Search

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]

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]

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]

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]

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]

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]

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]

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]

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]

Treatment of the tetraalkyldigallium compound R2Ga-GaR2 ( 1) [R = CH(SiMe3)2] with functionalized dicarboxylic acids (2,2′-bipyridyl-3,3′-dicarboxylic acid, 2,2′-iminodibenzoic acid, 2,2′-dithiodibenzoic acid) resulted in the formation of large heterocycles in which two Ga-Ga bonds were bridged by two dicarboxylato spacer ligands. Each Ga-Ga bond was bridged by two carboxylate groups in an almost ideal perpendicular arrangement that favors the formation of macrocyclic structures. The N-H groups of the imino-bridged compound pointed towards the center of the molecule and formed a network of hydrogen bonds through interactions with carboxylate oxygen atoms. Both disulfur groups of the dithio derivative adopted an ideal coplanar arrangement and came into relatively close contact, which might indicate a weak closed-shell bonding interaction between the sulfur atoms. [ABSTRACT FROM AUTHOR]

Ab-initio calculations have been used to investigate the phase stability and magnetic state of Cr n+ 1GaC n MAX phase. Cr2GaC ( n = 1) was predicted to be stable, with a ground state corresponding to an antiferromagnetic spin configuration. Thin-film synthesis by magnetron sputtering from elemental targets, including liquid Ga, shows the formation of Cr2GaC, previously only attained from bulk synthesis methods. The films were deposited at 650 °C on MgO(111) substrates. X-ray diffraction and high-resolution transmission electron microscopy show epitaxial growth of (000ℓ) MAX phase. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Abstract: GaFeO3‐type iron oxide is a promising room‐temperature multiferroic material due to its large magnetization. To expand its usability, controlling the ferroelectric and magnetic properties is crucial. In this study, high‐quality GaxFe2–xO3 (x = 0–1) epitaxial films are fabricated and their properties are systematically investigated. All films exhibit room‐temperature out‐of‐plane ferroelectricity, showing that the coercive electric field (Ec) decreases monotonically with x. Additionally, the films show in‐plane ferrimagnetism with a Curie temperature (TC) >350 K at x = 0–0.6. The coercive magnetic field (Hc) decreases with x at x ≤ 0.6, but shows a constant value at x > 0.6, whereas the saturated magnetization (Ms) increases with x at x ≤ 0.6, but decreases with x at x > 0.6. X‐ray magnetic circular dichroism reveals that the large magnetization at x = 0.6 is derived from Fe3+ (3d5) at octahedral sites. The controllable range of the Ec, Hc, and Ms values at room temperature (400–800 kV cm−1, 1–8 kOe, and 0.2–0.6 µB/f.u.) is very wide and differs from those of well‐known multiferroic BiFeO3. Furthermore, the GaxFe2−xO3 films exhibit room‐temperature magnetocapacitance effects, indicating that adjusting TC near room temperature is useful to achieve large room‐temperature magnetocapacitance behavior. [ABSTRACT FROM AUTHOR]

The ternary and quaternary Ga-containing chalcogenides of title are prepared by solid state reactions of the elements in stoichiometric quantities (evacuated silica tubes, 950 °C, 3 d). [ABSTRACT FROM AUTHOR]

Coarse-grained samples of Ga-stabilized tetragonal Li7La3Zr2O12 (LLZO), Li7-3xGaxLa3Zr2O12 (x = 0.1-0.6), are obtained by calcination of Li2CO3 (10 wt% excess), Ga2O3, La2O3, and ZrO2 in air (850 °C, 4 h) followed by annealing (1230 °C, 6 h). [ABSTRACT FROM AUTHOR]

Single crystals of the new title compound are grown from the elements in a reactive Cu/Ga melt (Ta:Ga:Cu = 0.5:14.4:2.4; evacuated silica tubes, 900 °C, 48 h). [ABSTRACT FROM AUTHOR]

Crystals of GaAsO4·2H2O are obtained as a minor product of the hydrothermal reaction of aqueous mixtures of VCl4, NaHAsO4, GaCl3, and guanidinium hydrochloride (autoclave, 456 K, 90 h) and characterized by high-pressure single crystal XRD and Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Using disubstituted alkynes instead of terminal alkynes, the formation of the title bisindole derivatives is not observed. [ABSTRACT FROM AUTHOR]

The new compounds (V), (VIII), and (X) are characterized by powder and single crystal XRD, SEM, UV/VIS spectroscopy, and luminescence spectroscopy. [ABSTRACT FROM AUTHOR]

Colorless, highly hygroscopic crystals of the title compound are synthesized from a mixture of Sb, SbCl3, Sb2O3, GaCl3, and Te (glass ampule, Ar, 6 x 10-2 mbar, 50 °C, 19 d). Ga2SbCl7O crystallizes in the monoclinic space group P21/m with Z = 2 (single crystal XRD). The structure consists of discrete molecules, in which a bent SbOCl unit is coordinated by two GaCl3 groups. The compound is further characterized by DFT calculations. [ABSTRACT FROM AUTHOR]