Fluorescence and cofluorescence enhancement of Tb(Ⅲ) complexes with pyromellitic acid by M (M = Gd, La, Ca, and Sr ions)

Fluorescence and cofluorescence properties of Tb(Ⅲ) solid complexes werestudied using pyromellitic acid (PMA) as ligand and fluorescence inert ions as doping elements. Thecofluorescence enhancement, a result of ligand sensitized fluorescence, was observed in Tb(Ⅲ) solidcomplexes doped with fluorescent inert ions La(Ⅲ), Gd(Ⅲ), Ca(Ⅲ), and Sr(Ⅲ). The effect of thetype and content of doping elements on fluorescence enhancement was studied, and optimum conditionswere determined. The results show that Gd (La, Ca, Sr) has clear cofluorescence effect in solidcomplex Tb-M-PMA system, and in present work, rare earth complex fluorescent powder that emitsbright green fluorescence at ultraviolet excitation was obtained, which had potential application asfluorescent anti-counterfeit ink.

Anti-wrinkle Finishing of Cotton Fabrics with Pyromellitic Acid Enhanced by Polyol Extenders

Pyromellitic acid(PMA)has been employed for formaldehyde-free anti-wrinkle finishing on cotton fabrics for its low damage to fibers and absence of phosphorus-containing catalysts.However,the wrinkle resistance performance of fabrics failed to meet the application expectation.In this work,the polyol extenders were introduced into PMA cross-linked cellulose for further improving fabric resilience by a two-step dipping-squeezing-curing method.Eleven polyols were employed as the chain extenders for PMA anti-wrinkle finishing on fabrics,among which sorbitol presented the best chain-spreading effect on wrinkle resistance.After screening the process parameters,the optimum process was obtained as follows.The dosage ratio of PMA to sorbitol was 1∶1,the curing condition was 150-160℃ for 2-3 min.Scanning electron microscopy(SEM),thermogravimetric analysis(TGA)and Fourier transform infrared(FTIR)spectroscopy were employed to characterize the fiber changes during the process.The results showed that the sorbitol incorporation could facilitate the remelting and redissolution of PMA on fiber surface.During the curing process,sorbitol could form ester linkages between PMA molecules and improve the fiber resilience.The treated samples presented excellent washing durability,and the wrinkle recovery angle A_(w)was still 265.1°after 10 washes,which was close to that of 1,2,3,4-butane tetracarboxylic acid(BTCA)but with lower tearing load loss.The results provide new insights for the application of PMA in formaldehyde-free anti-wrinkle finishing on cotton fabrics.

Synthesis and characterization of terbium(Ⅲ)-pyromellitic acid(H_4L)-1,10-phenanthroline (phen) luminescent complex

The terbium(Ⅲ)-pyromellitic acid(H4L)-1,10-phenanthroline(phen) luminescent complex was synthesized using a co-precipitation method.The chemical composition of the synthesized complex was speculated to be Tb4L3(phen)0.075·10H2O by elemental analysis,inductively coupled plasma-atomic emission spectroscopy(ICP-AES),and Fourier-transform infrared spectroscopy(FT-IR).The X-ray diffraction analytic results indicated that the synthesized complex is a new crystalline complex,whose structure was different from those of other two ligands.The scanning electron microscopy analytic results showed that the product was of spherical crystals with good dispersion property,and the mean diameter of the spheres was about 1-2 μm.The TG-DTA result showed that the complex had good stability below 489 °C.PL spectra showed that the complex emitted characteristic green fluorescence of Tb(Ⅲ) ion under ultraviolet excitation.

Synthesis and Optoelectronic Properties of Donor-acceptor Molecules Containing Pyromellitic Diimide Chromophore

Three donor-acceptor molecules containing pyromellitic diimide chromophore were designed and synthe- sized. The synthetic route towards the target compounds was systematically investigated and discussed in detail. The resulted organic semiconductors have shown promising optoelectronic properties as further revealed by UV-Vis ab- sorption spectroscopy, cyclic voltammetry, and theoretic calculation.

Synthesis and Crystal Structure of a New Zn(Ⅱ) Coordination Polymer Constructed by 1,2,4,5-Benzenetetracarboxylate

A new Zn（Ⅱ） coordination polymer [Zn3（btec）（OH）2（H2O）2]n （1, btec = 1,2,4,5- benzenetetracarboxylate） has been synthesized by hydrothermal reaction and its structure was determined by single-crystal X-ray diffraction analysis. The title compound crystallizes in mono- clinic, space group C2/c, with a = 19.580（3）, b = 5.0137（8）, c = 15.975（3）, β = 121.629（2）°, V = 1335.3（4）3, C10H8O12Zn3, Mr = 516.27, Z = 4, Dc = 2.568g/cm3, μ = 5.419 mm-1, F（000） = 1016, R = 0.0590 and Rw = 0.1279 for 1110 observed reflections （I 2σ（I））. X-ray analysis shows that the asymmetric unit of the title compound contains two crystallographically unique Zn（Ⅱ） atoms which are connected through the bridging carboxylate oxygen atoms of the btec ligands and μ2-bridging oxygen atoms of water molecules to generate an infinite one-dimensional chain. The adjacent chains are linked together through the benzene rings of the btec ligands to form a two-dimensional polymeric network. The adjacent two-dimensional layers are further connected together by the benzene rings of btec ligands to give the final three-dimensional structure. The benzene rings act as pillars between two layers.

Influences of Diamines on the Morphologies and the Chemical, Thermal, and Mechanical Properties of Polyurethane-Imide Elastomers

Polyurethane-imide elastomers (PUIEs) are formed from isocyanate, polyol, acid anhydride, and diamine by liquid polymerization. Unfortunately, many of the diamines have rarely been applied to the formation of PUIEs. Hence, investigating the effect of diamines on PUIEs remains a challenge in polymer chemistry. Herein, PUIEs prepared from 4,4'-diphenylmethane diisocyanate (MDI), polytetramethylene glycol (Mw: 1000), pyromellitic dianhydride, and aromatic diamines (such as p-phenylene diamine, 4,4'-oxydianiline, and 1,3-bis(4-aminophenoxy)benzene), and aliphatic diamines (such as 1,2-ethylene diamine, 1,6-hexamethylene diamine, and 1,12-dodecamethylene diamine) were synthesized by liquid polymerization. The morphologies and the chemical, thermal, and mechanical properties of the various PUIEs were investigated. The obtained elastomeric sheets were characterized in terms of the following tests and methods: solubility and swelling tests, X-ray diffraction and differential scanning calorimetry, dynamic mechanical analysis and thermogravimetric analysis, tensile tests, nuclear magnetic resonance spectroscopy, infrared spectroscopy, atomic force microscopy, contact angle microscopy, and scanning electron

Synthesis and Characterization of Eu_4(PMA)_3(phen)_(0.75)·7H_2O Ternary Luminescent Complex

Eu(Ⅲ)-Pyromellitic acid[PMA]-1, 10-phenanthroline (phen) ternary luminescent complex was prepared in ethanol and water mixed solvent. The elemental analysis, inductively coupled plasma-atomic emission spectroscopy (ICP-AES) fourier-transform infrared spectroscopy (FT-IR) indicates that its chemical constitution is Eu4( PMA)3( phen)0.75·7H2O. TG-DTA curves indicated that the complex is heat stable at the temperature of 430℃. The XRD patterns showed that the complex is a new crystal different from the two ligands' structures. SEM image indicates that the complex is in block shape and disperses well. Photoluminescence (PL) analysis indicates that the complex emits Eu3+ characteristic luminescence under ultraviolet excitation.

Carboxylic Acids and Esters as Scaffold for Cavities in Porous Single Layer Anti-Reflective Coatings of Silica-Titania with Excellent Optical and Mechanical Properties

Anti-reflective (AR) single layer of silica-titania (SiO2-TiO2) coatings were obtained from sols containing pyromellitic dianhydride (PMDA) derivatives and Ti and Si precursors on glass substrate by dip-coating method. The coatings showed very high optical quality and the transmission was improved to up to 98.5%. Furthermore, the coatings also presented good mechanical stability.

Zinc and Silver Salts-Containing Lamellar Titanium Phosphate: A Multifunctional Filler

Zinc and silver compounds have been studied because they have ultraviolet light barrier properties and bactericidal action, respectively. Materials with multifunctional characteristics have been sought to produce polymeric nanocomposites. In this work, the chemical modification of titanium phosphate (TiP) was carried out through a route with successive intercalations. TiP was synthesized and consecutively pre-expanded with ethylamine and pyromellitic acid. Then it was modified with zinc acetate and silver nitrate. The final product was characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, wide-angle X-ray diffractometry, field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and thermogravimetry. Infrared revealed dislocation and appearance of bands according to the intercalating agent. Inorganic salts interfered in the crystallization and melting processes of pyromellitic acid. Vanishing of the TiP hkl plane and variation and appearance of new crystallographic planes at low diffraction angles induced intercalation. SEM showed agglomerated structures. New thermal degradation events at higher temperatures endorsed the formation of zinc and silver carboxylate salts. We concluded that a new miscellaneous and multifunctional matter was achieved.

Architecting Branch Structure in Terpolymer of CO_(2),Propylene Oxide and Phthalic Anhydride:An Enhancement in Thermal and Mechanical Performances

Poly(propylene carbonate phthalate)(PPC-P)is a chemically modified poly(propylene carbonate)(PPC)biodegradable thermoplastic by introducing phthalic anhydride(PA)as the third monomer into the copolymerization of propylene oxide(PO)and CO_(2).To enhance the thermal and mechanical properties of PPC-P,a branching agent pyromellitic anhydride(PMDA)was introduced into the terpolymerization of PO,PA and CO_(2).The resulting copolymers with branched structure,named branched PPC-P,can be obtained using metal-free Lewis pair consisting of triethyl borane(TEB)and bis(triphenylphosphine)iminium chloride(PPNCl)as catalyst.The products obtained were analyzed by NMR spectroscopy and their thermal,mechanical properties and melt processability were evaluated by DSC,TGA,tensile test and melt flow index(MFI)measurement.The obtained branched PPC-P has a high molecular weight up to 156.0 kg·mol^(-1).It shows an increased glass transition temperature(Tg)higher than 50℃and an enhanced tensile strength as high as 38.9 MPa.Noteworthily,the MFI value decreases obviously,indicative of an improved melt strength arising from the branched structure and high molecular weight.What is more,the branched PPC-P exhibits reasonable biodegradability,which demonstrates the great potential as a new green thermoplastic for the family of biodegradable plastics.

Increasing the Solubility of a Hydrophobic Molecule with Thymine-like Face by DNA via Supramolecular Interaction

Poor water-solubility of hydrophobic drugs greatly hampers drug design and creats delivery problems.The traditional way to improve the solubility is to add hydrotropes or excipients to supress aggregations.Here,a novel mechanisim has been proposed based on supramolecular interactions and demonstrated with a small molecule,pvromellitic diimide(PD).This compound contains thymine-like ‘face’ and can interact with adenines through Wat-son-Crick and Hoogsteen hydrogen-bonding.Given the high water solubility of poly adenines[poly(A)],it is expectec that poly(A)will greatly increase the PD solubility.Indeed,such an increased solubility was confirmed by ultraviolet-visible spectroscopy(UV-Vis)and polyacrylamide gel electrophoresis(PAGE)analysis.We believe that this strategy could be used to improve the solubility of other similar hydrophobic molecules.

Preparation of starch esters with crosslinking structures derived from dianhydride

Starch is a kind of natural polymer used in many industrial fields because of its low cost,availability and biodegradation.Potato starch was modified by esterification with pyromellitic dianhydride,and the products were obtained with crosslinking structures.Orthogonal experiments showed that reactive temperature was the primary influencing factor.The product prepared at 40℃ for 3 h with the mass ratio of starch and dianhydride of 16∶1 and pH value of 7.5 exhibited a degree of substitution of 11%.FTIR and UV analysis verified the formation of starch esters.