Modulating radiative efficiency in -carboranyl luminophores through electron-donating substituents: insights from intramolecular-charge-transfer-based emissions.

In this study, we introduce six -carboranyl compounds derived from 9,9-dimethyl-9-fluorene 1CH-6CP, each possessing substituents with varying electron-donating capabilities. Their geometric features were comprehensively characterised through single X-ray crystallography. In rigid states (solutions at 77 K, films, aggregates, and crystals), these compounds exhibited intense intramolecular charge-transfer (ICT)-based emissions in the bluish-green spectrum.

Influence of Intermolecular Structural Effects on Radiative Efficiency in Xanthene-Based Carboranyl Luminophores.

Two -carboranes with (i) 9,9-dimethyl-9-xanthene and (ii) spiro[fluorene-9,9'-xanthene] moieties ( and , respectively) were prepared and characterized. Single X-ray crystallography analysis revealed the presence of intermolecular hydrogen bonds in crystals. Although both compounds did not exhibit emission in tetrahydrofuran solutions at 298 K, intense bluish emission was observed in the solid states and frozen tetrahydrofuran solutions at 77 K.

Improvement in Radiative Efficiency Intramolecular Charge Transfer in -Carboranyl Luminophores Modified with Functionalized Biphenyls.

In this study, we found that the electronic effects of the functional groups on aromatic units attached to -carboranyl species can enhance the efficiency of intramolecular charge transfer (ICT)-based radiative decay processes. Six -carboranyl-based luminophores having attached functionalized biphenyl groups with CF, F, H, CH, C(CH), and OCH substituents were prepared and fully characterized by multinuclear magnetic resonance spectroscopy. In addition, their molecular structures were determined by single-crystal X-ray diffractometry, which revealed that the distortion of the biphenyl rings and the geometries around the -carborane cages were similar.

High radiative efficiency based on intramolecular charge transfer in a 9,9'-bianthracene--carboranyl luminophore.

Herein, we prepared an -carborane compound (9biAT) linked to a 9,9'-bianthracene moiety at each C9-position. The compound exhibited reddish emission in solid and solution states. The solvatochromism effect and theoretical calculation results for the excited (S) state of 9biAT verified that the emission was attributed to ICT transition.

Relationship between the Molecular Geometry and the Radiative Efficiency in Naphthyl-Based Bis-Ortho-Carboranyl Luminophores.

The efficiency of intramolecular charge transfer (ICT)-based emission on π-aromatic-group-appended -carboranyl luminophores is known to be affected by structural fluctuations and molecular geometry, but investigation of this relationship has been in progress to date. In this study, four naphthyl-based bis--carboranyl compounds, in which hydrogen ( and ) or trimethysilyl groups ( and ) were appended at the -carborane cage, were synthesized and fully characterized. All the compounds barely displayed an emissive trace in solution at 298 K; however, and distinctly exhibited a dual emissive pattern in rigid states (in solution at 77 K and in films), attributed to locally excited (LE) and ICT-based emission, while and showed strong ICT-based greenish emission.

Synthesis, photophysical properties and photo-induced cytotoxicity of novel tris(diazatriphenylene)ruthenium (II) complex.

Novel bipyridine-based heterocyclic building block, 3,10-dichloro-benzo[f][1,10]phenanthroline and its Ruthenium(II) complex have been synthesized and fully characterized. The synthesized Ru(II)-complex is highly luminescent displaying emission at 590 nm with quantum yield of ∼0.8 in methanol.

Crucial Factors Regulating Intramolecular Charge-Transfer-Based Radiative Efficiency in -Carboranyl Luminophores: Planarity between Substituted Biphenyl Rings.

-Carboranyl compounds contain specific geometries, ranging from planar to orthogonally distorted biphenyl rings. Herein, 13 -carboranyl compounds, , were synthesized and fully characterized to determine the impact of structural formation of the aromatic group appended with the -carborane to estimate the efficiency of their radiative decay process. All the compounds exhibited significant intramolecular charge transfer (ICT)-based emission in the crystalline state at 298 K.

Strategic molecular design of -carboranyl luminophores to manifest thermally activated delayed fluorescence.

In this paper, we propose a strategic molecular design of -carborane-based donor-acceptor dyad system that exhibits thermally activated delayed fluorescence (TADF) in the solution state at ambient temperature. Planar 9,9-dimethyl-9-fluorene-based compounds with - and -carborane cages appended at the C2-, C3-, and C4-positions of each fluorene moiety (-type: , , , and , and -type: - = [-form of ]·[NBu]) were prepared and characterized. The solid-state molecular structure of exhibited a significantly distorted fluorene plane, which suggests the existence of severe intramolecular steric hindrance.