A rational design and green synthesis of 3D metal organic frameworks containing a rigid heterocyclic nitrogen-rich dicarboxylate: structural diversity, CO2 sorption and selective sensing of 2, 4, 6-TNP in water. Issue 7 (28th January 2019)

• Record Type: Journal Article
• Authors: Gogia, Alisha; Mandal, Sanjay K.
• Is Part Of: Dalton transactions. Volume 48:Issue 7(2019)
• Page Start: 2388
• Page End: 2398
• Publication Date: 2019-01-28
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt04474k
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : A rational design and green synthesis of two fluorescent and chemically/thermally stable 3D MOFs along with the selective sensing of TNP in water are reported. Abstract : A heterocyclic fluorogenic linker, thiadiazole dicarboxylate (H2 tdz), offering diverse coordination modes has been utilized to synthesize two three-dimensional (3D) metal organic frameworks {[Cd2 (tdz)2 (4, 4′-bpy)2 ]·6.5H2 O} n (1 ) and [Cu(tdz)(4, 4′-bpy)] n (2 ) from a one-pot self-assembly reaction under ambient conditions in high yields. MOFs1 and2 are structurally characterized by elemental analysis, FTIR and UV-Vis spectroscopy, single crystal and powder X-ray diffraction, and thermogravimetric analysis. Their single crystal molecular structures reveal that1 contains a permanent pore along the b -axis with dimensions of 14.576 × 17.567 Å 2 while2 forms a 3D two-fold interpenetrated structure with an extensively reduced pore size. The effect of interpenetration has been further elaborated by a comparison of their CO2 uptake capacities at 263 K, 273 K and 298 K. The uptake value of CO2 for non-interpenetrated1 (24.8 cm 3 g −1 ) is much higher compared to that of interpenetrated2 (5 cm 3 g −1 ) at 298 K. Furthermore, to obtain an insight into the adsorbate–adsorbent interaction owing to the presence of the polar thiadiazole moiety and polarizable CO2 molecules, the isosteric heat of adsorption ( Q st ) was calculated for1 (29.1 kJ mol −1 ) and2 (23.4 kJ mol −1 ). Thermal and chemical stabilities of1 in water were ascertained by variable temperature powder X-ray diffraction (VT-PXRD) analysis. MOF1 having a d 10 metal center was utilized to harness the availability of nitrogen atoms in the tdz 2− linker for the selective sensing of nitrophenols in water with a detection limit for TNP as low as 1.4 ppm. Moreover, 1 is found to be stable and recyclable up to four cycles.