The crystal structure and optical characteristics of two tin(IV) anthracene-9-carboxylate complexes and their use in OLEDs

The synthesis of two tin(IV)-carboxylate coordination complexes, 1 and 2, was achieved through the reaction of stannic chloride with anthracene-9-carboxylic acid (HL¹), 1,2-bis(4-pyridyl)ethane (4-bpe), and 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (4-bpdh) using a branched tube method. The complexes exhibited remarkable luminescent properties and unique structural characteristics. Comprehensive characterization was carried out through 1H NMR, IR, UV spectroscopy, and elemental analysis, while X-ray single-crystal analysis was used to determine their molecular structures. The crystal structures of complexes 1 and 2 primarily consist of two components: a complex anion and a cation. In these structures, L¹ employs a syn-syn bidentate bridging coordination mode, utilizing two oxygen atoms from the carboxylate group. Optical analysis emphasized the crucial role of auxiliary ligands in fine-tuning the optical properties of complexes 1 and 2. Compound 2 served as the light-emitting layer (LEL) in an organic light-emitting diode (OLED), where its electrical performance was evaluated. The OLED achieved a luminance of 6550 cd/m2 and a maximum power efficiency of 7.2 lm/W, representing the highest efficiency recorded for tin-based OLEDs. The device functioned at a driving voltage of around 7 V. These results indicate that this class of compounds holds potential for OLED production, providing stable quantum efficiency across different voltage ranges.