Photophysical properties and optical power limiting ability of Pt(II) polyynes bearing fluorene-type ligands with ethynyl units at different positions.

Two series of Pt(II) polyynes bearing fluorene-type ligands with ethynyl units at different positions have been synthesized. In the absorption spectra, the Pt(II) polyynes bearing fluorene-type ligands with ethynyl units at 3,6-position have blue-shift with respect to the corresponding analogs bearing fluorene-type ligands with ethynyl units at 2,7-position, showing better transparency in the visible light region. Moreover, the Pt(II) polyynes bearing fluorene-type ligands with ethynyl units at 3,6-position show stronger triplet emission than corresponding analogs bearing fluorene-type ligands with ethynyl units at 2,7-position in the photoluminescent (PL) spectra. Furthermore, these Pt(II) polyynes were applied to optical power limiting (OPL) field. The Pt(II) polyynes bearing fluorene-type ligands with ethynyl units at 2,7-position show better OPL performance than the corresponding analogs with fluorene-type ligands of ethynyl units at 3,6-position. Therefore, changing the position of the ethynyl units in fluorene-type ligands can not only effectively control the photophysical properties of the Pt(II) polyynes, but also has an important effect on their OPL ability. By changing the substitution positions of two ethynyl units in the fluorene-type ligands, the photophysical properties and optical power limiting performance of these Pt(II) polyynes can be effectively tuned. Image 1 • Two series of Pt(II) polyynes bearing fluorene-type ligands with ethynyl units at different positions. • Enhanced transparency and triplet emission of Pt(II) polyynes with fluorene-type ligands with ethynyl units at 3,6-position. • Better OPL performance of the Pt(II) polyynes bearing fluorene-type ligands with ethynyl units at 2,7-position. [ABSTRACT FROM AUTHOR]