Sonochemical synthesis and characterization of nano-sized lead(II) 3D coordination polymer: Precursor for the synthesis of lead(II) oxybromide nanoparticles

Nanoparticles of a three-dimensional coordination polymer, [Pb(L)(μ₂-Br)(H₂O)]_n (1), (L^? = 1H-1,2,4-triazole-3-carboxylate), have been synthesized by an ultrasonic method and characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analyses. The thermal stability of compound 1 both its bulk and nano-size has been studied by thermal gravimetric (TG) and differential thermal (DTA) analyses and compared each other. Concentration of initial reagents effects and the role of power ultrasound irradiation on size and morphology of nano-structured compound 1, have been studied. Calcination of the compound 1 at 500 °C under air atmosphere yields Pb₃O₂Br₂ nanoparticles.     

Sonochemical synthesis and characterization of new one-dimensional manganese(II) coordination polymer nanostructures

A new Mn(II) coordination polymer, [Mn (L₁)₂(NCS)₂]_n (1) [L₁ = 3,4-bis(4-pyridyl)-5-(2-pyridyl)-1,2,4-triazole] was synthesized by the reaction of ligand L₁ and mixtures of manganese(II) acetate and potassium thiocyanate using the heat gradient method. Compound 1 has been characterized by IR spectroscopy, elemental analyses and X-ray crystallography. The crystal structure of compound 1 was determined by single-crystal X-ray diffraction and shows a new interesting one-dimensional coordination polymer. Nanostructures of compound 1 have been synthesized by sonochemical method. The products were characterized by X-ray powder diffraction, scanning electron microscopy (SEM), and IR spectroscopy. The thermal stability of nano particles of compound 1 was studied by thermal gravimetric and differential thermal analyses.     

Synthesis and characterization of a new nano lead(II) 0-D coordination supramolecular compound: A precursor to produce pure phase nano-sized lead(II) oxide

Nano-structure of a new 0D Pb(II) coordination supramolecular compound, [Pb₄(8-Quin)₆](ClO₄)₂(1), L = 8-HQuin = 8-hydroxyquinolin ligand has been synthesized by use of a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR) and elemental analyses. The structure of compound 1 was determined by single-crystal X-ray diffraction. The single crystal X-ray data of compound 1 implies that the Pb⁺² ions are five coordinated. Each lead atom is coordinated to nitrogen and oxygen atoms of 8-hydroxyquinolin ligand. Topological analysis shows that the compound 1 is 1,2,3,4,4M12-1net. Nanoparticles of lead(II) oxide have been prepared by calcination of lead(II) coordination polymer at 500 °C that were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD) and IR spectroscopy.     

Application of ultrasound to the synthesis of a new nanostructured Mn(II) supramolecular compound: A precursor for γ-Mn2O3 nanoparticles

A new nanostructured Mn(II) supramolecular compound [Mn(hpydcH₂)₂(H₂O)₄] (1) (hpydcH₃ = 4-hydroxy-2,6-pyridinedicarboxylic acid) has been synthesized using a sonochemical process. The structure of compound 1 was determined by single crystal X-ray diffraction and it was revealed that each hpydcH₂⁻ anionic ligand has been coordinated to Mn(II) ion in a novel monodentate fashion leaving another functional carboxylic acid group intact. Compound 1 was also characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), FT-IR spectroscopy and elemental analysis. Thermal stability of compound 1 was studied by thermal gravimetric (TG) analysis and compared to that of its crystalline analogue. Subsequently, the role of concentration of the initial reactants on the size of nanostructures of compound 1, has been investigated. Compound 1 was proved to be a precursor for γ-Mn₂O₃ nanoparticles.     

Three-dimensional organometallic thallium(I) supramolecular polymer nanostructures synthesized with sonochemical process

A new three-dimensional thallium(I) supramolecular polymer, [Tl₂(μ₂-ATA)]_n (1), [H₂ATA = 2-aminoterephthalic acid]_, has been synthesized and characterized. The single-crystal X-ray data of compound 1 shows one type of Tl^I ion with a low coordination number. Compound 1 was self-assembled from Tl⋯C, Tl⋯O and Tl⋯N secondary interactions in thallium(I) coordination and the active lone pair on Tl^I in this compound may be involved in donor bonding. Two sides of the aromatic ring of ATA²⁻ anion have been involved in two types of secondary Tl⋯C approaches. Three samples of 1 were synthesized with three different concentrations of initial reagents under ultrasonic irradiation. The thermal stability of compound 1 samples were studied by thermo gravimetric (TG) and differential thermal analyses (DTA). These nano-structures were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM).     

Sonochemical synthesis,characterization, and effects of temperature,power ultrasound and reaction time on the morphological properties of two new nanostructured mercury(II) coordination supramolecule compounds

Two new mercury(II) coordination supramolecular compounds (CSCs) (1D and 0D), [Hg(L)(I)₂]_n (1) and [Hg₂(L′)₂(SCN)₂]·2H₂O (2) (L = 2-amino-4-methylpyridine and L′ = 2,6-pyridinedicarboxlic acid), have been synthesized under different experimental conditions. Micrometric crystals (bulk) or nano-sized materials have been obtained depending on using the branch tube method or sonochemical irradiation. All materials have been characterized by field emission scanning electron microscope (FESEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD) and FT-IR spectroscopy. Single crystal X-ray analyses on compounds 1 and 2 show that Hg²⁺ ions are 4-coordinated and 5-coordinated, respectively. Topological analysis shows that the compound 1 and 2 have 2C1, sql net. The thermal stability of compounds 1 and 2 in bulk and nano-size has been studied by thermal gravimetric (TG), differential thermal analyses (DTA) for 1 and differential scanning calorimetry (DSC) for 2, respectively. Also, by changing counter ions were obtained various structures 1 and 2 (1D and 0D, respectively). The role of different parameters like power of ultrasound irradiation, reaction time and temperature on the growth and morphology of the nano-structures are studied. Results suggest that increasing power ultrasound irradiation and temperature together with reducing reaction time and concentration of initial reagents leads to a decrease in particle size.     

Sonochemical synthesis and structural characterization of a new nanostructured Co(II) supramolecular coordination polymer with Lewis base sites as a new catalyst for Knoevenagel condensation

A new Co(II) mixed-ligand coordination supramolecular polymer with composition [Co₂(ppda)(4-bpdh)₂(NO₃)₂]_n (1) (where, ppda = p-phenylenediacrylic acid, 4-bpdh = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene) was synthesized using solvothermal, mechanochemical and sonochemical methods. Compound 1 and the new nanostructure have been characterized by single-crystal X-ray, infrared spectroscopy (IR), powder X-ray diffraction (PXRD) analysis and scanning electron microscopy (SEM). The thermal stability of compound 1 was also studied by thermal gravimetric analysis (TGA). The surface area of these compounds was determined by BET. The single-crystal X-ray data shows a new interesting two-dimensional coordination polymer (CP). In addition, the effect of various sonication concentrations of initial reagents, power of ultrasound irradiation and also the time on the size and morphology of nano-structured coordination polymer 1 were evaluated. Moreover, it has been demonstrated that the nanostructure of the CP1 can be used as a catalyst in Knoevenagel condensation reaction.     

Synthesis of a new Hg(II) coordination polymer: Ultrasonic-assisted synthesis and mechanical preparation of nanostructure

A new mercury(II) coordination polymer, [Hg(4-bpmo)I₂]_n (1), (4-bpmo = N,N′-bis(pyridin-4-ylmethyl)oxalamide), was synthesized, by branched tube method, and structurally characterized by single-crystal X-ray diffraction. Compound 1 is a polymer with a distorted tetrahedral HgN₂I₂ coordination environment. The thermal stability of 1 was studied by thermal gravimetric (TG) and differential thermal (DTA) analyses. Also 1 was prepared by a sonochemical process at ambient temperature. Reaction time and concentration of initial reagents effects on the size and morphology were studied. Nanoparticles of 1, was synthesized easily by a mechanical method (neat grinding). The resulting structures were characterized by scanning electron microscopy (SEM), IR spectroscopy and X-ray powder diffraction (XRD).     

Sonochemical synthesis of a new nano-sized cerium(III) supramolecular compound; Precursor for nanoceria

Using a sonochemical method, nanoparticles of a new Ce(III) supramolecular compound, (NAMH⁺)₂[Ce₄(pydc)₆(pydcH)₂(H₂O)₈]·8H₂O (1), (H₂pydc = 2,6-pyridinedicarboxylic acid, NAM = nicotinamide), have been synthesized. Compound 1 was characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), FT-IR spectroscopy and elemental analyses, and its structure was determined by X-ray crystallography. It has been revealed that its structure consists of tetra-nuclear building units that extend to a 3D supramolecular network via non-covalent interactions mainly hydrogen bonding. The thermal stability of complex 1 both for its crystals and nanostructures has been studied by the thermal gravimetric (TG) method and compared with each other. The role of ultrasound irradiation power and the concentration of initial reactants on the size and morphology of the nano-structured complex 1, has been investigated. Ceria nanoparticles were obtained upon the calcination of complex 1 at 800 °C under atmospheric air. Furthermore, the fluorescent properties of complex 1 at room temperature were studied.     

Ultrasound irradiation effect on morphology and size of two new potassium coordination supramolecule compounds

Two new potassium coordination supramolecular compounds (2D and 1D), [K(H₃L)(H₂L)(H₂O)]_n·H₂O (1) and [K(H₂L′)(HL′)(H₂O)₂]·H₂O (2), (L = 1,3,5-tricarboxylic acid, L′ = 2,6-pyridinedicarboxylic acid), have been synthesized under different experimental conditions. Micrometric crystals (bulk) or nano-sized materials have been obtained depending on using the branch tube method or sonochemical irradiation. All materials have been characterized by field emission scanning electron microscopy (FE-SEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), FT-IR spectroscopy and elemental analyses. Single crystal X-ray analyses on compounds 1 and 2 show that K⁺ ions are 3- and 7-coordinated, respectively. Additionally, H-bonds incorporate the layers and chains in 1 and 2 into 3D and 2D (along (0,0,1) direction) frameworks. Topological analysis shows that the compound 1 and 2 are 3,6-coordinated kgd and 2,4-coordinated 2,4C4 net. The thermal stability of compounds 1 and 2 in bulk and nano-size has been studied by thermal gravimetric (TG) and differential thermal analyses (DTA) and compared each other. The role of different parameters like temperature, reaction time and ultrasound irradiation power on the growth and morphology of the nano-structures are studied. Results suggest that an increase of temperature, sonication power and reduction of reaction time led to a particle size decrease.     

Sonochemical synthesis and characterization of new nanostructures cobalt(II) metal-organic complexes derived from the azo-coupling reaction of 4-amino benzoic acid with anthranilic acid,salicylaldehyde and 2-naphtol

Nanostructures of three new cobalt(II) complexes, (CoL₁)·0.5DMF·1.5MeOH (1), [H₂L₁ = 5-(4-Carboxy phenyl azo) anthranilic acid], (Co(L₂)₂)·1.5MeOH (2), [HL₂ = 5-(4-Carboxy phenyl azo) salicylaldehyde] and (Co(L₃)₂)·0.5 DMF·0.5MeOH (3), [HL₃ = 1-(4-Carboxy phenyl azo) 2-naphtol], have been synthesized by the reaction of H₂L₁, HL₂ and HL₃ with Co(OAc)₂·4H₂O through sonochemical process. Calcination of the nano-sized compounds 1–3 yield Co₃O₄ nanoparticles at 450 °C under air atmosphere. These nanostructures were characterized by X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM). Thermal stability of compounds 1–3 was studied by thermogravimetric (TG) and differential thermal analyses (DTA).     

Ultrasonic assisted-Fenton-like degradation of nitrobenzene at neutral pH using nanosized oxides of Fe and Cu

Ultrasonic-assisted heterogeneous Fenton reaction was used for degradation of nitrobenzene (NB) at neutral pH conditions. Nano-sized oxides of α-Fe₂O₃ and CuO were prepared, characterized and tested in degradation of NB (10 mg L⁻¹) under sonication of 20 kHz at 25 °C. Complete degradation of NB was effected at pH 7 in presence of 10 mM H₂O₂ after 10 min of sonication in presence of α-Fe₂O₃ (1.0 g L⁻¹), (k = 0.58 min⁻¹) and after 25 min in case of CuO (k = 0.126 min⁻¹). α-Fe₂O₃ showed also effective degradation under the conditions of 0.1 g L⁻¹ oxide and 5.0 mM of H₂O₂, even though with a lower rate constant (0.346 min⁻¹). Sonication plays a major role in enhancing the production of hydroxyl radicals in presence of solid oxides. Hydroxyl radicals-degradation pathway is suggested and adopted to explain the differences noted in rate constants recorded on using different oxides.     

Very high resolution far infrared synchrotron radiation spectrum of methanol-D1 (CH2DOH) in the first three torsional-vibrational modes

In our effort to systematically study the far infrared (FIR) spectra of asymmetrically mono deuterated methanol (CH₂DOH) and thereby obtain the transition wavenumbers with better and better accuracy (Mukhopadhyay, 2016a,b), the complete Fourier transform (FT) spectra from FIR to infrared (IR) vibrational bands (in the range 50–1190 cm⁻¹) have been re-recorded using the Synchrotron Radiation Source at the Canadian Light Sources in Saskatchewan, Canada. The resolution of the spectrum is unprecedented, reaching beyond the Doppler limited resolution as low as about 0.0008 cm⁻¹ with a signal to noise (S/N) ratio is many fold better than that can be obtained by commercially available FT spectrometer using thermal sources (e.g., Globar). Spectra were also recorded beyond 1190 cm⁻¹ to about 5000 cm⁻¹ at a somewhat lower resolution of 0.002–0.004 cm⁻¹. In this report the analysis of the b-type and c-type torsional - rotational spectra in the ground vibrational state corresponding to gauche- (e₁/o₁) to gauche- (e₁/o₁) and gauche- (e₁/o₁) to trans- (e₀) states in the ground vibrational state are reported and an atlas of the wavenumber for about 2500 FIR assigned absorption lines has been prepared. The transitions within a given sub-band are analyzed using state dependent expansion parameters and the Q-branch origins. The data from previous results (Mukhopadhyay, 2016a,b) along with the present work allowed a global analysis yielding a complete set of molecular parameters. The state dependent molecular parameters reproduce the experimental wavenumbers within experimental uncertainty. In addition, the sensitivity of the spectrum allowed observation of forbidden transitions previously unobserved and helped reassignment of rotational angular momentum quantum numbers of some ΔK = ±1, Q-branch transitions in highly excited states recently reported in the literature. To our knowledge the wavenumbers reported in the present work are the most accurate so far reported in the literature and represent the highest resolution spectra for this molecular species.     

Sonochemical synthesis of two new nano lead(II) coordination polymers: Evaluation of structural transformation via mechanochemical approach

Two new lead(II) mixed-ligand coordination polymers, [Pb(PNO)(SCN)]_n (1) and [Pb(PNO)(N₃)]_n (2), (HPNO = picolinic acid N-oxide) were synthesized by a sonochemical method and characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analysis. Compounds 1 and 2 were structurally characterized by single crystal X-ray diffraction. The thermal behavior of 1 and 2 were studied by thermal gravimetric analysis. Structural transformations of compounds 1 and 2 were evaluated through anion-replacement processes by mechanochemical method. Moreover, the effect of sonication conditions including time, concentrations of initial reagents and power of irradiation were evaluated on size and morphology of compounds 1 and 2.     

A Boubaker polynomials expansion scheme (BPES)-related protocol for measuring sprayed thin films thermal characteristics

Measurements of In₂S₃ and ZnIn₂S₄ sprayed thin films thermal characteristics have been carried out using the photodetection technique. The thermal conductivity k and diffusivity D were obtained using a new protocol based on photothermal signal parameters analysis. Measured values of k and D were respectively, (15.2 ± 0.85) W m⁻¹K⁻¹ and (69.8 ± 7.1) × 10⁻⁶ m²s⁻¹ for In₂S₃, (7.2 ± 0.7) W m⁻¹K⁻¹ and (32.7 ± 4.3) × 10⁻⁶ m²s⁻¹ for ZnIn₂S₄. These values are extremely important since similar compounds are more and more proposed as Cd-free alternative materials for solar cells buffer layers.     

Ionic and electronic conductivities,stability and thermal expansion of La10 − x(Si,Al)6O26 ± δ solid electrolytes

Apatite-type La_10 − xSi_6 − yAl_yO_{27 − 3x/2 − y/2} (x = 0–0.33; y = 0.5–1.5) exhibit predominant oxygen ionic conductivity in a wide range of oxygen partial pressures. The conductivity of silicates containing 26.50–26.75 oxygen atoms per formula unit is comparable to that of gadolinia-doped ceria at 770–870 K. The average thermal expansion coefficients are (8.7–10.8) × 10^− 6 K^− 1 at 373–1273 K. At temperatures above 1100 K, silicon oxide volatilization from the surface layers of apatite ceramics and a moderate degradation of the ionic transport with time are observed under reducing conditions, thus limiting the operation temperature of Si-containing solid electrolytes.     

Sonochemical syntheses of binuclear lead(II)-azido supramolecule with ligand 3,4,7,8-tetramethyl-1,10-phenanthroline as precursor for preparation of lead(II) oxide nanoparticles

The new neutral binuclear lead(II) azido coordination compound, [Pb₂(tmph)₂(μ-N₃)₂(CH₃COO)₂] (1) [tmph = 3,4,7,8-tetramethyl-1,10-phenanthroline], has been synthesized by a sonochemical method. Single crystal X-ray structure shows that the overall structure of 1 is binuclear unit. Complex 1 has a bridging azido pathway, end-to-end bridging azides between a pair of lead(II) centers. This is further extended into a one-dimensional (1D) and three-dimensional (3D) supramolecular structure by Pb⋯C and π–π weak directional intermolecular interactions. The coordination number of lead(II) ions is seven, PbN₄O₃, with two N-donor atoms from tmph ligands and three O-donors from acetate anions and two N-donors from two azide anions. It has a “stereo-chemically active” electron lone pair, and the coordination sphere is hemidirected. The PbO nanoparticles were obtained by thermolysis of 1 at 180 °C with oleic acid as a surfactant. The morphology and size of the prepared PbO samples were further observed using scanning electron microscopy (SEM).     

Synthesis and characterization of nano-peanuts of lead(II) coordination polymer [Pb(qcnh)(NO3)2]n with ultrasonic assistance: A new precursor for the preparation of pure-phase nano-sized PbO

A sonochemical method was used to synthesize nano-peanuts of a new lead(II) coordination 1D polymer, [Pb(qcnh)(NO₃)₂]_n (1), where qcnh = 2-quinolincarbaldehyde nicotinohydrazide. The compound was characterized by scanning electron microscopy (SEM), elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), and single crystal X-ray analysis. The X-ray structure revealed that the Pb(II) atom is coordinated by one oxygen and three nitrogen atoms from two qcnh ligands and five oxygen atoms from three nitrate ligands in an 8 + 1 fashion with a PbN₃O₆ donor set. One of the PdN distances in the vicinity of the central atom is a bit longer (Pb1N1 = 2.939(4) Å), which shows the effect of the 6s² lone electron pair localized within the valence shell of the lead(II) atom. PbO nanoparticles were obtained by thermolysis of 1 at 180 °C with oleic acid as a surfactant. The average diameter of the nanoparticles was estimated by XRD to be 28 nm. The morphology and size of the prepared PbO nanoparticles were further studied using SEM.     

Trapping of metastable high-spin species and weak cooperativity in a mononuclear Fe(II) spin-crossover system

The magnetic and structural properties of three gradual spin transition monomeric compounds based on the cation [Fe(Hpt)₃]²⁺ (Hpt=3-(pyrid-2-yl)-1,2,4-triazole) are presented. The non-cooperative character of the spin-crossover in [Fe(Hpt)₃](BF₄)₂·2H₂O (I) is evaluated in light of its calorimetric properties, which yielded the thermodynamic values Δ_trsH=5.81 kJ mol⁻¹ and Δ_trsS=39.5 J mol⁻¹ K⁻¹. The light-induced excited spin-state trapping effect is performed on [Fe(Hpt)₃](BF₄)₂·2H₂O (I) and [Fe(Hpt)₃](SO₄)_0.4(BF₄)_1.2·3H₂O (II), and the subsequent HS→LS relaxations are studied. Their merely first-order kinetics are affected by disorder in the structure of both complexes, which appears in the presence of a distribution of activation energies. HS species can also be frozen-in in I by rapid cooling. Continuous irradiation is shown to induce only apparent light-induced thermal hysteresis effect in I and II, stemming from slow kinetics of relaxation with respect to the kinetics of measurement.     

A general method for preparing lanthanide oxide nanoparticles via thermal decomposition of lanthanide(III) complexes with 1-hydroxy-2-naphthoic acid and hydrazine ligands

Six new lanthanide(III) complexes (i.e., [Ln(L)₂(NA)_1.5]·3H₂O, where Ln=La(III), Pr(III), Nd(III), Sm(III), Gd(III), and Ce(III) and L and NA indicate N₂H₄ and C₁₀H₆(1-O)(2-COO), respectively) with 1-hydroxy-2-naphthoic acid [C₁₀H₆(1-O)(2-COOH)] and hydrazine (N₂H₄) as co-ligands were characterized by elemental, FTIR, UV-visible, and XRD techniques. In the FT-IR spectra, the N-N stretching frequency in the range of 981–949 cm⁻¹ demonstrates evidence of the presence of coordinated N₂H₄, indicating the bidentate bridging nature of hydrazine in the complexes. These complexes show symmetric and asymmetric COO⁻ stretching from 1444 to 1441 cm⁻¹ and 1582 to 1557 cm⁻¹, respectively, indicating bidentate coordination. TG-DTA studies revealed that the compounds underwent endothermic dehydration from 98 to 110 °C. This was followed by the exothermic decomposition of oxalate intermediates to yield the respective metal oxides as the end products. From SEM images, the average size of the metal oxide particles prepared by thermal decomposition of the complexes was determined to be 39–42 nm. The powder X-ray and SEM coupled with energy dispersive X-ray (EDX) studies revealed the presence of the respective nano-sized metal oxides. The kinetic parameters of the decomposition of the complexes were calculated using the Coats-Redfern equation.