Rare earth doped organic–inorganic hybrid polyhedral oligomeric silsesquioxane phosphors applied for flexible sheet and anti-counterfeiting

We have developed organic–inorganic hybrid polyhedral oligomeric silsequioxane (POSS) type monomer ligand 2,6-pyridinediamine-bis-propanylheptaisobutyl POSS (PDC-POSS) and synthesized rare earth (RE =Eu3+) doped hybrid complex PDC-POSS phosphors. The PDC-POSS precursor was prepared using (3-aminopropyl)heptaisobutyl POSS, 2,6-pyridinedicarboxylic acid chloride (PDC) as the host material, and then coordinated with RE3+ using europium nitrate regents to synthesize PDC-POSS:Eu3+ phosphors. The photoluminescence (PL) spectra of the PDC-POSS:Eu3+ hybrid phosphors were detected at 592, 616, 649, 693 nm under UV light (λ= 288 nm) excitation. In addition, the synthesized hybrid phosphors showed red light emission under UV light. The phosphors were demonstrated on a flexible sheet that could be applied for red emitting LEDs, and for anti-counterfeiting, which requires the film to remain hidden and identifiable only by UV light.

Gram-Scale Synthesis of an Ultrastable Microporous Metal-Organic Framework for Efficient Adsorptive Separation of C2H2/CO2 and C2H2/CH4

A highly water and thermally stable metal-organic framework (MOF) Zn2(Pydc)(Ata)2 (1, H2Pydc = 3,5-pyridinedicarboxylic acid; HAta = 3-amino-1,2,4-triazole) was synthesized on a large scale using inexpensive commercially available ligands for efficient separation of C2H2 from CH4 and CO2. Compound 1 could take up 47.2 mL/g of C2H2 under ambient conditions but only 33.0 mL/g of CO2 and 19.1 mL/g of CH4. The calculated ideal absorbed solution theory (IAST) selectivities for equimolar C2H2/CO2 and C2H2/CH4 were 5.1 and 21.5, respectively, comparable to those many popular MOFs. The Qst values for C2H2, CO2, and CH4 at a near-zero loading in 1 were 43.1, 32.1, and 22.5 kJ mol−1, respectively. The practical separation performance for C2H2/CO2 mixtures was further confirmed by column breakthrough experiments.

Synthesis, characterization and fluorescence properties of mixed-ligand cobalt(II), copper(II), zinc(II) and cadmium(II) coordination polymer complexes involving 4,4’-bipyridine and 2,5-pyridinedicarboxylic acid

Four mixed-ligand coordination polymer complexes of cobalt(II), copper(II), zinc(II), and cadmium(II) were synthesized by solvothermal method in 1:1:1 metal: 4,4’-bipy: 2,5-pdc molar ratio using 2,5-pyridinedicarboxylic acid (2,5-pdc) and 4,4’-bipyridine (4,4’-bipy). These complexes are viz; 1. [Co2(4,4'-bipy)(2,5-pdc)2(H2O)4]n 2. [Cu2(4,4'-bipy) (2,5-pdc)2]n 3. [Zn2(4,4'-bipy)(2,5-pdc)2(H2O)4]n and 4. [Cd3(4,4'-bipy)(2,5-pdc)2(OOCCH3)2(H2O)4]n.. All these complexes (1-4) have been characterized by elemental analyses (C,H,N), FT-IR-spectra, thermal analyses (TGA/DTA/DTG), fluorescence spectra and powder X-ray diffraction (PXRD) analyses to arrive at conclusion regarding their geometrical structure.