Saratchandra Babu Mukkamala

Hydrothermal synthesis, crystal structure and luminescence property of a three dimensional Sm(III) coordination polymer with 2,5-pyridinedicarboxylic acid

AbstractA novel three dimensional coordination polymer [Sm(2,5-pydc)(NO3)(H2O)] ⋅(H2O) (2,5-pydc = 2,5-pyridine dicarboxylate) (1) had been synthesized hydrothermally and characterized by elemental analysis, FT-IR and single-crystal X-ray diffraction analysis. This coordination polymer crystallized in the monoclinic space group P2/n with cell parameters a= 9.3610(4) Å, b= 8.3498(3) Å, c= 16.7159(8) Å, β= 106.31(0)∘, V= 1253.98(184) Å3. Thermogravimetric analysis revealed that complex 1 is stable up to 400∘C which on photoexcitation at 365 nm exhibited yellow emission at 583 nm. Graphical AbstractA novel three dimensional coordination polymer, [Sm(2,5-pydc)(NO3)(H2O)]•H2O, built from dinuclear samarium(III) secondary building units exhibits yellow photoluminescence at 583 nm.

Simple and Efficient One-Pot Synthesis of 2-Substituted Benzimidazoles from θ-Diaminoarene and Aryl Aldehydes

Abstract An easy and efficient one-pot condensation method for the synthesis of substituted benzimidazoles from θ-phenylenediamines with aryl aldehydes using urea hydrogen peroxide (UHP) and I2 in dimethylsulfoxide (DMSO) provides wide substrate scope with good to excellent yields and simple and quick isolation of the products. GRAPHICAL ABSTRACT

Control of Phase and Morphology of Calcium Oxalate Crystals by Natural Polysaccharide, Gum Arabic

Controlled crystal growth of calcium oxalate was examined under the influence of Gum Arabic (GA) and urea at pH 4.0, 7.0, and 9.0. GA when alone directed the formation of calcium oxalate dihydrate (COD) up to 2.0% w/v concentration, whereas urea influenced the formation of calcium oxalate monohydrate (COM). The combination of urea and GA in mixed proportions (2.0% w/v each) led to the formation of nanocrystallites of COD. The present study on crystallization behavior of calcium oxalate under the influence of natural polysaccharides and urea may prove to be important in understanding the control of kidney stone formation.

Copper(I) iodide–catalyzed amidation of phenylboronic acids/aryl bromides using 4-dimethylaminopyridine as ligand

ABSTRACT An efficient one-pot synthesis of N-arylbenzamide is described via reaction of phenylboronic acid/aryl bromide with benzamide in the presence of CuI (5 mol%) as catalyst, 4-dimethylaminopyridine (20 mol%) as the ligand, and Cs2CO3 (2 mmol) as the base. This protocol was applied to synthesize a small library of N-arylbenzamide in high yields. GRAPHICAL ABSTRACT

Synthesis, Crystal Structure, and Luminescent Activity of 3D Supramolecular Cadmium(II) Complex Constructed From 2,5-Pyridine Dicarboxylic Acid

A new 3D supramolecular cadmium(II) complex, [Cd(Pydc)2(H2O)2].H2O(1), (Pydc = 2,5-pyridine dicarboxylate) has been synthesized under mild hydrothermal conditions. In the complex, the two adjacent Cd(II) atoms were bound together by two μ-oxo bridging and generated an infinite straight chains in 2D layer structure. The non-covalent interactions such as π-π stacking interactions between pyridyl rings are involved in strengthening of 2D structure and hydrogen bond interactions between two adjacent chains through lattice water molecules led to form an extended 3D supramolecular network structure. Moreover, complex 1 exhibits blue emission at 437 nm after photo excitation at 365 nm.

Influence of γ-radiation on photoluminescence properties of YPO4:Eu3+,Ce3+ and YPO4:Dy3+,Ce3+ phosphors

Hexagonal YPO4 phosphors doped with Eu3+/Dy3+ and co-doped with Ce3+ were synthesized by a hydrothermal route assisted using lauric acid as a capping agent. The prepared phosphors were characterized by transmission electron microscopy, infrared spectroscopy, powder X-ray diffraction and photoluminescence spectra. YPO4: Eu3+ gives two red emission peaks at 587 and 610 nm corresponding to 5D0→7F1 and 5D0→7F2 transitions, respectively. YPO4: Dy3+ exhibits two emission peaks at 485 nm (blue) and 575 nm (yellow) corresponding to 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions, respectively. Ce3+ ions enhanced the emission intensity as a co-dopant in both phosphors. Moreover, the effect of γ-radiation in the dose range 5–300 kGy on the photoluminescence behaviour of YPO4:Eu3+,Ce3+ and YPO4:Dy3+,Ce3+ was also investigated. Quenching of emission intensity, after irradiation at 5 and 300 kGy, was observed in both the phosphors due to loss of excess energy through a non-radiative relaxation process.

Effect of Reaction Media on Hydrogen Sorption Properties of Mg-Decorated MWCNTs

Synthesis of Mg-decorated multiwalled carbon nanotubes (Mg-MWCNTs) from carboxylate-functionalized multiwalled carbon nanotubes (COOH-MWCNTs) and its hydrogen sorption have been investigated. Mg-MWCNTs have been prepared in different reaction media, i.e., water, amine (Triethyl amine), and DMF. Morphology, functionalization, surface area, and hydrogen adsorption have been examined through SEM with EDAX, TEM, BET analysis, FT-IR, and adsorption isotherms. An increase in hydrogen sorption was observed from 0.3 to 0.67 wt% and 0.1 to 0.45 wt% at 253 K and 298 K, respectively, for Pristine MWCNTs to Mg-MWCNTs

Solvent induced surface modifications on hydrogen storage performance of ZnO nanoparticle decorated MWCNTs

Surface functionalization via decorating nanometal particles on MWCNTs for hydrogen uptake through a spillover mechanism is the key for hydrogen energy storage for transport sectors. To improve the spillover effect, the decoration of ZnO nanoparticles on the surface of carboxylate-functionalized multi-walled carbon nanotubes (f-MWCNTs) was examined by tuning the experimental conditions such as varying the solvent and metal content. Samples were characterized using SEM coupled with EDS, TEM and powder X-ray diffraction. The hydrogen uptake performance of materials was examined at non-cryogenic temperatures i.e. 253 K and 298 K up to 70 bar pressure. Zn decorated MWCNTs prepared in water, amine and DMF adsorbed 0.47, 0.51 and 0.87 wt% of hydrogen, respectively, at non-cryogenic temperatures and moderate pressures.

Synthesis, crystal structure and fluorescent properties of two metal-organic frameworks constructed from Cd(II) and 2,6-naphthalene dicarboxylic acid

ABSTRACT Aimed at exploring the effect of reaction conditions on the formation of crystal structures of metal-organic framework materials (MOFs), two new MOFs [Cd3(2,6-NDC)3(DMF)4(NO3)] (1) and [Cd2(2,6-NDC)2(DMF)2] (2), have been prepared using Cd(II) and 2,6-naphthalene dicarboxylic acid (2,6-NDC) at variable temperature and different solvents. 3-D framework structures of 1 and 2 are formed through interconnection of fully deprotonated 2,6-NDC with trinuclear cluster of secondary building units. Further, both MOFs emitted blue fluorescence with diverse intensities in solid state at room temperature.

Synthesis and Crystal Structure of a New Aluminum(III) Oxalate Complex, (C2H10N2)2 [Al2(μ-O2)(C2O4)4].2H2O

A new Al(III) oxalate complex, (C2H10N2)2.[Al2(μ-O2)(C2O4)4]·2H2O (1), has been synthesized by hydrothermal technique. Single-crystal X-ray diffraction analysis reveals that the compound crystallizes in triclinic space group P-1 (2) with cell parameters a = 7.5297 (5) Å, b = 8.1418 (6) Å, c = 9.8279 (8) Å, α = 107.48 (1)°, β = 99.96 (1)°, γ = 95.09 (1)°. Four oxalate ligands binds with two metal centers in bidentate fashion and creates a rare μ-oxo bridged Al(III) dimer. Further, these dinuclear subunits, [Al2(μ-O2)(C2O4)4]4−, are linked by ethylene diamine [(NH3CH2CH2NH3)2+] and water molecules via hydrogen bonding through ab-planes making a two-dimensional supramolecular layered structure.