Isomer Directed Synthesis of Two 3D Cadmium(II) Compounds: Structure Variation and Energetic Performance

Syntheses, crystal structures and thermal decomposition studies of two novel Mn(ii)-MOFs with tetrazole-based carboxylic acids

“…The Δ H value of 1 is lower than those reported for two MOFs with the H 2 L 1 ligand, [Ba(L 1 )(H 2 O) 4 ] 15 and [Cd(L 1 )(CH 3 OH) 2 ]. 13 The Δ H value of 2 is smaller than that found for the known MOFs with the HL 2 ligand, [Cd(L 2 ) 2 ] 20 but larger than those observed in [Pb(L 2 ) 2 ] 21 and [Sr(L 2 ) 2 (H 2 O) 2 ]. 24…”

“…29 Notably, the 3D structure of 2 is totally different from those found in the HL 2 -based MOFs with the 1D chains, [Pb(L 2 ) 2 ], 21 [Ca(L 2 ) 2 (H 2 O) 2 ], 22 [Zn(L 2 ) 2 (H 2 O) 4 ]·2H 2 O 23 and [Sr(L 2 ) 2 (H 2 O) 2 ], 24 but similar to a 3D Cd-MOF [Cd(L 2 ) 2 ] with the space group P 2 1 / c . 20 However, the careful topological analysis of the MOF [Cd(L 2 ) 2 ] reveals that it was incorrectly simplified as a 3D uninodel 6-connected net, 20 while it should be identified as a binodal 5,6-connected framework as well.…”

“…The ligands H 2 L 1 and HL 2 were synthesized according to the literature method. 13,20 The C, H and N elemental analyses were carried out on a PerkinElmer 2400 microanalyzer. The IR spectra (4000–400 cm −1 ) were recorded on a NICOLET 380 spectrometer with KBr discs.…”

“…2,13,19 However, blue shifts of 3 nm and 37 nm are observed for 1 and 2 , respectively, which are in good consistent with those of the reported Cd( ii )-MOFs with the H 2 L 1 and HL 2 ligands, [Cd(L 1 )(CH 3 OH) 2 ] 13 and [Cd(L 2 ) 2 ]. 20 Notably, the luminescence emission of 2 has a larger intensity than that of the free HL 2 ligand, showing that the rigid 3D network of 2 possesses a better conjugated system for luminescence enhancement. In contrast, the fluorescence intensity of 1 decreased obviously compared with the free H 2 L 1 ligand owing to the presence of the relatively big dihedral angles between the phenyl and tetrazole rings in the 2D layer of 1 .…”

“…In our previous work, a series of tetrazole-based carboxylic acids such as N -(1-carboxymethyltetrazole-5-yl)- N -(2′-carboxymethyltetrazole-5′-yl)amine, 11,12 1,3-bis(2-carboxymethyltetrazol-5-yl)benzene (H 2 L 1 ), 13–15 1,4-bis(2-carboxymethyltetrazol-5-yl)benzene, 16 1,3,5-tri(2-carboxymethyltetrazol-5-yl)benzene, 2,14,17–19 and 2-(5-(3-pyridyl)tetrazol-2-yl)propionic acid (HL 2 ) 20–24 have been designed and successfully prepared. Their MOFs with Mg( ii ), Ca( ii ), Sr( ii ), Ba( ii ), Pb( ii ), Mn( ii ), Co( ii ), Zn( ii ), and Cd( ii ) ions have been synthesized and the related properties like luminescence, 2,11,16 thermal decomposition, 13,16,17,20,21,24 proton conduction 2 and anticancer activity 22,23,25 have also been researched. As a continuation of our investigation on the tetrazole-based carboxylic acids, herein we present two new Mn( ii )-MOFs: [Mn(L 1 )(DMF)(H 2 O)]·0.375H 2 O ( 1 ) and [Mn(L 2 ) 2 ] ( 2 ) derived from H 2 L 1 and HL 2 ligands (Scheme 1).…”