IR Spectroscopic Studies Research Articles

Mixed H2S and H2O Clusters─New Insights into Dispersion-Dominated Hydrogen Bonding.

Here, we report the results of an IR spectroscopy study on heteroclusters of H2S and H2O and several of their isotopomers using mass-selective IR spectroscopy in superfluid helium nanodroplets in the range of 2560-2800 cm-1. Based on DFT calculations on the B3LYP-D3/6-311++G(d,p) level of theory, we were able to assign the experimentally observed O-D stretching bands to heterodimer and heterotrimer clusters. Since no bands of the S-H-bound conformer HSH···OH2 could be observed, we were able to determine the O-H-bound conformer HOH···SH2 to be the global minimum structure. A trapping of the local minima in helium nanodroplets was not observed. This is in line with the weaker hydrogen bond expected for H2S complexes. In these clusters, the interaction energy is expected to be more dominated by dispersion and less dictated by highly directional electrostatic forces.

Synthesis, Characterization and Identification of Mononuclear Transition Metals Complexes 1, 3-Bis-((5-methyl-1H-Imidazol-4-yl) Methyleneamino) Propan-2-ol Ligand

The ligand 1,3-bis-((5-methyl-1H-imidazol-4-yl)methyleneamino)propan-2-ol (H3L) derived from 1,3-diaminopropan-2-ol and 5-methyl-1H-imidazole-4-carbaldehyde has been synthetized and used to prepare five complexes in which the ligand acts in tetradentate fashion. Complexes formulated as [Mn(H3L)(H2O)2].2SCN (1), [(Co(H3L)].2SCN (2), [(Ni(H3L)].2SCN (3), [(Cu(H3L)(NO3)].(NO3).2H2O (4), and [(Zn(H3L)].2SCN (5) were synthesized by mixing an equimolar amount of an methanol solution containing the appropriate nitrate salt and KSCN, in 1:2 ratio, in the case of 1, 2, 3 and 5 and an ethanol solution containing the appropriate ligand H3L. The complex 4 has been synthetized in the absence of KSCN. In all the complexes the ligand acts in its neutral form and in tetradentate fashion, its hydroxy group remaining free and non-deprotonated. The ligand is coordinated to metal ion through two azomethine nitrogen atoms and two pyrazole sp2 nitrogen atoms. The complexes are characterized by elemental analysis, conductance and room temperature magnetic moments measurements, UV–Vis and IR spectroscopic studies. The structure of the copper(II) complex 4 is confirmed by X-ray diffraction. 4 crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 8.5459 (3) Å, b = 10.9177 (3) Å, c = 22.4562 (6) Å, b = 96.954 (3)°, V = 2079.79 (11) Å3, Z = 4, R1 = 0.050 and wR2 = 0.131. The CuII cation in N4O inner is situated in a distorted square pyramidal environment.

Luminescent yttrium organic frameworks: Cell imaging, gas adsorption and nitro sensing applications

The flexibility of ligand (L) yield, two different yttrium organic frameworks, denoted as {[Y(L)2(H2O)4]·Cl3·DMF·(H2O)3·(S)}n (MOF-1) and {[Y(L)3/2(H2O)2]·(NO3)3·(S)}n (MOF-2), where L denotes 9,10-bis((4-carboxylatopyridinium-1-methylene)anthracene and S denotes the disordered solvent molecules. Detailed single crystal X-ray study established a one dimensional (1D) chain for MOF-1 and a three dimensional (3D) frameworks with one channel voids structure for MOF-2, respectively, due to different conformation of the ligand. In both MOFs, Y(III) have bicapped trigonal prismatic geometry. The phase purity of both MOFs has been confirmed by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and IR spectroscopic studies. MOF-1, with its particle size in nano range, good fluorescence property and solubility in water, is a suitable candidate for cell imaging study. In contrast, three dimensional framework of MOF-2, with small voids, makes it well suited for gas adsorption and sensing of nitro aromatics compounds.

Phase behavior and biological activity of lyotropic liquid crystal systems doped with 1,2,3-triazole derivative

Heterocyclic compounds are important for the synthesis of pharmaceuticals, especially substituted triazoles, which have high biological activity. The development of approaches to the creation of delivery systems for bioactive heterocyclic compounds is of particular importance for improving the biopharmaceutical aspects of therapy. In this work, we report synthesis and characterization of a new 1,2,3-triazole: ethyl 2-((1-decyl-1H-1,2,3-triazol-4-yl)methyl)-3-oxobutanoate (TR). The efficient incorporation into lyotropic mesophases as a drug delivery platform demonstrated. Polarized optical microscopy studies confirmed formation of a lyotropic mesophase in the binary P123/TR system as well as in tertiary systems with added water, ethanol, and DMSO. This allows to dope 5 % of triazole into lyomesophases. IR and UV spectroscopy studies detected intermolecular interactions occurring in the P123/TR system. Release of TR from binary and tertiary lyomesophases was studied. Impacts of composition and temperature on the release time were analyzed. Evaluation of cytotoxicity to M-Hela and HuTu-80 cancer lines and Chang Liver living cells revealed antitumor properties of the studied substituted 1,2,3-triazole. The lowest IC50 of TR is 57 μg·mL−1 toward HuTu-80. This is at the level of the reference drug Fluconazol. For the P123/DMSO/TR LLC system in concentration range of 31.3–124 µg·ml−1, the viability percentage of liver cells is comparable to those of cancer cells. These results demonstrate the potential opportunity for application LLC P123/DMSO used as a TR delivery for and enhance its antitumor effect.

Synthesis and Effect of MgSO4 co-doping on the Optical, IR, and Raman Spectroscopic Studies of Eu3+-Doped Alkaline Silica Borate Glasses Produced with SLS Glass as a Silica Source

Synthesis and Effect of MgSO4 co-doping on the Optical, IR, and Raman Spectroscopic Studies of Eu3+-Doped Alkaline Silica Borate Glasses Produced with SLS Glass as a Silica Source

Synthesis and structural characterization of 2,2′:6,2″-Terpyridine zinc Formate: Hydroboration and hydrosilylation of CO2 and carbonyl compounds

The zinc formate compound (terpy)Zn(O2CH)2 is obtained via the reaction of Zn(O2CH)2 with 2,2′:6′,2″-terpyridine (terpy) and has been structurally characterized by X-ray diffraction as possessing formate ligands that coordinate via a κ1-monodentate coordination mode, which is in accord with IR spectroscopic studies. In terms of reactivity, (terpy)Zn(O2CH)2 participates in catalytic transformations involving CO2 and carbonyl compounds via hydrosilylation and hydroboration reactions. For example, (terpy)Zn(O2CH)2 achieves hydroboration of Me2CO and Ph2CO by HBpin to afford R2C(H)OBpin, and triple insertion of Ph2CO, PhC(O)Me, Me2CO and PhCHO into the Si–H bonds of PhSiH3 to afford PhSi[OCH(R)R’]3. In addition, CO2 also undergoes hydroboration and hydrosilylation by HBpin and (MeO)3SiH in the presence of (terpy)Zn(O2CH)2 to afford HCO2Bpin and HCO2Si(OMe)3, respectively.

Metal-polymer-clay nanocomposites based electrochemical sensor for detecting hydrazine in water sources

AgNPs embedded polymer-clay (AgNPs@PEI-HNT) nanocomposites were successfully employed to sensitively detect hydrazine in water samples using differential pulse voltammetry (DPV) and amperometry methods. In-situ polymerization was utilized for assembling the polymer-clay composites, which were subsequently coated with AgNPs. PEI improves conductivity and absorbs AgNPs on the surface of HNTs, as evidenced with the help of UV-Visible, IR spectroscopy, XRD, XPS and morphological studies (FE-SEM and TEM). Nanocomposites were coated with GCE, which improved their electrocatalytic performance during hydrazine oxidation. The Tafel plot, Galus and Cottrell equations were used to compute the electron transfer coefficient (0.64), catalytic reaction rate constant (4.81 × 104 M−1s−1) and diffusion coefficient (2.56 × 10−5 cm2/s) of hydrazine at AgNPs@PEI-HNT/GCE. Amperometry technique was used to determine the LOD along with sensitivity of hydrazine, which were 0.22 nm and 116.76 µA µM−1 cm−2. Modified electrode offers enhanced properties for example strong anti-interference capability, good reproducibility, long-term stability, sensitivity, and so on. The designed sensor successfully detects hydrazine in water samples with high recovery rates (R.S.D. < 5 %).

Salicylic Acid-Modified Sm-TiO2 for Photoluminescence and Photocatalysis under Real Sunlight: Synergistic Effects between Ligand-to-Metal Charge Transfer (LMCT) and Sm3+ Dopant.

A salicylic-acid (SA)-modified samarium-doped TiO2 complex (Sm-TiO2/SA) was synthesized via a sol-gel method followed by impregnation. A Raman Fourier transform IR and X-ray photoelectron spectroscopic study showed that SA (as an electron donor) forms a surface complex on the Sm-TiO2 surface through its phenolic/carboxylic functional groups. In the Sm-TiO2/SA complex, a ligand-to-metal charge transfer (LMCT) is active, inducing a marked red-shift in the absorption spectrum of TiO2, which extends to 550-600 nm. The synergetic effect between the LMCT process and the luminescent properties of the lanthanide ions (Sm3+) is discussed and supported by the photoluminescence spectra. Further photocatalytic experiments (under sunlight) and the study of the effect of different scavengers show the presence of competitive reactions between de-ethylation and cleavage of Rhodamine B (RhB) during its degradation. With the Sm-TiO2/SA complexes, the superoxide radical ion (O2 •-) is the main active species responsible for the N-de-ethylation pathway under sunlight irradiation. The cleavage of RhB by the hydroxyl radical (•OH) appears, instead, to dominate with the Sm-TiO2 photocatalysts.

Molecular Photothermal Effect on the 2D-IR Spectroscopy of Acetonitrile-Based Li-Ion Battery Electrolytes.

Advancements in Li-ion battery (LIB) technology hinge on an understanding of Li-ion solvation and charge transport dynamics. Ultrafast two-dimensional infrared (2D-IR) spectroscopy has been used to investigate these dynamics in electrolytes by probing chemical exchange processes through time-dependent cross-peak analysis. However, accurate interpretation is complicated by factors such as vibrational energy transfer and molecular photothermal effect (MPTE), affecting cross-peak evolution. Pinpointing the precise origin of these cross-peaks has posed a significant challenge in time-resolved IR spectroscopic studies of LIB electrolytes. Here, we trace the origin of 2D-IR cross-peaks of LIB electrolytes utilizing acetonitrile as a solvent. Time-dependent analysis of LiSCN and CH3SCN mixtures in CD3CN revealed distinctive MPTE features. Furthermore, direct observation of intermolecular MPTE through two-color IR pump-probe spectroscopy lends support to the findings. Our results emphasize the non-negligible artifacts induced by MPTE and the necessity of considering these effects to accurately observe the ultrafast dynamics within LIB electrolytes.

Implication of carbohydrazide chemosensors in selective sensing of Fe(III) and construction of molecular devices

Two new and two reference sensors L1-L2 and R1-R2, respectively, based on the hydrazide core were synthesized in good yields (70–86 %). A variety of analytical methods, including NMR, HRMS, and single-crystal XRD, were used to characterize these sensors. Cyclic voltammetry, UV–visible absorption, and emission spectroscopies were then used to confirm the electrochemical and photophysical characteristics of these sensors. Moreover, theoretical calculations at the level of DFT and TD-DFT were carried out to compare the experimental findings with the theoretical ones. The sensors were found to exhibit luminescence attributed to singlet ligand-centered (1LC) transitions. Based on their luminescent properties and the previous literature reports where structurally analogous sensors have been used for the detection of metal ions, these sensors were investigated as selective chemosensors for Fe(III) detection, with a "turn-off" fluorescence behaviour in a binding stoichiometry of 1:1 = sensor:M(III) [M = Fe(III)] with a limit of detection of 2.71–39 µM, or 0.15–2.81 ppm. The mechanistic details regarding the sensing of Fe(III) ion by the sensors was provided by NMR, IR, XPS and UV-visible absorption spectroscopic studies. To increase the usefulness of the sensors, L2 was also applied for the successful fabrication of the molecular logic gate and molecular lock keypad. Paper strip test and sensing of Fe(III) contaminated water by the sensors accounted for the practical applicability of the sensors in real life.

Monometallic heteroleptic complexes of Dy(III) ion incorporating β-diketone and ancillary moieties: Photophysical and electrochemical analyses

Several luminescent ternary dysprosium complexes were synthesized and examined using diketone ligand 1,3-diphenylprop-1,3-dione (DPD) and various auxiliary ligands. Spectroscopic analysis was carried out to determine the structural and photophysical features of Dy (III) complexes. IR and proton NMR spectroscopic studies suggested the bonding of chelating moieties to the metal ion through oxygen and nitrogen atom. The optical and electronic band gap is evaluated which proposed the conducting behaviour of dysprosium complexes. Upon excitation with UV radiation, three distinct emission peaks of the Dy (III) ion are appeared at about 485 nm (J = 15/2), 575 nm (13/2) and 664 nm (11/2) corresponding to the transitions of type 4F9/2 → 6HJ. The strongest emission peak obtained at ∼ 575 nm is responsible for yellow emission of Dy (III) complexes. The yellow to blue (Y/B) ratio estimated for the transition J = 13/2 / J = 15/2 were found to be in the range of 4.19 – 2.80. The quantum yield was also determined for the Dy (III) complexes which is as: Φ1 = 0.315, Φ2 = 0.261, Φ3 = 0.183, Φ4 = 0.157. The synthesized dysprosium complexes demonstrate luminescence lifetime in decreasing order i.e. 0.600 ms > 0.510 ms > 0.431 ms > 0.323 ms. Furthermore, the chromaticity coordinates also confirm their yellow luminous behavior. These newly synthesized complexes could be utilized for developing systems significant for lighting, OLEDs and displays due to their luminous features.

URANYL IODOACETATES OF MAGNESIUM, MANGANESE AND NICKEL

Syntheses, IR spectroscopic and X-ray diffraction studies of new uranyl iodoacetate complexes with divalent metals were carried out: R[UO2(CH2ICOO)3]2·6H2O (R = Mg2+ (I), Mn2+ (II), Ni2+ (III)). It was established that isostructural I–III crystallize in the cubic crystal system and contain octahedral aqua complexes [R(H2O)6]2+, which connect hexagonal-bipyramidal complexes [UO2(CH2ICOO)3]– into a three-dimensional framework by hydrogen bonds. Using molecular Voronoi–Dirichlet polyhedra, it was found that bifurcate halogen bonds O⋅⋅⋅I−C are also involved in the interconnection of anionic complexes. On the example of two series of stoichiometrically similar compounds dependence of the ratio of sizes of carboxylate ligands and counter cations on crystal system was observed and crystal systems for the compounds that have not yet been structurally characterized were assumed.

Probing the electronic structure and ground state symmetry of gas phase C60+ via VUV photoionization and comparison with theory.

Recently, some of us reviewed and studied the photoionization dynamics of C60 that are of great interest to the astrochemical community as four of the diffuse interstellar bands (DIBs) have been assigned to electronic transitions in the C60+ cation. Our previous analysis of the threshold photoelectron spectrum (TPES) of C60 [Hrodmarsson et al., Phys. Chem. Chem. Phys. 22, 13880-13892 (2020)] appeared to give indication of D3d ground state symmetry, in contrast to theoretical predictions of D5d symmetry. Here, we revisit our original measurements taking account of a previous theoretical spectrum presented in the work of Manini et al., Phys. Rev. Lett. 91(19), 196402 (2003), obtained within a vibronic model parametrized on density functional theory/local-density approximation electronic structure involving all hg Jahn-Teller active modes, which couple to the 2Hu components of the ground state of the C60+ cation. By reanalyzing our measured TPES of the ground state of the C60 Buckminsterfullerene, we find a striking resemblance to the theoretical spectrum calculated in the work of Manini et al., Phys. Rev. Lett. 91(19), 196402 (2003), and we provide assignments for many of the hg modes. In order to obtain deeper insights into the temperature effects and possible anharmonicity effects, we provide complementary modeling of the photoelectron spectrum via classical molecular dynamics (MD) involving density functional based tight binding (DFTB) computations of the electronic structure for both C60 and C60+. The validity of the DFTB modeling is first checked vs the IR spectra of both species which are well established from IR spectroscopic studies. To aid the interpretation of our measured TPES and the comparisons to the abinitio spectrum we showcase the complementarity of utilizing MD calculations to predict the PES evolution at high temperatures expected in our experiment. The comparison with the theoretical spectrum presented in the work of Manini et al., Phys. Rev. Lett. 91(19), 196402 (2003), furthermore, provides further evidence for a D5d symmetric ground state of the C60+ cation in the gas phase, in complement to IR spectroscopy in frozen noble gas matrices. This not only allows us to assign the first adiabatic ionization transition and thus determine the ionization energy of C60 with greater accuracy than has been achieved at 7.598 ± 0.005eV, but we also assign the two lowest excited states (2E1u and 2E2u) which are visible in our TPES. Finally, we discuss the energetics of additional DIBs that could be assigned to C60+ in the future.

Water Adsorption on π-Surfaces of Open-Fullerenes.

Understanding the water adsorptive behavior of fullerenes is of particular importance for their material application in aqueous media. The conventional fullerenols usually provide complex physical pictures of water adsorption due to their uncontrollable hydroxylation degree and substitution pattern. Herein, we focus on poorly hydroxylated fullerenes with well-defined structures. The water adsorptive behavior was examined by synchrotron IR spectroscopy and computational studies. As a result, three types of IR bands were observed for adsorbed water. The population of the three states was considerably altered by the orientational difference of the hydroxy groups. Nevertheless, water adsorption could not occur for 9-fluorenol and catechol. This indicates that the Lewis acidic fullerene π-surface plays a prominent role in water adsorption, while the rather Lewis basic π-surface of 9-fluorenol is unable to attract much water at a boundary with humid air.

Dinuclear cadmium(II) complexes with distorted octahedral/monocapped trigonal prism coordination geometries: synthesis, crystal structure, DFT/TD-DFT calculation and photocatalytic degradation of methylene blue

Two Cd(II) complexes [Cd2(L1)2(dca)(NO3)] (1) and [Cd2(L2)2(SCN)(NO3)] (2) (HL1 = 2-methoxy-6-[(2-phenylamino-ethylimino)-methyl]-phenol; and HL2 = 2-[(2-ethylamino-ethylimino)-methyl]-6-methoxy-phenol), have been synthesized and characterized by single crystal structure analysis, IR and mass spectroscopic studies. Both the complexes 1 and 2 possess a triclinic crystal system with space group P1¯. In complex 1, geometry around one metal centre is distorted octahedral and other centre is distorted monocapped trigonal prism, whereas in complex 2, both the metal centres possess distorted octahedral geometries. Strong NH⋅⋅⋅O and weak aromatic CH⋅⋅∙O hydrogen bonding interactions in 1 and strong NH⋅⋅⋅O and NH⋅⋅⋅S hydrogen bonding in 2 results 1D and 2D supramolecular structures, respectively. Experimentally determined electronic spectral data have been compared with the calculated data obtained by DFT and TD-DFT calculation. Photocatalytic abilities of 1 and 2 have been examined by using spectroscopic technique and found that in presence of UV light both the complexes catalytically decomposed methylene blue by 54.0 % and 50.3 %, respectively.

Bioactive porphyrin magnesium (II) complex. Synthesis, molecular structure and spectroscopic characterization. Biological activity and molecular docking studies

We have synthesized and characterized porphyrin structures by UV–visible, IR and fluorescence spectroscopy studies and single crystal XRD analysis; H2(TPP) (I) (meso-tetraphenylporphyrin), [Mg(TPP)(DMF)] (II); (DMF: dimethylformamide) and [Mg(TPP)(H2O)]0.2(4-CNpy) (III); (4-CNpy: 4-Cyanopyridine). The crystal packing of the porphyrin structures is stabilized by intermolecular hydrogen bonds and by intermolecular CH⋯Cg π interactions where Cg is the centroid of the phenyl and pyrrole rings. UV–Vis spectroscopic data confirmed the creation of Mg-meso-porphyrin complexes by the red-shifted Soret bands for our derivatives compared to the free-base porphyrin. The optical gap energy values of (I), (II) and (III) are 1.92, 2.07 and 2.00 eV. Gram-positive and Gram-negative bacteria were tested against free porphyrin (I), metallated porphyrin (II) and complex (III). The results show that the magnesium porphyrin derivative is highly effective compared to H2TPP free-base porphyrins and metallated porphyrin [Mg(TPP)] and has higher inhibition character against the tested bacteria. The molecular docking of the complex (III), in the active sites of bacterial proteins was carried out to detect the degree of antibacterial activity of recognition.

From 'halogen' to 'tetrel' bonds: matrix isolation IR spectroscopic and quantum mechanical studies of the effect of central atom substitution in donor tetrahalogens on binary complex formation with formic acid.

Binary complex formation between silicon tetrachloride (SiCl4) and formic acid (FA) has been observed in an argon matrix environment. Such complex formation manifests as spectral shifts in signature vibrations of the latter, namely the νCO, νC-O and νO-H vibrations. Quantum chemical calculations reveal that the most stable conformers of the complex involve predominantly the tetrel bond, which has been defined in existing literature as a variant of the "σ-hole" interactions. Here, regions of positive electrostatic potential on the tetrahedral face of SiCl4 act as electrophilic centers (σ-hole) to which the nucleophilic carbonyl group of FA is able to bind. Atoms-in-molecules analysis predicts a bond critical point along the non-covalent contact between the tetrel atom Si and the carbonyl oxygen on FA, corroborating the presence of the tetrel bond. The hyperconjugative interaction parameters at the binding interface obtained from Natural Bond Orbital (NBO) analysis are also consistent with such observations. Although apparently similar to SiCl4, there are noticeable differences in the binding preferences of the lower homologue carbon tetrachloride (CCl4). The binary complexes of the latter with the same FA acceptor molecule have been previously shown to involve halogen bonded, rather than tetrel bonded interactions (Banerjee and Bhattacharya, Spectrochim. Acta Mol. and Biomol. Spectrosc., 2021, 250, 119355). Such variations in the nature of non-covalent interactions of these tetrahalogens are attributed to differences in the distribution of electronic charge density surrounding the central tetrel atom, as obtained from mappings of their electrostatic potential surfaces. Our combined experimental and theoretical findings therefore provide direct evidence of the growing propensity of tetrel atoms to engage in tetrel bonding as we move lower down Group 14, and re-assert the reluctance of the smaller and more electronegative carbon atom to serve as a tetrel bond participant.

Palladium(ii) complexes bearing mesoionic carbene ligands: catalytic application in domino Sonogashira coupling/cyclization reactions for one-pot synthesis of benzofuran and indole derivatives.

Bioactive heterocycles such as benzofuran and indole derivatives were synthesized from commercially available 2-iodoarenes and alkynes via domino Sonogashira coupling followed by cyclization reaction using well-defined palladium PEPPSI (Pyridine Enhanced Precatalyst Preparation Stabilization and Initiation) complexes (2a and 2b). These reactions tolerate a variety of 2-iodoarenes and diversely substituted terminal alkynes, resulting in the corresponding product in moderate to good yields in an open-air atmosphere. In particular, two palladium(ii) PEPPSI complexes 2a and 2b were synthesized in good yields from the reaction of corresponding 1,2,3-triazol-5-ylidene (MIC: mesoionic carbene), PdCl2, KI, and K2CO3 in pyridine at 110 °C and structurally characterized by various spectroscopic techniques including NMR spectroscopy, IR spectroscopy, HRMS and elemental analysis studies. Complex 2b is also characterized by X-ray crystallography.

Anticancer and Antioxidant Activities of Biologically Active Newly Synthesized α-Amino Acid-Dithiocarbamate Complexes of Some Bivalent Metals

The present study focuses on the synthesis and characterization of L-proline dithiocarbamate and its L-prodtc metal(II) (M = Ni2+, Cu2+ and Se2+) complexes. The ligand was synthesized in the presence of an alkali through the reaction of one mole of carbon disulphide and L-proline in ethanol under ice cold condition. The solubility of this ligand in the media is attributed to its high hygroscopic character and therefore, its metal(II) complexes were synthesized using a freshly prepared ligand. The characterization of the metal(II) complexes were carried out by molar conductance, magnetic susceptibility, elemental analysis, TGA/DTA, mass, IR, Raman, UV-Visible, 1H and 13C NMR spectroscopic studies. The biological activity of all the metal(II) complexes has been examined using an inhibition method for bacteria and pathogenic fungus, which will assess their possible antibacterial, antioxidant, anticancer activities and anti-inflammatory. It has been observed that Se(L-Prodtc)2 exhibits anticancer activity against breast cancer cells (MCF7) and also observed that antioxidant activity of Se(L-Prodtc)2 is more as compared to standard BHT, whereas Cu(L-Prodtc)2 complex shows appreciable anti-inflammatory activity.

A rhodamine-6G based chromo and fluorogenic sensor for the selective turn-ON detection of Fe3+ in aqueous medium with potential applications as INHIBIT logic gate, memory device and live cell imaging

A novel rhodamine-6G based biocompatible chromo- and fluorogenic “OFF-ON” sensor L2, having amide based metal ion receptor, has been synthesized using Michael addition reaction and characterized by IR, NMR and HRMS spectroscopic studies. It exhibits an excellent selectivity and sensitivity towards Fe3+ in aqueous medium over mono- and di-valent and other trivalent metal ions. A 14-fold enhancement of fluorescence intensity was found upon addition of 11.5 equivalent Fe3+ ion into the probe L2 in H2O (pH 7.2, 10 mM HEPES buffer) with colour change from colourless to reddish yellow, providing an opportunity for naked eye detection of Fe3+. The corresponding binding constant Kf was evaluated to be (1.16 ± 0.04) x 104 M−1 with 1:1 stoichiometry. Quantum yields of L2 and [L2 - Fe3+] complex in H2O (pH 7.2, 10 mM HEPES buffer) were found to be 0.013 and 0.523, respectively using Rhodamine-6G as standard. LOD of L2 for Fe3+ detection in aqueous medium determined by 3σ/slope method was found to be 4.184 μM. Cyanide ion scavanges Fe3+ from [L2 - Fe3+] resulting quenching of fluorescence due to re-attainment of the non-fluorescent spirolactam ring form of the probe. As the sensing phenomenon is reversible, it helps to frame INHIBIT logic gate and memory devices.