1,3,5-Triazine-Based Pt(II) Metallogel Material: Synthesis, Photophysical Properties, and Optical Power-Limiting Performance

A new Pt(II) acetylide metallogel material (Pt-1) with 1,3,5-triazine core and 3,4,5-tris(dodecyloxy)benzamide terminal units was synthesized and characterized. Its photophysical properties were studied by UV-vis absorption, emission, transient absorption, Z-scan, and nonlinear transmission spectroscopy/technique. Pt-1 exhibits ligand-centered n-π∗ and ¹π-π∗ transitions in the UV region, and broad, strong absorption bands mixed with intraligand charge transfer (¹ILCT)/ligand-to-ligand charge transfer (¹LLCT)/metal-to-ligand charge transfer (¹MLCT) in the visible spectral region (forward slashes expression indicates that all three processes can be involved, in any proportion). Meanwhile, it shows much stronger triplet transient absorption from the visible to near-infrared region. Thus, the optical power-limiting (OPL) performance of Pt-1 was demonstrated in solution and gel state for a 532 nm nanosecond laser pulse, both of which exhibit a significant decrease of output energy density when the incident light energy increases. In addition, the gel properties of Pt-1 in 15 solvents were studied and a gel sheet with good optical transparency was obtained after cooling the heating sols in dimethylformamide solution. This study can open a new outlet for OPL gelation materials and devices on the basis of the reverse saturable absorption mechanism.