Synthesis and Characterization of Brominated Derivatives of 9,10-BN-Naphthalene as Versatile Building Blocks for π-Conjugated BN Materials

Boron-nitrogen (BN) units are valuable structural motifs for modulating the photoelectric properties of π-conjugated systems. In this work, we report the synthesis and structural elucidation of a series of brominated 9,10-BN-naphthalene derivatives that serve as versatile intermediates for subsequent cross-coupling functionalization. Controlled bromination afforded mono- to poly brominated species, including two distinct tribrominated regioisomers that enabled diverse derivatization pathways. Through Suzuki-Miyaura reactions, a range of multiarylated 9,10-BN-naphthalenes were obtained, significantly expanding the structural diversity of BN-embedded aromatic frameworks. The resulting compounds were characterized by NMR spectroscopy, DFT calculations, and single-crystal X-ray diffraction for selected examples. Their photophysical properties revealed substituent-dependent variations in absorption and emission profiles, highlighting the tunable electronic nature of the BN-doped propeller-shaped molecules. This study establishes an efficient and modular approach for diversifying BN-naphthalene scaffolds and deepens understanding of their structure-property relationships.