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Complex metal hydrides are one of the most effective hydrogen storage materials due to their unique property to absorb and desorb hydrogen with the hydrogen storage capacity of about 5-7 wt%. In this study, lithium aluminium hydride (LiAlH4) was coated on glass substrate using dip coating method. The coating conditions investigated were LiAlH4 concentrations of 6 g/l, 10 g/l and 20 g/l and post-annealing time from 0 to 60 min. Phase and grain size of the deposited LiAlH4 were analyzed using X-ray powder diffraction (XRD). Scanning electron microscope (SEM) was used for surface morphology analysis. The hydrogen storage capacity of the deposited thin films was analyzed using thermogravimetric analysis (TGA). The experimental results revealed that the phase of the deposited LiAlH4 thin films on glass substrate were mixed with lithium aluminium hydroxide hydrate (LiAl2(OH)7·2H2O) and lithium hexahydroaluminate (Li3AlH6). The intensity of the LiAl2(OH)7·2H2O and LiAlH4 peaks tends to decrease with increasing LiAlH4 concentration and post-annealing time while the intensity of the Li3AlH6 peaks increased with increasing LiAlH4 concentration and post-annealing time. The grain size was decreased with increasing LiAlH4 concentration and post-annealing time. The smaller grain size the better the hydrogen storage capacity. The hydrogen storage capacity of the deposited LiAlH4 thin film was increased from 0.124 wt % using LiAlH4 concentration of 6 g/l without post-annealing to 1.675 wt % using LiAlH4 concentration of 20 g/l with 60 min post-annealing time.

The reduction of the 1‐phospha‐2‐azanorbornene derivate endo‐1 with lithium aluminium hydride leads to an unprecedented 1‐phosphabicyclo[3.2.1]octa‐2,5‐diene, while a phospholide anion is formed with lithium. The latter can be protonated resulting in formation of an unusual 2H‐phosphole dimer. Furthermore, 3H‐phospholes, previously assumed to have no synthetic relevance as intermediates, were proposed to act as dienophile in the dimerisation of 3,4‐dimethyl‐1‐phenylphosphole at elevated temperatures based on theoretical calculations., 1‐Phospha‐2‐azanorbornenes (PAN) are shown to be suitable starting materials for novel bridged 7‐membered phosphorus heterocycles (using lithium aluminium hydride as reducing agent) or lithium phospholide (with elemental lithium as reducing agent). Artwork by Dr. Christoph Selg.

3D printing of carbon-based nanocomposites, which combine the electrical properties of carbon additives with the benefits of thermoplastics, has emerged as a promising route towards rapid and low-cost manufacturing of customised-shaped electronic devices with minimised waste. However, their poor electrical activity in their pristine state makes activation post-treatments mandatory to reduce the amount of insulating polymer. These post-treatments typically involve the use of toxic organic solvents or costly thermal annealing methods. Herein, a simple eco-friendly wet-chemical post-treatment is presented for the quick and general activation of carbon-based 3D printed electronic devices by employing reducing agents like ascorbic acid or sodium borohydride. We tested a range of reducing agents, such as sodium borohydride, lithium aluminium hydride, hydrazine and ascorbic acid, as well as a model oxidising agent like hydrogen peroxide. We found that ascorbic acid and sodium borohydride are the most effective chemicals to achieve electrically active devices while preserving the shape and structure of the 3D printed carbon objects. Thus, this work allows the development of advanced carbon-based 3D printed electrodes by employing an eco-friendly activation approach.

The addition of a catalyst and ball milling process was found to be one of the efficient method to reduce the decomposition temperature and improve the desorption kinetics of lithium aluminium hydride (LiAlH4). In this paper, a transition metal oxide, LaFeO3 was used as a catalyst. Decomposition temperature of the 10 wt% of LaFeO3-doped LiAlH4 system was found to be lowered from 143 °C to 103 °C (first step) and from 175 °C to 153 °C (second step), respectively. In isothermal desorption kinetics, the amount of hydrogen released of the doped sample was improved to 3.9 wt% in 2.5 h at 90 °C. Meanwhile, the undoped sample had released less than 1.0 wt% of hydrogen under the same condition. The activation energy of the LaFeO3-doped LiAlH4 sample was measured to be 73 kJ/mol and 90 kJ/mol for the first two dehydrogenation reactions compared to 107 kJ/mol and 119 kJ/mol for the undoped sample. The improvements of desorption properties were the results from the formation of LiFeO2, Fe and La or La-containing phase during the heating process.

BACKGROUND Chlorophyllin is used in traditional Chinese medicine because of its anticancer properties. This article describes the preparation and cytotoxic activity of a reduced chlorophyllin derivative (RCD) on tumour cell lines. MATERIALS AND METHODS RCD was prepared by reducing chlorophyllin with lithium aluminium hydride, and its solubility in the alkaline and organic phases are different from that of the parent compound chlorophyllin. RESULTS RCD also has different chromatographic behaviour from chlorophyllin on thin-layer chromatography and high-pressure liquid chromatography, and excitation and emission spectra. RCD has cytotoxic activity against ZR-75, MCF-7 and HT-29, human tumour cell lines. A clonogenic assay showed that the growth of tumour colonies on soft agar was reduced by RCD in a dose-dependent manner. CONCLUSION RCD is a novel compound exhibiting anticancer activity.

Rocket fuels are subjected to intense in-flight inertial, pressure and thermal loads that has drastic effect on its performance. In order to achieve optimal results, we require functionally-graded solid propellant (FGSPs), specifically designed for each flight condition. A novel series of FGSPs were developed using Paraffin Wax (as fuel) and Hydroxyl-terminated polybutadiene (as binder); treated with Dioctyl adipate (C22H42O4), Toluene diisocyante (C9H6N2O2) and Glycerol (C3H8O3). These FGSPs were further doped with light metal hydride nano-powders including Lithium aluminium hydride (LiAlH4) and Magnesium hydride (MgH2). The FGSPs were investigated for thermo-physical and ballistic performance using several characterisation techniques. The Magnesium hydride-doped FGSPs exhibited lower viscosity that fostered entrainment-aided combustion. FGSPs doped with Lithium aluminium hydride featured solid-like behaviour that makes them more stable in solid phase and less susceptible to in-flight loads. Thermal characterisation revealed that Lithium aluminium hydride makes FGSPs comparatively more resistant towards pyrolysis thereby producing greater char-yield. Eventually, combustion characteristics were evaluated by performing static ballistic firings of the developed FGSPs. The doped FGSPs exhibited significant enhancement in regression compared to the base fuel and conventional HTPB fuel. The MgH2-doped FGSP exhibited maximum enhancements of up to 224% and 353% as compared with the base fuel and HTPB, respectively. Accepted version The corresponding author thankfully acknowledge the grant from Science and Engineering Research Board, Department of Science and Technology, Government of India vide file no. ECR/001003/2017.

In this study, the modification of the desorption behavior of LiAlH4 by the addition of K2NbF7 was explored for the first time. The addition of K2NbF7 causes a notable improvement in the desorption behavior of LiAlH4. Upon the addition of 10 wt.% of K2NbF7, the desorption temperature of LiAlH4 was significantly lowered. The desorption temperature of the LiAlH4 + 10 wt.% K2NbF7 sample was lowered to 90°C (first-stage reaction) and 149°C (second-stage reaction). Enhancement of the desorption kinetics performance with the LiAlH4 + 10 wt.% K2NbF7 sample was substantiated, with the composite sample being able to desorb hydrogen 30 times faster than did pure LiAlH4. Furthermore, with the presence of 10 wt.% K2NbF7, the calculated activation energy values for the first two desorption stages were significantly reduced to 80 and 86 kJ/mol; 24 and 26 kJ/mol lower than the as-milled LiAlH4. After analysis of the X-ray diffraction result, it is believed that the in situ formation of NbF4, LiF, and K or K-containing phases that appeared during the heating process promoted the amelioration of the desorption behavior of LiAlH4 with the addition of K2NbF7.

Hybrid propulsion offers safe, reliable and environment friendly alternative to conventional systems. There is a wide range of propellants and additives reported for hybrid propulsion. In this paper some energetic particles comprising metals, and light metal hydrides and their advantages in terms of regression behavior are discussed. Additive particles like aluminium, boron, boron carbide, tungsten, iron, carbon, magnesium, magnesium hydride, aluminium hydride, lithium aluminium hydride, ammonium perchlorate and ammonia borane are discussed. Regression rate enhancement of 20%-150% has been reported and found to be dependent on additive percentage. Metals have high density and heat of oxidation which helps in regression rate augmentation. Metal hydrides are good source of hydrogen varying from 7.6% for Magnesium hydride to 19.6% for Ammonia borane. These hydrides release nascent hydrogen during combustion and improve regression rate thereby boosting specific impulse and characteristic velocity of the rocket. Energetic particle laden hybrid rocket fuel has potential to make chemical propulsion safer, economical and sustainable.

Lithium aluminium hydride (LiAlH 4 ) is a promising hydrogen storage material with a storage capacity of 10.6 mass % H 2 . However, its practical use is hampered by the lack of direct rehydrogenation routes. In this study, we report on the confinement of LiAlH 4 into the nanoporosity of a high surface area graphite resulting in a remarkable improvement of its hydrogen storage properties. Nanoconfined LiAlH 4 started hydrogen desorption near 135 °C and after full dehydrogenation at 300 °C limited rehydrogenation was observed at the same temperature and 7 MPa of hydrogen pressure. Rehydrogenation took place through the formation of Li 3 AlH 6 with some limited rehydrogenation back to LiAlH 4 indicating the existence of different (de)hydrogenation paths upon nanoconfinement as compared to the known dehydrogenation path of bulk LiAlH 4 .

In this paper, we investigated the LiAlH4-reduction of 5-acetyl-1,6-dimethyl- 4-phenyl-3,4-dihydropyrimidin-2(1H)-one (N-methylated Biginelli compound). Following the reduction and SiO2-promoted dehydration, (Z)-5-ethylidene-1-methyl-6- methylene-4-phenyltetrahydropyrimidin-2(1H)-one was isolated as the major product (33% yield). Chromatographic separation of the reaction products also allowed us to isolate (yield in parentheses) and fully spectrally characterize: 1,6-dimethyl-4-phenyl- 5-vinyl-3,4-dihydropyrimidin-2(1H)-one (20%), 5-ethyl-1,6-dimethyl-4-phenyl-3,4- dihydro-pyrimidin-2(1H)-one (9%), 5-(1-hydroxyethyl)-1,6-dimethyl-4-phenyl-3,4- dihydropyrimidin-2(1H)-one (5%). A possible mechanism explaining the formation of these products is proposed.

Highly functionalized fluorenones were synthesized by an intramolecular cyclization of 2''-halo-[1,1':3',1''-terphenyl]-4'-carbonitriles in the presence of n-butyllithium or lithium aluminium hydride. The precursor was synthesized by ring transformation of 2-oxo-6-aryl/heteroaryl-4-(sec.amino)-2H-pyran-3-carbonitriles or 2-oxobenzo[h]chromenes with o-bromo/chloro/fluoro-acetophenone under basic conditions in moderate yield. We performed the control experiment to understand the proposed mechanism and found that the presence of a secondary amine in the starting material directs the reactivity. The photophysical properties of 3-methoxy-7-(piperidin-1-yl)-5H-indeno[2,1-b]phenanthren-8(6H)-one was explored and solvent dependent emission was observed. These compounds were also tested against HIV-1 and low to moderate activity was observed.

In this work, a new composition based on Paraffin wax and HTPB fuel, loaded with nanoparticles has been proposed for hybrid propulsion system. Lithium aluminium hydride (LiAlH4) and Magnesium hydride (MgH2) nanoparticles have been used as additives. A detailed rheological, thermal and ballistic characterisation has been carried out. The Magnesium hydride doped hybrid fuel exhibits lower viscosity as compared to the Lithium aluminium hydride doped one, leading to comparatively enhanced entrainment-aided combustion. LiAlH4 doped hybrid fuels also exhibit solid-like behaviour and thus greater stability in the solid phase in contrast to the MgH2 doped fuel. LiAlH4 doped fuel is thermally more stable and produces relatively greater residual-mass. The loading of nanoparticles significantly improves the fuel regression performance during ballistic firing. This can be attributed to the release of nascent hydrogen and metal nanoparticles during dehydrogenation of metal hydrides. Regression rate enhancement in the range of 350%–475% is observed in comparison to the conventional HTPB hybrid fuels. A power law governing regression rate has been proposed for the tested hybrid fuels. Accepted version

Trimeric betaine surfactants tri[(N-alkyl-N-ethyl-N-sodium carboxymethyl)-2-ammonium bromide ethylene] amines were prepared with raw materials containing tris(2-aminoethyl) amine, alkyloyl chloride, lithium aluminium hydride, sodium chloroacetate, and bromoethane by alkylation, Hoffman degradation reaction, carboxymethylation and quaternary amination reaction. The chemical structures of the prepared compounds were confirmed by FTIR, 1H NMR, MS and elemental analysis. With the increasing length of the carbon chain, the values of their critical micelle concentration initially decreased. Surface active properties of these compounds were superior to general carboxylate surfactants C10H21CHN+(CH3)2COONa. The minimum cross-sectional area per surfactant molecule (A min), standard Gibbs free energy adsorption (ΔG ads) and standard Gibbs free energy micellization (ΔG mic) are notably influenced by the chain length n, and the trimeric betaine surfactants have greater ability to adsorb at the air/water interface than form micelles in solution. The efficiency of adsorption at the water/air interface (pC20) of these surfactants increased with the increasing length of the alkyl chain. Their foaming properties, wetting ability of a felt chip, and lime-soap dispersing ability were also investigated.

A series of liquid polycarbosilanes were successfully synthesized by a sequential Grignard coupling reaction of (chloromethyl)triethoxysilane and vinylmagnesium bromide, followed by reduction with lithium aluminium hydride. The use of non-corrosive, easily handleable and storage stable (chloromethyl)triethoxysilane as starting material is an attractive advantage for this route. The as-synthesized polymers containing Si-CH=CH2 and Si - H groups are storage stable and can be easily cured in an inert atmosphere. The ceramic yield of the cured polycarbosilane and the C:Si ratio of the derived ceramic were varied by adjusting the mole ratio of starting materials in the feed. Among them, the polymer with a mole ratio of Si-CH=CH2 to Si - H of 1:10 has the highest ceramic yield at 89.6% after curing at 220 degrees C and the C:Si ratio of the derived ceramic is 1.48. This kind of polycarbosilane shows high potential as an SiC ceramic precursor in the fabrication of an SiC matrix by the precursor infiltration pyrolysis process. (c) 2015 Society of Chemical Industry

Polyhydroxylated piperidines are a functionally rich class of biologically active molecules that have broad therapeutic potential. Recently developed aza-[4 + 3] cycloadditions of putative aza-oxyallylic cations provide heterocyclic scaffolds that enabled a concise synthesis of polyhydoxylated piperidines. Chemoselective amide reduction and reductive hemiaminal ring opening was achieved in one pot by the action of aluminium hydride generated in situ via aluminium chloride and lithium aluminium hydride. Aziridinium ion mediated ring contraction and chloride displacement was triggered by silver acetate, followed by simple acetate hydrolysis using potassium carbonate to give four tetrahydropyridine diols. Olefin oxidation by osmium tetroxide installed the final hydroxyl groups, which yielded four novel polyhydroxylated N-alkoxypiperidines in good overall yield and high diastereoselectivity.

The heterogeneous reduction process for synthesis of poly(propylene imine) (PPI) dendrimer has been replaced by a novel and homogeneous process. Accordingly, to prepare half generations, acrylonitrile was added to amine groups via Michael addition reaction. Then, nitrile groups were reduced via homogeneous hydrogenation using lithium aluminium hydride to synthesize fifth-generation PPI dendrimers with ethylenediamine core. Also, peripheral primary amine groups were conjugated with folic acid (FA). Fourier transform infrared and 13C NMR spectroscopies and gel permeation chromatograph y were used to prove the synthesis of the various structures. Finally fifth-generation and FA-conjugated fifth-generation PPI dendrimers were loaded with doxorubicin and exposed to environments with different pH values to examine the release properties of the structures. Also, drug release kinetics was investigated by fitting experimental data with various release models. The synthesized dendritic structures showed Higuchi model release behaviour due to better solubility of drug in release media with respect to dendrimer cavities.

This chapter describes relevant chemical procedures used for purification of solvents and substances. Greater selectivity in purification can often be achieved by making use of differences in chemical properties between the substance to be purified and the contaminants. Unwanted metal ions may be removed by precipitation in the presence of a collector . Many classes of organic chemicals can be purified by conversion into suitable derivatives, followed by regeneration. Metal impurities can be determined qualitatively and quantitatively by atomic absorption spectroscopy, x-ray photoelectron spectroscopy, various mass spectrometric methods and/or inductively coupled plasma mass spectrometry. Reagents such as water, ammonia, hydrochloric acid, nitric acid, perchloric acid, and sulfuric acid can be purified via distillation using an all-glass still. Application of ion-exchange columns facilitate the removal of heavy metal ions such as Cu2+, Zn2+ and Pb2+ from aqueous solutions of many reagents and they are also useful for demineralising biochemical preparations such as proteins. In removing traces of impurities by precipitation, it is necessary to include a material to act as a collector of the precipitated substance so as to facilitate its removal by filtration or decantation. Metal hydrides, such as lithium aluminium hydride, calcium hydride, sodium borohydride and potassium borohydride are used extensively in the purification of chemicals. Because of the difficulty in regenerating the starting material, relatively few derivatives of organic substances are used for purification.

Lithium aluminium hydride (LiAlH 4 ) has long been identified as a viable hydrogen storage material, due to its high attainable theoretical gravimetric hydrogen capacity of 7.9 wt%. The main impediment to its viability for technical application is its limitation for regeneration. Recently, solvent-mediated regeneration has been achieved at room temperature using dimethyl-ether, Me 2 O, although the reaction pathway has not been determined. This in situ multinuclear NMR spectroscopy study ( 27 Al and 7 Li) has confirmed that the Me 2 O-mediated, direct synthesis of LiAlH 4 occurs by a one-step process in which LiAlH 4 · x Me 2 O is formed, and does not involve Li 3 AlH 6 or any other intermediates. Hydrogenation has been shown to occur below ambient temperatures (at 0 °C) for the first time, and the importance of solvate adducts formed during the process is demonstrated.

We demonstrate in-situ synthesis of homogeneously dispersed Ni-containing mesoporous carbon scaffold (Ni-MCS) for improving dehydrogenation kinetics of LiAlH4 (hereafter denoted as LAH). LAH was impregnated into Ni-MCS scaffold (LAH confined-Ni-MCS) and also into pure mesoporous carbon scaffold (MCS) (LAH confined-MCS). The XRD patterns of LAH confined in Ni-MCS system indicate its amorphous nature, while 27Al MAS NMR spectroscopy confirmed the nanoconfinement of LAH in the Ni-MCS system. TPD-MS demonstrated the released of H2 at 66°C for the LAH confined-Ni-MCS system, with 84°C reduction of the onset desorption temperature (Tonset) as compared to the pure LAH. The H2 desorption from LAH confined-Ni-MCS is about 6.19 wt% H2. This strategy enables the exertion of nanoconfinement, Ni catalyst and compartmentalization effects over the growth of particle size and aggregation, which also significantly contributed to reduce the activation energy (Ea) (39.67 kJ/mol) of the system.

Nearly quantitative mechanochemical synthesis of non-solvated AlH3 from lithium aluminium hydride (LiAlH4) and aluminium chloride (AlCl3) has been achieved at room temperature under reasonably low pressure of hydrogen (210 bar) or inert gas (125 bar for He or 90 bar for Ar). X-ray diffraction, solid-state 27Al NMR spectroscopy, and temperature programmed desorption analyses of as-milled materials reveal a nearly complete conversion of a 3 : 1 (molar) mixture of LiAlH4 and AlCl3 to a 4 : 3 (molar) mixture of AlH3 and LiCl in ca. 30 min. By applying pressure of 210 bar or less (depending on the gas: hydrogen, helium, or argon), competing reactions leading to formation of metallic aluminium can be completely suppressed. X-ray diffraction and NMR analyses of products extracted at various stages of the mechanochemical reaction between LiAlH4 and AlCl3 reveal, for the first time, that the solid-state transformation proceeds with LiAlCl4 as an intermediate. Evidently, the critical pressure required to suppress the formation of metallic aluminium depends on the rate at which mechanical energy is supplied during milling. For example, the critical pressure is reduced from 210 bar to 1 bar of hydrogen when the milling speed of a standard planetary mill is reduced from 300 rpm to 150 rpm, although at the expense of sluggish kinetics and much longer reaction time.

Lithium aluminium hydride reduction of bis-unsymmetric-diaryloxamides 3 is difficult to accomplish especially for the sterically hindered mesityl derivative. Using microwaves LAH reduction of 3a,d was successful in a short time, however, with cleavage of the ether linkage to give compounds 11a,d. Extension of this method enabled the reduction of bis-oxamide derivatives 13 to the corresponding tetraamine derivative 14 which was then converted to the bis-imidazolidinium salt 15. Application of this method led to rapid reduction of unsymmetric N,N'-diaryloxamides 16 to the corresponding N,N'-diarylethylenediamines 17 which were converted to their corresponding imidazolidinium salts 18.

Two series of new benzoxazepines substituted with different alkyl amino ethyl chains were synthesized comprising synthetic steps of inter and intramolecular Mitsunobu reaction, lithium aluminium hydride (LAH) reduction, debenzylation, bimolecular nucleophilic substitution (SN2) reaction. The present study investigates the effect of a tyrosine-based benzoxazepine derivative in human breast cancer cells MCF-7 and MDA-MB-231 and in breast cancer animal model. The anti-proliferative effect of 15a on MCF-7 cells was associated with G1 cell-cycle arrest. This G1 growth arrest was followed by apoptosis as 15a dose dependently increased phosphatidylserine exposure, PARP cleavage and DNA fragmentation that are hallmarks of apoptotic cell death. Interestingly, 15a activated components of both intrinsic and extrinsic pathways of apoptosis characterized by activation of caspase-8 and -9, mitochondrial membrane depolarization and increase in Bax/Bcl2 ratio. However, use of selective caspase inhibitors revealed that the caspase-8-dependent pathway is the major contributor to 15a-induced apoptosis. Compound 15a also significantly reduced the growth of MCF-7 xenograft tumors in athymic nude mice. Together, 15a could serve as a base for the development of a new group of effective breast cancer therapeutics.

A Diol with endocyclic structure that is 1-methyl-4-isopropyl-bicyclo [2,2,-2,3-two hydroxymethyl-5-Octene (MIBHO), deriving from terpene, was synthesized using the aid of lithium aluminium hydride (LAH) as reductant in THF media at 65 °C. The optimum synthesis conditions were confirmed by analysing the factors on reacting temperature, reacting time, different solvents and reductants. The molecular structure of the novel compound has been characterized by FT-IRGC-MS and 1H-NMR analysis. The data reveal that LAH could effectively reduce terpene maleic anhydride to corresponding alcohol, and the conversion rate of raw material could reach 84%.

Finding novel pathways for the reduction of carbon oxides is important for the ongoing search for new systematic entries to hydrocarbon feedstocks. The CO to formyl conversion with readily available hydrides represents an important step along this way. Using boranes as the reducing reagents is desirable and potentially useful. Reactions of trialkylboranes with carbon monoxide are synthetically established. H. C. Brown had shown that R3B systems readily react with CO at 100 to 125 8C at normal pressure to yield the respective tertiary alcohols after oxidative workup. They modified this procedure to achieve the synthesis of ketones and aldehydes. In the latter case lithium aluminium hydride reagents were added. However, carbon monoxide is surprisingly reluctant to be reduced with [B]H boranes. Carbon monoxide is reported to react with B2H6 at 100 8C and 20 atm to give “borane carbonyl” [H3B-CO], a gas (b.p. 64 8C) that dissociates at atmospheric pressure. We have now found that B H borane reduction of carbon monoxide can be carried out with a suitable borane at a frustrated phosphane/borane Lewis pair (FLP) template. We stirred a mixture of the bulky cyclopentenylphosphane 1 with the hydroboration reagent [HB(C6F5)2] [9] for about 15 minutes at RT and then subjected the resulting mixture to an atmosphere of carbon monoxide (2 bar). Workup after 12 h at RT eventually gave the reduction product 2 as a colorless solid in 63% yield (see Scheme 1). Single crystals of 2 were obtained from dichloromethane/n-pentane. In the crystal compound 2 contains a “h-formyl” B(C6F5)2 subunit that is bonded through the acyl carbon atom (C1) to the phosphorus atom and through the acyl oxygen atom (O1) to the boron center (B1) of the FLP framework (see Figure 1 and Table 1). The resulting six-membered heterocycle fea