I na ddition, these systems are free from the problem of the so-called aggregation caused quenching, [9] while aggregation induced emission has also been developed by sophisticated molecular design. [10] TheM MLCT absorption/emission energies distinctly reflect the intermolecular Pt•••Pt interactions determined by the Pt•••Pt distances and the orientation of the stacks;that is, the Pt•••Pt interaction can change sensitively when the stack is inclined from the parallel arrangement (A!Bi nF igure 1), and the effect increases for the shifted stack formed by the effect of the ligands (C in Figure 1).…”