Presence Of Organic Amines Research Articles

Hydrothermal assembly strategy for the construction of oxygen‐bridging lanthanide‐substituted bilacunary Keggin‐type germanotungstate tetramers encapsulating [W3O12]6− connector

AbstractUnder the hydrothermal condition and presence of organic amines, incorporating lanthanide (Ln) ions into monolacunary Keggin‐type germanotungstate precursor resulted in the formation of two new complex clusters formulated as H17(H2en)5[K3(H2O)(GeW10O37TbOTb)4(μ6‐W3O12)] ⋅ 45H2O (GeW‐Tb) and H22(H2en)3[K2(GeW10O37EuOEu)4(H2O)(μ6‐W3O12)] ⋅ 44H2O (GeW‐Eu) (en=ethylenediamine), which have been structurally characterized by elemental analyses, ICP analysis, IR spectra, thermogravimetric analysis, bond valence sum calculations and single‐crystal X‐ray diffraction. The most prominent structural feature of GeW‐Eu and GeW‐Tb revealed an unprecedented oxygen‐bridging Ln‐substituted bilacunary Keggin‐type germanotungstate tetramers encapsulating [W3O12]6− connector. What's more interesting is that a versatile library of linkable units including bilacunary germanotungstate [α‐GeW10O37]10−, internal oxo group between two Ln ions, as well as central tritungstate intermediate [W3O12]6− are all generated in situ thanks to the potential promotion of hydrothermal reaction system. In particular, the possible assembly mechanism for the complex clusters is proposed, and their solid‐state photoluminescence properties are also discussed in detail. To our knowledge, both [α‐GeW10O37]10− and [W3O12]6− intermediates are the highly robust POM building blocks that were first discovered. The studies highlight the structural diversity of Ln‐substituted germanotungstates and provide a new direction in the design of other functional germanotungstate based POMs in the future.

A butterfly shaped Eu4(OH)2 cluster-based luminescent metal-organic framework with Lewis basic triazole sites demonstrating turn off sensing in the presence of organic amines.

The effective detection of organic amines is particularly important for environmental protection and human health. Herein, according to hard and soft acid base theory, a novel three-dimensional (3D) butterfly shaped Eu4(OH)2 cluster-based metal-organic framework with Lewis basic triazole sites, {[Eu4(taip)4(ox)(OH)2(H2O)4]·3H2O}n (1) (H2taip = 5-(1,2,4-triazol-1-yl) isophthalic acid, H2ox = oxalic acid), was successfully synthesized under solvothermal conditions, and was characterized by single crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, infrared spectroscopy and thermogravimetric analysis. Structural analysis reveals that compound 1 is a 3D net constructed from butterfly shaped Eu4(OH)2 clusters and contains isosceles triangular channels with dimensions of 8.84 × 8.84 × 8.63 Å3, which shows an unprecedented 8-connected topology with a Schläfli symbol {36·418·53·6}. Fluorescence experiments of compound 1 show sensitive luminescence quenching responses to organic amines such as diethylamine (DEA), trimethylamine (TMA), triethylamine (TEA), ethylenediamine (EDA) and aniline, and the quenching constants (KSV) decrease in the following order: EDA > DEA > TMA > TEA > aniline. The fluorescence quenching responses may be attributed to the energy gap between the LUMO energy values of H2taip and organic amines, which hinders the transfer of excited state energy to the emission state of Eu3+ and results in luminescence quenching. The fluorescence lifetimes of compound 1 in ethanol and organic anilines indicate that the fluorescence recognition process of organic amines was static.

A naphthalenediimide-based Cd-MOF as solvatochromic sensor to detect organic amines

A novel naphthalenediimide-based metal-organic framework, {[Cd(DPNDI)(2,6-NDC)]·2DMF}n (1), has been constructed from mixed ligands of N,N′-Di(4-pyridyl)-1,4,5,8-naphthalene -tetracarboxydiimide (DPNDI) and naphthalene-2,6-dicarboxylic acid (2,6-NDC). 1 displays a two-fold interpenetrated 3D framework related to the 6-c connected pcu topology, which exhibits solvatochromic behavior in the presence of organic amines (electron rich). This solvatochromic behavior was investigated by solid state UV–Vis diffuse reflectance spectra and photo-luminescent spectra, which was arise from the inter-molecular electron-transfer transition from the different solvents to the DPNDI ligand depending on the electron-donating ability of the guest solvents. This work shows that the naphthalenediimide-based MOFs could be used as solvatochromic sensor to detect organic amines.

Free chlorine formation in the process of the chlorine dioxide oxidation of aliphatic amines

Chlorine dioxide (ClO2) is commonly used as an alternative disinfectant to chlorine because it has a high bactericidal effect and may produce limited concentrations of halogenated disinfection byproducts (DBPs). However, previous studies have reported that free available chlorine (FAC) was produced when ClO2 reacted with some compounds, such as phenol, leading to the formation of halogenated DBPs. In this study aliphatic amines was found to react rapidly with ClO2 to form significant amount of FAC and its related DBPs. This study investigated the formation of FAC when ClO2 reacts with six model aliphatic amines (including primary amines, secondary amines and tertiary amines). FAC was formed immediately as ClO2 was added to the precursor solution. The maximum yield of FAC even reached 45% (based on consumed ClO2) when ClO2 reacted with 20 μM methylamine at a dose of 10 μM, which is close to a realistic maximum dose (about 0.8 mg/L) in the U.S.. The reactivity of amines to result FAC follows the sequence tertiary amines < secondary amines < primary amines. It was verified that the addition of aliphatic amines may enhance the formation of FAC during ClO2 oxidation in actual water samples. Organic chloramines and other chlorinated DBPs, such as cyanogen chloride, were detected when ClO2 was used as the sole oxidant of real water samples. This study demonstrated that chlorine-related byproducts may also be formed in the presence of organic amines during ClO2 treatment.

Sustainable Production of Benzylamines from Lignin.

Catalytic conversion of lignin into heteroatom functionalized chemicals is of great importance to bring the biorefinery concept into reality. Herein, a new strategy was designed for direct transformation of lignin β-O-4 model compounds into benzylamines and phenols in moderate to excellent yields in the presence of organic amines. The transformation involves dehydrogenation of Cα -OH, hydrogenolysis of the Cβ -O bond and reductive amination in the presence of Pd/C catalyst. Experimental data suggest that the dehydrogenation reaction proceeds over the other two reactions and secondary amines serve as both reducing agents and amine sources in the transformation. Moreover, the concept of "lignin to benzylamines" was demonstrated by a two-step process. This work represents a first example of synthesis of benzylamines from lignin, thus providing a new opportunity for the sustainable synthesis of benzylamines from renewable biomass, and expanding the products pool of biomass conversion to meet future biorefinery demands.

Sustainable Production of Benzylamines from Lignin

AbstractCatalytic conversion of lignin into heteroatom functionalized chemicals is of great importance to bring the biorefinery concept into reality. Herein, a new strategy was designed for direct transformation of lignin β‐O‐4 model compounds into benzylamines and phenols in moderate to excellent yields in the presence of organic amines. The transformation involves dehydrogenation of Cα−OH, hydrogenolysis of the Cβ−O bond and reductive amination in the presence of Pd/C catalyst. Experimental data suggest that the dehydrogenation reaction proceeds over the other two reactions and secondary amines serve as both reducing agents and amine sources in the transformation. Moreover, the concept of “lignin to benzylamines” was demonstrated by a two‐step process. This work represents a first example of synthesis of benzylamines from lignin, thus providing a new opportunity for the sustainable synthesis of benzylamines from renewable biomass, and expanding the products pool of biomass conversion to meet future biorefinery demands.

Excitation Management of Lead-Free Perovskite Nanocrystals Through Doping.

Despite their low toxicity and phase stability, lead-free double perovskite nanocrystals, Cs2AgInCl6 in specific, have suffered from low quantum yield of photoluminescence. This is mainly due to two reasons, including (i) the quenching effect from metal silver which was usually formed at high temperature from Ag+ reduction in the presence of organic amines and (ii) the parity-forbidden transition of pristine double perovskites. Here, we reported a room-temperature synthesis of Cs2AgInCl6 nanocrystals in an inverse microemulsion system, where Ag+ reduction was largely suppressed. By codoping Bi and Na ions, dark self-trapping excitons (STEs) were converted into bright ones, enabling a bright phosphor of photoluminescence quantum yield up to 56%. Importantly, the doping approach at room temperature relaxed the parity-forbidden transition (1S0 → 3P2) of Bi-6s2 orbitals, revealing a fine structure of a triband excitation profile. Such spin-rule relaxation was ascribed to symmetry breaking of the doped lattice, which was evidenced by Raman spectroscopy. In a proof-of-concept experiment, the bright nanocrystals were used as a color-converting ink, which enabled a stable white light light-emitting diode to operate in various environments, even under water, for long-term service.

Photocatalytic Hydrogen Production by RGO/ZnIn2S4 under Visible Light with Simultaneous Organic Amine Degradation.

In this work, the study of photocatalytic hydrogen production by RGO/ZnIn2S4 with simultaneous degradation of organic amines was carried out in the presence of organic amines in wastewater as the sacrificial agents. The effects of several factors, such as organic amine types, pH value, catalyst concentration, organic amine concentration, and sunlight source, on the photocatalytic activity of RGO/ZnIn2S4 for H2 production were investigated. At the same time, its performance of degrading organic amines during H2 production was also examined. The results showed that the order of H2 production activity of RGO/ZnIn2S4 in six organic amine solutions was N(CH2CH3)3 > N(HOCH2CH2)3 > N(CH3)3 > HO(CH2)2NH2 > C6H5–N2> CO(NH2)2, and the highest H2 production was in N(CH2CH3)3 (triethylamine) solution, being 1597 μmol·g–1·h–1, which is 2.6 times as high as that using the aqueous solution mixture of Na2S and Na2SO3 as the sacrificial agent. In addition, when the pH was 13, the catalyst concentration was 1.0 g·L–1, and the triethylamine concentration was 1.0 mol·L–1, the photocatalytic activity was the highest. Furthermore, the relationship between triethylamine concentration and H2 production was analyzed according to the theory of dynamics.

Preparation of Spherical Mordenite Zeolite Assemblies with Excellent Catalytic Performance for Dimethyl Ether Carbonylation.

Millimeter-sized spherical mordenite (MOR) zeolite with good mechanical strength was successfully prepared via vapor-assisted transformation of Na- and Al-doped SiO2 spheres. It is demonstrated that the precursor prepared by vacuum impregnation is essential for the achievement of well-retained morphology; the presence of organic amine (such as TEAOH, TMAOH, and HMI) in the vapor can help promote the crystallization, avoid the core-shell morphology, and improve the zeolite Si/Al ratio, although the MOR crystal morphology in the spherical products varies with the choice of organic amines. The resultant MOR-TEAOH spheres, which were synthesized under the assistance of TEAOH, possess large amount of Brønsted acid sites in the 8-MR side pockets (0.76 mmol/g), which is about 3 times higher than in the 12-MR main channels. The preferential siting of H+ sites in the 8-MR helps MOR-TEAOH show excellent catalytic performance in the DME carbonylation reaction. A 90% of DME steady conversion is observed on MOR-TEAOH, which is obviously higher than that on commercial sample (23%). This work offers millimeter-scale spherical MOR with good mechanical strength and excellent catalytic performance, which is very promising for the industrial applications.

Hydrothermal synthesis, structures and visible light harvest of three titanium complexes

Hydrothermal syntheses have been extensively used in the area of polyoxometalates and metal organic frameworks. However, the hydrothermal synthesis of crystalline titanium(IV) complexes is a daunting challenge. The reason is that the high reactivity and spontaneous hydrolysis of titanium(IV) ions always leading to fast precipitation of corresponding oxide rather crystalline compounds. Herein, we reported an effective way towards crystalline titanium(IV) complexes. In the presence of organic amines, we successfully isolated three titanium(IV) compounds. It is worth noting that organic amines play a vital role in the synthesis process, while the introduction of chromophores largely enhanced the visible light harvest.

Photoluminescence and self-assembly of cesium lead halide perovskite nanocrystals: Effects of chain length of organic amines and reaction temperature

All-inorganic halide perovskites have become one of the most prospective materials for lightening and display technology due to their color-tunable and narrow-band emission. Herein, we have systematically studied the effects of organic amines with different hydrocarbon chain length on the optical properties and morphology as well as the crystal structure of colloidal CsPbBr3 nanocrystals (NCs), which were synthesized in the presence of oleic acid (OA) and organic amines by using a simple hot-injection approach. The hydrocarbon chain length has shown an independent correlation to the morphology and crystal structure of the as-obtained CsPbBr3 NCs at 160°C, but their optical properties can be affected to some extent. The photoluminescence quantum yields (PLQYs) of the CsPbBr3 NCs synthesized in the presence of organic amines with long carbon chain length are generally in the range of 55–80% for different reaction time, but the PLQYs of less than 20% are obtained for the products synthesized in the presence of octylamine (OTAm) with short carbon chain length. The effects of the reaction temperature on the optical properties, size and crystal structure of the CsPbBr3 NCs synthesized in the presence of cetylamine (CTAm) are studied. Interestingly, some nanoplates also appear in these CsPbBr3 NCs obtained at relatively low temperatures (120 and 140°C), which have a strong tendency to self-assemble into face-to-face nanostructures. Such a similar self-assembly behavior is also observed in the product synthesized in the presence of oleylamine (OLAm), but only flat nanoplates are observed in the products in the presence of OTAm at 120°C. The results indicate that the lower reaction temperature and hydrocarbon chain length of the organic ligands play a significant role in the self-assembly of CsPbBr3 NCs. This work opens up an alternative approach to controllable-synthesis of perovskite NCs through varying the carbon chain length of organic surfactants, and enlightens the fabrication of different nanostructures via self-assembly methods for further optoelectronic applications.

Amine-templated synthesis of two metal phosphonates based on 5-phosphononicotinic acid

Two metal phosphonates, namely [Co3(OOCC5H3NPO3)2(H2O)6]·2(H2O) (1) and [Ni5(OOCC5H3NPO3H)2(OOCC5H3NPO3)2(H2O)8]·2(H2O) (2) were hydrothermally synthesized by reacting 5-phosphononicotinic acid with corresponding metal sulfate in the presence of organic amines as templates. In compound 1, bicobaltic clusters are corner-shared with {CPO3} tetrahedrons and subsequently connected by phosphonyl and pyridyl groups into layered structures. These layers are further linked with {Co3O6} octahedrons through carboxyl groups forming a three dimensional pillared layered frameworks. In compound 2, {NiO6} and two {NiO5N} octahedrons are linked by μ-OH2 bridge of water forming a trimeric cluster of Ni3. Subsequently, Ni3 clusters are corner-shared with {CPO3} tetrahedron and link to {Ni3O5N} octahedron forming a double-chain structure. These double-chains are further connected to a three dimensional structure by three functional groups of ligands. Magnetic property of compound 2 was investigated.

Planar {Ni6} cluster-containing polyoxometalate-based inorganic-organic hybrid compound and its extended structure.

Two {Ni6} cluster-containing inorganic-organic hybrid compounds have been successfully synthesized in the presence of organic amine under hydrothermal conditions, and they were characterized by powder and single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, and IR spectroscopy. Structural analysis indicates that [Ni0.5(H2O)3][{Ni6(μ3-OH)3en(H2O)10}(H2P2W15O56)]·10H2O (1, en = ethylenediamine) is a triangular inorganic {Ni6} cluster substituted polyoxotungstate with only one en to stabilize the {Ni6} cluster. However, [Ni(dap)2]{[Ni1.5(dap)1.5(H2O)3][Ni6(μ3-OH)3(dap)2(en)(H2O) {O2C(CH2)2CO2}0.5(CH3COO)(P2W15O56)]}·15H2O (2, dap = 1,2-diaminopropane) is a three-dimensional inorganic-organic hybrid compound linked by succinic acid. The magnetic properties of both compounds were studied. In addition, the adsorption properties of compound 2 have also been investigated.

A spectroscopic investigation of the photophysical behaviour of 9-aminoacridine hydrochloride hydrate in presence of organic amines in homogeneous and heterogeneous media

Photoinduced interactions of 9-aminoacridine hydrochloride hydrate (9AA-HCl) with aromatic and aliphatic amines, N,N'-dimethylaniline (DMA) and triethylamine (TEA) respectively have been investigated in homogeneous water–acetonitrile (1:1) mixture as well as in heterogeneous cetyltrimethyl ammonium bromide (CTAB) micellar media using UV–vis absorption, steady-state as well as time-resolved fluorescence spectroscopies and laser flash photolysis technique associated with a weak external magnetic field (MF). Differential modes of fluorescence quenching of 9AA-HCl with DMA and TEA corroborated with absorption studies reveal their disparity in the mechanism of interactions. Excited state proton transfer (ESPT) and photoinduced electron transfer (PET) are the phenomenon that have been found to be involved in with DMA, whereas with TEA ground-state complex formation, ground-state proton transfer and PET are prevalent. Discrepancy in pH of the interfacial and hydrophobic regions of CTAB facilitates the partitioning of the protonated and neutral forms of 9AA-HCl leading to differential occupational sites of the acceptor and donor moieties in the micellar medium, thus making the study more intriguing. Another important aspect of the present study is the use of MF to confirm the occurrence of PET, authenticate the spin-state of the intermediates thus formed and also to resolve the process of PET and ESPT.

Syntheses, characterization and magnetic properties of two novel inorganic–organic tungstoferrites, [FeIII4(H2O)2(B-α-FeIIIW9O34)2]10−

Interaction of the lacunary [α-SbW9O33]9– with Fe3+ in the presence of organic amines under hydrothermal conditions yields two novel inorganic–organic hybrid tungstoferrites [dapH2]3[enH2][enH]Na[Fe4(H2O)2(FeW9O34)2]·7H2O (dap=1,2-diaminopropane, en=ethylenediamine) (1) and [dapH2]5[Fe4(H2O)2(FeW9O34)2]·11H2O (2), which have been characterized by IR, elemental analysis, UV–Vis, TG and single-crystal X-ray diffraction. Both 1 and 2 consist of two [B-α-FeIIIW9O34]11− units joined by a rhomb-like tetranuclear iron cluster. Interestingly, 1 displays a new example of 1D chain-like architecture, in which adjacent [Fe4(FeW9O34)2]10– anions are interconnected by two unusual W–O–Fe bridges. Meanwhile, the neighboring chains are further assembled by Na+ ions, forming the 2D extended network. 2 exhibits a discrete dimeric TMSP structure constructed from two trivacant [B-α-FeIIIW9O34]11− subunits encapsulating a rhomb-like tetranuclear iron cluster with five isolated diprotoned dap molecules. Magnetic measurements indicate that antiferromagnetic exchange interactions are dominant in the hexanuclear {Fe6O22} clusters in 1 and 2.

The Self Assembly of Superhydrophobic Copper Thiolate Films on Copper in Thiol Solutions

Abstract It is common to think of thiols as molecules that form self-assembled monolayers on gold or similar metals, they have also been used as corrosion inhibitors on copper and steel, but we show here that if the copper remains in thiol solution corrosion is accelerated and a thick layer of corrosion products with a very rough surface forms. The layer is superhydrophobic; repelling water so effectively that it rolls off leaving the surface completely dry. It is composed of a copper (I) thiolate complex and growth occurs quite rapidly under normal conditions. The film morphology depends upon the solvent and thiol used. The presence of organic amines in the solution alters the reaction leading to the formation of thinner layers by removing corrosion products into solution, allowing the removal of native oxide layers.

Three-Dimensional Open-Framework Zinc Phosphite: Synthesis and Characterization

Generally, open-framework metal phosphites like phosphates, are synthesized under hydrothermal or solvothermal conditions in the presence of organic amines, which may act as structure-directing agent or template to avoid the formation of dense phase, but few of them has been successfully prepared at room temperature which seems to be difficult to synthesize these compounds. In this work, at room temperature, employing n-propylamine as a template, a three-dimensional zinc phosphite (C3H10N) 2·[Zn3(HPO3)4] has been prepared and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis, powder X-ray diffraction, and thermogravimetric analysis. The compound crystallizes in the orthorhombic space group Pccn, with cell parameters, a = 9.839(3) Å, b = 23.356(8) Å, c = 8.970(3) Å, V = 2050.2(8) nm3 and Z = 4.

Three-Dimensional Open-Framework Zinc Phosphite: Synthesis and Characterization

Generally, open-framework metal phosphites like phosphates, are synthesized under hydrothermal or solvothermal conditions in the presence of organic amines, which may act as structure-directing agent or template to avoid the formation of dense phase, but few of them has been successfully prepared at room temperature which seems to be difficult to synthesize these compounds. In this work, at room temperature, employing n-propylamine as a template, a three-dimensional zinc phosphite (C3H10N) 2·[Zn3(HPO3)4] has been prepared and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis, powder X-ray diffraction, and thermogravimetric analysis. The compound crystallizes in the orthorhombic space group Pccn, with cell parameters, a = 9.839(3) Å, b = 23.356(8) Å, c = 8.970(3) Å, V = 2050.2(8) nm3 and Z = 4.

Selective catalytic formic acid decomposition for hydrogen generation in ionic liquids

Abstract Effect of ionic liquids (ILs) as media for the decomposition of formic acid in the presence of organic amine was investigated, and this activity was observed to be markedly promoted by the addition of ILs, especially for BMImCl. Based on this finding and to avoid volatile organic amine, a series of amine-functionalized ILs were further designed and prepared as both reaction media and co-catalyst for homogeneous decomposition of formic acid. Among the ILs investigated, i-Pr 2NEMImCl-HCOONa system exhibited high activity (TOF > 600 mol/mol/h). This efficient and green method to produce hydrogen by formic acid decomposition has practical potentiality.

Synthesis and structure of the first organic–inorganic hybrid tin (II) chlorosulfate: [C 6N 2H 14][SnCl 2SO 4

The first organic–inorganic hybrid tin (II) chlorosulfate [C 6N 2H 14][SnCl 2SO 4] ( I) has been synthesized hydrothermally in the presence of organic amine 1,4-diazobicyclo[2,2,2]octane (DABCO) and characterized by single-crystal X-ray diffraction, IR, ICP and elemental analysis and thermogravimetric analysis and its structure solved by single-crystal X-ray diffraction. The structure of I consists of [SnCl 2SO 4] 2− anions and diprotonated DABCO cations resulting in the formation of a 2D supramolecular network based on hydrogen bonds which contact between diprotonated DABCO cations and [SnCl 2SO 4] 2− anions. Crystal data for compound I, orthorhombic space group C222 1, a = 9.354(6) Å, b = 9.6880(7) Å, c = 13.2888(9) Å, V = 1204.32(14) Å 3, Z = 4, M = 399.84(1), D calc = 2.205 g cm −3, Mo Kα, R 1 = 0.0254, wR 2 = 0.0616, GOF = 1.092.