Photophysical and Fluorescence Nitroaromatic Sensing Properties of Methylated Derivative of a Pamoic Acid Ester.

Rapid and selective detection of nitroaromatic explosives is very important for public safety, life, and environmental health. Current instrumental techniques suffer from high cost and poor site used. In order to investigate fluorescence sensing of nitroaromatics, we prepare a new small fluorescence probe derived from pamoic acid. This study covers the synthesis of Pamoic acid based [diisopropyl 4,4'-methylenebis(3-methoxy-2-naphthoate)] (2) material and characterization of its structure. The methylation of Pamoic acid ester, which we have successfully synthesized in our previous studies, was carried out in this study. Determination of the photophysical and fluorescent nitroaromatic detection properties of the compound forms the basis of the study. Structural characterization of the synthesized compound [diisopropyl 4,4'-methylenebis(3-methoxy-2-naphthoate)] (2) was characterized using spectroscopic methods. In addition, Molecular structure of the synthesized compound was determined by single crystal X-ray diffraction studies. In the final step, compounds [diisopropyl 4,4'-methylenebis(3-hydroxy-2-naphthoate)] (1) and [diisopropyl 4,4'-methylenebis(3-methoxy-2-naphthoate)] (2) were tested as fluorescent probes for the detection of some nitroaromatic explosives. It is seen that Nitrobenzene provides the best quenching effect on the compound [diisopropyl 4,4'-methylenebis(3-hydroxy-2-naphthoate)] (1) containing the -OH group, with lowest the limit of detection (LOD) value. It was observed that Picric acid provided the best quenching effect with lowest the limit of detection (LOD) value in the compound [diisopropyl 4,4'-methylenebis(3-methoxy-2-naphthoate)] (2) obtained by methylation of the -OH group in the compound [diisopropyl 4,4'-methylenebis(3-hydroxy-2-naphthoate)] (1).

Pyrene, Anthracene, and Naphthalene-Based Azomethines for Fluorimetric Sensing of Nitroaromatic Compounds.

Special attention is given to the development of rapid and sensitive detection of nitroaromatic explosives for homeland security and environmental concerns. As part of our contribution to the detection of nitroaromatic explosives, fluorescent materials (A), (B) and (C) were synthesized from the reaction of 1,2-diaminocyclohexane with pyrene-1-carbaldehyde, anthracene-9-carbaldehyde and 2-hydroxy-1-naphthaldehyde, respectively. The structures of the prepared fluorescent azomethine probes were confirmed using FTIR, 1H-NMR and 13C-NMR spectroscopies. The basis of the study is the use of the synthesized materials as fluorescent probes in the photophysical and fluorescence detection of some nitroaromatic explosives. Emission increases occurred due to aggregation caused by π-π stacking in synthesized azomethines. To measure the nitroaromatic detection capabilities of fluorescence probes, fluorescence titration experiments were performed using the photoluminescence spectroscopy. It was observed that compound A containing pyrene ring provided the best emission intensity-increasing effect due to aggregation with the lowest LOD value (14.96 µM) for the sensing of 4-nitrophenol. In compounds B and C, nitrobenzene with the lowest LOD (16.15 µM and 23.49 µM respectively) caused the most regular emission increase, followed by picric acid.

Investigation of Chemosensing and Color Properties of Schiff Base Compounds Containing a 1,2,3-triazole Group.

A series of Schiff base compounds (ER1-ER5) containing a 1,2,3-triazole and carboxylic acid groups were synthesized and their chemosensory properties towards anions (I-, CO32-, SO42-, NO2-, NO3-, CH3COO-, ClO3-, CNO-, N3-) and cations (Al3+, Ag+, Co2+, Cr3+, Cu2+, Fe3+, Hg2+, Mn2+, Ni2+, Zn2+, Cd2+, Pb2+). The compounds were also used as fluorescence probs for the detection of nitroaromatic compounds. The structural characterization of the synthesized compounds was elucidated using methods such as FT-IR, UV, FL, LC-MS, MALDI-TOF MS, 1H(13C) NMR. The effect of substitute groups (-CH3, -OCH3, -OH, -Cl and -Br) on the synthesized Schiff bases (ER1-ER5) on the chemosensory properties were compared. As the groups changed, the sensor and quenching effects of the molecule against anions and cations changed. Compound ER3 having methoxy (OCH3) group exhibited selective sensor properties against Fe3+ ion while compound ER5 with a chloride substitute (Cl) group showed selectivity for Cr3+ ion under 254 nm UV-lamp. The substitute effect was also observed for the sensing of anions. Under 254 nm UV-lamp, ER2 having the -OH group has a selective sensing property for CNO- and ER4 with the bromide (Br) group exhibited selectivity for N3- ion. The synthesized Schiff base compounds were also tested as fluorescence probs for the sensing of some nitroaromatic explosives.

Electromagnetically Induced Transparency in Circuit Quantum Electrodynamics with Nested Polariton States.

Quantum networks will enable extraordinary capabilities for communicating and processing quantum information. These networks require a reliable means of storage, retrieval, and manipulation of quantum states at the network nodes. A node receives one or more coherent inputs and sends a conditional output to the next cascaded node in the network through a quantum channel. Here, we demonstrate this basic functionality by using the quantum interference mechanism of electromagnetically induced transparency in a transmon qubit coupled to a superconducting resonator. First, we apply a microwave bias, i.e., drive, to the qubit-cavity system to prepare a Λ-type three-level system of polariton states. Second, we input two interchangeable microwave signals, i.e., a probe tone and a control tone, and observe that transmission of the probe tone is conditional upon the presence of the control tone that switches the state of the device with up to 99.73% transmission extinction. Importantly, our electromagnetically induced transparency scheme uses all dipole allowed transitions. We infer high dark state preparation fidelities of >99.39% and negative group velocities of up to -0.52±0.09 km/s based on our data.

A macroscopic mechanical resonator driven by mesoscopic electrical back-action.

Systems with coupled mechanical and optical or electrical degrees of freedom have fascinating dynamics that, through macroscopic manifestations of quantum behaviour, provide new insights into the transition between the classical and quantum worlds. Of particular interest is the back-action of electrons and photons on mechanical oscillators, which can lead to cooling and amplification of mechanical motion. Furthermore, feedback, which is naturally associated with back-action, has been predicted to have significant consequences for the noise of a detector coupled to a mechanical oscillator. Recently it has also been demonstrated that such feedback effects lead to strong coupling between single-electron transport and mechanical motion in carbon nanotube nanomechanical resonators. Here we present noise measurements which show that the mesoscopic back-action of electrons tunnelling through a radio-frequency quantum point contact causes driven vibrations of the host crystal. This effect is a remarkable macroscopic manifestation of microscopic quantum behaviour, where the motion of a mechanical oscillator-the host crystal, which consists of on the order of 10(20) atoms-is determined by statistical fluctuations of tunnelling electrons.

Suspended graphene devices with local gate control on an insulating substrate.

We present a fabrication process for graphene-based devices where a graphene monolayer is suspended above a local metallic gate placed in a trench. As an example we detail the fabrication steps of a graphene field-effect transistor. The devices are built on a bare high-resistivity silicon substrate. At temperatures of 77 K and below, we observe the field-effect modulation of the graphene resistivity by a voltage applied to the gate. This fabrication approach enables new experiments involving graphene-based superconducting qubits and nano-electromechanical resonators. The method is applicable to other two-dimensional materials.

Investigation of photoluminescence and DNA binding properties of benzimidazole compounds containing benzophenone group.

The synthesis of benzimidazole compounds containing benzophenone group in accordance with the literature and the investigation of DNA binding properties of these compounds by using UV-vis and photoluminescence spectroscopy methods constitute the basis of this research. The structures of the compounds were determined by methods such as FT-IR, 1H, 13C NMR, UV-vis, Photoluminescence spectroscopy, and X-ray crystallography. By using methods such as UV-vis, Photoluminescence spectroscopy, and viscosity tests, information were collected about the binding types, binding mode, and binding energies of the compounds with DNA. In addition, the binding interactions of the compounds with DNA were investigated using the molecular docking technique. Using this information, calibration equations, correlation coefficients (r2), and DNA binding constants (Kb) were calculated for their compounds. The binding constants (Kb) calculated for substances A, B, and C were found to be 3.0 × 104, 7.0 × 104, and 3.0 × 104 M-1, respectively. UV-vis, EB competitive binding, and viscosity tests showed that the compounds tended to bind to the DNA structure via the groove binding mode. At the end of molecular docking studies, it was determined that compound B showed the best DNA binding activity in in vitro studies. Compared with the studies in the literature, it is thought that the synthesized compounds can take place in cancer drug research as DNA binding agents.Communicated by Ramaswamy H. Sarma.