| Abstrakt: |
The optical performance of metal oxo clusters has attracted increasing research attention. Here, we investigate the photophysical properties of heterometallic Sn–Ti oxo clusters incorporating conjugated ligands. Three unprecedented dual-layered Sn–Ti oxo clusters were prepared using 1,10-phenanthroline as a functional ligand with formulas: [Sn II2 Ti IV12 (μ3-O)6(μ2-O)12(phen)8(Pr)10Cl2]·(SnIICl3)2·(Pr)2·(CH3CN)2 (TOC-61, HPr = propionic acid; phen = 1,10-phenanthroline), [Sn II2 Ti IV12 (μ3-O)8(μ2-O)10(phen)8(IPA)4(Pr)8Cl2]·(SnIICl3)2 (TOC-62, HIPA = isopropanol), and [Sn II6 Ti IV14 (μ3-O)9(μ2-O)14(phen)6(Pr)14Cl6]·SnIICl3·Pr (TOC-63). The distances between the 1,10-phenanthroline ligands in the three structures are in the ranges of 3.636–4.139, 3.692–4.388 and 3.422–4.001 Å, respectively, so that they all have strong intramolecular π⋯π interactions. Moreover, TOC-62 exhibits stronger intermolecular π⋯π interactions than TOC-61 and TOC-63. The optical gap values of TOC-61 to TOC-63 are 2.04, 1.95 eV, and 2.27 eV, respectively. The open aperture (OA) Z-scan measurements show that the three compounds all exhibit an obvious third-order nonlinear optical (NLO) response, as well as laser irradiation stability and repeatability. Interestingly, with the enhancement of the π⋯π interactions in these heterometallic Sn–Ti oxo clusters, the general trend of the optical gaps is gradually reduced and optical limiting (OL) effects are gradually enhanced. This work offers a route for preparing heterometallic Sn–Ti compounds with interesting optical properties, and provides a platform for studying the structure–performance relationship of heterometallic materials at the molecular level. [ABSTRACT FROM AUTHOR] |
