Colorimetric and near-infrared spectrophotometric monitoring of bisulfite using glyoxal modified chromenylium-cyanine chemosensor: Smartphone and paper strip applications for on-site food and beverages control.

Detection of bisulfite (HSO3-) in food and beverages has vital importance because the excessive amount leads to ill effects on the human body. Colorimetric and fluorometric chromenylium-cyanine-based chemosensor CyR was synthesized and applied for high selective and sensitive analysis of HSO3- in red wine, rose wine and, granulated sugar with high recovery ranges and very fast response time without any interference from other competitive species. The limits of detection (LOD) for the UV-Vis and fluorescence titrations were found as 11.5 µM and 3.77 µM, respectively. The on-site and very rapid methods based on paper strips and smartphone which depend on the color changes from yellow to green have been successfully developed to analyze HSO3- concentration (10-5-10-1 M for paper strip and 163-1205 µM for smartphone). CyR and the bisulfite-adduct formed in the nucleophilic addition reaction with HSO3- were verified by FT-IR, 1H NMR, and MALDI-TOF results as well as Single-Crystal X-Ray Crystallography for CyR.

A methionine biomolecule-modified chromenylium-cyanine fluorescent probe for the analysis of Hg2+ in the environment and living cells.

The objective of the study is, for the first time, to construct a new near infrared (NIR) fluorophore, spectrophotometric, colorimetric, ratiometric, and turn-on probe (CSME) based on chromenylium cyanine platform decorated with methionine biomolecule to provide an efficient solution for critical shortcoming to be encountered for analysis of hazardous Hg2+ in environment and living cell. The CSME structure and its interaction with Hg2+ ion were evaluated by NMR, FTIR, MS, UV-Vis and fluorescence methods as well as Density Functional Theory (DFT) calculations. The none fluorescence CSME having spirolactam ring only interacted with Hg2+ in aqueous solution including competing ions. This interaction caused the fluorescence CSME with opened spirolactam form which exhibited spectral and colorimetric changes in the NIR region. The probe based on UV-Vis and fluorescence techniques respond in 90 s, has wide linear ranges (for UV-Vis: 6.29 × 10-8 - 1.86 × 10-4 M; for fluorescence: 9.49 × 10-9 - 1.13 × 10-5 M), and has a lower Limit of Detection (LOD) value (for fluorescence: 4.93 × 10-9 M, 0.99 ng/mL) than the value predicted by the US Environmental Protection Agency (EPA) organization. Hg2+ analysis was performed in drinking and tap water with low Relative Standard Deviation (RSD) values and high recovery. Smartphone and living cell applications were successfully performed for colorimetric sensing Hg2+ in real samples and 3T3 cells, respectively.

A new Fe3+-selective, sensitive, and dual-channel turn-on probe based on rhodamine carrying thiophenecarboxaldehyde: Smartphone application and imaging in living cells.

A new dual-channel probe based on rhodamine B derivative (MSB) was successfully designed, synthesized, characterized by Nuclear Magnetic Resonance (NMR) Spectroscopy, Fourier Transform Infrared Spectrophotometer (FTIR), Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS), X-ray Photoelectron Spectroscopy (XPS), and Single Crystal X-rayDiffraction, and the sensing abilities toward Fe3+ cation have been demonstrated and the probe was successfully utilized for fluorescence imaging of Fe3+ in living cells. The probe demonstrated quite fast, sensitive, and selective response to Fe3+ by causing an extreme enhancement in UV-vis and fluorescence spectroscopy techniques in the buffered aqueous media which makes MSB a dual-channel probe. While the color of MSB solution was initially light yellow, it turned pink in the presence of Fe3+, which provided highly selective naked-eye determination among several ions as alkaline, alkaline-earth, and transition metal ions. After that, the probe was easily applied to paper strips and real samples such as drinking waters and supplementary iron tablets for sensing Fe3+ in an aqueous solution. The detection limit (LOD) and the response time of the probe were determined as 4.85x10-9 M and 4 min, respectively, which are quite lower compared with other rhodamine based Fe3+ sensors in the literature. According to Job's plot, 1H NMR titration, MALDI-TOF MS, XPS, and DFT study techniques, the complexation ratio between MSB and Fe3+ was found as 1:1. Moreover, the spectral response was reversible with alternately addition of Fe3+ or Na2EDTA to the MSB solution. In addition, fluorescence imaging in NIH/3T3 mouse fibroblast cells and studies in real samples with a quite high recovery rate exhibited that the probe is qualified for detection of Fe3+ ion with multiple practical usages.

Construction of anthraquinone functional zinc phthalocyanine sensor platform for ultra-trace amount of water determination in tetrahydrofuran and N,N-Dimethylformamide.

Anthraquinone functional zinc phthalocyanine sensor platform was utilized for ultra-trace amount of water determination in THF and DMF. Using the fluorometric method, the water content in THF was determined with a LOD of 2.27 × 10-4 M and a response time of 1 s. The sensor is based on the mechanism of aggregation depended on quenching of emission. Although the aggregation is known as an undesirable property in the application of phthalocyanine, this property has been successfully applied in the quantification of water content in THF. By using the shift of the third reduction wave of the sensor, the water content in DMF was measured with a LOD value of 5.64 × 10-7 M. The voltammetric response mechanism is based on the hydrogen bonding depended shifting of the reduction potential of quinone moiety on phthalocyanine. Redox potentials of phthalocyanine are used as a calibrant for accurate quantification of water content in DMF. Water molecules (n and m) and equilibrium constants (K1 and K2) for the formation of hydrogen bonding for the first and third reduction processes were calculated as 1.18 (n), 10.4 (m) and 19.3 (K1), 1.6 × 1011 (K2) M-(m-n), which demonstrated why the third reduction process was chosen to set the calibration plots.

Superior Sensor for Be2+ Ion Recognition via the Unprecedented Octahedral Crystal Structure of a One-Dimensional Coordination Polymer of Crown Fused Zinc Phthalocyanine.

The unprecedented one-dimensional (1-D) coordination polymer of crown fused zinc phthalocyanine (P-CfZnPc) with an octahedral crystal structure and with intermolecular packing that has superior multichannel sensor ability for Be2+ ion recognition was prepared and characterized by single-crystal X-ray diffraction analysis (XRD) and a wide range of spectroscopic and voltammetric methods. An exceptional feature of the crystal structure of P-CfZnPc is that each zinc ion in the phthalocyanine (Pc) polymer is coordinated by the four isoindole nitrogen atoms and an outer oxygen atom of the Pc molecule. This structure is the first example of an octahedral arrangement in a 1-D polymeric chain for zinc phthalocyanines (ZnPcs) and zinc porphyrins (ZnPs) reached without the presence of a coordinating solvent, which was confirmed by XRD analysis. Interestingly, this (1-D) coordination polymer preserves its conformation in THF (tetrahydrofuran) solution, thereby effectively preventing aggregation. This result was confirmed by the particle size of the molecule (125 nm) using dynamic light scattering (DLS) and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectra as well as UV-vis spectroscopy. The sensor has long-term stability (more than 3 months in solution), a very low response time (less than 1 s), and nonaggregating ability, facilitating the accurate determination of ultra-trace amounts of Be2+ (lower than 1 ppb), which is extremely important in terms of human health and environmental protection. The sensor can highly selectively and sensitively bind Be2+ among Li+, Na+, K+, Cs+, Mg2+, Ca2+, Ba2+, Al3+, Co2+, Hg2+, Ni2+, Pb2+, and Zn2+ ions via Be2+-induced J aggregation of Pc molecules. Such a binding leads to not only a significant decrease in Pc absorption (677 nm) as well as the creation of new absorption (720 nm) but also fluorescence emission quenching (690 nm). Furthermore, the sensor displayed highly selective voltammetric recognition for Be2+ following J aggregation/disaggregation in the second reduction process. The binding mechanism of the sensor and Be2+ ion was also explained on the basis of TD-DFT calculations.