Synthesis, Characterization, and Properties of Sila-Annulated Phenanthrene Imides

A series of sila-annulated phenanthrene imides were synthesized through a three-step synthetic route, which represent a hybrid class of biphenyl-based π-conjugated molecules incorporating an imide unit and silole. A comprehensive investigation of their structural, photophysical, and electronic properties was studied by experiment and theoretical calculations. Notably, sila-annulated phenanthrene imides with significant aggregation-induced emission (AIE) properties were observed.

Synthesis, structures, and photophysical properties of π-extended arsaborins

In this study, various (hetero)arene-fused arsaborins were synthesized. All the synthesized arsaborins were stable under ambient conditions and allowed for the chemical modification of the lone pair of the arsenic atom. Experimental and computational studies revealed that these compounds possessed planar structures and weak anti-aromatic properties. Fluorescence with large Stokes shifts was observed due to drastic structural relaxation at 298 K, whereas intense phosphorescence due to the heavy-atom effect of arsenic was observed at 77 K. Furthermore, a thiophene-fused derivative demonstrated a temperature-dependent emission color change in the solid state, attributable to the gradual alteration in the ratio of monomer fluorescence, excimer fluorescence, and phosphorescence.

Synthesis and Photophysical Properties of Heavier Pnictogen Complexes

Recent success in the synthesis of π-conjugated heavier pnictogen (As, Sb, and Bi) compounds and their transition metal complexes has led to the current surge in interest that led to significant development in the field of photophysical and optoelectronic properties of heavier pnictogens and their transition metal complexes. The presence of heavier pnictogens (As, Sb and Bi) in the molecular skeleton promotes inter-system crossing (ISC) and reverse inter-system crossing (RISC), because of the heavy atom effect, via altering the intermolecular interactions and orbital energy levels. As a result, π-conjugated heavier pnictogen compounds such as arsines, dibenzoarsepins, arsinoquinoline, heterofluorene, benzo[b]heterole (heterole=arsole, bismole, and stibole) show unique optoelectronic properties such as narrow bandgap, low-energy absorption, and long-wavelength emission than lighter pnictogen-based compounds. This review focuses on recent advances in the synthesis and photophysical properties of heavier pnictogen compounds. The synthesis and photophysical properties of heavier pnictogens are discussed and elaborated.

Systematic Study of Pnictogen-Fused Heterofluorenes

Heteroatom-fused π-conjugated molecules have attracted considerable attention, and various elements for such fusion have been investigated. Herein, we focused on pnictogen-fused heterofluorenes. The structures, reactivity with O₂ and I₂, coordination ability to AuCl, and photophysical properties were systematically studied to better understand the effects of pnictogen atoms on the nature of π-conjugated molecules.

Direct formation of 4,5-disubstituted carbazoles via regioselective dilithiation

Carbazoles are widely exploited for their interesting photophysical and electronic properties, however bay (4,5-) functionalization is challenging, and previously inaccessible through carbazole C-H activation. We report a simple methodology which introduces a range of versatile 4,5-functionality, enabling the wider investigation of ring annulation and close proximity effects on carbazole properties.