Five 8-hydroxyquinolinate-based coordination polymers with tunable structures and photoluminescent properties for sensing nitroaromatics

Abstract

Using two 8-hydroxyquinolinate ligands (L1-MOM and L2-MOM) containing 3-pyridyl or 4-pyridyl groups, five novel coordination polymers, namely, [Zn3(L1)6] (1), [Zn(L1)2]·2MeOH (2), [Zn(L2)2] (3), [Cd(L2)2] (4), and [Cd4(L1)6]·13H2O (5), were synthesized and characterized by a variety of techniques. Single-crystal X-ray structures have revealed that these coordination polymers exhibit a structural diversification due to the different choices of metal salts and the effect of pyridyl nitrogen position. Compounds 1-5 exhibited different fluorescence emissions and lifetimes upon excitation in the solid state. The sensing behavior of these polymers was also investigated upon exposure to vapors of various nitroaromatic molecules (analytes). The results show that all five polymers are capable of sensing these nitroaromatic molecules in the vapor phase through fluorescence quenching. Interestingly, 3 exhibits superior sensitivity to the analytes in comparison with other polymers. 2-Nitrotoluene quenches the emission of 3 by as much as 96%.

Metallo-Supramolecular Coordination Polymers Based on Amidopyridine Derivatives of Pillar[5]arene and Cu(II) and Pd(II) Cations: Synthesis and Recognition of Nitroaromatic Compounds

“…To date, many metallo-supramolecular coordination polymers have been developed to analyze and/or extract nitroaromatic compounds. − However, they have common disadvantages including complex synthesis, poor functionality and insufficient thermodynamic stability. The use of macrocyclic compounds as ligands to assemble metallo-supramolecular coordination polymers removes some of these drawbacks. , For example, molecular recognition occurs within macrocyclic cavities rather than voids in the coordination lattice, and their spatially preorganized functional groups allow the creation of structurally ordered polymers. , In the literature, metallo-supramolecular coordination polymers based on functionalized calixarenes, cyclodextrins, , cucurbiturils, pyrogallol[4]­arenes, and cyanostars have been described.…”

Luminescent Coordination Polymers of Naphthalene Based Diamide with Rigid and Flexible Dicarboxylates: Sensing of Nitro Explosives, Fe(III) Ion, and Dyes

“…As the popularity of global terrorism has increased, the ability to quickly detect the presence of explosive compounds and precursors has become even more crucial. Recently, some luminescent PCP based chemical sensors have been synthesized for detecting nitroaromatic explosives in vapor phase. , Due to moderate vapor pressure and limited chemical reactivity, detection of NACs is not easy. Among all organic nitro-explosives, 2,4,6-trinitrophenol (TNP) is highly dangerous for human health (toxicology based drinking water value: 0.2 μg/L) and is extensively used for manufacturing explosive materials .…”

From a Well-Defined Organozinc Precursor to Diverse Luminescent Coordination Polymers Based on Zn(II)-Quinolinate Building Units Interconnected by Mixed Ligand Systems

“…One of the ligand systems known for its capability to form luminescent molecular complexes [ 22 ] and metal-organic materials [ 23 ] is 8-hydroxyquinoline (Hq) and its derivatives, which have been successfully applied in biomedicine [ 24 ] and the fabrication of optoelectronic devices such as organic light emitting diodes or solar cells [ 25 , 26 ]. Moreover, extended organic ligands based on the quinoline core have been applied in the development of luminescent coordination polymers, which represents an efficient strategy, albeit, often requiring multi-step preparation of organic ligand systems [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. Alternatively, simple quinolinate ligands could be incorporated into mixed-ligand CPs as co-ligands, an approach which has the challenge of designing and controlling the self-assembly of multicomponent supramolecular systems [ 35 ], therefore it is not surprising that this approach has been explored to a lesser extent and only a few examples of well-defined functional quinolinate-based CPs [ 36 , 37 , 38 ], including materials with valuable luminescent properties [ 39 , 40 ], are reported.…”