Color Tuning of Cyclometalated Iridium Complexes through Modification of Phenylpyrazole Derivatives and Ancillary Ligand Based on ab Initio Calculations

Various iridium complexes consisting of phenylpyrazole (<i>ppz</i>) ligands and isoquinolinecarboxylic acids (<i>iq</i>) as ancillary ligands were designed by energy band-gap calculations via ab initio calculations and synthesized to give rise to various emission wavelengths as expected. Fine color tuning was achieved through varying the position of the methyl substituent on the phenylpyrazole moiety with HOMO electron densities. Additional color tuning was made possible by altering the LUMO through the use of different ancillary ligands such as 1-isoquinolinecarboxylic acid (1<i>iq</i>) and 3-isoquinolinecarboxylic acid (3<i>iq</i>).