Efficient 8-oxyquinolinato emitters based on a 9,10-dihydro-9,10-diboraanthracene scaffold for applications in optoelectronic devices

Abstract

A detailed experimental characterization and theoretical evaluation of optical as well as other relevant physicochemical properties of a series of 9,10-dihydro-9,10-diboraanthracene bis(8-oxyquinolinates) and a few other related systems is reported. The obtained compounds exhibit green luminescence with quantum yields of emission up to 63% in CH 2 Cl 2 . Single crystal X-ray diffraction studies indicate that 9,10-dihydro-9,10-diboraanthracene complexes exist either as bent conformers (stabilized by a weak intramolecular CH…O interaction bringing two 8-oxyquinolinato ligands closer to each other) or symmetrical ones (bearing both ligands related by the centre of symmetry and separated one from the other). Theoretical calculations revealed that the LUMO levels are lower for the bent conformers than for the symmetrical ones. This suggests that the luminescent properties of the studied compounds are affected by their specific structural properties. The obtained compounds were used as emitters for the construction of organic light emitting diodes (OLEDs). The highest luminance of ca. 2,000 cd·m −2 was recorded for the device containing only 2.0 wt% of 1,6-difluoro-9,10-dihydro-9,10-diboraanthracene core in the poly(Nvinylcarbazole/2-t-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PVK:PBD) matrix. The fabricated OLEDs exhibit current efficiency in the range from 0.5 to 1.1 cd·A −1 .

Doping Polycyclic Aromatics with Boron for Superior Performance in Materials Science and Catalysis

“…Finally, we note reports of OLEDs and organic solar cells (OSCs) that contain borafluorene or DBA moieties with four‐coordinate boron atoms and chelating 2‐(2‐hydroxyphenyl)benzimidazole, 8‐hydroxyquinoline, and aza‐dipyrromethene ligands …”

Expedient Synthesis of Oxaboracyclic Compounds Based on Naphthalene and Biphenyl Backbone and Phase‐Dependent Luminescence of their Chelate Complexes

“…The latter form exhibits bright sky‐blue emission at 480 nm with extraordinary fluorescent quantum yield of 95 %. This represents the highest Φ value for organoboron Q complexes, and one of the highest values for all luminescent boron complexes known up to date [49–53] . It should be noted that reports on such a strong solvation‐induced luminescent amplification are scarce.…”

“…Overall, the spectral features of both complexes in solution are typical of organoboron Q complexes. [29,[49][50][51][52][53] Concordantly, TD-DFT calculations performed at the wB97XD/6-311 + + G(d,p) level of theory within CPCM solvation model (DCM) predicted that the observed transition occurs at the Q moiety and possesses expected π-π* character. This is reflected by the location of both the highest occupied and lowest unoccupied natural transition orbitals (HONTO and LUNTO) at the Q moiety (Figure 8c).…”

Spectroelectrochemical Behaviour of 1,4‐Dimethoxypillar[5]arene (P5A) and its Monomer in Different Organic Solvents

“…Because the main measurements were carried out in three solvents, acetonitrile (ACN), dichloromethane (DCM), and dichloroethane (DCE), the formal potential of Fc/Fc + was measured in these three solvents containing 0.1 M Bu 4 NPF 6 (TBAHPF). The formal potential of Fc/Fc + in 0.1 M TBAHPF in acetonitrile was 97 � 4 mV; [22][23][24] in 0.1 M TBAHPF in dichloromethane was 205 � 8 mV; [25,26] and in 0.1 M TBAHPF in dichloroethane was 201 � 7 mV. [25] The solvent dependence of the formal redox potentials of the ferrocene/ferrocenium couples is well known.…”