Theoretical study of two-photon absorption properties of a series of platinum (II) acetylide complexes

• The Pt acetylide compounds have the outstanding two-photon absorption property compared with Ni and Pd.
• This contribution provides an effective way for designing of large TPA cross-section platinum (II) acetylides compounds.
• Intramolecular charge transfer between center metal and π-conjugated organic fragment dominates in TPA transitions.

Transition metal acetylide compounds have attracted enormous attention because of the extraordinary photophysical properties arising from the electronic interaction between the transition metal and the organic molecular fragment. In this study, the geometrical structure, electronic structure, one-photon absorption (OPA) and two-photon absorption (TPA) properties of a series of D–π′–A–π–[Pt]–π–A–π′–D type and A′–π′–A–π–[Pt]–π–A–π′–A′ type platinum(II) acetylides were studied theoretically by using density functional theory (DFT) and Zerner's intermediate neglect of differential overlap (ZINDO) methods for getting TPA materials possessing large TPA cross-section. Our analysis suggests that intramolecular charge transfer between center metal and π-conjugated organic fragment dominates in TPA transitions, in which metal center increases conjugation length in the direction of long ligand. This contribution provides detailed theoretical analysis of one- and two-photon absorption property of Platinum (II) acetylide compounds and an effective way for designing of platinum (II)/nickel (II) acetylide compounds possessing large TPA cross-section.