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The promising fields of gallium oxide application are the production of hybrid cars, electrical equipment of high-power, ultraviolet radiation sensors and uninterruptible power supplies. However, the main factor hindering its massive commercial use is the lack of synthesis technologies, that should be cheap, reproducible, and scalable. In this work we develop a novel plasma-chemical method of Ga2O3 synthesis. The high-purity elemental gallium was used as the precursor, which was delivered by argon flow to the reaction zone, where the interaction with iodide pentoxide took place. RF (40.68 MHz) non-equilibrium plasma discharge at low pressure (0.1 Torr) was employed for the initiation of interactions between precursors. Optical Emission Spectroscopy in tandem with quantum-chemical calculations allowed us to find out the reactive species formed in the plasma discharge. The properties of the solid phase obtained were studied as well. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ga 2 S 3 quantum dots were synthesized for the first time by the one-pot method. • These uncoated quantum dots have a stronger fluorescence than Ga 2 S 3 bulk materials. • The Ga 2 S 3 quantum dots emit light from blue to yellow by tuning feed Ga/S ratio. Abstract Ga 2 S 3 quantum dots are successfully synthesized by the one-pot method. Compared with Ga 2 S 3 bulk materials, Ga 2 S 3 quantum dots can dramatically enhance the fluorescence performance. The Ga 2 S 3 quantum dots have a quantum efficiency of up to 25.7%. They can emit light from blue to yellow by adjusting the feed Ga/S ratio. Their luminescence might be related to the donor levels and acceptor level caused by defects. These Ga 2 S 3 quantum dots are potential optoelectronic materials and fluorescent probe materials. [ABSTRACT FROM AUTHOR]

Multidimensional, conjugated building blocks have been formed through the axial coordination of polyynes to the central Ga atom of tetraarylporphyrins. Electron deficient pentafluorophenyl substituents in the meso‐positions provide more stable σ‐acetylide complexes to Ga than analogous structures with tert‐butylphenyl groups. Mono‐, di‐, and triynes have been used, including a pyridyl endcapped diyne that allows for formation of porphyrin triads through coordination of the pyridyl ligand to a Ru porphyrin. Hierarchical assembly: σ‐Acetylide complexes derived from mono‐, di‐, and triynes have been efficiently appended to the central metal of Ga‐porphyrins. Terminal functionalization of an acetylide with a metal‐coordinating pyridyl end‐group allows construction of a new class of bimetallic porphyrin triads through self‐assembly. [ABSTRACT FROM AUTHOR]

Graphical abstract In this work, we present a new synthetic route to access gallium- and iron-functionalized polyoxovanadate-alkoxide clusters. Additionally, we summarize the synthesis of a hexanuclear, low-valent V(IV) cyclic structure, templated around a chloride ion. Abstract Incorporating transition metal ions into Lindqvist polyoxovanadate-alkoxide (POV-alkoxide) clusters has been shown to be an effective method for tuning the electronic properties of these molecular assemblies. Herein, we report the synthesis of a gallium-functionalized POV-alkoxide cluster, extending the family of heterometal-functionalized clusters to a metalloid ion. Complex [V 5 O 6 (OCH 3) 12 GaCl] was characterized by infrared and electronic absorption spectroscopies and cyclic voltammetry, revealing the retention of the extensive delocalization upon installation of the 3d10 ion. The new reaction conditions developed for [V 5 O 6 (OCH 3) 12 GaCl] were shown to successfully generate the iron analogue, [V 5 O 6 (OCH 3) 12 FeCl], from a ferric salt precursor. However, attempts at installing other group 13 ions, e.g. InIII, instead produced the cyclic hexavanadate cluster, [Bu 4 N][V 6 O 6 (OCH 3) 12 Cl]. [ABSTRACT FROM AUTHOR]

Radiolabelled lipophilic cations that accumulate in mitochondria according to the magnitude of the mitochondrial membrane potential can be used to report non-invasively on mitochondrial dysfunction in cardiovascular disease, cardiotoxicity, and cancer. While several such cations are already commercially available for SPECT imaging, PET offers greater promise in terms of sensitivity, resolution, and capacity for dynamic imaging and pharmacokinetic modelling. We have therefore synthesised a series of three triarylphosphonium-functionalised DO3A chelators for positron emitter gallium-68, with differing alkyl-functionalisation motifs to provide opportunities for tunable lipophilicity as a means of optimising their pharmacokinetics. To assess their capacity to report on mitochondrial membrane potential, we assessed their pharmacokinetic profiles in isolated tumour cells and isolated perfused rat hearts before and after mitochondrial depolarisation with the ionophore CCCP. All three compounds radiolabelled with over 97% RCY and exhibited log D values of between −3.12 and −1.81. In vitro assessment of the uptake of the radiotracers in cultured tumour cells showed a three-fold increase in uptake compared to unchelated [68Ga]Ga(iii). However, each complex exhibited less than 1% retention in healthy hearts, which was not significantly diminished by mitochondrial depolarisation with CCCP. This preliminary work suggests that while this approach is promising, the lipophilicity of this class of tracers must be increased in order for them to be useful as cardiac or cancer imaging agents. [ABSTRACT FROM AUTHOR]

Direct synthesis of higher alcohols by CO hydrogenation is one of the most important processes for the utilization of syngas, but obtaining high selectivity to higher alcohols (C 2+ –OH) remains a challenge. In this work, a series of gallium-doped activated carbon-supported cobalt catalysts (15Co– x Ga/AC, representing 15 wt% Co and x wt% Ga) were developed and they were found to be favorable for enhancing the selectivity to alcohols ( S ROH ). The optimized S ROH value reached 30.3 mol% over the 15Co–2.5Ga/AC catalyst, while that was 17.0 mol% over the Ga-free catalyst. The characterization results indicated that the doping of Ga increased the reduction temperature of Co 3 O 4 and modulated the distribution of the surface Co 2+ and Co 0 species. It was found that the Co 2+ –Co 0 dual active sites were responsible for the formation of alcohols and the enhancement of S ROH arose from moderate ratio of Co 2+ /(Co 2+  + Co 0 ). The results revealed that the addition of Ga could be an effective way to elevate the selectivity of higher alcohols by CO hydrogenation. [ABSTRACT FROM AUTHOR]

The catalyst for direct ethanol synthesis (DES) from syngas was investigated in this work, which is Co/La 2 O 3 -doped La 4 Ga 2 O 9 . The catalyst was prepared by using LaCo 1−x Ga x O 3 with perovskite phase as the precursor to intensify the interaction in the elements of Co, La and Ga. The catalysts were characterized by using XRD, H 2 -TPR, TEM, EDS, XPS, BET, ICP and TG techniques. This catalyst showed high selectivity to ethanol and excellent stability including excellent resistance to sintering and carbon deposition. It seems that the ethanol is generated in the interface between metallic Co and La 4 Ga 2 O 9 , and in the interface cobalt would be positively charged due to the interaction between Co nanoparticles and La 4 Ga 2 O 9 . The results and the related discussions indicate that Co/La 2 O 3 -doped La 4 Ga 2 O 9 catalyst is a promising catalyst for DES from syngas. Graphical abstracts. [ABSTRACT FROM AUTHOR]

Abstract: Studies have been focused on the synthesis of N→Ga‐coordinated organogallium selenides and tellurides [L1Ga(μ‐Se)]2 (1), [L2Ga(μ‐Se)]2 (2) and [L1Ga(μ‐Te)]2 (3), respectively, containing either N,C,N‐ or C,N‐chelating ligands L1, 2 (L1 is {2,6‐(Me2NCH2)2C6H3}− and L2 is {2‐(Et2NCH2)‐4,6‐tBu2‐C6H2}−) having Ga/E (E=Se or Te) atoms in 1/1 ratio. To change the Ga/E ratio, an unusual N→Ga‐coordinated organogallium tetraselenide L1Ga(κ2‐Se4) (4) was prepared. An unprecedented complex (L1Ga)2(μ‐Te2)(μ‐Te) (5), as the result of the non‐stability of 3, was also isolated. Compound 2 is a suitable single‐source precursor for the preparation of amorphous GaSe thin films by the spin coating. Moreover, simple heating of an octadecylamine solution of 2 provided, after work up, monoclinic Ga2Se3 crystals with different crystallinity according to conditions used. Therefore, compound 2 may be also used as a source of Ga2Se3 in the low‐temperature doping process of Bi2Se3. [ABSTRACT FROM AUTHOR]

Nearly monodisperse, single-crystalline gallium oxide hydroxide particles have been synthesized via a hydrolysis process in the presence of sodium acetate, under acidic conditions, at 70 °C. The presence of sodium acetate resulted in the formation of α-GaOOH particles shaped in the form of wedges, bound by four {110} and eight {212} faces (orthorhombic, Pbnm space group). Varying the sodium acetate concentration enabled us to control the shape of the wedge-like particles, by suppressing growth along the c-axis. [ABSTRACT FROM AUTHOR]

This article reports the syntheses and evaluation of 68Ga‐ and 153Sm‐complexes of a new DOTA (1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid)‐conjugated geminal bisphosphonate, DOTA‐Bn‐SCN‐BP, for their potential uses in the early detection of skeletal metastases by imaging and palliation of pain arising from skeletal metastases, respectively. The conjugate was synthesized in high purity following an easily adaptable three‐step reaction scheme. Gallium‐68‐ and 153Sm‐complexes were prepared in high yield (>98%) and showed excellent in vitro stability in phosphate‐buffered saline (PBS) and human serum. Both the complexes showed high affinity for hydroxyapatite particles in in vitro binding study. In biodistribution studies carried out in normal Wistar rats, both the complexes exhibited rapid skeletal accumulation with almost no retention in any other major organ. The newly synthesized molecule DOTA‐Bn‐SCN‐BP would therefore be a promising targeting ligand for the development of radiopharmaceuticals for both imaging skeletal metastases and palliation of pain arising out of it in patients with cancer when radiolabeled with 68Ga and 153Sm, respectively. A systematic comparative evaluation, however, showed that there was no significant improvement of skeletal accumulation of the 153Sm‐DOTA‐Bn‐SCN‐BP complex over 153Sm‐DOTMP (1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetramethylenephosphonic acid) as the later itself demonstrated optimal properties required for an agent for bone pain palliation. [ABSTRACT FROM AUTHOR]

We predict the formation of a polarization-induced two-dimensional electron gas (2DEG) at the interface of ε-Ga2O3 and CaCO3, wherein the density of the 2DEG can be tuned by reversing the spontaneous polarization in ε-Ga2O3, for example, with an applied electric field. ε-Ga2O3 is a polar and metastable ultra-wide band-gap semiconductor. We use density-functional theory (DFT) calculations and coincidence-site lattice model to predict the region of epitaxial strain under which ε-Ga2O3 can be stabilized over its other competing polymorphs and suggest promising substrates. Using group-theoretical methods and DFT calculations, we show that ε-Ga2O3 is a ferroelectric material where the spontaneous polarization can be reversed through a non-polar phase by using an electric field. Based on the calculated band alignment of ε-Ga2O3 with various substrates, we show the formation of a 2DEG with a high sheet charge density of 1014 cm−2 at the interface with CaCO3 due to the spontaneous and piezoelectric polarization in ε-Ga2O3, which makes the system attractive for high-power and high-frequency applications. [ABSTRACT FROM AUTHOR]

A series of new homo- and heteroleptic gallium ketoiminate compounds, namely, tris[4-[2-(ethoxyethyl)imino]-2-pentanone] gallium(iii) [Ga(eeki)3] [1], tris[4-[3-(methoxypropyl)imino]-2-pentanone] gallium(iii), [Ga(mpki)3] [2], tris[4-[3-(methoxyethyl)imino]-2-pentanone] gallium(iii), [Ga(meki)3] [3], dichloro[4-[(isopropyl)imino]-2-pentanone] gallium(iii) [Ga(ipki)Cl2] [4], bisdimethylamido[4-[(isopropyl)imino]-2-pentanone] gallium(iii) [Ga(ipki)(NMe2)2] [5] and chloro-(bis[4-[3-(ethoxypropyl)imino]-2-pentanone]) gallium(iii) [Ga(epki)2Cl] [6], was synthesised through molecular engineering. The literature known compound chloro-(bis[4-[(isopropyl)imino]-2-pentanone]) gallium(iii) [Ga(ipki)2Cl] [7] was synthesised for comparison. Confirmation of the successful formation and spectroscopic purity of the compounds was determined using nuclear magnetic resonance (NMR) spectroscopy, single crystal X-ray diffraction (XRD), electron ionisation mass spectrometry (EI-MS), and elemental analysis (EA). The thermal properties of the compounds were assessed with thermogravimetric (TG) analysis and revealed compound [4] was suitable for vapour phase deposition processes while the others displayed a decompositional behaviour favourable for solution based thin film deposition processes. The EI-MS fragmentation behaviour of compound [1], with its thermal properties, and excellent solubility in a wide variety of organic solvents, suggested that it was highly eligible to be applied for chemical solution deposition (CSD). Thus, compound [1] was applied for the spin-coating of Ga2O3 thin films without the need for additives or aging to stabilise the solution prior to processing. The as-deposited thin films were amorphous, while annealing under ambient conditions at higher temperatures (850–1000 °C) yielded β-gallium oxide as indicated by XRD. The morphology and composition were analysed by scanning electron microscopy (SEM) and Rutherford backscattering spectrometry (RBS) respectively, while the optical properties were determined using UV-vis spectroscopy and illustrated that films grown with a spin-cycle number ＜5 were highly transparent (＞80%) in the visible range. [ABSTRACT FROM AUTHOR]

One-dimensional β-Ga 2 O 3 nanostructures were grown at different temperatures on c-plane sapphire substrates by MOCVD using Au as catalyst. The structural, morphological and photoluminescence properties of β-Ga 2 O 3 nanostructures grown at different temperatures were characterized and compared in detail. As the growth temperature was increased, β-Ga 2 O 3 nanostructures exhibited improved crystalline quality and possessed a typical β-Ga 2 O 3 structure with high purity. The β-Ga 2 O 3 nanostructures grown at 750 °C showed intense ultraviolet-blue emission at room temperature. Different morphologies including islands-like, nanowires, nanorods, grain-like structures were obtained depending on the growth temperature. The correlation between the nanostructures shapes and the growth processes was also discussed. [ABSTRACT FROM AUTHOR]

A comparative study of the thermodynamic and magnetic properties of the Ga-substituted magnesium ferrite polycrystalline samples Mg(Fe 1- x Ga x ) 2 O 4 with x = 0.2 and x = 0.4 was carried out. The low-temperature heat capacity of the sample with x = 0.2 was measured by adiabatic calorimetry. Based on the smoothed heat capacity data C p,m °( T ) for Mg(Fe 0.8 Ga 0.2 ) 2 O 4 , the standard thermodynamic functions were determined in a temperature range 2–800 K. A broad heat capacity anomaly below 60 K, which can be attributable to the magnetic order-disorder transition, was observed for both samples. The field-dependence of magnetizations in an applied magnetic field up to ± 50 kOe revealed the ferrimagnetic behaviour of the samples. The values of Curie temperature ( T C ) and the blocking temperature ( T B ) were determined from ZFC-FC magnetization measurements. Based on the results of heat capacity and magnetic measurements, the low temperature state in the Mg(Fe 0.6 Ga 0.4 ) 2 O 4 sample may be attributed to a spin glass-like state. [ABSTRACT FROM AUTHOR]

The sterically demanding β-diketiminate ligand Ldmp [Ldmp = HC{(CMe)N(dmp)}2, dmp = C6H3-2,6-Me2] was used to stabilize various gallium complexes in the formal oxidation states +II and +III. The reaction of in situ generated [LdmpLi] with gallium chloride affords [LdmpGaCl2] (1), which was used as starting complex to synthesize a variety of gallium(III) compounds [LdmpGaX2] [X = F (2), I (3), H (4), and Me (5)]. Synthesis of the dinuclear complex [LdmpGaI]2 (6), with gallium in the formal oxidation state +II was accomplished by converting "GaI" with in situ generated [LdmpLi] in toluene. All compounds were characterized by elemental analyses, NMR spectroscopy, LIFDI-TOF-MS, and single-crystal X-ray diffraction. Additionally DFT calculations were performed for analysis of the bonding in 6. [ABSTRACT FROM AUTHOR]

By dissolving gallium chloride (GaCl 3 ), indium chloride (InCl 3 ), zinc acetate dihydrate [Zn(OAc) 2 ·2H 2 O] and monoethanolamine (MEA) into a solvent of 2-methoxyethanol, the IGZO ink was synthesized. Five types of IGZO ink were prepared with different molar ratios of In:Ga:Zn, which can be used for ink-jet printing process. The thermal behaviors of IGZO ink with different formulas were investigated and the ideal annealing temperature for film formation was found to be ∼450 °C. Based on the prepared ink, amorphous IGZO thin films were directly printed on the glass substrate with a FujiFilm Dimatix ink-jet printer, followed by a thermal annealing at 450 °C for 1 h. The surface morphology, crystal structure, optical transmittance, electron mobility and carrier concentration were characterized and investigated. The ink-jet printed amorphous IGZO thin films fabricated in this work can be used as switching medium in flexible resistive random access memory devices. [ABSTRACT FROM AUTHOR]

A new layered gallium phosphate Ga 3 (PO 4 ) 4 (C 2 N 2 H 8 )·(H 2 C 2 N 2 H 8 ) 2 ·Cl (compound 1 ), has been ionothermally synthesized in the presence of deep eutectic solvent (DES) comprising mixtures of choline chloride and 2-imidazolidone (IMI). Single-crystal X-ray diffraction analysis reveals that compound 1 shows 2D layered framework with 10-ring windows, which is constructed from unusual heptamer second building units (SBUs). The ethylenediamine (en) units deriving from the decomposition of IMI, play a dual role as bidentate ligands coordinated with 6-fold coordinate gallium atoms and the templates. Additionally, compound 1 shows photoluminescence property in solid state at room temperature. [ABSTRACT FROM AUTHOR]

Corroles have been previously demonstrated to be a new and promising photosensitizer (PS) in photodynamic therapy (PDT) for cancer cells. This research reported the preparation of an electron-deficient flat gallium(iii) tris(ethoxycarbonyl)corrole (1-Ga). Its in vitro PDT activities towards different cancer cell lines were examined, and the best PDT activity was observed in A549 cell lines. 1-Ga could penetrate the cell membrane rapidly and exhibit remarkable photo-cytotoxicity. 1-Ga can induce A549 cell apoptosis via ROS-mediated mitochondrial pathways, in which p38 and sirt-1 proteins play a key role. A PTD test in vivo showed that 1-Ga can significantly reduce the growth of A549 xenografted tumor cells without an obvious loss of mice weight upon PDT treatment. [ABSTRACT FROM AUTHOR]

An efficient solvent extraction process was developed for extraction of gallium (III) from acidic chloride medium using the ionic liquid Cyphos IL 104 diluted with toluene. The kinetics of gallium extraction was very fast. The extraction percent of gallium was found to increase with increase in hydrochloric acid concentration in the feed and 99.8% extraction of gallium was achieved with 3 M HCl. The stoichiometry of the formation of gallium-Cyphos IL 104 complex was found to be 1:1 and the corresponding extracted species was proposed as [R 3 R′PGaCl 4 ]. Presence of sodium chloride increased the percentage extraction of gallium. The thermodynamic parameters calculated from the temperature variation study suggested the process was spontaneous and endothermic. Loading capacity of the ionic liquid was executed and the stripping study of the loaded organic phase was investigated using four stripping agents namely HCl, H 2 SO 4 , NH 3 and HNO 3 each having concentrations of 0.5 mol/L. It was found that HCl performance was poor and the rest three could recover > 90% gallium from the loaded organic phase. Binary separation studies were carried out using commonly associated metal ions with gallium (Al (III)/Zn (II)/Fe (III)/Cu (II)/Ni (II)) and the process was extended to study the recovery of gallium from leach liquors of photodiodes and red mud sample. [ABSTRACT FROM AUTHOR]

Phase relations in the pseudo-binary systems RFeO 3 -R 2 Ti 2 O 7 (R: Lu, Ho and Dy), RGaO 3 -R 2 Ti 2 O 7 (R: Lu and Er), LuAlO 3 -Lu 2 Ti 2 O 7 and RAO 3 -R 2 Ti 2 O 7 (R: Lu and Yb. A: Cr and Mn) at elevated temperatures in air were determined by means of a classic quenching method. There exist Lu(Fe 1−x Ti x )O 3+x/2 , R(Ga 1−x Ti x )O 3+x/2 (R: Lu and Er) and Lu(Al 1−x Ti x )O 3+x/2 (2/3≤ x≤3/4) having the Yb(Fe 1−x Ti x )O 3+x/2 -type of crystal structure (x=0.72, space group: R 3 m , a(Å)=17.9773 and c(Å)=16.978 as a hexagonal setting) in these pseudo binary systems. Eighteen compounds R(A 1−x Ti x )O 3+x/2 (R: Lu-Sm and Y, A: Fe, Ga and Al) were newly synthesized and their lattice constants as a hexagonal setting were measured by means of the X-ray powder diffraction method. The R occupies the octahedral site and both A and Ti does the trigonalbipyramidal one in these compounds. Relation between lattice constants for the rhombic R(A 1−x Ti x )O 3+x/2 and the monoclinic In(A 1−x Ti x )O 3+x/2 are as follows, a h ≈5 x b m , c h ≈3 x c m x sin β and a m =3 1/2 x b m , where a h and c h are the lattice constants as a hexagonal setting for R(A 1−x Ti x )O 3+x/2 and a m , b m , c m and β are those of the monoclinic In(A 1−x Ti x )O 3+x/2 . Crystal structural relationships among α-InGaO 3 (hexagonal, high pressure form, space group: P 63/ mmc ), InGaO 3 (rhombic, hypothetical), (RAO 3 ) n (BO) m and RAO 3 (ZnO) m (R: Lu-Ho, Y and In, A: Fe, Ga, and Al, B: divalent cation element, m, n: natural number), the orthorhombic-and monoclinic In(A 1−x Ti x )O 3+x/2 (A: Fe, Ga, Al, Cr and Mn) and the hexagonal-and rhombic R(A 1−x Ti x )O 3+x/2 (R: Lu-Sm and Y, A: Fe, Ga and Al) are schematically presented. We concluded that the crystal structures of both the α-InGaO 3 (high pressure form, hexagonal, space group: P 63/ mmc ) and the hypothetical InGaO 3 (rhombic) are the key structures for constructing the crystal structures of these compounds having the cations with CN=5. [ABSTRACT FROM AUTHOR]

Vascular adhesion protein 1 is a leukocyte homing-associated glycoprotein, which upon inflammation rapidly translocates from intracellular sources to the endothelial cell surface. It has been discovered that the cyclic peptide residues 283-297 of sialic acid-binding IgG-like lectin 9 (Siglec-9) 'CARLSLSWRGLTLCPSK' bind to vascular adhesion protein 1 and hence makes the radioactive analogues of this compound ([68Ga]Ga-DOTA-Siglec-9) interesting as a noninvasive visualizing marker of inflammation. Three different approaches to the radiosynthesis of [68Ga]Ga-DOTA-Siglec-9 are presented and compared with previously published methods. A simple, robust radiosynthesis of [68Ga]Ga-DOTA-Siglec-9 with a yield of 62% (non decay-corrected) was identified, and it had a radiochemical purity >98% and a specific radioactivity of 35 MBq/nmol. Furthermore, the protein binding and stability of [68Ga]Ga-DOTA-Siglec-9 were analyzed in vitro in mouse, rat, rabbit, pig, and human plasma and compared with in vivo pig results. The plasma in vitro protein binding of [68Ga]Ga-DOTA-Siglec-9 was the lowest in the pig followed by rabbit, human, rat, and mouse. It was considerably higher in the in vivo pig experiments. The in vivo stability in pigs was lower than the in vitro stability. Despite considerable species differences, the observed characteristics of [68Ga]Ga-DOTA-Siglec-9 are suitable as a positron emission tomography tracer. [ABSTRACT FROM AUTHOR]

Low temperature metalorganic chemical vapor deposition using trimethylgallium and water was investigated. The surface morphology of the film was almost flat at a deposition temperature below 182 °C. This flat film was a mixture of nanocrystalline and amorphous phase. The film deposited at a temperature of 272 °C resulted in a nanowire structure. X-ray diffraction measurements revealed that the nanowire film was a mixture of gallium hydroxide, gallium oxyhydroxide, and gallium tohdite or gallium oxide. We also found that post-deposition annealing above 600 °C significantly changed the crystal structure of the both flat and nanowire films. Monoclinic gallium oxide phase was dominant after the post-deposition annealing above 600 °C. [ABSTRACT FROM AUTHOR]

We analyzed the decomposition mechanisms of trimethylgallium (TMG) used for the gallium source of GaN fabrication based on first-principles calculations and thermodynamic analysis. We considered two conditions. One condition is under the total pressure of 1 atm and the other one is under metal organic vapor phase epitaxy (MOVPE) growth of GaN. Our calculated results show that H 2 is indispensable for TMG decomposition under both conditions. In GaN MOVPE, TMG with H 2 spontaneously decomposes into Ga(CH 3 ) and Ga(CH 3 ) decomposes into Ga atom gas when temperature is higher than 440 K. From these calculations, we confirmed that TMG surely becomes Ga atom gas near the GaN substrate surfaces. [ABSTRACT FROM AUTHOR]

Uniformly sized and monodispersed β-Ga 2 O 3 crystalline micro-rods and ellipsoids have been successfully synthesized through a facile direct precipitation technique, respectively, using Ga(NO 3 ) 3 and NH 4 OH solution as starting materials. The as-prepared particles were characterized by XRD, FESEM equipped with EDS, TEM equipped with SAED, TG-DSC and Laser diffraction particle size analyzer, respectively. The results showed that the obtained β-Ga 2 O 3 particles with a narrow particle size distribution were assembled with single crystalline β-Ga 2 O 3 nano-sheets with the thickness of 100 nm. Furthermore, the reaction parameters including aging temperature, the molar concentration of Ga 3+ and pH value had an essential effect on the morphology and size of the particles. Ostwald ripening and oriented attachment growth mechanism of the uniformly hierarchical β-Ga 2 O 3 crystals were proposed. Finally, the target fabricated by using the as-prepared β-Ga 2 O 3 particles as the raw materials exhibited a density as high as 6.01 g/cm 3 , showing potential applications in the high-quality thin film formed by magnetron sputtering for optoelectronic devices. [ABSTRACT FROM AUTHOR]

Nine metals (Ti, In, Ag, Sn, W, Mo, Sc, Zn, and Zr) have been investigated as electrical contacts to n-type single-crystal β-GaO substrates as a function of annealing temperature up to 800°C (in flowing Ar). For each contact metal, we investigated its electrical behavior and morphology at each annealing temperature, as well as the effects of adding a Au capping layer. Select metals displayed either ohmic (Ti and In) or pseudo-ohmic (Ag, Sn, and Zr) behavior under certain conditions; however, the morphology was often a problem. It was concluded that metal work function is not a dominant factor in forming an ohmic contact to β-GaO and that limited interfacial reactions play an important role. [ABSTRACT FROM AUTHOR]

Inverted organic solar cells (OSCs) have been fabricated with conventional Sn-doped indium oxide (ITO) and amorphous indium gallium zinc oxide (a-IGZO)/Ag/a-IGZO (39 nm/19 nm/39 nm) (a-IAI) electrodes and their electrical characteristics characterized. The ITO and optimized a-IAI electrodes showed high transmittance of 96% and 88% at 500 nm, respectively. The carrier concentration and sheet resistance of the ITO and a-IAI films were 8.46 × 10 cm and 7.96 × 10 cm and 14.18 Ω/sq and 4.24 Ω/sq, respectively. Electron transport layer (ETL)-free OSCs with the a-IAI electrode exhibited power conversion efficiency (PCE) of 2.66%, similar to that of ZnO ETL-based OSCs with ITO electrode (3.27%). However, the ETL-free OSCs with the a-IAI electrode showed much higher PCE than the ETL-free OSCs with the ITO electrode (0.84%). Ultraviolet photoelectron spectroscopy results showed that the work function of the a-IAI electrode was 4.15 eV. This improved performance was attributed to the various roles of the a-IAI electrode, e.g., as an effective ETL and a hole blocking layer. [ABSTRACT FROM AUTHOR]

GaSnO thin films were deposited on c-plane AlO (0001) substrates with different Sn content by laser molecular beam epitaxy technology (L-MBE). The Sn content x was varied from 0 to 1.0. ( $$\bar{2}01$$ ) oriented β-phase GaSnO thin films were obtained at the substrate temperature of 850°C in the vacuum pressure of 5 × 10 Pa. The crystal lattice expanded and the energy band-gap decreased with the increase of Sn content for Sn ions incorporated into the Ga site. The n-type conductivity was generated effectively through doping Sn ions in the GaO lattice in the oxygen-poor conditions. The solar-blind (SB) photodetectors (PDs) based on GaSnO ( x = 0, 0.2) thin films were fabricated. The current intensity and responsivity almost increased by one order of magnitude and the relaxation time constants became shorter for x = 0.2. Our work suggests that the performance of PD can be improved by doping Sn ions in GaO thin films. [ABSTRACT FROM AUTHOR]

The first gallium-containing nitridosilicate CaGaSiN3 was synthesized in newly developed high-pressure autoclaves using supercritical ammonia as solvent and nitriding agent. The reaction was conducted in an ammonobasic environment starting from intermetallic CaGaSi with NaN3 as a mineralizer. At 770 K, intermediate compounds were obtained, which were subsequently converted to the crystalline nitride at temperatures up to 1070 K (70-150 MPa). The impact of other mineralizers (e.g., LiN3, KN3, and CsN3) on the product formation was investigated as well. The crystal structure of CaGaSiN3 was analyzed by powder X-ray diffraction and refined by the Rietveld method. The structural results were further corroborated by transmission electron microscopy, 29Si MAS-NMR, and first-principle DFT calculations. CaGaSiN3 crystallizes in the orthorhombic space group Cmc21 (no. 36) with lattice parameters a=9.8855(11), b=5.6595(1), c=5.0810(1) Å, ( Z=4, Rwp=0.0326), and is isostructural with CaAlSiN3 (CASN). Eu2+ doped samples exhibit red luminescence with an emission maximum of 620 nm and FWHM of 90 nm. Thus, CaGaSiN3:Eu2+ also represents an interesting candidate as a red-emitting material in phosphor-converted light-emitting diodes (pc-LEDs). In addition to the already known substitution of alkaline-earth metals in (Ca,Sr)AlSiN3:Eu2+, inclusion of Ga is a further and promising perspective for luminescence tuning of widely used red-emitting CASN type materials. [ABSTRACT FROM AUTHOR]

The first gallium-containing nitridosilicate CaGaSiN3 was synthesized in newly developed high-pressure autoclaves using supercritical ammonia as solvent and nitriding agent. The reaction was conducted in an ammonobasic environment starting from intermetallic CaGaSi with NaN3 as a mineralizer. At 770 K, intermediate compounds were obtained, which were subsequently converted to the crystalline nitride at temperatures up to 1070 K (70-150 MPa). The impact of other mineralizers (e.g., LiN3, KN3, and CsN3) on the product formation was investigated as well. The crystal structure of CaGaSiN3 was analyzed by powder X-ray diffraction and refined by the Rietveld method. The structural results were further corroborated by transmission electron microscopy, 29Si MAS-NMR, and first-principle DFT calculations. CaGaSiN3 crystallizes in the orthorhombic space group Cmc21 (no. 36) with lattice parameters a=9.8855(11), b=5.6595(1), c=5.0810(1) Å, ( Z=4, Rwp=0.0326), and is isostructural with CaAlSiN3 (CASN). Eu2+ doped samples exhibit red luminescence with an emission maximum of 620 nm and FWHM of 90 nm. Thus, CaGaSiN3:Eu2+ also represents an interesting candidate as a red-emitting material in phosphor-converted light-emitting diodes (pc-LEDs). In addition to the already known substitution of alkaline-earth metals in (Ca,Sr)AlSiN3:Eu2+, inclusion of Ga is a further and promising perspective for luminescence tuning of widely used red-emitting CASN type materials. [ABSTRACT FROM AUTHOR]

The structural and optical properties of GaP and GaPN layers synthesized by molecular-beam epitaxy on Si(100) substrates misoriented by 4° are studied. The possibility of producing GaP buffer layers that exhibit a high degree of heterointerface planarity and an outcropping dislocation density of no higher than ~2 × 10 cm is shown. Emission from the Si/GaP/GaPN structure in the spectral range of 630-640 nm at room temperature is observed. Annealing during growth of the Si/GaP/GaPN structure makes it possible to enhance the room-temperature photoluminescence intensity by a factor of 2.6, with no shift of the maximum of the emission line. [ABSTRACT FROM AUTHOR]

A robust gallium carboxylate Ga(OH)(btec)·0.5H2O (MIL-61) was synthesized under mild hydrothermal conditions and selected as the parent MOF to prepare Eu-MIL-61 by post-synthetic modification due to the uncoordinated carbonyl group of the ligand (pyromellitic acid (H4btec)). The firm framework, permanent porosity, and non-coordinated sites make MIL-61 a good scaffold for immobilizing and sensitizing Eu3+. The products showed excellent luminescence and, more significantly, Eu-MIL-61 showed excellent selectivity with photoluminescence enhancement, fast response time, and low detection limit for Ag+ ions in the aqueous solutions. In addition, the frameworks were not susceptible to the acid–base property of solutions, which can be further applied to monitor the concentration of Ag+ in several daily water samples. [ABSTRACT FROM AUTHOR]

Partial solid solutions of In1-xGaxBO3 (0 ≤ x ≤ 0.5) were synthesized by the solvothermal method, and they were characterized by powder X-ray diffraction, scanning and transmission electron microscopy, UV/Vis absorption spectroscopy, and N2 adsorption-desorption, in order to identify the phase purity and micromorphology. Nanocrystallites of InBO3 exhibit a particular anisotropic growth along the [110] direction, forming spindlelike morphology (with a diameter of ca. 20 nm and a length of ca. 200 nm). These nanocrystallites further aggregate into microspheres. With Ga3+ substitution, the anisotropic growth was depressed; the nanocrystallites thus exhibited a typical rodlike morphology. Metal borates are well-known optical materials; however, their photocatalytic properties have been rarely studied. Here, post-annealing under O2 flow at 350 °C improved the photocatalytic H2 evolution rate of InBO3 from 18.2(6) to 29.5(8) μmol h-1 g-1. A loading of Pt, RuOx, or NiOx as cocatalyst resulted in further enhancement of the H2 evolution rate, with an optimal value of 56.1(5) μmol h-1 g-1 under UV light. [ABSTRACT FROM AUTHOR]

This study presents the synthesis of single crystalline β-Ga2O3 nanosheets on SiC by low pressure chemical vapor deposition. High purity gallium (Ga) metal and oxygen as source materials and argon as carrier gas were utilized for the synthesis of the nanosheets on a 3C-SiC-on-Si substrate. These single-crystal Ga2O3 nanosheets are free-standing 2D extrusions from their 1D rods, typically 1.5-7 lm in lateral size and 20-140 nm in thickness, featuring aspect ratios ranging from ∼10 to 350. Structural studies based on transmission electron microscopy and Raman spectroscopy revealed the monoclinic phase of Ga2O3 with a single crystalline nature. High resolution transmission electron microscopy with a selected area electron diffraction pattern recorded on a single β-Ga2O3 nanosheet further confirmed their single crystalline nature, with a growth direction perpendicular to (111) crystallographic plane. The growth process governing the formation of these nanosheets is a vapor-solid growth mechanism since no metal catalyst was used. These b-Ga2O3 nanosheets exhibit new possibilities and potential for future functional nanodevices that would benefit from their extremely large surface area to volume ratios. [ABSTRACT FROM AUTHOR]

Two-dimensional layered structures have recently drawn worldwide attention because of their intriguing optical and electrical properties. GaS and GaSe are attractive layered materials owing to their wide band gap. Herein, we synthesized GaS1-xSex belt-type multilayers (nanobelts) with uniform morphology ([21̅1̅0] hexagonal-phase long axis) by a chemical vapor transport method, and investigate their composition-dependent optical and optoelectronic properties. The GaS1-xSex exhibited strong visible-range photoluminescence at 490-620 nm (2.0-2.5 eV), with a unique composition dependence: longer decay time for the S-rich compositions (x ≤ 0.5). Photocurrent measurements were performed on individual nanobelts by fabricating photodetector devices; higher photocurrents were found for x ≤ 0.5. First-principles calculations predicted that oxygen chemisorption can cause the direct and indirect band gaps of GaS to converge, similar to the band structures of GaSe, and thus enhance the optical properties. On the basis of the band alignment (predicted by calculation) for the Schottky barriers in the metal-semiconductor-metal photodetector, we proposed the origin of the higher photocurrent for GaS than for GaSe. [ABSTRACT FROM AUTHOR]

To our best knowledge, β-Ga 2 O 3 via hierarchical gallium precursors from nanoparticles to microrods was successfully synthesized for first time using the forced-hydrolysis method and the calcination process. We report the growth mechanism and formation of various morphological gallium precursors such as Ga 4 (OH) 10 SO 4 nanospheres and ɑ-GaOOH microrods. The influence of the growth time on the crystal structure and its morphology was studied. The results indicate that the growth time played an important role in the transformation from amorphous to single-crystal structures. After calcination at 1000 °C for 1 h, well-crystallized and porous β-Ga 2 O 3 microrods are formed. The enhanced broad blue emission of porous β-Ga 2 O 3 microrods were related to defect band emission, such as oxygen vacancies and gallium-oxygen vacancy pairs. We propose that this oriented growth and transformation model may also be applicable to crystal growth and phase transformations and support the fabrication of other three-dimensional hierarchical materials, which is potentially important for a broad range of optoelectronic applications. [ABSTRACT FROM AUTHOR]

A reaction of digallane [(dpp-bian)Ga-Ga(dpp-bian)] ( 1) (dpp-bian is the 1,2-bis[(2,6-disopropylphenyl)imino]acenaphthene) with one equivalent of I leads to oxidation of (dpp-bian) in compound 1 to (dpp-bian)-and gives [(dpp-bian)GaI-GaI(dpp-bian)] ( 2). In the reaction of compound 2 with two equivalents of (acac)Na, not only exchange of the iodide and acetylacetonate ions takes place, but also a transfer of electrons from the metal-metal bond to dpp-bian with the formation of the complex [(dpp-bian)Ga(acac)] ( 3), in which the dpp-bian ligand is a dianion. A reaction of digallane 1 with 2,2´-bipyridyl at 200 °C in toluene in a sealed tube leads to the reduction of 2,2´-bipyridyl and gives the complex [(dpp-bian)Ga(bipy)] ( 4), which contains two different chelate redox-active ligands. The new compounds were characterized by IR ( 3, 4), NMR ( 3), and ESR spectra ( 4), the structures of both derivatives were established by X-ray diffraction. [ABSTRACT FROM AUTHOR]

A family of group 13 metal dimethyl complexes of the general formula [Me2M{MeC(O)CHC(NCH2CH2OMe)CF3}] [M = Al ( 2), Ga ( 3) or In ( 4)] was synthesised by reaction of the isolated free ligand 1 with the corresponding trimethyl metal reagents. The isolated complexes 2-4 were characterised by elemental analysis and NMR spectroscopy, and the molecular structures of the complexes were determined by single-crystal X-ray diffraction, which revealed them to be monomeric five-coordinate complexes with coordination of the pendent ether-bearing lariat in the solid state. Thermogravimetric analysis showed complexes 2- 4 all to have residual masses at 200 °C of 2.4 % or less, well below the value for the respective metal oxides, and vapour pressure measurements showed the indium complex 4 to be an order of magnitude less volatile (0.09 Torr at 80 °C) than the Al ( 2) and Ga ( 3) analogues, despite their being isoleptic systems. Complexes 2- 4 were investigated for their utility in the low-pressure metal organic chemical vapour deposition of the respective metal oxides in the absence of additional oxidant at 400 °C on silicon substrates. [ABSTRACT FROM AUTHOR]

A family of group 13 metal dimethyl complexes of the general formula [Me2M{MeC(O)CHC(NCH2CH2OMe)CF3}] [M = Al ( 2), Ga ( 3) or In ( 4)] was synthesised by reaction of the isolated free ligand 1 with the corresponding trimethyl metal reagents. The isolated complexes 2-4 were characterised by elemental analysis and NMR spectroscopy, and the molecular structures of the complexes were determined by single-crystal X-ray diffraction, which revealed them to be monomeric five-coordinate complexes with coordination of the pendent ether-bearing lariat in the solid state. Thermogravimetric analysis showed complexes 2- 4 all to have residual masses at 200 °C of 2.4 % or less, well below the value for the respective metal oxides, and vapour pressure measurements showed the indium complex 4 to be an order of magnitude less volatile (0.09 Torr at 80 °C) than the Al ( 2) and Ga ( 3) analogues, despite their being isoleptic systems. Complexes 2- 4 were investigated for their utility in the low-pressure metal organic chemical vapour deposition of the respective metal oxides in the absence of additional oxidant at 400 °C on silicon substrates. [ABSTRACT FROM AUTHOR]

The MF 3 ·3H 2 O (M = Al, Ga or In) dissolve in hot dimethylsulfoxide (dmso) to form [MF 3 (OH 2 ) 2 (dmso)]; further dmso is not incorporated even after prolonged reflux. The X-ray structure of [GaF 3 (OH 2 ) 2 (dmso)] shows mer fluorides and trans OH 2 ligands. The [GaF 3 (OH 2 ) 2 (dmso)] reacts with Me 3 tacn (1,4,7-trimethyl-1,4,7-triazacyclononane) or 2,2′-bipyridyl to give good yields of [GaF 3 (Me 3 tacn)]· x H 2 O and [GaF 3 (bipy)(OH 2 )]·2H 2 O at room temperature, previously obtained from GaF 3 ·3H 2 O by a hydrothermal route. [MF 3 (OH 2 ) 2 (dmso)] (M = Al or Ga) do not react with R 3 PO (R = Me or Ph) in CH 2 Cl 2 or MeOH, but with pyNO (pyridine-N-oxide), the products were [AlF 3 (OH 2 ) 2 (pyNO)] and [GaF 3 (OH 2 ) 2 (pyNO)]·pyNO·H 2 O. The structure of the latter shows equal numbers of the geometric isomers with mer – trans and mer – cis geometries, as well as lattice pyNO and H 2 O. Pentamethyldiethylenetriamine (PMDTA) and [GaF 3 (OH 2 ) 2 (dmso)] react to produce the zwitterion [GaF 4 (PMDTAH)]·2H 2 O, which contains κ 2 -PMDTA with the ‘free’ NMe 2 group protonated to balance the charge of the GaF 4 − unit. Crystals of [⊂Me 2 N(CH 2 ) 2 NMe(CH 2 ) 2 ] 2 [Ga 2 F 8 (OH 2 ) 2 ]·H 2 O containing a 1,1,4-trimethylpiperazinium cation, were obtained as a minor by-product. The anion is an edge-shared fluoride-bridged dimer, with the coordinated water ligands arranged anti . Attempts to prepare complexes with phosphine or thioether ligands by Cl/F exchange from the corresponding chloro-complexes with [NMe 4 ]F were unsuccessful, halide exchange being accompanied by liberation of the soft donor ligand. X-ray structures are also reported for [Me 2 NH 2 ][ trans -GaF 4 (OH 2 ) 2 ] and [AlCl 3 (OAsPh 3 )]. [ABSTRACT FROM AUTHOR]

Ga 2 O 3 were synthesized by controlled thermal oxidation of GaAs substrates at atmospheric pressure. The crystalline structure and vibrational modes were studied as a function of growth temperature within a range of 750–950 °C. Samples grown in the range of 750–850 °C present nanostructured surface and the samples obtained at higher temperature are oriented to the (004) β-phase. Crystalline structure was confirmed by X-ray diffraction, and Raman scattering studies. The evolution of the surface morphology was analyzed by atomic force microscopy, and scanning electron microscopy. [ABSTRACT FROM AUTHOR]

Anchoring a BODIPY onto Ga(iii)corrole via a meso-β linkage facilitated PeT in polar solvents, which quenched the fluorescence, and is further confirmed by electrochemical studies. The triad exhibits unprecedented crystal emission, which is not known for a corrole derivative, due to unique packing. Compound 4 hosts the first example of a novel B–F…F interaction as well. [ABSTRACT FROM AUTHOR]

A co-precipitation method was used for the synthesis of a novel copper–ceria catalyst promoted with gallium. Structural characterization was performed by SEM, EDS, BET, XRD, and XPS techniques. Methanol steam reforming was conducted inside a miniaturized LTCC packed bed reactor in the temperature range of 300–400 °C, and hydrogen was successfully produced from a water and methanol mixture. The kinetics of the reforming process were evaluated and the operation of the miniaturized reactor was described with a 3D finite element model, which included all governing mechanisms: fluid dynamics, transport phenomena and reaction kinetics. [ABSTRACT FROM AUTHOR]

The β-ketoimine ligand [(Me)CN(H){iPr}–CHC(Me)=O] (L1H) and the bis(β-ketoimine) ligands [(CH2)2{N(H)C(Me)–CHC(R)=O}2] (L2H2, R = Me; L3H2, R = C6H5) linked by ethylene bridges have been used to form aluminium and gallium complexes: [Al(L1)Et2] (1), [Ga(L1)2Cl] (2), [AlL2(OiPr)] (3) and [GaL3Me] (4). The complexes were characterised by NMR spectroscopy, mass spectroscopy, and single crystal X-ray diffraction, with the exception of 1 which was isolated as an oil. Compounds 1–4 have been used for the first time as single source precursors for the deposition of Al2O3 (1, 3) and Ga2O3 (2, 4) respectively. Thin films were deposited via aerosol assisted (AA)CVD with toluene as the solvent. [ABSTRACT FROM AUTHOR]

Six new phases in the gallium–fluoride–arsenate system have been synthesised hydrofluorothermally using a fluoride-rich medium and “HAsF6” (HF : AsF5) as a reactant. RbGaF3(H2AsO4), KGaF(H2AsO4) and [piperazine-H2]2[Ga2F8(HAsO4)]·H2O have one dimensional structures, [DABCO-H2]2[Ga4F7O2H(AsO4)2]·4H2O consists of two dimensionally connected polyhedral layers, while GaF(AsO3[OH,F])2 and (NH4)3Ga4F9(AsO4)2 both have three-dimensionally connected polyhedral frameworks. [ABSTRACT FROM AUTHOR]

Two gallium-based 3-D metal–organic frameworks, [C6H11N2][Ga(BDC)2] (1) and [C7H13N2][Ga(BDC)2] (2) (BDC = 1,4-benzenedicarboxylate), have been synthesized under ionothermal conditions and characterized by elemental analysis, FT-IR, XRD, and TG. Single-crystal X-ray diffraction studies reveal that1and2are isostructural. Both complexes crystallize in the monoclinic system with space groupP21/c. Their structures are characterized as a 3-D framework with larger rings constructed by GaO4polyhedra and BDC2−linkers, in which three sets of frameworks are interpenetrated along theaaxis. The used IL cation is located in the pore and compensates for the negative charge of the framework. Thermal behavior and fluorescence of1have been studied. Two gallium-1,4-benzenedicarboxylate-based MOFs, [C6H11N2][Ga(BDC)2] (1) and [C7H13N2][Ga(BDC)2] (2), were synthesized under ionothermal conditions. Their structures are characterized as a 3-D framework with larger rings constructed by the GaO4polyhedra and BDC2−linkers, in which three sets of frameworks are interpenetrated to form a three-fold interpenetration. [ABSTRACT FROM PUBLISHER]

This communication highlights a simple and facile biphasic synthesis of sub-10 nm Cr doped ZnGa2O4 nanoparticles (NPs) for the first time. These smallest Cr:ZnGa2O4 NPs demonstrate stable persistent luminescence emission more than 40 min after excitation. This synthesis strategy not only enables the controlled synthesis of these mixed metal oxide NPs unprecedentedly with smallest size to date but also allows them to be solution processable, which is advantageous for relevant applications with feasible and economic device fabrication. [ABSTRACT FROM AUTHOR]

The synthesis and solid-state characterization of a complete series of new heterometallic aqueous nanoscale Ga/In tridecameric clusters is presented. These hydroxo-aquo species significantly expand the library of discrete, aqueous group 13 clusters. This report details the synthetic and structural characterization of these compounds, which are of interest as precursors (inks) for thin-film oxides with materials applications. Single-crystal X-ray diffraction (XRD) data show that the hexagonal unit cell lengths of these clusters fall within the range a, b = 20.134-20.694 Å and c = 18.266-18.490 Å. The unit cell volumes become larger (V = 6494-6774 A³) with increasing indium occupancy. The compositions of several Ga/In clusters determined by electron probe microanalysis and elemental analysis are in agreement with single-crystal XRD results. The transformation of the Ga/In clusters to metal oxides at high temperature was studied using variable-temperature powder XRD. With heating, the Ga/In clusters with lower indium occupancies convert to the β-Ga2O3 structure. For clusters with higher indium occupancies, phase separation occurs, and an In2O3 bixbyite-type structure forms. The stoichiometric control at the molecular level demonstrated herein is important in designing functional thin films of metal oxides due to the tunable nature of these heterometallic solution precursors. In addition, information about the solid-state structure of these compounds leads to a fundamental understanding of the materials properties of these clusters for future thin-film and precursor development. [ABSTRACT FROM AUTHOR]

La0.9Ba0.1GaO3-δhas been synthesized through solid-state reaction method. X-ray diffraction, AC conductivity, and scanning electron microscopy are used to investigate the structural properties and morphology of the system. X-ray refinement indicates that LaGaO3is the major phase having an orthorhombic structure with the space groupIbmm. The study revealed that the Ba-dopant in the LaGaO3creates oxygen vacancies, which are responsible to increase the ionic conductivity through hopping mechanism. The activation energy of the system is nearly ∼0.65 eV. It indicates that the major contribution to overall conductivity is ionic in the present system. The impedance behavior of the sample with frequency and temperature has been investigated using the Bode's plots. The loss tangent variation with temperature has been plotted to verify the relaxation behavior of the present system. [ABSTRACT FROM AUTHOR]

Insertion of aromatic nitriles into Al-N and Ga-N bonds are reported. Sterically less hindered aluminum amide [PhNHAlMe2]2 (1) undergoes C=N insertion with benzonitrile to give an isomeric mixture of tetracyclic triazaalanes {[PhNC(Ph)N]3[PhNC(Ph)NH]Al[AlMe][AlMe2]2} (2 and 3). A similar reaction with analogous gallium amide affords a tetracyclic triazagallane {[PhNC(Ph)N]3[PhNC(Ph)NH]Ga[GaMe][GaMe2]2} (6) along with a novel bowl shaped carbon containing Ga-N cluster {[PhNC(Ph)N][PhN][GaMe]2}3 (5). On the other hand, when sterically bulky gallium amide (Dipp on N, Dipp = 2,6-diisopropylphenyl) is employed, a tetrameric gallium amidinate {[(Dipp)NC(Ph)N]GaMe}4 (8) is obtained. Tetracyclic triazagallazane 6 is also synthesized from the condensation reaction of N-phenylbenzamidine with GaMe3·OEt2. Unlike AlMe3, this reaction produces only one isomer. In case of amidines with bulkier substituents on N such as Dipp, formation of a bicyclic triazagallane {[(Dipp)NC(Ph)NH]2[(Dipp)NC(Ph)N][GaMe]2} (14) is also observed along with tetrameric gallium amidinate 8, whereas N-tert-butylbenzamidine affords exclusively a tetrameric gallium amidinate {[(tert-Bu)NC(Ph)N]GaMe}4 (15) similar to its Al analogue. However, treating N-(Dipp)acetamidine with GaMe3·OEt2 gives only a bicyclic triazagallane {[(Dipp)NC(Me)NH]2[(Dipp)NC(Me)N][GaMe]2} (16). An intermediate [(tert-Bu)N(H) C(Ph)NGaMe2]2 (17), which is involved in the formation of tetrameric gallium amidinate 15, is also characterized. A comparison of the structural parameters of Ga-N-C and Al-N-C frameworks synthesized in this study is reported. [ABSTRACT FROM AUTHOR]

To answer the question as to whether gallium in its oxidation state +1 favors a σ- or a π-coordination of aromatic nitrogen bases, we reacted [Ga(C6H5F)2]+[Al(ORF)4]- {RF = C(CF3)} with pyrazine and 2,6-di- tert-butyl-4-methylpyridine (DTBMP). In doing so, we obtained the first tricoordinate, nonchelated, homoleptic N-donor complex of gallium(I): [Ga(pyrazine)3]+[Al(ORF)4]-, in which each gallium(I) cation is coordinated in a trigonal-pyramidal fashion by three η1-donating pyrazine ligands. Hence, the gallium(I) cations favor σ- over π-coordination. Depending on the reaction conditions, and due to the bifunctionality of pyrazine, 1D coordination polymers of {[Ga(μ-pyrazine)2(η1-pyrazine)]+[Al(ORF)4]-}∞ were also obtained. With the sterically demanding DTBMP, which is conventionally used as a proton scavenger, the mixed complex [Ga(C6H5F)2(DTBMP)]+[Al(ORF)4]- was isolated, thus proving incorrect the perception of DTBMP being 'non-nucleophilic'. The structural findings were confirmed by multinuclear NMR investigations and density functional performed at the RI-BP86/SV(P) level. [ABSTRACT FROM AUTHOR]