Roles of Ancillary Chelates and Overall Charges of Bis-tridentate Ir(III) Phosphors for OLED Applications.

A series of charge-neutral bis-tridentate Ir(III) complexes (, , and ) were prepared via employing three distinctive tridentate prochelates, that is, (pzpph)H, [(phpyim)H·(PF)], and [(pimb)H·(PF)], which possess one dianionic pzpph, together with a second monoanionic tridentate chelate, namely, (pzpph)H, phpyim, and pimb, respectively. Moreover, a homoleptic, charge-neutral complex was obtained by methylation of chelating (pzpph)H of in basic media, while closely related cationic complexes were obtained by further methylation of the remaining pyrazolate unit of previously mentioned neutral complexes , followed by anion metatheses. All of these Ir(III) metal complexes showed a broadened emission profile with an onset at ∼450 nm, a result of an enlarged ligand-centered ππ* transition gap, but with distinct efficiencies ranging from 0.

Bis-tridentate Ir Phosphors Bearing Two Fused Five-Six-Membered Metallacycles: A Strategy to Improved Photostability of Blue Emitters.

Iridium complexes bearing chelating cyclometalates are popular choices as dopant emitters in the fabrication of organic light-emitting diodes (OLEDs). In this contribution, we report a series of blue-emitting, bis-tridentate Ir complexes bearing chelates with two fused five-six-membered metallacycles, which are in sharp contrast to the traditional designs of tridentate chelates that form the alternative, fused five-five metallacycles. Five Ir complexes, Px-21-23, Cz-4, and Cz-5, have been synthesized that contain a coordinated dicarbene pincer chelate incorporating a methylene spacer and a dianionic chromophoric chelate possessing either a phenoxy or carbazolyl appendage to tune the coordination arrangement.