Structural Investigation and Optical Properties of Dysprosium (Dy3+) Ions Doped Oxyfluoro Antimony Borate Glasses for Photonics Applications.

Dysprosium oxide-doped glasses with a composition of 60B2O3-10Sb2O3-10Al2O3-10NaF-(10-x) LiF-xDy2O3 (x = 0.1,0.5, 1.0,1.5,2.0,2.5 mol%) were prepared using a conventional melt-quenching technique. The glasses were characterized through various analytical investigations, including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, refractive index, density, optical absorption, excitation, photoluminescence (PL) studies, decay measurements and radiation shielding parameters. The XRD and FT-IR confirms the glassy nature and functional groups present in the titled glass. The absorption spectra were used to determine the oscillator strength of the Dy3+ absorption transitions as well as the bond created with the O-2 ion in the titled glass network. The degree of the suitability of developed glasses for lasing applications was demonstrated by radiative parameters determined using Judd-Ofelt theory. In the prepared glass samples, the optical bandgap measurements indicate the presence of non-bridging oxygen (NBOs), localization of charges and donor centers in the titled glasses. Due to the de-excitation of 4F9/2 to the corresponding 6H15/2,6H13/2 and 6H11/2 states, the PL emission spectrum shows two main strong emissions at blue(480nm), yellow (575nm) and one less emission at red (663nm). The CIE coordinates determined using PL emission spectra reveal the coordinates that are falling within the white light region. Various shielding parameters such as mass attenuation coefficient, mean free path, effective atomic number were estimated to understand the radiative shielding nature of the titled glasses. Within the addition of Dy2O3, it was found that the shielding parameters values of the titled glass samples are increasing. The Mass Attenuation Coefficient, Half Value Layer and Mean Free Path of the as prepared glasses has been compared with different types of concretes to understand the shielding effectiveness of prepared glass.

Zn(ii)-based coordination polymer: An emissive signaling platform for the recognition of an explosive and a pesticide in an aqueous system.

A new emissive Zn(ii)-based coordination polymer (Zn-CP) bearing paddle-wheel clusters has been developed and the same has been demonstrated to have potential for recognising a nitroaromatic-based explosive (TNP) and a pesticide (2,6-DCNA) in aqueous solution. The structural integrity of this newly developed 2D material was established through single-crystal analysis, whereas the stability of Zn-CP in aqueous medium after the recognition process was investigated by the powder-XRD technique. A combination of experimental and theoretical studies revealed that the change in fluorescence intensity of Zn-CP while interacting with TNP and 2,6-DCNA was possibly due to simultaneous operation of PET and FRET. Experimentally, it was also established that Zn-CP can be reused in up to three cycles for the detection of TNP and 2,6-DCNA.

A metal-organic framework based multifunctional catalytic platform for organic transformation and environmental remediation.

Given the need for an efficient reaction platform, a multifunctional material has been developed through the integration of iodine into a Cd2+ based MOF as a new catalytic system for organic transformation. Furthermore, the Cd-MOF itself has been successfully used as a potential material for photocatalytic dye degradation. The iodine incorporated MOF showed tremendous efficiency in organic catalysis for the synthesis of a library of benzimidazole derivatives with yield >80%. In addition, the same iodine loaded MOF (I2@Cd-MOF) exhibits good applicability and reusability for the synthesis of thienyldipyrromethane. Apart from this, the photocatalytic activity of the Cd-MOF was also evaluated under visible light irradiation which revealed excellent photocatalytic activity (82%) for MB degradation without the use of any enhancers. Altogether, this catalytic platform established its efficacy as a multifunctional catalyst in the organic synthesis of biologically active motifs and photocatalytic dye degradation.

A long-range emissive mega-Stokes inorganic-organic hybrid material with peripheral carboxyl functionality for As(v) recognition and its application in bioimaging.

We demonstrate a strategy for the recognition of As5+ in aqueous solution using a red-emissive probe based on a perylene-Cu2+ ensemble decorated with peripheral free carboxyl functionality. Single crystal analysis helped us to understand the chemical structure of the probe. To the best of our knowledge, this is the first probe for arsenic detection which emits in the red region (λem = 600 nm). The perylene-Cu2+ ensemble exhibited a mega-Stokes shift (>100 nm) with a high degree of selectivity upon interaction with As5+, which indicated that the present probe has the potential to be used as a turn-on optical sensor for selective detection of As5+ with fewer experimental limitations. The detection limit was found to be 26 nM. Inspired by its good emissive properties, the ensemble was further explored for imaging As5+ in live cells. Because of its long-range emissive nature, no autofluorescence from the cellular species was observed during the imaging process. The probe was evaluated to be non-toxic and successfully permeated the cell membrane without the help of any permeabilizing agent to image As5+.

Novel metal-organic framework with tunable fluorescence property: supramolecular signaling platform for polynitrophenolics.

With the aid of a rotational C3-symmetric tricarboxytriphenylamine based ligand, a new Cd-MOF was synthesized and characterized by various spectroscopic techniques as well as by single-crystal X-ray diffraction analysis. The structural investigation of the crystalline Cd-MOF complex revealed the existence of unique three symmetry independent coordination environments of Cd(ii) ions with common octahedral and pentagonal bipyramidal geometries. Small cavities with dimensions 6.40 Å × 6.41 Å were present in the crystal system. The tunable fluorescence property of the complex was explored to detect selectively polynitrophenol based explosive materials in the presence of other nitro explosives such as RDX, HMX, TNT and so on. Thermogravimetric analysis and powder X-ray diffraction data support the high thermal stability and crystallinity of the complex.

Turn-on trivalent cation selective chemodosimetric probe to image native cellular iron pools.

A new turn-on cell permeable chemodosimetric probe has been developed and its application in the selective detection of trivalent cations (Fe(3+)/Cr(3+)/Al(3+)) at a sub-nanomolar level has been demonstrated. The selectivity of over a broad spectrum of mono- and divalent metal ions was established using fluorescence spectroscopy. Moreover, the changes in the absorption spectra of in the presence of trivalent cations enabled the most bio-relevant metal ion Fe(3+) over Cr(3+)/Al(3+) to be distinguished. The probe was found to be successful in the fluorescence imaging of native cellular iron pools. The fluorescence imaging of the native iron pools of banana pith further supported the high sensitivity of towards Fe(3+) present in living systems. To the best of our knowledge, this is the first example of a turn-on chemodosimetric probe to image native cellular Fe(3+) pools.