Jian Zhong Huo

Syntheses, structural diversities and characterization of a series of coordination polymers with two isomeric oxadiazol-pyridine ligands

In this work two positional-isomeric oxadiazol-pyridine ligands 3-(5-methyl-1,3,4-oxadiazol-2-yl)pyridine (L1) and 4-(5-methyl-1,3,4-oxadiazol-2-yl)pyridine (L2) have been designed and synthesized. A series of novel coordination polymers, namely [Cd2(μ2-L1)2(μ2-NCS)4]n (1), {[Cd(L1)(μ2-dca)2(H2O)]·H2O}n (2), {[Cu(μ2-L1)2(NCS)2]·0.5H2O}n (3), {[Ag2(μ2-L1)(μ3-L1)2]·2PF6}n (4), {[Ag3(μ2-L1)4(μ2-CF3SO3)(CF3SO3)]·CF3SO3} (5), {[Cd(L2)2(μ2-NCS)2]}n (6), [Ag(μ2-L2)(μ2-CF3SO3)]n (7) and {[Ag(μ2-L2)]·BF4}n (8) have been isolated. Both 1 and 2 are 2D CdII coordination polymers containing infinite {Cd–NCS–Cd} chains (for 1) or infinite {Cd–dca–Cd} layers (for 2), respectively. 3 is a 2D CuII coordination polymer, in which central metal ions are bridged via a bidentate bridging L1 ligand. While when different AgI salts were introduced into the reaction system, 1D AgI coordination polymers 4 and 5 with diverse coordination modes can be isolated. Furthermore, when the isomeric oxadiazol-pyridine L2 is used to replace L1 in the reaction system, 6–8 can be isolated. 6 is a 2D CdII coordination polymer containing {Cd–NCS–Cd} layers. 7 is a 2D neutral AgI coordination polymer while 8 is a 2D cationic AgI coordination polymer. Variable temperature magnetic susceptibility measurements (2–300 K) reveal anti-ferromagnetic interactions between central copper(II) ions for 3. Solid-state luminescent properties of 1, 2 and 4–8 have been investigated indicating strong fluorescent emissions. Additionally, luminescent measurements illustrate that complex 8 exhibits highly sensitive luminescence sensing for Cr2O72− ions in aqueous solutions with high quenching efficiency Ksv = 2.08 × 104 L mol−1 and low detection limit (0.19 μM (S/N = 3)). 8 also represents the first report of a coordination polymer based on oxadiazol-pyridine derivatives with a luminescence response to Cr2O72− anion pollutants in aqueous solutions.

Solvo-thermal synthesis of a unique alkaline earth-transition Ba-Cd micro-porous coordination framework as hetero-metallic luminescent sensor for Cu 2+ and real-time detection of benzaldehyde

In this work a unique hetero-metallic alkaline earth-transition Ba-Cd luminescent micro-porous metal-organic framework {[BaCd(μ6-tp)1.5(μ2-Cl)(H2O) (DMF)2]·0.75H2O}n (H2tp=terephthalic acid) (1) has been prepared under solvo-thermal conditions. In 1 infinite 1D {Ba-X-Cd} (X=O, Cl) inorganic chains are linked via these full de-pronated tp2- ligands forming a unique 3D I1O2 type micro-porous coordination framework. PXRD patterns of 1 have been determined confirming pure phases of 1. Luminescence investigations suggested that 1 exhibits highly selective and sensitive sensing for trace amounts of benzaldehyde in ethanol, which provides a facile method for real-time detection of benzaldehyde. Meanwhile 1 also exhibits highly selective and sensitive sensing for Cu2+ over other cations with high quenching efficiency Ksv value 1.15×104L·mol-1. As far as we know, 1 represents the first example of alkaline earth-transition hetero-metallic Ba-Cd micro-porous coordination framework as bi-functional luminescent probes for Cu2+ and benzaldehyde.

Anion directing self-assembly of 2D and 3D water-stable silver(I) cation metal organic frameworks and their applications in real-time discriminating cysteine and DNA detection

Two water-stable silver(i) cation metal organic frameworks (MOFs), namely 2D MOF {[Ag(L)2]BF4}n (1) and 3D MOF {[Ag3(L)3]·(H2O)·(CF3SO3)3}n (2) (L = 1-(4-aminobenzyl)-1,2,4-triazole), have been prepared. 1 is the first example of a 2D MOF-based sensor for real-time discrimination of l- and d-cysteine from other amino acids through the quenching effect. Through deliberately tuning the nanoparticles of 2 under ultrasound conditions, these nanoparticles are, for the first time, successfully applied as an excellent DNA detecting platform.

Hydrothermal Preparation of Five Rare-Earth (Re = Dy, Gd, Ho, Pr, and Sm) Luminescent Cluster-Based Coordination Materials: The First MOFs-based Ratiometric Fluorescent Sensor for Lysine and Bifunctional Sensing Platform for Insulin and Al3+

Through the powerful hydrothermal method, five rare-earth (Re = Dy, Gd, Ho, Pr, and Sm) three-dimensional (3D) cluster-based metal-organic frameworks (MOFs) have been synthesized, namely, [Dy(L)(H2O)(DMF)] n (1), {[Gd(L)(H2O)(DMF)]·DMF} n (2), {[Ho(L)(H2O)(DMF)]·0.5DMF} n (3), {[Pr(L)(H2O)(DMF)]·0.5DMF} n (4), and {[Sm(L)(H2O)1.55(DMF)0.45]·DMF} n (5; H3L = terphenyl-3,4″,5-tricarboxylic acid), which have been determined by single crystal X-ray analyses and PXRD characterization. Structural analyses reveal that, in 1-5, these L3- ligands are linked by five different rare-earth centers, forming the iso-structural nanoporous frameworks. PXRD patterns of bulky samples 1-5 also are consistent with theoretical PXRD patterns confirming their purity. Solid state photoluminesce of free H3L and 1-5 at room temperature also has been investigated indicating strong ligand-based emissions. Besides these, fluorescent dye Rhodamine B (RhB) can be introduced into MOF1 forming the composite material RhB@MOF1 with a high quantum yield of 35%. It is noted that, through deliberately tuning the morphologies of nanoparticle MOF1 under different ultrasonic conditions, RhB@MOF1 can be utilized as the first ratiometric fluorescent sensor to effectively discriminate l- and d-lysine from other amino acid molecules with high Ksv values and low LOD values. On the other hand, 2 was for the first time to be utilized as an excellent bifunctional MOFs-based sensing platform to detect insulin and Al3+ with a low detection limit in the human serum solution.