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Low‐cost molecular emitters that merge circularly polarized luminescence (CPL) and thermally activated delayed fluorescence (TADF) properties are attractive for many high‐tech applications. However, the design of such emitters remains a difficult task. To address this challenge, here, we propose a simple and efficient strategy, demonstrated by the design of pseudochiral‐at‐metal complexes [Cu(L*)DPEPhos]PF6 bearing a (+)/(−)‐menthol‐derived 1,10‐phenanthroline ligand (L*). These complexes exhibit a yellow CP‐TADF with a record‐high quantum yield (close to 100 %) and high dissymmetry factor (|glum|~1×10−2). Remarkably, the above compounds also show a negative thermal‐quenching (NTQ) of luminescence in the 300–77 K range. Exploiting the designed Cu(I) emitters, we fabricated efficient CP‐TADF OLEDs displaying mirror‐imaged CPL bands with high |gEL| factors of 1.5×10−2 and the maximum EQE of 6.15 %. Equally important, using the (+)‐[Cu(L*)DPEPhos]PF6 complex, we have discovered that an external magnetic field noticeably suppresses CP‐TADF of Cu(I) emitters. These findings are an important contribution to the CPL phenomenon and provide access to highly efficient, low‐cost and robust CP‐TADF emitters. [ABSTRACT FROM AUTHOR]

A series of small coinage metal(I) clusters has been selectively synthesized using 2-(diphenylphosphino)-1,10-phenanthroline (L), a new promising dimetal-binding P,N,N′-ligand (L). Its reaction with CuI yields the complex [Cu2L2(μ2-I)]2[Cu2I4], while the treatment of L with Au(tht)Cl/Ag+ or Au(tht)Cl/Cu+ systems leads to the assembly of [Au2AgL2Cl2]+, [Au2CuL2Cl2]+, [CuAuL2]2+ and [AgAuL2]2+ clusters. Theoretical analysis revealed pronounced intermetallic close shell interactions in these di- and trinuclear ensembles. At 298 K, the title compounds exhibit an orange and near-infrared (NIR) phosphorescence with lifetimes of 0.344–38 μs and quantum efficiencies of 1–21%. Theoretical considerations suggest a 3(M+L)LCT type for the observed phosphorescence. In addition, the above clusters exhibit a strong dose-dependent cytotoxic effect on A549, HepG2, Hep2 and MRC5 human cells with IC50 values ranging from 1.26 to 11.1 μM. [ABSTRACT FROM AUTHOR]

Dinuclear Au(I) complexes with bisphosphine ligands, namely [Au2Cl2(L)], where L = 4,6-bis(diphenylphosphino)pyrimidine (Au1) or 1,7-bis(di-o-tolylphosphinyl)-m-carborane (Au2), have been synthesized. The complexes were characterized by analytical and spectroscopic methods and their crystal structures were determined by X-ray diffraction analysis. Both complexes demonstrated photoluminescence in the solid state at 300 K when excited at 300–400 nm: from blue emission (∼400 nm) for Au1 to green emission (∼500 mn) for Au2. The lifetimes of the excited state were determined to be in the microsecond range, indicating the triplet nature of the emission levels. Preliminary bioactivity tests for complexes Au1 and Au2 in comparison with the respective ligands and cisplatin have been performed. [ABSTRACT FROM AUTHOR]

Self-assembly reaction of Ln3+ and Ag+ ions with a multidentate N,O-donor ligand has been successfully applied to isolate the first examples of 4f-4d heterometallic coordination compounds based on a phosphine oxide linker. In particular, a series of one-dimension coordination polymers [LnAg(Py3PO)2(NO3)4]n (Ln = Sm, Eu, Tb, Dy) have been synthesized employing tris(2-pyridyl)phosphine oxide (Py3PO) as a bridging ligand. Coordination polymers exhibit good photostability and high thermal stability above 300 ℃. Their solid-state photoluminescence spectra represent a combination of emissions originating from the lanthanide f-f transitions and Ag+-involved charge transfer, resulting in the color-tunable luminescence depending on excitation light. [ABSTRACT FROM AUTHOR]

Reactions between Ln(NO3)3 and cucurbit[6]uril in HNO3 have been studied, aiming to create novel light-emitting systems. Aquanitrato complexes of lanthanides were obtained as supramolecular assemblies 1–10 with the organic macrocyclic cavitand cucurbit[6]uril. X-ray diffraction study demonstrated that these compounds have the following compositions: [{Ln(H2O)5(NO3)}2(C36H36N24O12)](NO3)4·HNO3·nH2O (Ln = Pr(1), Nd(2), Sm(3), Eu(4), Gd(5), Tb(6)) and 2[Ln(H2O)8](NO3)3·C36H36N24O12·2HNO3·mH2O (Ln = Dy(7), Ho(8), Er(9), Yb(10)). Compounds with different structures were shown to crystallize under the same synthesis conditions for the early and late lanthanides. The compounds were characterized by powder X-ray diffraction, thermogravimetric and elemental analyses, and IR spectroscopy. The magnetic property of compound 5 was also examined. The luminescent properties for compounds 1–10 were studied. The chromaticity coordinates (CIE) for compounds 1–10 were calculated. The color purity of compound 4 was found to be 96%, which is very close to that of the standard red light source. Compound 4 can be considered a potential red-emitting candidate for near-UV WLEDs. The color purity of compound 7 is very close to zero, so it is well suited for generation of white light, which further suggests its utility for W-LED applications. A cool white LED device was fabricated for the first time by combining the supramolecular coordination polymer 7 and a UV LED chip (365 nm) under a voltage of 3.0 V; the CIE, CCT and CP were (0.301, 0.325), 7228 K and 7%, respectively. [ABSTRACT FROM AUTHOR]

The reactions of Eu(III) and Tb(III) hexafluoroacetylacetonates (hfac−) with 2,4-bis(diphenylphosphino)pyrimidine dioxide (L1), 4,6-bis(diphenylphosphino)pyrimidine dioxide (L2), or 3,6-bis(diphenylphosphino)pyridazine dioxide (L3) afforded a new series of one-dimensional coordination polymers [LnL(hfac)3]n (L = L1, L2, and L3). Compounds [TbL2(hfac)3]n and [LnL3(hfac)3]n (Ln = Eu, Tb) consist of the eight-coordinated Ln(III) atoms linked by L2 and L3 ligands in the O,O′-bridging manner (an O8 polyhedron). In [LnL1(hfac)3]n (Ln = Eu, Tb) and [EuL2(hfac)3]n, one of the N atoms of bridging diphosphine dioxide is involved in the coordination to the Ln3+ ion resulting in a N1O8 polyhedron. All coordination polymers exhibit high thermal stability above 300 °C. The Eu(III) coordination polymers display strong photoluminescence with the solid-state quantum yield up to 61% observed for [EuL1(hfac)3]n. The chelating coordination of L1 and L2 increases considerably the energy transfer efficiency from the ligands to Eu(III) compared to that of L3. The centrosymmetric coordination polymers [LnL1(hfac)3]n exhibit strong triboluminescence that is clearly observed even in daylight at ambient temperature, while their non-centrosymmetric analogue [EuL2(hfac)3]n displays lower triboluminescent activity, which is visible only in the dark. [ABSTRACT FROM AUTHOR]

Exploiting 2-(alkylsulfonyl)pyridines as 1,3-N,S-ligands, herein we have constructed 1D CuI-based coordination polymers (CPs) bearing unprecedented (CuI)n chains and possessing remarkable photophysical properties. At room temperature, these CPs show efficient TADF, phosphorescence or dual emission in the deep-blue to red range with outstandingly short decay times of 0.4–2.0 μs and good quantum performance. Owing to great structural diversity, the CPs demonstrate a variety of emissive mechanisms, spanning from TADF of 1(M + X)LCT type to 3CC and 3(M + X)LCT phosphorescence. Moreover, the designed compounds emit strong X-ray radioluminescence with the quantum efficiency of up to an impressive 55% relative to all-inorganic BGO scintillators. The presented findings push the boundaries in designing TADF and triplet emitters with very short decay times. [ABSTRACT FROM AUTHOR]

A novel terbium (Tb3+) and ytterbium (Yb3+) co-doped optical quality CsGd(MoO4)2 single crystals were grown by the low-thermal-gradient Czochralski method. Photoluminescence spectra were measured and studied for Tb3+– Yb3+ doubly doped CsGd(MoO4)2 crystals at 77–340 K temperature range. Under 330 nm excitation the main peaks of Tb3+ and Yb3+ emission were observed. Decay curves were obtained for the energy levels 5D4 of Tb3+ and 2F7/2 of Yb3+ in CsGd(MoO4)2 crystals. Decay time for Tb3+ transitions significantly varies at temperatures close to ambient. Such behaviour allows to assume perspective application of this effect for non-contact luminescence lifetime thermometry. The emission colour chromaticity coordinates of CsGd(MoO4)2: Tb3+ -Yb3+ crystals are close to SMPTE (Society of Motion Picture and Television Engineers) standard for green colour, as shown on CIE 1931 diagram. Correlated colour temperature varies from 5538 K at 77 K to 4297 K at 340 K. [ABSTRACT FROM AUTHOR]