Substituent effect of fluorine ligand on spectroscopic properties of Pt(N^C^N)Cl complexes, a theoretical study

Time-Dependent Density Functional Theory (TDDFT) method was used to investigate the substituent effect of fluorine ligand on geometrical structures, electronic properties, electroluminescent properties, absorption and emission spectra of six tridentate cyclometalated Pt(II) complexes. M062X hybrid functional was proved to be suitable for calculating the lowest triplet excited state (T1) characters in TDDFT calculations. The energies of d–d transitions both in absorption and emission were larger than HOMO–LUMO energy gaps, so d–d transitions did not easily occur. With the introduction of fluorine ligand, the energy levels did not show regularity changes, while the IP (ionization potentials) values and EA (electron affinities) values increased correspondingly. The phosphorescence emissions of the complexes were all assigned as 3ILCT mixed with 3MLCT. In addition, one dimeric form of cyclometalated Pt(II) complexes have also been investigated.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► d–d Transitions did not easily occur. ► The energy levels did not show regularity changes. ► One dimeric form of cyclometalated Pt(II) complexes have also been investigated.