Chiral Tetrakis Eu(III) Complexes with Ammonium Cations for Improved Circularly Polarized Luminescence.

Large dissymmetry factor of the circularly polarized luminescence (g) was observed in ligand and coordination tuned chiral tetrakis europium (Eu(III)) complexes with ammonium cations. The g value was estimated to be -1.54, which is the largest among chiral luminescent molecules.

Circularly polarized luminescence and high photoluminescence quantum yields from rigid 5,10-dihydroindeno[2,1-]indene and 2,2'-dialkoxy-1,1'-binaphthyl conjugates and copolymers.

5,5,10,10-Tetramethyl-5,10-dihydroindeno[2,1-]indene (COPV1(Me)) was installed into either the 3,3'- or 6,6'-positions of chiral 2,2'-dioctyloxy-1,1'-binaphthyl to afford 2 : 1 conjugates (monomeric compounds) and 1 : 1 copolymers. These compounds showed high photoluminescence quantum yields of >0.95 whilst also exhibiting circular dichroism (CD) and circularly polarized luminescence (CPL).

Rapid Synthesis of Chiral Figure-Eight Macrocycles Using a Preorganized Natural Product-Based Scaffold.

Chiral D -symmetric figure-eight shaped macrocycles are promising scaffolds for amplifying the chiroptical properties of π-conjugated systems. By harnessing the inherent and adaptable conformational dynamics of a chiral C -symmetric bispyrrolidinoindoline (BPI) manifold, we developed an enantio-divergent modular synthetic platform to rapidly generate a diverse range of chiral macrocycles, spanning from 14- to 66-membered rings, eliminating the need for optical resolution. Notably, a 32-membered figure-eight macrocycle showed excellent circularly polarized luminescence (CPL: |g |=1.

Optical Resolution of Carboxylic Acid Derivatives of Homoleptic Cyclometalated Iridium(III) Complexes via Diastereomers Formed with Chiral Auxiliaries.

We report on a facile method for the optical resolution of cyclometalated iridium(III) (Ir(III)) complexes via diastereomers formed with chiral auxiliaries. The racemic carboxylic acids of Ir(III) complexes (- (-Ir(ppyCOH) (ppy: 2-phenylpyridine)), - (-Ir(tpyCOH) (tpy: 2-(4'-tolyl)pyridine)), and - (-Ir(mpiqCOH) (mpiq: 1-(4'-methylphenyl)isoquinoline))) were converted into the diastereomers, Δ- and Λ-forms of - (from -), - (from -), - (from -), and - (from -), respectively, by the condensation with (12)-1,2-diaminocyclohexane or (12)-2-aminocyclohexanol. The resulting diastereomers were separated by HPLC (with a nonchiral column) or silica gel column chromatography, and their absolute stereochemistry was determined by X-ray single-crystal structure analysis and CD (circular dichroism) spectra.

Synthesis of Bicyclo[1.1.1]pentane (BCP)-Based Straight-Shaped Diphosphine Ligands.

[1.1.1]Propellane, which is structurally simple and compact, exhibits promising potential for the synthesis of disubstituted straight-shaped bicyclo[1.

Enhanced circularly polarized luminescence of chiral Eu(III) coordination polymers with structural strain.

Three types of Eu(III) coordination polymers with different distorted chiral ligands, [Eu(+tfc)(-dpeb)], [Eu(+pfc)(-dpeb)], and [Eu(+hfc)(-dpeb)] (+tfc: (+)-3-(trifluoroacetyl)camphorate, +pfc: (+)-3-(pentafluoropropionyl)camphorate, +hfc: (+)-3-(heptafluorobutyryl)camphorate, -dpeb: 1,4-bis(diphenylphosphorylethynyl)benzene), were prepared for elucidating the relationship between their structural distortions, ligand-to-metal charge transfer (LMCT), and circularly polarized luminescence (CPL) properties. Their strain factors in the ligands were evaluated using crystallographic data obtained by single-crystal X-ray structural analyses. The characteristics of the LMCT excited states were estimated from theoretical calculations.

Asymmetric Lumino-Transformer: Circularly Polarized Luminescence of Chiral Eu(III) Coordination Polymer with Phase-Transition Behavior.

A chiral Eu(III) coordination polymer with phase-transition behavior, [Eu(+tfc)(-dpeb)], (+tfc: (+)-3-trifluoroacetylcamphorato, -dpeb: 1,3-bis(diphenylphosphorylethynyl)benzene) was reported for understanding the effect of polymer chain arrangement (orientation effect) on the circularly polarized luminescence (CPL) in a solid system. The phase-transition behavior of the transformable Eu(III) coordination polymer was characterized using differential scanning calorimetry and powder X-ray diffraction. The Eu(III) coordination polymer exhibited phase transition at approximately 180 °C.

Bright red emission with high color purity from Eu(iii) complexes with π-conjugated polycyclic aromatic ligands and their sensing applications.

Eu(iii) complexes emit red light with a high color purity and have consequently attracted attention for development toward display and physical sensing applications. The characteristic pure color emission originates from the intra-4f-4f transition, and the brightness strongly depends on the electronic and steric structures of organic ligands. A large π-conjugated ligand design with a large absorption coefficient has been actively studied for achieving bright emission.

Strong circularly polarized luminescence of mixed lanthanide coordination polymers with control of 4f electronic structures.

This paper reports chiral mixed Eu(iii)-Ln(iii) coordination polymers (Ln = Gd and Sm) with a high dissymmetry factor of circularly polarized luminescence (gCPL = 0.15) for the enhancement of the emission quantum yield (Φtot ≥ 50%), achieved via control of 4f electronic structures.

Long-wavelength visible to near infrared photoluminescence from carbon-bridged styrylstilbene and thiadiazole conjugates in organic and aqueous media.

Donor-acceptor-donor conjugates composed of electron-donating carbon-bridged styrylstilbene (COPV2) and electron-accepting thiadiazole derivatives equipped with carbazolyl (Cz) terminators, Cz-COPV2-A-COPV2-Cz (A = benzothiadiazole (BTz), naphthobis(thiadiazole) (NTz), or benzobis(thiadiazole) (BBTz)), were newly synthesized and found to serve as efficient and stable long-wavelength photoluminescent dyes in organic and aqueous media. In particular, Cz-COPV2-BBTz-COPV2-Cz showed photoluminescence in the near infrared region (895-927 nm) with a photoluminescence quantum yield (PLQY) of up to 0.19 in cyclohexane and of 0.

Circularly Polarized Absorption and Luminescence of Semiconductor Eu-OCN Nanocrystals in the Blue Region of the Electromagnetic Spectrum.

Semiconductor nanomaterials with efficient polarized-light control in the blue region of the visible spectrum are promising candidates for modern and future photo-information technology, display devices, and optical sensing applications. New-type semiconductor Eu(OCN) nanocrystals with circularly polarized absorption (CD: circular dichroism) and emission (CPL: circularly polarized luminescence) under an applied magnetic field are demonstrated here for the first time. The effective CD signal at 1.

Electronic strain effect on Eu(iii) complexes for enhanced circularly polarized luminescence.

Luminescent Eu(iii) complexes with point-chiral phosphine oxide ligands, [Eu(hfa)3((R,R)-B2QPO)] (hfa: hexafluoroacetylacetonato, B2QPO: 2,3-bis(tert-butylmethylphosphine oxide)quinoxaline) and [Eu(hfa)3((R)-B3QPO)] (B3QPO: 2-tert-butylmethylphosphine oxide-3-(di-tert-butylphosphineoxide)quinoxaline), are reported for the investigation of the electronic strain effect on the coordination sphere. Single crystal X-ray crystallography reveals the strong structural strain of the hfa ligands in [Eu(hfa)3((R,R)-B2QPO)]. The emission quantum yields of [Eu(hfa)3((R,R)-B2QPO)] in solution (55%) and solid (63%) are comparable to those of previously reported bright luminescent Eu(iii) complexes.

Steric and Electronic Control of Chiral Eu(III) Complexes for Effective Circularly Polarized Luminescence.

Circularly polarized luminescence (CPL) is characterized by the differential emission of right and left circularly polarized light by a chiral molecule. This mini-review describes the recent developments in chiral trivalent europium (Eu(III)) complexes with effective CPL. CPL has many potential applications in security tags, lasers, and three-dimensional organic electroluminescence devices, which is one of the most intensely investigated topics in molecular luminophores.

Luminescent Coordination Polymers Constructed from a Flexible, Tetradentate Diisopyrazole Ligand and Copper(I) Halides.

One- and two-dimensional coordination polymers composed of a structurally flexible, tetradentate diisopyrazole ligand and copper(I) halides were synthesized as crystalline solids. Complexation with copper(I) chloride or bromide resulted in the formation of infinite coordination chains through connecting each diisopyrazole ligand with two copper(I) ions in a trigonal planar coordination geometry. Contrarily, the combination of a diisopyrazole ligand and copper(I) iodide gave a two-dimensional coordination network comprising Cu I units with stair-step type geometry and diisopyrazoles that acted as both tetradentate and bidentate bridging ligands.