Synthesis and photophysical characterization of organotin compounds derived from Schiff bases for organic light emitting diodes

• Synthesis, chemical-optical characterization of two new organotin compounds derived from Schiff bases.
• The quantum yields in solution of imines and tin complexes were ca. 4%.
• A good strategy improves of the quantum yield for the organotin complexes.
• The OLED was fabricated with the organotin compound and showed electroluminescence.

The multicomponent reaction of the 2-hydroxynaphthaldehyde with 2-aminophenol derivatives and their in situ complexation with diphenyltin oxide in acetonitrile provided, in high yield, the products: (((E)-12-nitro-8,8-diphenylbenzo[d]naphtho[1,2-h][1,3,6,2]dioxazastannonine and (E)-11-nitro-8,8-diphenylbenzo[d]naphtho[1,2-h][1,3,6,2]dioxazastannonine), where tin atom is pentacoordinated. The synthesis of their ligands ((E)-1-(((2-hydroxy-5-nitrophenyl)imino)methyl)naphthalen-2-ol and (E)-1-(((2-hydroxy-4-nitrophenyl)imino)methyl)naphthalen-2-ol) is also reported. The chemical structure of all the compounds has been established by nuclear magnetic resonance (1H, 13C, and 119Sn), infrared spectroscopy, and high resolution mass spectrometry. The 12-nitroanalogue was characterized by single-crystal X-ray structural analysis. The structure indicates that the backbone is essentially planar and the metal center resides in trigonal bipyramid geometry. The photophysical properties of the imines and those of the tin complexes were determined in solution exhibiting quantum yields around 4% with lifetimes in the range 10−10−10−11 s. In a preliminary study, a diode was fabricated by a spun film of the 12-nitroanalogue, the device showed intrinsic electroluminescence properties with a threshold voltage at 13 V, a high current density (500 mA/cm2) but a low luminance (0.03 cd/m2).

Figure optionsDownload as PowerPoint slide