Tetraalkylammonium cations as templates in the construction of two cadmium( ii ) metal–organic frameworks

Hydrothermal reaction of cadmium salts with HATZ in the presence of R4NBr (R = Et, Pr) led to two organic cation templated Cd(II) MOFs, (Et4N)[Cd6Br5(ATZ)8]·H2O (1) and (Pr4N)[Cd4Br5(ATZ)4] (2) (HATZ = 5-amino-tetrazolate, Et = ethyl and Pr = propyl), which are the first examples of tetraalkylammonium cations templated N-heterocyclic ligand based MOFs. These two MOFs have been fully characterized by single crystal X-ray diffraction, XRD, TGA, IR, elemental analysis, photoluminescence spectra and combustion heat measurement. The anionic frameworks of 1 and 2 are three- and two-dimensional, respectively. Topological analyses show that compound 1 exhibits an unprecedented binodal (4,10)-connected network, which is a subnet of the (12,12)-connected tcj net, and compound 2 is a 2-D uninodal four-connected network when the Cd6 clusters in these two MOFs are viewed as nodes. Moreover, compound 1 maybe have potential application as an energetic material due to its high enthalpy of formation.