Sensitivity to NH3 Vapor: Synthesis and Characterization of Five New Coordination Polymers Based on 2,2-Dimethylglutaric Acid and Bis(triazole)-Derived Ligands.

Five new coordination polymers (CPs) were obtained as a result of hydrothermal reactions of 2,2-dimethylglutaric acid (H2dmg) and 1,4-bis(1H-1,2,4-triazol-1-ylmethyl)benzene (pbtx)/1,2-bis(1H-1,2,4-triazol-1-ylmethyl)benzene (obtx) ligands with some metal ions [Co(µ-dmg)(µ-obtx)]n (1), [Zn(µ-dmg)(µ-obtx)]n (2), [Cd(µ-dmg)(µ-obtx)]n (3), [Co2(µ-dmg)2(µ-pbtx)2]n (4), and [Cd(µ-dmg)(H2O)(µ-pbtx)]n (5). All of the compounds were characterized by elemental analysis, FT-IR spectroscopy, single-crystal X-ray diffraction, powder X-ray diffraction, and thermal analysis techniques. The single-crystal X-ray studies show that all compounds exhibit 2D layer structures. To examine the ammonia sensing properties of five new coordination complexes (1-5), the absorption and emission spectra of CPs embedded in ethyl cellulose thin films were measured by exposure to different concentrations of ammonia (NH3) vapor. The [Co2(µ-dmg)2(µ-pbtx)2]n (4)-based sensor agent was found to show promising sensor properties in detecting NH3 vapor.

Tuning CO2 sensing properties of HPTS along with newly synthesized coordination polymers (CPs).

Coordination polymers (CPs), new functional hybrid materials, have received important attention due to their structural features and many different applications such as gas storage, catalysis, energy storage, small molecule adsorption, luminescence, and chemical sensors. In this study, two newly synthesized metal-organic frameworks (MOFs); [Mn2(µ4-dmg)-(µ4-dmg)(µ-bipy)]n (CP1) and [Mn2(µ4-dmg)(µ4-dmg)(µ-dpeten)]n (CP2); were used for sensing of gaseous carbon dioxide with a spectrofluorometric method with a dye, 8-hydroxypyrene-1, 3, 6-trisulfonic acid (HPTS) as matrix additive material for the first time. The ion-pair form of the HPTS was used in the polymethyl methacrylate matrix as a thin film form. When the HPTS based sensing slides along with the CPs, resulted in many advances such as high relative signal change and larger linear response range, improved sensor dynamics, and higher sensitivity with respect to the additive-free form. More specifically, in the presence of silver nanoparticles (AgNPs), the variation in relative signal intensities of CP1 and CP2 doped HPTS sensing agents were measured as 60 and 40% for the concentration range of 0-10% pCO2, respectively. The aim of this study is to enhance the CO2 response of HPTS with doped CPs due to their useful attributes and potential applications containing selective gas absorption.

Ruthenium (II) complexes of thiosemicarbazone: synthesis, biosensor applications and evaluation as antimicrobial agents.

A conformationally rigid half-sandwich organoruthenium (II) complex [(η(6)-p-cymene)RuClTSC(N-S)]Cl, (1) and carbonyl complex [Ru(CO)Cl(PPh3)2TSC(N-S)] (2) have been synthesized from the reaction of [{(η(6)-p-cymene)RuCl}2(µ-Cl)2] and [Ru(H)(Cl)(CO)(PPh3)3] with thiophene-2-carboxaldehyde thiosemicarbazon (TSC) respectively and both novel ruthenium (II) complexes have been characterized by elemental analysis, FT-IR and NMR spectroscopy. The peripheral TSC in the complexes acts as an electrochemical coupling unit providing the ability to carry out electrochemical deposition (ED) and to form an electro-deposited film on a graphite electrode surface. The biosensing applicability of complexes 1 and 2 was investigated by using glucose oxidase (GOx) as a model enzyme. Electrochemical measurements at -0.9V versus Ag/AgCl electrode by following the ED Ru(II) reduction/oxidation due to from the enzyme activity, in the presence of glucose substrate. The designed biosensor showed a very good linearity for 0.01-0.5mM glucose. The in vitro antimicrobial activities of complexes 1 and 2 were also investigated against nine bacterial strains and one fungus by the disc diffusion test method. No activity was observed against the Gram-negative strains and fungus, whereas complex 1 showed moderate antibacterial activities against Gram-positive bacterial strains.