Stabilization of the Anionic Metalloligand, [Ag₆(mna)₆]^6– (H₂mna = 2-Mercapto Nicotinic Acid), in cor, α-Po, and sql Nets Employing Alkaline Earth Metal Ions: Synthesis, Structure, and Nitroaromatics Sensing Behavior

Abstract

Three new heterometallic metal organic frameworks, [{[Ca6(H2O)18]­[Ag6(mna)6]2}­·[Ag6(Hmna)6]­·20H2O], 1, {[Sr3(H2O)10]­[Ag6(mna)6]­·12H2O}, 2, and {[Ba3(H2O)10]­[Ag6(mna)6]­·8H2O}, 3, have been synthesized following hard–soft acids–bases principle. Compounds 1 and 2 have three-dimensional structures with cor and pcu (α-Po) topology, whereas compound 3 has a two-dimensional sql topology. Smaller calcium and strontium ions form a simple dimer (Ca2/Sr2, 1/2) and tetramer units (Sr4, 2), whereas the larger barium ion forms infinite Ba–O–Ba chains. The presence of the electron-rich mna ligand in all the compounds paved the way for the detection of electron-deficient hazardous nitroaromatics employing photoluminescence quenching methods. The luminescence intensities of the compounds are strongly quenched by picric acid, p-nitro phenol, and 2-nitro toluene at low concentration, which indicates that these compounds are excellent materials for the detection of these nitroaromatics in solution.

Cu6S6 Clusters as a Building Block for the Stabilization of Coordination Polymers with NiAs, NaCl, and Related Structures: Synthesis, Structure, and Catalytic Studies

“…A similar observation was also made for the [Ag 6 (mna) 6 ] 6– cluster with Na + ions in 4Na + · 2[C 4 O 3 H 12 N] + · [Ag 6 (mna) 6 ] 6– · 10H 2 O . The connectivity between the [Ag 6 (mna) 6 ] 6– clusters and alkaline‐earth metal ions (Ca, Sr, Ba), on the other hand, leads to many different structures . Of these, the connectivity of Sr 2 dimers and Sr 4 tetramers with [Ag 6 (mna) 6 ] 6– gives rise to the α‐ Po structure (Figure ).…”

“…(g) Na 4 tetramer in ref ,. and (i) Sr 2 dimer and Sr 4 tetramer in ref . Nodal representation of the structures observed in (b) II , (d) IV , (f) ref ,.…”

“…In the present study we stabilized the Cu 6 S 6 cluster in NiAs‐ ( I ) and NaCl‐like structures ( II and IV ) as well as preparing a new type of network structure ( III ). We have previously reported other NaCl network structures based on the Cu 6 S 6 cluster, namely [{Mn 4 (OH) 2 (H 2 O) 10 }{Cu 6 (2‐mna) 6 } · 8H 2 O]” by “We have previously reported other NaCl network structures based on the Cu 6 S 6 and Ag 6 S 6 clusters, namely [{Mn 4 (OH) 2 (H 2 O) 10 }{Cu 6 (2‐mna) 6 } · 8H 2 O] and [{Sr 3 (H 2 O) 10 }{Ag 6 (2‐mna) 6 } · 12H 2 O] . Lewis acid catalyzed nitroaldol reactions were shown to be promoted by these compounds, which exhibited very good catalytic activity.…”

“…Over the years, many inorganic–organic coordination polymers have been prepared by employing different metal clusters as nodes . For example, silver clusters, such as Ag 6 S 6 and Ag 9 S 9 , have been incorporated as part of the framework during the preparation of coordination polymer compounds . We were intrigued by the possibility of utilizing the ideas of HSAB theory for the design of building blocks that may lead to new inorganic–organic coordination polymers.…”

Calcium‐Based Metal–Organic Frameworks and Their Potential Applications

“…The synergistic effect of the size selectivity of regular nanopores and weak intermolecular interactions between toluene vapors and the framework affords the high selectivity and sensitivity toward toluene vapor. [85,86] Natarajan and co-workers [87] reported another bimetallic LMOF that exhibits sensitive and selective detection of nitroaromatics.…”