Selective sensing of picric acid using a Zn(II)-metallacycle: experimental and theoretical validation of the sensing mechanism and quantitative analysis of sensitivity in contact mode detection.

A combination of ,',''-tris(3-pyridyl)-1,3,5-benzenetricarboxamide (L1) and -chlorobenzoic acid (HL2) with Zn(NO)·6HO resulted in the formation of a dinuclear metallacycle [ZnL1(L2)(DMF)] (1(DMF)4). In 1(DMF)4, the Zn(II) centre adopts a square pyramidal geometry, while one of the pyridyl N out of the three pyridyl groups in L1 remained uncoordinated. Solvated DMF molecules are present in 1(DMF)4.

Two pillared-layer metal-organic frameworks based on the pinwheel trinuclear carboxylate-clusters of Zn(II) and Co(II): synthesis, crystal structures, magnetic study, and Lewis acid catalysis.

Using a dicarboxylic acid, [1,1'-biphenyl]-4,4'-dicarboxylic acid (HL1) and an exobidentate ligand, (1,1')-,'-(1,4-phenylene)bis(1-(pyridin-4-yl)methanimine) (L2), two 3D interpenetrated networks, {[Zn(L1)(L2)]·9HO} (Zn-MOF) and {[Co(L1)(L2)(DMF)]·0.5DMF} (Co-MOF), have been prepared in good yields. The crystal structure analysis of Zn-MOF and Co-MOF revealed that both have a 3D pillared-layer structure based on pinwheel trinuclear metal-carboxylate clusters as secondary building units (SBUs).