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Ethide abstraction from Et3M (M = Al and Ga), (2,6-Ph2C6H3)AlEt2, 1, and (2,6-Dipp2C6H3)GaEt2, 2 (Dipp = 2,6-iPr2C6H3), using the silylium ion [Et3Si][CHB11Cl11] afforded crystalline ion-like compounds [Et2M][CHB11Cl11] (M = Al, 3; Ga, 5) and [(2,6-Ph2C6H3)AlEt][CHB11Cl11], 4, and the likely solvent-separated ion pair [(2,6-Dipp2C6H3)GaEt][CHB11Cl11], 6. Crystalline compounds 3-5feature cation•••anion contacts in the solid state, and their solubility in low polarity benzene indicates that these contacts are maintained in solution. All compounds catalyze the reduction of CO2 with Et3SiH, but the activity of the gallium compound 5 is significantly lower due to its polymeric structure and the lower Lewis acidity of gallium. Whereas the reduction products from the reactions catalyzed by compounds 3-5 are mostly methane and toluene (from Friedel-Crafts alkylation of the benzene solvent), catalysis by 6 led mostly to Et3SiOCH3. [ABSTRACT FROM AUTHOR]

Fully integrated quantum technology based on photons is in the focus of current research, because of its immense potential concerning performance and scalability. Ideally, the single-photon sources, the processing units, and the photon detectors are all combined on a single chip. Impressive progress has been made for on-chip quantum circuits and on-chip single-photon detection. In contrast, nonclassical light is commonly coupled onto the photonic chip from the outside, because presently only few integrated single-photon sources exist. Here, we present waveguide-coupled single-photon emitters in the layered semiconductor gallium selenide as promising on-chip sources. GaSe crystals with a thickness below 100 nm are placed on Si3N4 rib or slot waveguides, resulting in a modified mode structure efficient for light coupling. Using optical excitation from within the Si3N4 waveguide, we find nonclassicality of generated photons routed on the photonic chip. Thus, our work provides an easy-to-implement and robust light source for integrated quantum technology. [ABSTRACT FROM AUTHOR]

The potential of cesium polysulfide-flux reactions for the synthesis of chalcogenogallates was investigated by using X-ray diffraction and Raman spectroscopy. An investigation of possible factors influencing the product formation revealed that only the polysulfide content x in the Cs2S x melts has an influence on the crystalline reaction product. From sulfur-rich melts (x > 7), CsGaS3 is formed, whereas sulfur-poor melts (x < 7) lead to the formation of Cs2Ga2S5. In situ investigations using high-temperature Raman spectroscopy revealed that the crystallization of these solids takes place upon cooling of the melts. Upon heating, CsGaS3 and Cs2Ga2S5 release gaseous sulfur due to the degradation of S2 2- units. This decomposition of CsGaS3 to Cs2Ga2S5 and finally to CsGaS2-mC16 was further studied in situ by using high-temperature X-ray powder diffraction. A combination of the polysulfide reaction route and the high-temperature decomposition leads to the possibility of the directed interconversion of these thiogallates. The presence of disulfide units in the anionic substructures of these thiogallates has a significant influence on the electronic band structures and their optical properties. This influence was studied by using UV/vis-diffuse reflectance spectroscopy and DFT simulations, revealing a trend of smaller band gaps with increasing S2 2- content. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate that a preferential Ga-for-Zn cation exchange is responsible for the increase in photoluminescence that is observed when gallium oleate is added to InZnP alloy QDs. By exposing InZnP QDs with varying Zn/In ratios to gallium oleate and monitoring their optical properties, composition, and size, we conclude that Ga3+ preferentially replaces Zn2+, leading to the formation of InZnP/InGaP core/graded-shell QDs. This cation exchange reaction results in a large increase of the QD photoluminescence, but only for InZnP QDs with Zn/In ≥ 0.5. For InP QDs that do not contain zinc, Ga is most likely incorporated only on the quantum dot surface, and a PL enhancement is not observed. After further growth of a GaP shell and a lattice-matched ZnSeS outer shell, the cation-exchanged InZnP/InGaP QDs continue to exhibit superior PL QY (over 70%) and stability under long-term illumination (840 h, 5 weeks) compared to InZnP cores with the same shells. These results provide important mechanistic insights into recent improvements in InP-based QDs for luminescent applications. [ABSTRACT FROM AUTHOR]

A rapid cellular microstructure of Ti-48Al-2Cr-2Nb (in atom %) intermetallic was grown without peritectic reaction by the method of melt-quenching in Ga-In liquid. After characterization of the microstructures and phase constituents, it is observed that the cellular crystals mainly consist of the α2 phase and directionally grew in the outer layer of the melt droplet, with the growth length and cellular spacing about 358-460 μm and 0.68-3.6 μm, respectively. Upon detailed analysis of the cellular growth process, it is found that the formation of this characteristic microstructure is derived from the extremely rapid cooling effect of Ga-In liquid, mainly determined by the heat transfer process; the dominant heat transfer mechanism changes from heat convection to heat conduction at a growth distance of about 70 μm. By using the semireverse method, the dependence of the cooling rate on the cellular growth distance can be estimated accurately and conveniently, which ranges from 2.61 × 106 to 1.26 × 105 K/s. The nanoindentation examination proved that the rapid cellular microstructure possesses excellent micromechanical properties (8.457 ± 0.336 GPa in nanohardness), with a significant improvement of about 15-60% than the general microstructures. [ABSTRACT FROM AUTHOR]

Hydroalumination or hydrogallation of a sterically encumbered hydrazone, H10C5N-N-C(C9H14) (NC5H10 = piperidine, C(C9H14) = 2-adamantdiyl), afforded hydrazides that, depending on the steric shielding by the substituents at the metal atoms, had different molecular structures. While both di(tert-butyl)metal derivatives (1a, 1b) are monomeric in the solid state with highly strained MN2 heterocycles (M = Al, Ga), the dimethylmetal compounds (1c, 1d) are dimeric with M2N2 heterocycles and exocyclic N-N bonds. The latter compounds are highly dynamic in solution. 1d crystallized as a mixture of cis- and trans-isomers as detected by crystal structure determinations. These compounds react as active Lewis pairs by their specific donor-acceptor functionality and are able to activate C-H bonds of moderately acidic substrates. Reaction of 1a (M = Al) with H-C-C-C6H5 afforded by C-H bond activation and release of H-CMe3 trialkynyl compound 4, in which three alkynyl groups and a neutral hydrazine ligand are bound to Al. 1b (M = Ga) gave only the known dimeric monoalkynyl derivative [(Me3C)2Ga-C-C-C6H5]2 (5b). The sterically less shielded dimethyl compounds 1c and 1d similarly yielded trialkynylmetal compounds by methane and hydrogen elimination. In this case a hydrazone ligand is coordinated to the metal atoms. 1d reacted with pentafluorobenzene in an unprecedented reaction to yield a diaryl-methylgallium compound with the metal atom bound to two electron-withdrawing groups and a hydrazone ligand completing the coordination sphere of Ga. [ABSTRACT FROM AUTHOR]

The structure solution of the modulated, delafossite-related, orthorhombic Ga3-xIn3TixO9+x/2 for x = 1.5 is reported here in conjunction with a model describing the modulation as a function of x for the entire system. Previously reported structures in the related A3-xIn3TixO9+x/2 (A = Al, Cr, or Fe) systems use X-ray diffraction to determine that the anion lattice is the source of modulation. Neutron diffraction, with its enhanced sensitivity to light atoms, offers a route to solving the modulation and is used here, in combination with precession electron diffraction tomography (PEDT), to solve the structure of Ga1.5In3Ti1.5O9.75. We construct a model that describes the anion modulation through the formation of rutile chevrons as a function of x. This model accommodates the orthorhombic phase (1.5 ≤ x ≤ 2.1) in the Ga3-xIn3TixO9+x/2 system, which transitions to a biphasic mixture (2.2 ≤ x ≤ 2.3) with a monoclinic, delafossite-related phase (2.4 ≤ x ≤ 2.5). The optical band gaps of this system are determined, and are stable at ∼3.4 eV before a ∼0.4 eV decrease between x = 1.9 and 2.0. After this decrease, stability resumes at ∼3.0 eV. Resistance to oxidation and reduction is also presented. [ABSTRACT FROM AUTHOR]

The 17 valence electron (VE) open-shell nickel gallanediyl complex [CpArNi{Ga(nacnac)}] (3, Ar = C5(C6H4-4-Et)5, nacnac = HC[C(Me)N(C6H3-2,6-iPr2)]2), having an unsupported Ni-Ga bond, was synthesized from [CpArNi(µ-Br)]2 (1) by reducing the adduct [CpArNi(μ-Br){Ga(nacnac)}] (2) or, alternatively, trapping the "CpArNiI" synthon with Ga(nacnac); spectroscopic and DFT studies showed that the single unpaired electron in 3 resides mainly at the Ni center. [ABSTRACT FROM AUTHOR]

Gallium(III) tetraphenylporphyrinates (TPP) containing anionic sulfur ligands have been prepared and characterized in the solid state and solution. The complexes serve as structural models for iron(III) heme sites containing sulfur coordination that otherwise prove challenging to synthesize due to the propensity for reduction to iron(II). The compounds prepared include the first well-characterized example of a trivalent metalloporphyrinate containing a terminal hydrosulfide ligand, [Ga(SH)(TPP)], as well as [Ga(SEt)(TPP)], [Ga(SPh)(TPP)], and [Ga(SSiiPr3)(TPP)]. The stability of these compounds toward reduction has permitted an investigation of their solid-state structures and electrochemistry. The structural features and reaction chemistry of the complexes in relation to their iron(III) analogs is discussed. [ABSTRACT FROM AUTHOR]

A thermodynamic study was performed on the growth of Ga3+-doped LiNbO3 (LN) thin film. Some Ga3+-doped LN thin films were grown on the LN surface by thermal diffusion of Ga2O3 film in the temperature range of 1000-1100 °C. After growth, the Ga3+ ion in the grown thin film was profiled, and its diffusion-growth characteristics were studied. The temperature dependences of diffusion-growth coefficient and solubility were quantified. These dependences are crucial to the design and growth of a Ga3+-doped LN thin film for various photonic applications. A comparison with the case of Ti4+ diffusion-growth, which induces an increase of LN refractive index and hence formation of an optical waveguide, shows that Ga3+ grows considerably faster than Ti4+ because of its smaller ionic radius. In addition, Ga3+-doping contribution to LN refractive index was studied by measuring and comparing the refractive indices at Ga3+-grown and Ga3+-free parts of the crystal surface. The results show that the contribution is small. [ABSTRACT FROM AUTHOR]

The 6-coordinated cation site is the fundamental building block of the most effective transparent conducting oxides. Ga2In6Sn2O16, however, maintains 4-, 6-, 7-, and 8-coordinated cation sites and still exhibits desirable transparency and high conductivity. To investigate the potential impact of these alternative sites, we partially replace the Sn in Ga2In6Sn2O16 with Ti, Zr, or Hf and use a combined approach of density functional theory-based calculations, X-ray diffraction, and neutron diffraction to establish that the substitution occurs preferentially on the 7-coordinate site. In contrast to Sn, the empty d orbitals of Ti, Zr, and Hf promote spd covalency with the surrounding oxygen, which decreases the conductivity. Pairing the substitutional site preference with the magnitude of this decrease demonstrates that the 7-coordinate site is the major contributor to conductivity. The optical band gaps, in contrast, are shown to be site-independent and composition-dependent. After all 7-coordinate Sn has been replaced, the continued substitution of Sn results in the formation of a 7-coordinate In antisite or replacement of 6-coordinate Sn, depending on the identity of the d0 substitute. [ABSTRACT FROM AUTHOR]

A series of novel gallium dimethylmalonateand cyclopropane-1,1-dicarboxylate complexes have been synthesizedusing gallium halides as Lewis acids. The structure and propertiesof the resulting complexes as well as the mechanisms of reactionsinvolved have been studied. Some complexes have ionic structures andconsist of ligand-bound Ga cations and tetrahalogallate anions. Thestructures of gallium complexes were studied by multinuclear NMR spectroscopy,including that on 71Ga nuclei. Furthermore, X-ray diffractionanalysis was carried out for the six complexes. Dimethyl cyclopropanedicarboxylatewas considered as the simplest analogue of donor–acceptor cyclopropanes.It is a convenient model for studying such cyclopropanes, while thecomplexes obtained are analogues of intermediates in their reactionscatalyzed by Lewis acids. In particular, elongation of the C–CH2bond in the cyclopropane ring and activation of the latterby gallium halides have been shown experimentally. The data obtainedare a new step in studies on this very interesting and promising classof substrates. [ABSTRACT FROM AUTHOR]

Introducing multiple luminescentcenters into colloidal nanocrystalsis an attractive way to impart new optical properties into this classof materials. Doping disparate ions into specific nanocrystals isoften challenging, due to the preferential incorporation of one typeof dopant. Here, we demonstrate the coexistence of europium dopantsas divalent and trivalent ions in colloidal Ga2O3nanocrystals, achieved by controlled in situreductionof Eu3+to Eu2+. The two dopant species exhibitdistinctly different steady-state and time-resolved photoluminescence,and their ratio can be modified via doping concentration, reactiontemperature, or thermal treatment of as-synthesized NCs. The Eu2+ions are proposed to be stabilized internally owing to theattractive interaction with oxygen vacancies, while Eu3+dopants partly reside in the nanocrystal surface region. The relationshipbetween the electronic structure of the native defects and the dopantcenters is discussed in the context of the overall emission properties.The exposure of these samples to X-ray radiation leads to the reductionof Eu3+to Eu2+, demonstrating an alternativeway of manipulating the oxidation state and suggesting the potentialapplication of this material as an X-ray storage phosphor. The coexistenceof Eu2+and Eu3+and the ability to controltheir relative fraction over the full oxidation state range in groupIII oxide nanocrystals allow for the design and preparation of newphotonic and light emitting materials. [ABSTRACT FROM AUTHOR]

Amidoxime is of broadinterest as a functional group for extractionand separation of different metals from aqueous solution due to itshigh affinity for a wide range of metal ions. Resins which containan amidoxime group have exhibited good extractive properties for galliumand are adopted as the most efficient adsorbent for the recovery ofgallium from Bayer liquor. However, the coordination mechanism betweenthe amidoxime functional group of the resin and Ga(III) in Bayer liquoris unclear so far. Here, to identify the preferred action and thebinding motif when amidoxime binds with Ga(III), we performed densityfunctional theory (DFT) calculations and subsequent FT-IR spectraanalysis for the amidoxime resin before and after adsorption of Ga(III)in Bayer liquor. Single-crystal X-ray diffraction was also used tovalidate the prediction. The fully relaxed structure and binding energycalculations of a series of complexes containing acetamidoximate (AO–) and gallium species, [Ga(OH)4-x(AO–)x]−, showed that, of the three general binding motifsof the amidoxime group toward metal ions, complexes with oxygen bindingmotif I are more stable than complexes with chelate binding motifII or η2binding motif III; and Ga(III) in Bayerliquor prefers to coordinate with only one amidoximate rather thantwo or more amidoximates. The FT-IR spectrum of the resin after adsorptionconfirmed the coordination between Ga and oximido by the shiftingof N–O and O–H stretching vibrations to higher wavenumberand the appearance of Ga–O stretching vibrations. No characteristicstretching band of Ga–N was found in the FT-IR spectra, indicatingbinding motifs II and III unlikely happened. Structural analysis ofthe single-crystal X-ray diffraction date revaled that the amidoximeligand is deprotonated at a single oxime oxygen atom and coordinatesto one gallium atom only through this oxygen, confirming the oxygenbinding motif. Accordingly oxygen binding mode I might be the mainbinding motifs of amidoxime toward Ga(III) in Bayer liquor, whichvalidated the prediction of DFT calculations. [ABSTRACT FROM AUTHOR]

Simple sphere packings of metallic atoms are generally assumed to exhibit highly delocalized bonding, often visualized in terms of a lattice of metal cations immersed in an electron gas. In this Article, we present a compound that demonstrates how covalently shared electron pairs can, in fact, play a key role in the stability of such structures: Mo2CuxGa6-x (x ≈ 0.9). Mo2CuxGa6-x adopts a variant of the common TiAl3 structure type, which itself is a binary coloring of the fee lattice. Electronic structure calculations trace the formation of this compound to a magic electron count of 14 electrons/T atom (T = transition metal) for the TiAl3 type, for which the Fermi energy coincides with an electronic pseudogap. This count is one electron/T atom lower than the electron concentration for a hypothetical MoGa3 phase, making this structure less competitive relative to more complex alternatives. The favorable 14 electron count can be reached, however, through the partial substitution of Ga with Cu. Using DFT-calibrated Hückel calculations and the reversed approximation Molecular Orbital (raMO) method, we show that the favorability of the 14 electron count has a simple structural origin in terms of the 18 -- n rule of T -- E intermetallics (E = main group element): the T atoms of the TiAl3 type are arranged into square nets whose edges are bridged by E atoms. The presence of shared electron pairs along these T -- T contacts allows for 18 electron configurations to be achieved on the T atoms despite possessing only 18 - 4 = 14 electrons/T atom. This bonding scheme provides a rationale for the observed stability range of TiAl3 type TE3 phases of ca. 13-14 electrons/T atom, and demonstrates how the concept of the covalent bond can extend even to the most metallic of structure types. [ABSTRACT FROM AUTHOR]

A number of pentacoordinated gallium complexes iSQ2GaR (1-7) (R = Et (1), Me (2), N3 (3), Cl (4), Br (5), I (6), NCS (7)) where iSQ is a radical anion of 4,6-di-tert-butyl-N-(2,6-diisopropylphenyl)-o-iminobenzoquinone were synthesized, and crystalline samples of 1-7 were characterized using magnetic susceptibility measurements. The character of magnetic exchange interaction between spins of o-iminosemiquinonate radicals was found to be strongly influenced by the nature of the apical substituent. The antiferromagnetic coupling is predominant when the apical position is occupied by halogens or other tested inorganic anions, and the value of exchange interaction parameter varies from -99 to -176 K for R = I and NCS, respectively. In the case of alkyl groups the ferromagnetic exchange prevails and, as the result, the triplet ground state for pentacoordianted biradical compounds was observed. Compounds 1-7 demonstrate a biradical X-band EPR spectrum in frozen toluene matrix. The molecular structures of 4, 6, and 7 have been established by single-crystal X-ray analysis. A computational DFT UB3LYP/6-31G(d,p) study was performed on complexes 1-7 in order to understand the reason for changes in the magnetic behavior of the related diradical gallium compounds. The calculations showed that the magnetic behavior of the complexes with inorganic anions is conditioned by the presence of antiferromagnetic exchange channel formed as a consequence of overlapping between donor atomic orbitals of iminoquinone with p-orbitals of halogen atoms (4-6) or nitrogen atom (3, 7). [ABSTRACT FROM AUTHOR]

High-performance solar-blind (200–280nm) avalanche photodetectors (APDs) were fabricated based on highlycrystallized ZnO–Ga2O3core–shellmicrowires. The responsivity can reach up to 1.3 × 103A/W under −6 V bias. Moreover, the corresponding detectivitywas as high as 9.91 × 1014cm·Hz1/2/W. The device also showed a fast response, with a rise time shorterthan 20 μs and a decay time of 42 μs. The quality of thedetectors in solar-blind waveband is comparable to or even higherthan that of commercial Si APD (APD120A2 from Thorlabs Inc.), witha responsivity ∼8 A/W, detectivity ∼1012cm·Hz1/2/W, and response time ∼20 ns. The high performanceof this APD make it highly suitable for practical applications assolar-blind photodetectors, and this core–shell microstructureheterojunction design method would provide a new approach for realizingan APD device. [ABSTRACT FROM AUTHOR]

Device configurations that enablea unidirectional propagation of carriers in a semiconductor are fundamentalcomponents for electronic and optoelectronic applications. To realizesuch devices, however, it is generally required to have complex processesto make p–n or Schottky junctions. Here we report on a unidirectionalpropagation effect due to a self-induced compositional variation inGaAsSb nanowires (NWs). The individual GaAsSb NWs exhibit a highlyreproducible rectifying behavior, where the rectifying direction isdetermined by the NW growth direction. Combining the results fromconfocal micro-Raman spectroscopy, electron microscopy, and electricalmeasurements, the origin of the rectifying behavior is found to beassociated with a self-induced variation of the Sb and the carrierconcentrations in the NW. To demonstrate the usefulness of these GaAsSbNWs for device applications, NW-based photodetectors and logic circuitshave been made. [ABSTRACT FROM AUTHOR]

Ultrathin gallium oxide layers witha thickness of 2.8 ± 0.2nm were transferred from the surface of liquid gallium onto solidsubstrates, including conjugated polymer poly(3-hexylthiophene) (P3HT).The gallium oxide exhibits high mechanical stability, withstandingnormal pressures of up to 1 GPa in contact mode scanning force microscopyimaging. Moreover, it lowers the rate of photodegradation of P3HTby 4 orders of magnitude, as compared to uncovered P3HT. This allowsus to estimate the upper limits for oxygen and water vapor transmissionrates of 0.08 cm3m–2day–1and 0.06 mg m–2day–1, respectively.Hence, similar to other highly functional coatings such as graphene,ultrathin gallium oxide layers can be regarded as promising candidatesfor protective layers in flexible organic (opto-)electronics and photovoltaicsbecause they offer permeation barrier functionalities in conjunctionwith high optical transparency. [ABSTRACT FROM AUTHOR]

Cyclization of 1,6-diynes promoted by stoichiometric Ga(III) halides produces vinyl halides in good to excellent yields. Under acidic conditions, initially formed iodocyclization products undergo in situ Friedel-Crafts cyclizations, giving access to iodoindenopyridines. Application of the vinyl halides in cross-coupling reactions has been explored, and mechanistic aspects of the cyclization are discussed. [ABSTRACT FROM AUTHOR]

Treatment of (dpp-Bian)Ga-Ga(dpp-Bian) (1) (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) with iodine gives (dpp-Bian)Ga(I)-Ga(I)(dpp-Bian) (2), which reacts in situ with K(C5H4CH2CH2NMe2) (KCpDo) or K(OCH2CH2NMe2) (KORDo) to produce the monomeric species (dpp-Bian)GaCpDo (3) and (dpp-Bian)GaORDo (4), respectively. Complex 3 reacts with PhC≡CH to give the paramagnetic derivative (dpp-Bian)Ga(C≡CPh)2 (5), while compound 4 is inert toward this alkyne. In contrast, monomeric (dpp-Bian) Ga (S2CNMe2) (6) reacts with PhC≡CH and HC≡CH to give the cycloaddition products [dpp-Bian(PhC≡CH)] Ga (S2CNMe2) (7) and [dpp-Bian(HC≡CH)]Ga(S2CNMe2) (8). The related compounds [dpp-Bian(MeC≡CC(O)OMe)]Ga(S2CNMe2) (9) and [dpp-Bian(CH2CH≡C(Me)O)]Ga(S2CNMe2) (10) have been obtained in the reactions of complex 6with methyl 2-butynoate and methyl vinyl ketone, respectively. New complexes have been characterized by 1H NMR (3, 4, and 7-10) and ESR (5) spectroscopy; their molecularstructures have been established by single-crystal X-ray analysis. The catalytic activity of complex 6 in the hydroamination and hydroarylation of alkynes has been examined. [ABSTRACT FROM AUTHOR]

The thermal and photochemical reactionsof (CH3)3Ga and O3have been exploredusing a combinationof matrix isolation, infrared spectroscopy, and theoretical calculations.Experimental data using twin jet deposition and theoretical calculationsdemonstrate the formation of multiple product species after deposition,annealing to 35 K, and UV irradiation of the matrices. The productswere identified as (CH3)2GaOCH3,(CH3)2GaCH2OH, (CH3)(CH3O)Ga(OCH3), (CH3)2GaCHO,and (CH3)Ga(OCH3)(CH2OH). Productidentifications were confirmed by annealing and irradiation behavior, 18O substitution experiments, and high level theoretical calculations.Merged jet deposition led to a number of stable late reaction products,including C2H6, CH3OH, and H2CO. A white solid film was also noted on the walls of themerged (flow reactor) region of the deposition system, likely dueto the formation of Ga2O3. [ABSTRACT FROM AUTHOR]

Borates are well-known candidates for optical materials, but their potentials in photocatalysis are rarely studied. Ga3+-containing oxides or sulfides are good candidates for photocatalysis applications because the unoccupied 4s orbitals of Ga usually contribute to the bottom of the conducting band. It is therefore anticipated that Ga4B2O9 might be a promising photocatalyst because of its high Ga/B ratio and three-dimensional network. Various synthetic methods, including hydrothermal (HY), sol-gel (SG), and high-temperature solid-state reaction (HTSSR), were employed to prepare crystalline Ga4B2O9. The so-obtained HY-Ga4B2O9 are micrometer single crystals but do not show any UV-light activity unless modified by Pt loading. The problem is the fast recombination of photoexcitons. Interestingly, the samples obtained by SG and HTSSR methods both possess a fine micromorphology composed of well-crystalline nanometer strips. Therefore, the excited e- and h+ can move to the surface easily. Both samples exhibit excellent intrinsic UV-light activities for pure water splitting without the assistance of any cocatalyst (47 and 118 µmol/h/g for H2 evolution and 22 and 58 µmol/h/g for O2 evolution, respectively), while there is no detectable activity for P25 (nanoparticles of TiO2 with a specific surface area of 69 m²/g) under the same conditions. [ABSTRACT FROM AUTHOR]

Quantumspin Hall (QSH) effect is promising for achieving dissipationlesstransport devices but presently is achieved only at extremely lowtemperature. Searching for the large-gap QSH insulators with strongspin–orbit coupling (SOC) is the key to increase the operatingtemperature. We demonstrate theoretically that this can be solvedin the chloridized gallium bismuthide (GaBiCl2) monolayer,which has nontrivial gaps of 0.95 eV at the Γ point, and 0.65eV for bulk, as well as gapless edge states in the nanoribbon structures.The nontrivial gaps due to the band inversion and SOC are robust againstexternal strain. The realization of the GaBiCl2monolayerwill be beneficial for achieving QSH effect and related applicationsat high temperatures. [ABSTRACT FROM AUTHOR]

Five new polar intermetallic compounds in the Ae-Ga-Au system (Ae = Ba, Eu), BaAu5Ga2 (I), BaAu4.3Ga2.7 (II), Ba1.0Au4.5Ga2.4 (III), EuAu4.8Ga2.2 (IV), and Eu1.1Au4.4Ga2.2 (V), have been synthesized and their crystal structures determined by single-crystal X-ray diffraction. I crystallizes in the orthorhombic crystal system with a large unit cell [Pearson symbol oP64; Pnma, Z = 8, a = 8.8350(5) Å, b = 7.1888(3)Å, c = 20.3880(7) Å], whereas all other compounds are hexagonal [hP24; P62m, Z = 3, a = 8.54-8.77(1) Å, c = 7.19-7.24(1) Å]. Both structures contain mutually orthogonal layers of Au6 hexagons in chair and boat conformations, resulting in a hexagonal diamond-like network. Ae atoms and additional (Au/Ga)3 groups are formally encapsulated by (Au6)2 distorted hexagonal prisms formed of three edge-sharing hexagons in the boat conformation or, alternatively, lie between two Au6 hexagons in the chair conformation. The (Au/Ga)3 groups can be substituted by Ae atoms in some of the hexagonal structures with no change to the structural symmetry. Tight-binding electronic structure calculations using linear-muffin-tin-orbital methods on idealized models "BaAu5Ga2" and "BaAu4Ga3" show both compounds to be metallic with evident pseudogaps near the corresponding Fermi levels. The integrated crystal orbital Hamilton populations are dominated by Au-Au and Au-Ga orbital interactions, although Ba-Au and Ba-Ga contributions are significant. Furthermore, Au-Au interactions vary considerably along different directions in the unit cells, with the largest values for the hexagons in the boat conformation and the lowest values for those in the chair conformation. II revealed that partial substitution of Au atoms in the hexagonal diamond net by a post-transition element (Ga) may occur in this family, whereas the sizes of the (Au/Ga)3 groups and strong Ba-Au covalent interactions allow for their mutual replacement in the voids. [ABSTRACT FROM AUTHOR]

To our best knowledge, monodispersedβ-Ga2O3nanospheres were successfullysynthesized for first time via morphology-controlled gallium precursorsusing the forced hydrolysis method, followed by thermal calcinationprocesses. The morphology and particle sizes of the gallium precursorswere strongly dependent on the varying (R= SO42–/NO3–) concentrationratios. As Rdecreased, the size of the preparedgallium precursors decreased and morphology was altered from sphereto rod. The synthesized S2 (R= 0.33) consists ofuniform and monodispersed amorphous nanospheres with diameters ofabout 200 nm. The monodispersed β-Ga2O3nanospheres were synthesized using thermal calcination processesat various temperatures ranging from 500 to 1000 °C. Monodispersedβ-Ga2O3nanospheres (200 nm) consist ofsmall particles of approximately 10–20 nm with rough surfaceat 1000 °C for 1 h. The UV (375 nm) and broad blue (400–450nm) emission indicate recombination via a self-trapped exciton andthe defect band emission. Our approach described here is to show theexploration of β-Ga2O3nanospheres asan automatic dispersion, three-dimensional support for fabricationof hierarchical materials, which is potentially important for a broadrange of optoelectronic applications. [ABSTRACT FROM AUTHOR]

The synthesis of 1,2-cis-homoiminosugars bearingan NHAc group at the C-2 position is described. The key step to preparethese α-d-GlcNAc and α-d-GalNAc mimicsutilizes a β-amino alcohol skeletal rearrangement applied toan azepane precursor. This strategy also allows access to naturallyoccurring α-HGJ and α-HNJ. The α-d-GlcNAc-configurediminosugar was coupled to a glucoside acceptor to yield a novel pseudodisaccharide.Preliminary glycosidase inhibition evaluation indicates that the α-d-GalNAc-configured homoiminosugar is a potent and selectiveα-N-acetylgalactosaminidase inhibitor. [ABSTRACT FROM AUTHOR]

The solubility of Ce in the La1-xCexSrGa3O7+d and La1.54-xCexSr0.46Ga3O7.27+d melilites was investigated, along with the thermal redox stability in air of these melilites and the conductivity variation associated with oxidization of Ce3+ into Ce4+. Under CO reducing atmosphere, the La in LaSrGa3O7 may be completely substituted by Ce to form the La1-xCexSrGa3O7+d solid solution, which is stable in air to ~600 °C when x = 0.6. On the other side, the La1.54-xCexSr0.46Ga3O7.27+d compositions displayed much lower Ce solubility (x = 0.1), irrespective of the synthesis atmosphere. In the as-made La1-xCexSrGa3O7+d, the conductivity increased with the cerium content, due to the enhanced electronic conduction arising from the 4f electrons in Ce3+ cations. At 600 °C, CeSrGa3O7+d showed a conductivity of ~10-4 S/cm in air, nearly 4 orders of magnitude higher than that of LaSrGa3O7. The oxidation of Ce3+ into Ce4+ in CeSrGa3O7+d slightly reduced the conductivity, and the oxygen excess did not result in apparent increase of oxide ion conduction in CeSrGa3O7+d. The Ce doping in air also reduced the interstitial oxide ion conductivity of La1.54Sr0.46Ga3O7.27. Neutron powder diffraction study on CeSrGa3O7.39 composition revealed that the extra oxygen is incorporated in the four-linked GaO4 polyhedral environment, leading to distorted GaO5 trigonal bipyramid. The stabilization and low mobility of interstitial oxygen atoms in CeSrGa3O7+d, in contrast with those in La1+xSr1-xGa3O7+0.5x, may be correlated with the cationic size contraction from the oxidation of Ce3+ to Ce4+. These results provide a new comprehensive understanding of the accommodation and conduction mechanism of the oxygen interstitials in the melilite structure. [ABSTRACT FROM AUTHOR]

Ferromagnetic Sr(GaxTiyFe0.34–o.4o)O3–δ (0.1 ≤ x, y ≤ 0.5) films with single-crystal perovskite structure were epitaxially grown on (001) (LaAlO3)0.3(Sr2AlTaO6)0.7 substrates by combinatorial pulsed laser deposition (CPLD) and compared with previous results from films grown from single targets. In CPLD films the Fe was present as both Fe2+ and Fe3+. The distribution of Sr, Ga, Ti, and O was homogeneous, but Fe-rich nanowires with diameter of 3 nm were present perpendicular to the film plane. The unit cell was tetragonally distorted with the ratio of out-of-plane to in-plane lattice parameter decreasing from 1.06 to 1.02 as the Ga content increased. The magnetic easy axis of the films changed from out-of-plane when Ti content y > 0.3 to isotropic as the Ga content increased, consistent with a reduction in magnetoelastic anisotropy. The Ga lowered the Faraday rotation and the magnetization but increased the optical transmittance. [ABSTRACT FROM AUTHOR]

The III–Vsemiconductor nanowires (NWs) have a great potentialfor applications in a variety of future electronic and photonic deviceswith enhanced functionality. In this work, we employ polarization-resolvedmicrophotoluminescence (μ-PL) spectroscopy to study polarizationproperties of light emissions from individual GaNP and GaP/GaNP core/shellNWs with average diameters ranging between 100 and 350 nm. We showthat the near-band-edge emission, which originates from the GaNP regionsof the NWs, is strongly polarized (up to 60% at 150 K) in the directionperpendicular to the NW axis. The polarization anisotropy can be retainedup to room temperature. This polarization behavior, which is unusualfor zinc blende NWs, is attributed to local strain in the vicinityof the N-related centers participating in the radiative recombinationand to preferential alignment of their principal axis along the growthdirection. Our findings therefore show that defect engineering viaalloying with nitrogen provides an additional degree of freedom totailor the polarization anisotropy of III–V nanowires, whichis advantageous for their applications as nanoscale emitters of polarizedlight. [ABSTRACT FROM AUTHOR]

Thedistilled fraction (DF) from bio-oil molecular distillation can beused for the generation of aromatic hydrocarbons by cocracking withethanol over HZSM-5. In this work, typical model compounds were selectedto simulate the DF, and a modified Ga2O3/HZSM-5was adopted to promote the aromatization reaction. Compared with unmodifiedHZSM-5, 15% Ga2O3/HZSM-5 could increase theyield of the oil phase from 31.5 to 39.2 wt % during cocracking ofa mixture of model compounds and ethanol, with an obvious decreasein the C3–C4gaseous hydrocarbon yield.Moreover, the total content of aromatic hydrocarbons in the oil phasewas around 95%. The production of monoaromatics, especially xylenes,was favored. The influences of reaction temperature and feedstockweight hourly space velocity (WHSV), as well as the catalyst regeneration,were also investigated. On the basis of the experimental results,a reaction mechanism is proposed and the promotion of aromatic hydrocarbongeneration by Ga2O3is discussed. [ABSTRACT FROM AUTHOR]

Thispaper investigates the influence of the atmosphere used inthe fabrication of top electrodes from the liquid eutectic of galliumand indium (EGaIn) (the so-called “EGaIn” electrodes),and in measurements of current density, J(V) (A/cm2), across self-assembled monolayers (SAMs) incorporated intoAg/SR//Ga2O3/EGaIn junctions, on values of J(V) obtained using these electrodes. A gas-tight measurementchamber was used to control the atmosphere in which the electrodeswere formed, and also to control the environment in which the electrodeswere used to measure current densities across SAM-based junctions.Seven different atmospheresair, oxygen, nitrogen, argon, andammonia, as well as air containing vapors of acetic acid or waterweresurveyed using both “rough” conical-tip electrodes,and “smooth” hanging-drop electrodes. (The manipulationof the oxide film during the creation of the conical-tip electrodesleads to substantial, micrometer-scale roughness on the surface ofthe electrode, the extrusion of the drop creates a significantly smoothersurface.) Comparing junctions using both geometries for the electrodes,across a SAM of n-dodecanethiol, in air, gave log |J|mean= −2.4 ± 0.4 for the conicaltip, and log |J|mean= −0.6± 0.3 for the drop electrode (and, thus, Δlog |J| ≈ 1.8); this increase in current density is attributedto a change in the effective electrical contact area of the junction.To establish the influence of the resistivity of the Ga2O3film on values of J(V), junctionscomprising a graphite electrode and a hanging-drop electrode werecompared in an experiment where the electrodes did, and did not, havea surface oxide film; the presence of the oxide did not influencemeasurements of log |J(V)|, and therefore did notcontribute to the electrical resistance of the electrode. However,the presence of an oxide film did improve the stability of junctionsand increase the yield of working electrodes from ∼70% to ∼100%.Increasing the relative humidity (RH) in which J(V)was measured did not influence these values (across methyl (CH3)- or carboxyl (CO2H)-terminated SAMs) over therange typically encountered in the laboratory (20%–60% (RH)). [ABSTRACT FROM AUTHOR]

Red (no styryl), green (monostyryl), and blue (distyryl) BODIPY-gallium(III) (BODIPY = boron-dipyrromethene) corroie dyads have been prepared in high yields using click chemistry, and their photophysical properties are reported. An original and efficient control of the direction of the singlet energy transfers is reported, going either from BODIPY to the gallium-corrole units or from gallium-corroles to BODIPY, depending upon the nature of the substitution on BODIPY. In one case (green), both directions are possible. The mechanism for the energy transfers is interpreted by means of through-space Förster resonance energy transfer (FRET). [ABSTRACT FROM AUTHOR]

Fromthe standpoint of green chemistry, tris(pentafluorophenyl)gallium(7) and tris(pentafluorophenyl)aluminum (8) outperform all previously explored perfluoroarylated Lewis acids(PFLAs) for the polymerization of isobutene. In comparison to otherPFLA based systems, 7and 8do not requireultrahigh purity monomer, toxic chlorinated solvents, or expensiveand highly sensitive initiators (e.g., metallocenes). Moreover, comparedto other PFLA based initiator systems they provide much larger yieldsof high to medium molecular weight polyisobutene even at polymerizationtemperatures up to ambient. Stopping experiments indicate that strongBrønsted acids formed in situ by reaction with adventitious moisture(9and 10, respectively) induce cationicpolymerization protonically. Unlike other PFLA compounds which requireexpensive and/or energetically unstable precursors, 7and 8are readily synthesized from their correspondinggroup 13 halides in conjunction with bis(pentafluorophenyl)zinc (6), thereby lending themselves to commercial implementation. [ABSTRACT FROM AUTHOR]

The three-coordinate complex Me2Ga[B-(NArCH)2] (Ar = C6H3iPr2-2,6) is accessible via a tandem Lewis acid-base metathesis protocol employing (THF)2Li[B(NArCH)2] and GaMe3. It features a very short Ga-B bond of 2.067(3) A, which was further investigated by DFT calculations and the analysis of the electron density. Reaction of MeLi with Me2Ga[B- (NArCH)2] forms tetrameric [LiMe3Ga{B(NArCH)2}]4 with a "nanowheel" structure. [ABSTRACT FROM AUTHOR]

Methods for the synthesisof dialkylgalium compounds with alkoxideor aryloxide ligands possessing N-heterocyclic carbene functionalitieshave been established. As a result, the synthesis of a series of dialkylgalliumcomplexes Me2Ga(O,C) (1, 3–5), and Me2Ga(O,C)·Me3Ga (2, 6) is described, where (O,C) represents analkoxide or aryloxide monoanionic chelate ligand with an N-heterocycliccarbene functionality. All complexes have been fully characterizedusing spectroscopic and X-ray techniques. The presence of a stronglybasic NHC functionality in alkoxide or aryloxide ligands resultedin the formation of monomeric Me2Ga(O,C) species. The reactionof those complexes with the Lewis acid Me3Ga leads to Me2Ga(O,C)·Me3Ga adducts (2and 6) with a strong Me3Ga–O dative bond. Theeffect of (O,C) ligands with various steric and electronic propertieson the structure of obtained Me2Ga(O,C) and Me2Ga(O,C)·Me3Ga has been discussed on the basis ofspectroscopic data. Finally, the bond valence vector model has beenused to estimate the effect of a chelating (O,C) ligand on strainsin complexes 1–6on the basis ofX-ray data. [ABSTRACT FROM AUTHOR]

The ability of gallium(lll) complexes to catalyze the epoxidation of alkenes by peracetic acid has been examined with density functional theory calculations. According to the calculations, the chloride anions of the precatalyst [Ga(phen)2Cl2]+ (phen = 1,10-phenanthroline) can be displaced by either acetic or peracetic acid through dissociative ligand exchange pathways; both acetic and peracetic acid deprotonate upon binding to the formally tricationic metal center. Because of the high basicity of peracetate relative to that of chloride, only the acetate for chloride exchange occurs spontaneously, providing a rationale for the preponderance of gallium acetate adducts observed in the reaction mixtures. With respect to the mechanism of olefin epoxidation, the computational results suggest that the peracetic acid is most effidently activated for redox activity when it binds to the metal center in a k² fashion, with the carbonyl oxygen atom serving as the second point of attachment. The phen ligands' coordination to the gallium is essential for the catalysis, and the lowest energy pathways for alkene oxidation proceed through hexacoordinate Ga(lll) species with four Ga--N bonds. A natural bond order analysis confirms the electrophilic nature of the metal-containing oxidant. [ABSTRACT FROM AUTHOR]

Six new molecular GaCl3 adducts of electron rich compounds of the carbone (carbodiphosphorane, tetraaminoallene) and cyclic alkyl amino carbene (CAAC) families have been synthesized and characterized by X-ray crystallography. The sum of their Cl-Ga-Cl angles has been compared to those of 20 other complexes exhibiting various oxygen-, nitrogen-, phosphorus-, and carbon-donor ligands for which good quality X-ray analyses have been reported. The pyramidalization of the GaCl3 moiety in L·GaCl3 complexes has been checked against the computed antisymmetric stretching of the Ga-Cl bonds. It has also been compared to the symmetric stretching of the C-O bonds of the corresponding L·Ni(CO)3 complexes (Tolman Electronic Parameter). On this basis, a relationship between the pyramidalization observed in the gallium complexes and the electronic ligand properties has been established. [ABSTRACT FROM AUTHOR]

We study the Mott insulator compoundGaTa4Se8in which we previously discovered anelectric-field-induced resistivetransition. We show that the resistive switching is associated tothe appearance of metallic and super-insulating nanodomains by meansof scanning tunneling microscopy/spectroscopy (STM/STS). Moreover,we show that local electronic transitions can be controlled at thenanoscale at room temperature using the electric field of the STMtip. This opens the way for possible applications in resistive randomaccess memories (RRAM) devices. [ABSTRACT FROM AUTHOR]

Use of focused ion-beam scanning electron microscopy (FIB-SEM) to investigate the internal composition of atmospheric particles is demonstrated for assessing particle optical properties. In the FIB-SEM instrument equipped with an X-ray detector, a gallium-ion beam mills the particle, while the electron beam images the slice faces and energy-dispersive X-ray spectroscopy provides element maps of the particle. Differences in assessments of optical behavior based on FIB-SEM and conventional SEM were shown for five selected urban dust particles. The benefit of FIB-SEM for accurately determining the depth and size of optically important phases within particles was shown. FIB-SEM revealed that iron oxide grains left undetected by conventional SEM could potentially shift the single-scattering albedo of the particle from negative to positive radiative forcing. Analysis of a coke-like particle showed that 73% of the light-scattering inclusion went undetected with conventional SEM, causing the bulk absorption coefficient to vary by as much as 25%. Optical property calculations for particles as volume-equivalent spheres and as spheroids that approximated actual particle shapes revealed that the largest effect between conventional SEM and FIB-SEM analyses was on backscattering efficiency, in some cases varying several-fold. [ABSTRACT FROM AUTHOR]

Self-assembled arrays of hemisphericalgallium nanoparticles depositedby molecular beam epitaxy on a sapphire support are explored as anew type of substrate for ultraviolet plasmonics. Spin-casting a 5nm film of crystal violet upon these nanoparticles permitted the demonstrationof surface-enhanced Raman spectra, fluorescence, and degradation followingexcitation by a HeCd laser operating at 325 nm. Measured local Ramanenhancement factors exceeding 107demonstrate the potentialof gallium nanoparticle arrays for plasmonically enhanced ultravioletdetection and remediation. [ABSTRACT FROM AUTHOR]

New quaternary alkali-metal gallium selenites, AGa(SeO3)2 (A = Li, Na, K, and Cs), have been synthesized through hydrothermal reactions. Single-crystal X-ray diffraction has been used to determine the structures of the reported materials. The stoichiometrically equivalent materials crystallize in three-dimensional framework structures and share a similar bonding network that is composed of distorted GaO6 octahedra and asymmetric SeO3 polyhedra. However, all four materials exhibit different framework geometries attributable to the size of the alkali-metal cations and the orientation of lone pairs on Se4+ cations. Macroscopic centricities of the materials are also affected by interactions between the cation and the oxide ligands on GaO6 and SeO3 groups. Complete characterization including infrared spectroscopy, elemental analyses, thermal analyses, dipole moment calculations, and second-harmonic generation properties for the compounds is also presented. [ABSTRACT FROM AUTHOR]

Thefirst GaS nanosheet-based photodetectors are demonstrated onboth mechanically rigid and flexible substrates. Highly crystalline,exfoliated GaS nanosheets are promising for optoelectronics due tostrong absorption in the UV–visible wavelength region. Photocurrentmeasurements of GaS nanosheet photodetectors made on SiO2/Si substrates and flexible polyethylene terephthalate (PET) substratesexhibit a photoresponsivity at 254 nm up to 4.2 AW–1and 19.2 AW–1, respectively, which exceeds thatof graphene, MoS2, or other 2D material-based devices.Additionally, the linear dynamic range of the devices on SiO2/Si and PET substrates are 97.7 dB and 78.73 dB, respectively. Bothsurpass that of currently exploited InGaAs photodetectors (66 dB).Theoretical modeling of the electronic structures indicates that thereduction of the effective mass at the valence band maximum (VBM)with decreasing sheet thickness enhances the carrier mobility of theGaS nanosheets, contributing to the high photocurrents. Double-peakVBMs are theoretically predicted for ultrathin GaS nanosheets (thicknessless than five monolayers), which is found to promote photon absorption.These theoretical and experimental results show that GaS nanosheetsare promising materials for high-performance photodetectors on bothconventional silicon and flexible substrates. [ABSTRACT FROM AUTHOR]

High quality single crystals of YbCuGa3wereobtainedfrom the reaction of Yb and Cu in excess liquid gallium as a solventat 1173 K. The crystal structure of YbCuGa3was refinedusing X-ray diffraction data on a selected high quality single crystal.YbCuGa3crystallizes in a new structure type in the monoclinicspace group C2/mand lattice constants a= 11.6891(8) Å, b= 4.162(4) Å, c= 8.3196(7) Å, and β = 110.834(5)°. Thecrystal structure of YbCuGa3is composed of eight cappedhexagonal prism cages [Yb4Cu4Ga12] occupying one ytterbium atom in each ring, which is shared throughthe edge Cu and Ga atoms along theabplane resultingin a three-dimensional network. The magnetic susceptibility of YbCuGa3was investigated in the temperature range 2–300 Kobeying the Curie–Weiss law above 130 K and the experimentallymeasured magnetic moment indicates mixed valent ytterbium and a deviationin inverse susceptibility data below 130 K. Electrical conductivitymeasurements show that the compound exhibits metallic nature. [ABSTRACT FROM AUTHOR]

Photoirradiation of the mixtures of Cp′(dppe)FeGaM(CO)5(Cp′ = η5-C5Me5(Cp*), M = W (2), Cr (3); Cp′ =η5-C5H5(Cp), M = W (5), Cr (6)) and Fe(CO)5in C6D6caused formal gallylene transfer from 2, 3, 5, and 6to the Fe(CO)4fragmentto afford the gallium-bridged diiron complexes Cp′(dppe)FeGaFe(CO)4(Cp′ = Cp* (1), Cp (4))in moderate yields. Gallylene transfers with Cp(dppe)FeGaFe(CO)4(4) and M(CO)6(M = W, Cr) also tookplace to produce 5and 6, respectively;however, that with Cp*(dppe)FeGaFe(CO)4(1) and M(CO)6did not proceed. Photoirradiation of 4alone in toluene caused CO dissociation and dimerizationto afford the gallylene-bridged tetrametallic complex {μ-Cp(dppe)FeGa}2Fe2(CO)6(μ-CO) (8). In contrast to 4, the Cp* analogue 1gave no gallylene-bridged complex in a similar reaction. [ABSTRACT FROM AUTHOR]

Two new isostructural molecular metals-- (BDH- TTP)6[MIII(C505)3]-CH2C12 (BDH-TTP = 2,5-bis(1,3-dithioian-2-ylidene)-l,3,4,6-tetrathiapentalene, where M = Fe (1) and Ga (2))--have been prepared and fully characterized. Compound 1 is a molecular conductor showing paramagnetic behavior, which is due to the presence of isolated [Fe(C5O5)3]3- complexes with high-spin S = 5/2 Fe (III) metal ions. The conductivity originates from the BDH-TTP organic donors arranged in a K-type molecular packing. At 4 kbar, compound 1 behaves as a metal down to ~100 K, showing high conductivity (~10 S cm-1) at room temperature. When applying a pressure higher than 7 kbar, the metal--insulator (M-I) transition is suppressed and the compound retains the metallic state down to low temperatures (2 K). For 1, ESR signals have been interpreted as being caused by the fine structure splitting of the high-spin (S = 5/2) state of Fe(III) in the distorted octahedral crystal field from the ligands. At 4 kbar, the isostructural compound 2 behaves as a metal down to ~100 K, although it is noteworthy that the M-I transition is not suppressed, even at pressures of 15 kbar. For 2, only the signal assigned to delocalized π-electrons has been observed in the ESR measurements. [ABSTRACT FROM AUTHOR]

The article presents information on a research related to the chemical communication in homoleptic gallium chemical complex. It mentions that structural characterization of the chemical complex were determined through near-infrared spectroscopic methods and through interpretation of density functional theory calculations. It highlights that the utilized methods were effective in analysis of chemical communication in a single atom bridge chemical complex between two chemical ligand groups.

Preliminary experiments with the novel acyclic triazole-containing bifunctional chelator H₂azapa and the radiometals 64Cu, 67Ga, 111In, and 177Lu have established its significant versatile potential as an alternative to 1,4,7,10-tetraazacyclododecane-l,4,7,10-tetraacetic acid (DOTA) for metal-based radiopharmaceuticals. Unlike DOTA, H₂azapa radiolabels quantitatively with 64Cu, 67Ga, 111In, and 177Lu in 10 min at room temperature. In vitro competition experiments with human blood serum show that 64Cu remained predominantly chelate-bound, with only 2% transchelated to serum proteins after 20 h. Biodistribution experiments with [64Cu(azapa)] in mice reveal uptake in various organs, particularly in the liver, lungs, heart, intestines, and kidneys. When compared to [64Cu(DOTA)]2-, the lipophilic neutral [64Cu(azapa)] was cleared through the gastrointestinal tract and accumulated in the liver, which is common for lipophilic compounds or free 64Cu. The chelator H₂azapa is a model complex for a dick-based bifunctional chelating agent, and the lipophilic benzyl "place-holders" will be replaced by hydrophilic peptides to modulate the pharmacokinetics and direct activity away from the liver and gut. The solid-state molecular structure of [In(azapa)(H₂O)][ClO₄] reveals a very rare eight-coordinate distorted square antiprismatic geometry with one triazole arm bound, and the structure of [64Cu(azapa)] shows a distorted octahedral geometry. The present study demonstrates significant potential for bioconjugates of H₂azapa as alternatives to DOTA in copper-based radiopharmaceuticals, with the highly modular and "clickable" molecular scaffold of H₂azapa easily modified into a variety of bioconjugates. H₂azapa is a versatile addition to the "pa" family, joining the previously published H₂dedpa (67/68Ga and 64Cu), H₄octapa (111In, 177Lu, and 90Y), and H₅decapa (225Ac) to cover a wide range of important nuclides. [ABSTRACT FROM AUTHOR]

In this manuscript, we demonstrate a new process forthe atomiclayer deposition (ALD) of gallium oxide (Ga2O3) thin films using trimethylgallium (TMGa) and ozone. We evaluateda variety of oxygen sources for Ga2O3ALD usingTMGa but found that only ozone was effective. We explored the mechanismfor Ga2O3ALD using in situ quartz crystal microbalance,Fourier transform infrared spectroscopy, and quadrupole mass spectrometrystudies. We found that TMGa dissociatively adsorbs onto the Ga2O3surface to form Ga(CH3)2surface species and liberate ∼20% of the methyl ligands asCH4. Next, the ozone reacts with these methyl species toform hydroxyl and formate surface groups and liberate CH2O. We prepared ALD Ga2O3films on Si(100) andfused SiO2substrates and analyzed the films using a varietyof techniques. We found the Ga2O3growth tobe self-limiting with a growth rate of ∼0.52 Å/cycle between200 and 375 °C. Moreover, the Ga2O3filmswere stoichiometric, free of residual carbon, and exhibited propertiessimilar to bulk Ga2O3. Scanning electron microscopyrevealed smooth films with good step coverage over trench structures,and X-ray diffraction showed that the films were amorphous as-depositedbut crystallized to β-Ga2O3upon annealingat 900 °C. [ABSTRACT FROM AUTHOR]

The carbocationic polymerization of isobutylene (IB),co-initiatedby GaCl3or FeCl3·dialkyl ether 1:1 complexeshas been investigated in hexanes in the −20 to 10 °C temperaturerange. In contrast to AlCl3·diisopropyl ether (AlCl3·i-Pr2O) complexes,(1) GaCl3·i-Pr2O and FeCl3·i-Pr2O readily co-initiate polymerization with 2-chloro-2,4,4-trimethylpentane(TMPCl) or tert-butyl chloride (t-BuCl) in the presence or absence of proton trap. In the absenceof proton trap, chain transfer to monomer readily proceeded, resultingin close to complete monomer conversion and up to 85% exo-olefinicend group content. Diisopropyl ether complexes gave the highest polymerizationrates, while nonbranched alkyl ether complexes were completely inactive.A polymerization mechanism is proposed to involve ether-assisted protonelimination to yield PIB exo-olefin, and the abstracted proton cansubsequently start a new polymer chain by protonation of IB. AlternativelyPIB+may be deactivated by ion collapse to yield PIBCl,which can be reactivated by the Lewis acid. The reasons for the differencein behavior between the Ga and Fe catalysts and the Al-based catalystsare described. [ABSTRACT FROM AUTHOR]