Controllable Synthesis Of N-donor Ligands Metal-Organic Frameworks And Their Properties Of Catalysis

Objective To investigate the influence of reactive conditions on the structures of Keggin POM based metal-organic frameworks(MOFs) and the relations between structures and activities, eight new compounds were hydrothermally synthesized by tuning the reactive species, pH values and selected ligands reasonable.Methods POMOFs were hydrothermally synthesized and characterized by routine methods(IR and XPRD) and single-crystal X-ray crystallography. Furthermore, the photocatalytic activies for the decomposition of Rhodamine B was investigated.Results Three metal–organic networks with different degrees of interpenetration based on Keggin-type polyoxometalates have been hydrothermally synthesized by a simple change in the organic ligand and structurally characterized, namely([Cu2(bipy)2][H2SiW12O40]·(bipy))(1);([Cu(bpyb)2(H2O)2][H2SiW12O40]·(bpyb))(2);([Cu(bib)][H2SiW12O40]·(bib)·2H2O)(3). Porous polyoxometalates based coordination polymers(POMCPs) constructed form Keggin POMs and Ag+ with pyttz were synthesized, [Ag4(H2pyttz-I)(H2pyttz-II)(Hpyttz-II)][HSiW12O40]·4H2O(4) and [Ag4(H2pyttz-I)(Hpyttz-II)2][H2SiW12O40]·3H2O(5).(H2pyttz-I = 3-(pyrid-2-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl; H2pyttz-II = 3-(pyrid-4-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl). Both compounds have the similar building units, similar stick-like units and similar 1D inorganic chains, but finally obtain the different motifs of tunnels(tunnel A in 4 and tunnel A&B in 5). Using POM with template successfully synthesis three Ag-carbene cages, namely,([Ag10(L5)4][H2SiW12O40]·(H2O))(6),([Ag10(L5)4][PW12O40]·2(H2O))(7),([Ag10(L5)4][HAsW12O40]·(H2O))(8).Conclusions Compound 1, 2 and 3 explain the first example on ligand molecule controlling over the degree of interpenetrating system in POMOFs. So the work provides not only novel examples of POMOFs with different fold interpenetration, but also a new strategy for control of the interpenetrating system. By careful inspection of the structures of 4 and 5, it is believed that the isomerous pyttz molecules can precisely refine the structure of porous POMCPs without changing the underlying framework, which is favor of study about the structure-activity relationship of POMCPs. Through replace the carboxyl with Ag and select the kegging-shape POM as template, we successfully synthsis three metal-carbene POMOFs.