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]·DMF}n(1) and {[NH4][WS4Cu4(tpb)Cu2(CN)5]·DMF}n(2) have been successfully synthesized and fully characterized. 1possesses 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. 2is 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 (γ) of 1is 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 1can efficiently detect TNP in a water medium.