Two W/S/Cu-Cluster-Containing Metal-Organic Frameworks Fabricated by Multidentate Organic Ligands: New Topologies, Strong NLO Properties, and Efficient Luminescent Detection

Multidentate organic ligands 3,5-bis(4-pyridyl)pyridine (dpypy) and 1,2,4,5-tetrakis(4-pyridyl)benzene (tpb) are first exploited to construct cluster-containing metal-organic frameworks (C-MOFs). Two W/S/Cu C-MOFs {[NH4][WS4Cu4(dpypy)Cu(CN)(4)]center dot DMF}(n) (1) and {[NH4][WS4Cu4(tpb)Cu-2(CN)(5)]center dot DMF}(n) (2) have been successfully synthesized and fully characterized. 1 possesses an unprecedented (3,3,7)-c 3D framework with the first 7-connected (7-c) W(Mo)/S/Cu building clusters, 3-c Cu+ and dpypy building units, and single/double CN- bridges. 2 is fabricated by the rare 8-c [WS4Cu4](2+) building clusters, 3-c Cu+ and 4-c tpb building units, and single CN- to form a new (3,4,8)-c 3D architecture. Z-scan experiments reveal that they exhibit strong NLO properties. Especially, the hyperpolarizability (gamma) of 1 is 10 or even a hundred times higher than those of the reported [W(Mo)S4Cu4](2+)-cluster-containing MOFs or coordination polymers. Moreover, luminescence tests demonstrate that 1 can efficiently detect TNP in a water medium.

Automated summary

Two cluster-containing metal-organic frameworks (C-MOFs) were successfully synthesized using multidentate organic ligands, exhibiting strong nonlinear optical properties and efficient detection of TNP in a water medium.