Coordination Architectures of energetic Cd (II) coordination polymers constructed by the bifunctional substituted-tetrazole-carboxylate ligands

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

A 2D sql framework and an unprecedented binodal 5,6-connected 3D net have been constructed from Mn(ii) ions and two tetrazole-based carboxylic acids.

Ba-MOFs with tetrazole-based acetic acids: unusual configuration, novel topology and high proton conductivity

Metal-organic frameworks (MOFs) as proton-conductive materials have attracted increasing attention due to their applications in proton-exchange membrane fuel cells. While the majority of the MOFs are based on transition metals, group II metals with unusual configurations have received relatively less attention. In this work, we selected three tetrazole-based acetic acids, N,N-di(2-carboxymethyltetrazol-5-yl)amine (H₂L¹), 1,3,5-tri(2-carboxymethyltetrazol-5-yl)benzene (H₃L²), and 4,5-di(tetrazol-5-yl)imidazolylacetic acid (H₃L³), as ligands and prepared three MOFs with barium(ii) ions: [Ba₂(L¹)₂(H₂O)₅]·2H₂O (1), (Me₂NH₂)[Ba(L²)(H₂O)]·3H₂O (2), and [Ba₃(μ₂-H₂O)(L³)₂(H₂O)₃]·2H₂O (3). Ba-MOFs have been unambiguously characterized by elemental, FT-IR spectroscopy and single-crystal X-ray diffraction analyses. In the solid state, 2D MOF 1 with two nine-coordinated Ba(ii) centers shows a rare hula hoop-like geometry at the Ba1 atom and a distorted tricapped trigonal prismatic geometry around the Ba2 one. Unusual sphenocorona geometry is also found in MOF 2 with a ten-coordinated Ba(ii) ion. In MOF 3, three different Ba(ii) ions coexist with two nine-coordinated Ba1 and Ba2 displaying a muffin-like configuration and a distorted tricapped trigonal prism geometry, respectively, and an eight-coordinated Ba3 having a distorted biaugmented trigonal prism geometry. In addition, MOF 2 exhibits an unprecedented trinodal 3,7,7-connected 3D network with the Schläfli symbol (3⁷·4⁶·5²·6²·7⁴)(3⁷·4⁶·5²·6³·7³)₂(6³) and MOF 3 displays a novel trinodal 4,5,9-connected 3D framework with the Schläfli symbol (4²¹·6¹⁵)(4⁵·6)(4⁸·6²). Due to the presence of extensive hydrogen bonded networks consisting of dimethyl ammonium and water molecules in the 1D channels, MOF 2 shows a high proton conductivity of 4.47 × 10^-3 S cm^-1 at 85 °C and 98% relative humidity (RH).

Synthesis, crystal structure, and thermal properties of Ni(NH3)4(AFT)2

Ni(NH3)4(AFT)2 [NiC6H16N18O2, AFT = 4-amino-3-(5-tetrazolate)furazan] is synthesized and characterized by elemental analysis and Fourier-transform infrared spectroscopy for the first time. X-ray diffraction measurements are used to determine the crystal structure of compound 1. The results demonstrate that compound 1 crystallized in the orthorhombic crystal system. The nickel(II) ion is six-coordinated by N atoms from two AFT-ligands and four NH3 molecules. Its thermal properties are investigated by differential scanning calorimetry and thermogravimetry-derivative thermogravimetry methods, with the results demonstrating that the differential scanning calorimetry curve exhibits two endothermic and one exothermic processes. The endothermic processes are in the range of 130–510 °C with a peak temperature of 188 °C. The temperature from 230 to 400 °C is the exothermic process in which the peak temperature is 314.58 °C. In addition, Kissinger’s and Ozawa-Doyle’s methods are used for calculating the non-isothermal kinetics parameters. Moreover, the apparent activation energy ( E), safety, and thermal stability parameters ( TSADT, TTIT, Tb) for Ni(NH3)4(AFT)2 are calculated. In addition, the calculated thermodynamic functions ( ∆S≠, ∆H≠, and ∆G≠) for the exothermic decomposition process of Ni(NH3)4(AFT)2 are 55.07 J mol−1 K−1, 196.18 kJ mol−1, and 164.90 kJ mol−1, respectively.

5-(2-Pyridil)-1H-tetrazole complexes with Mo(iv) and W(iv) cyanides

The reactions of tetrazole ligand derived from 2-cyanopyridine with K₃Na[Mo(CN)₄O₂]·6H₂O and K₃Na[W(CN)₄O₂]·6H₂O in water–ethanol solution result in isolation of two new complexes with the following formulae: (PPh₄)₂[Mo(CN)₃O(pdt)]·2H₂O (1) (Hpdt = 5-(2-pyridil)-1H-tetrazole) and (PPh₄)₂[W(CN)₃O(pdt)]·3H₂O (2).