In this work, we synthesized two tailored phosphorescent Pt(II) complexes bearing a cyclometalating tridentate thiazole-based C^N*N pincer luminophore () and exchangeable chlorido () or cyanido () coligands. While both complexes showed photoluminescence from metal-perturbed ligand-centered triplet states (MP-LC), reached the highest phosphorescence quantum yields and displayed a significant sensitivity toward quenching by O. We encapsulated them into two Zn-based metal-organic frameworks, namely, and . The incorporation of the organometallic compounds in the resulting composites , , , and was verified by powder X-ray diffractometry, scanning electron microscopy, time-resolved photoluminescence spectroscopy and microscopy, as well as N- and Ar-gas sorption studies. The amount of encapsulated complex was determined by graphite furnace atomic absorption spectroscopy, showing a maximum loading of 3.7 wt %. If compared with their solid state forms, the solid-solution composites showed prolonged O-sensitive excited state lifetimes for the complexes at room temperature, reaching up to 18.4 μs under an Ar atmosphere, which is comparable with the behavior of the complex in liquid solutions or even frozen glassy matrices at 77 K.
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http://dx.doi.org/10.1021/acs.inorgchem.0c00678 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Republic of Korea.
In this study, a tetradentate Pt(II) complex designed to have -heterocyclic carbene ligands modified with an anchor-shaped 2,6-diisopropylphenyl (dip) group is described to enhance molecular rigidity for narrow emission and high efficiency. The tetradentate ligand with the dip group significantly hinders steric interactions and restricts π-conjugation from benzocarbene, leading to shallow lowest unoccupied molecular orbital levels and a consequent reduction in the triplet metal-to-ligand charge transfer character. These structural modifications result in narrow emission spectra and enhanced efficiency for blue organic light-emitting diodes (OLEDs) over wide doping concentration ranges.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China.
Among the various challenges in the field of organic light-emitting diodes (OLEDs), simultaneously achieving high efficiency, a long lifespan, and a narrow full-width at half maximum (FWHM) in blue OLEDs remains a significant hurdle. Herein, we demonstrate a strategy to improve the color purity of tetradentate Pt(II) complexes with the assistance of ⋅⋅⋅H interaction by incorporating trifluoromethyl (-CF) groups into the well-known blue tetradentate Pt(II) phosphorescent complex. The results show that the different substitution positions of -CF have significantly varying effects on the FWHM values of the complexes; specifically, introducing -CF on the benzene ring of carbazole effectively reduces the FWHM, while introducing it on the benzene ring linked to the carbene unit has a minimal impact.
View Article and Find Full Text PDFInorg Chem
December 2024
Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, China.
Bidentate Pt(II) complexes with cyclometalated -heteroarene or -heterocyclic carbene (NHC) ligands have been extensively studied as phosphorescent emitters over the past two decades. Herein, we introduce a difluoromethyl group (CFH) into the wingtip of NHCs, where CFH acts as a lipophilic hydrogen bond (HB) donor. Their cyclometalated Pt(II) complexes show excellent PLQYs (up to 93%) and phosphorescence lifetimes mainly due to the rigid structure with hydrogen bonding between the CFH group and the adjacent O atom at the β-diketonate ligand.
View Article and Find Full Text PDFChem Sci
October 2024
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 P. R. China
Chiral organometallic Pt(ii) complexes have been demonstrated to be excellent circularly polarized luminescence (CPL) materials due to their rich phosphorescence and strong self-assembly characteristics. However, it remains a formidable task to simultaneously achieve high luminance () and electroluminescence dissymmetry factor ( ) values for circularly polarized electroluminescence (CP-EL) devices of Pt(ii) complex-based emitters. In this study, we carry out a straightforward and efficient protocol to construct highly CPL-active helical columnar () emitters by using chiral homoleptic triazolatoplatinum(ii) metallomesogens (/-HPt).
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2024
Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), School of Flexible Electronics (Future Technologies), Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China.
Utilizing a single organic light-emitting diode (OLED) architecture for multicolor emissions can significantly simplify manufacturing progress and broaden applications. Here, we report on a carbene-based Pt(II) complex, designated as , which exhibits an unusual dimeric packing mode solely by hemiligand π···π stacking. This feature is distinct from the well-known Pt···Pt or Pt···ligand interactions.
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