Gallium Chloride Research Articles

Nonlinear optical properties of complexes of π‐conjugated polymers

AbstractNovel host–guest complexes of conjugated polyimines with gallium chloride have been proposed and studied as an approach to enhance the third‐order nonlinear optical properties of the host conjugated polymers. The third‐order nonlinear optical susceptibility χ(3) (–3ω;ω,ω,ω) of two conjugated polyimines and their GaCl3 complexes, measured by third harmonic generation spectroscopy in the wavelength range 0.9 ∼ 2.4 μm, shows that χ(3) is enhanced in the nonresonant region, whereas it is reduced in the resonant region due to complexation. These results are explained by complexation mediated modifiction of the electronic structure of the host polymers. Two theoretical models consisting of four electronic energy levels were found to give a good description of the frequency dispersion and resonances in the χ(3) (–3ω;ω,ω,ω) spectrum of the host–guest complexes. The resulting fitting parameters were used to predict the degenerate four wave mixing χ(3) (–ω;ω,–ω,ω) spectrum for the new materials. The results of the present study suggest that host–guest complexation is a promising approach for improving the third‐order nonli‐near optical properties of conjugated polymers.

Lewis acid coordination complexes of polymers. 1. Boron chloride, aluminum chloride and gallium chloride complexes of poly(p-phenylenebenzobisthiazole)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLewis acid coordination complexes of polymers. 1. Boron chloride, aluminum chloride and gallium chloride complexes of poly(p-phenylenebenzobisthiazole)Michael F. Roberts and Samson A. JenekheCite this: Chem. Mater. 1993, 5, 12, 1744–1754Publication Date (Print):December 1, 1993Publication History Published online1 May 2002Published inissue 1 December 1993https://doi.org/10.1021/cm00036a012RIGHTS & PERMISSIONSArticle Views290Altmetric-Citations33LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Selective epitaxy of compound semiconductors: novel sources

The development of selective epitaxial techniques has centred on the use of conventional precursors such as trimethyl gallium in combination with AsH3. Recently, the development of new precursors, such as diethyl gallium chloride, or the use of conventional precursors in conjunction with HCl or AsCl3 has offered greater flexibility in the development of a selective-area epitaxial process. In addition, wide process windows have been demonstrated whereby excellent material properties and high selectivity can be achieved under typical MOVPE conditions. This compatibility with conventional MOVPE growth conditions allows for the integration of selective-area growth into the existing MOVPE growth processes. This paper will present recent results on the development of these alternative precursors for selective-area growth. The achievement of a selective epitaxial process is discussed in terms of the chemistry of the inorganic-based growth techniques.

Theoretical study of the gallium chloride molecule and its interaction with arsenic dangling bonds.

Ab initio molecular-orbital calculations have been carried out on the ground, excited, and ionized states of the gallium monochloride GaCl, which is used as a source molecule to generate Ga layers in GaAs epitaxial crystal growth. The calculated spectroscopic constants show good agreement with the experimental data. The calculated molecular properties of GaCl explain reasonably well the mechanism of its adsorption onto the As surface. The adsorption process is investigated by using a cluster model of GaCl-(${\mathrm{AsH}}_{2}$${)}_{2}$. The adsorption is found to occur as the result of covalent-bond formation with the As atoms through electronic-configuration mixing.

Thermodynamics of aqueous gallium chloride: Activity coefficients in dilute and high chloride solutions with consideration of the effects of hydrolysis and chloride complex formation

An attempt is made to evaluate the Pitzer parameters for activity and osmotic coefficients in aqueous GaCl 3 solutions on the basis of literature data. Anion exchange data demonstrate the necessity of incorporating the formation of the GaCl − 4 complex and allow estimation of the following parameters at 25°C: β 0 (GaCl 3) = 0.3761 kg mol −1; β 1 (GaCl 3) = 15.72 kg mol −1; C(GaCl 3) = −0.0034 kg 2 mol −2; log K 4 = −8.28 for the reaction Ga 3+ + 4Cl − ⇌ GaCl 4 −; β 0 (HGaCl 4) = 0.0641 kg mol −1; β 1 (HGaCl 4) = 0.2945 kg mol −1; C (HGaCl 4) = 0.0004 kg 2 mol −2. The latter β 1 and C parameters are taken equal to those of HCl. These results indicate that at 25°C GaCl 4 − complex formation in nearly pure GaCl 3 solutions becomes important only above concentrations of about 4 mol kg −1 GaCl 3. In solutions with low Ga/Cl ratio's, complexation is dominant above chloride concentrations of about 8 mol kg −1. With increase in temperature complexation extends to lower concentrations. Renewed evaluation of potentiometric data confirms that the NBS-value of −159 kJ mol −1 for the standard Gibbs free energy of formation of aqueous Ga 3+ is a reasonable estimate.

Improvement in Layer Quality of CuGaS2 Grown by Vapor Phase Epitaxy with Metal Chlorides and H2S Sources

In vapor phase epitaxial growth of CuGaS2 on GaP substrates under simultaneous feeding of H2S and metal chlorides, two-step growth was found to be useful for obtaining thick layers with single orientation of c-axis of the chalcopyrite normal to the substrate. Under alternate feeding of H2S and mixed gas of the chlorides, saturation behavior of growth rate was observed for the feeding amount of copper chloride and that of gallium chloride, and also for the supplying period of H2S gas. These results strongly suggest atomic layer epitaxy of CuGaS2. The layers grown under alternate feeding as well as layers by the two-step process under simultaneous feeding showed strong free exciton emission at low temperatures, indicating high quality of these layers.

Growth behavior of (C 2H 5) 2GaCl and AsH 3 based GaAs: low reactor pressure and temperatures

Alternative metalorganic precursors can often yield improvements in the purity or changes in the growth behavior of the epitaxial layer. Diethyl gallium chloride ((C 2H 5) 2GaCl or DEGaCl) belongs to this class of source molecules and has been used in the selective area growth of GaAs. Selectively grown submicron and quantum-sized structures, as well as the atomic layer epitaxy (ALE) of GaAs, have been demonstrated using the DEGaCl growth chemistry. This paper presents the growth characteristics of DEGaCl over a wide range of conventional growth conditions. The growth behavior and the impurity incorporation at both low growth temperatures (400–800°C) and low reaction pressures (10–78 Torr) have been investigated. The GaAs growth rate appears to be relatively independent of temperature at high reactor pressures and temperatures. The growth efficiency was, however, reduced from that found with (CH 3) 3Ga within the same reactor. Carbon and silicon were the major impurities in the epitaxial GaAs. The carbon concentration increases with decreasing growth temperature. The silicon depth profiles, obtained from low growth temperature samples, indicate an apparent surface segregation of Si during the growth. The Si concentration increases towards the sample surface eventually reaching a plateau, after which uniform doping is observed. The magnitude of the Si concentration within this plateau region increases with decreasing growth temperature. Electrical measurements indicate that the Si in these samples is either electrically inactive or highly compensated by the carbon acceptors.

Combination chemotherapy with cisplatin, etoposide and gallium chloride for lung cancer: Individual adaptation of doses

Combination chemotherapy with cisplatin, etoposide and gallium chloride for lung cancer: Individual adaptation of doses

Solar neutrinos observed by GALLEX at Gran Sasso

We have measured the rate of production of 71Ge from 71Ga by solar neutrinos. The target consists of 30.3 t of gallium in the form of 8.13 M aqueous gallium chloride solution (101 t), shielded by ≈ 3300 m water equivalent of standard rock in the Gran Sasso Underground Laboratory (Italy). In nearly one year of operation, 14 measurements of the production rate of 71Ge were carried out to give, after corrections for side reactions and other backgrounds, an average value of 83 + 19 (stat.) ± 8 (syst.) SNU (1 σ) due to solar neutrinos. This conclusion constitutes the first observation of solar pp neutrinos. Our result is consistent with the presence of the full pp neutrino flux expected according to the “standard solar model” together with a reduced flux of 8B + 7Be neutrinos as observed in the Homestake and Kamiokande experiments. Astrophysical reasons remain as a possible explanation of the solar neutrino problem. On the other hand, if the result is to be interpreted in terms of the MSW effect, it would fix neutrino masses and mixing angles within a very restricted range.

Syntheses and Structures of [NMe2(μ-NMe2)GaCl]2and [TMP(μ-OEt)GaCl]2(TMP = 2,6-Tetramethylpiperidide)

Abstract The bis-dimethylamido gallium chloride, [NMe2(μ-NMe2)GaCl]2 (I) may be prepared by the reaction of two equivalents of lithium amide with GaCl3. The amido ethoxide gallium chloride, [TMP(μ-OEt)GaCl]2 (2), (TMP = tetramethylpiperidide) is formed in the reaction of lithium amide with GaCl3 in diethylether. The structures of 1 and 2 have been determined by X-ray methods. Crystals of 1 are orthorhombic, space group P212121, with a = 8.428(4), b=15.10(1), c=13.138(6) A, Z = 4. Crystals of 2 are monoclinic, space group P21/n, with a = 8.542(1), b = 12.457(1), c = 12.959(1)A, β = 95.483(9), Z = 2. The R values for 1 and 2 are 0.066 and 0.054, respectively. The solid state structure of 1 consists of a nitrogen-bridged dimer, while 2 consists of an oxygen-bridged dimer.

Synthesis and characterization of potential antitumour and antiviral gallium(III) complexes of N-heterocycles

Ten water-soluble gallium(III) complexes of N-heterocycles were synthesized and characterized by elemental analysis, conductivity measurements, IR spectroscopy, 1H NMR spectroscopy and optical activity measurements. Raman spectra were measured with two complexes and an X-ray singe-crystal study performed with one complex— trans-dichlorotetrakis-(5-methylpyrazole)gallium(III)tetrachlorogallate(III). The gallium(III) complexes had the general formulae: [L 4GaCl 2]GaCl 4 (L = ligand) (L = indazole, 1,2,3-benzotriazole, pyrazole, 5-methylpyrazole, 4-methylpyrazole), having a trans-octahedral structure (symmetry C i ), [L 4GaCl 2]Cl (L = imidazole, benzimidazole), also with a trans-octahedral configuration, and LGaCl 2 (L = 2-α-oxybenzylbenzimidazolato (HBB) and the respective enantiomers d(−)-HBB and l(+)-HBB) having a tetrahedral structure. So far, eight gallium(III) complexes have been tested in the in vitro anti-HIV test (HIV = human immunodeficiency virus) of the National Cancer Institute (NCI) in the U.S.A., and four of these were found to be moderately active: trans-dichlorotetrakis-(5-methylpyrazole)gallium(III) tetrachlorogallate(III), trans-dichlorotetrakis-(4-methylpyrazole)gallium(III)tetrachlorogallate(III), dichloro-(2-α-oxybenzylbenzimidazolato-N,O) gallium (III) and trans-dichlorotetrakis(benzimidazole)gallium(III) chloride, the latter exhibiting the highest therapeutic index (TI) of 77. For comparison, the therapeutic index for 3′-azido-3′-deoxythymidine (AZT) ranges from TI = 1000 to 4000.

Synthesis and Structures of two Bulky Gallium Chlorides

Abstract The bulky gallium chlorides, (t-BuGaCl2)2 (1) and (Cy2GaCl)2 (Cy = C6H11) have been prepared via the reaction of GaCl3 with t-BuLi and CyMgCl, respectively. The structures of 1 and 2 have been determined by X-ray methods. Crystals of 1 are monoclinic, space group P21/c, with a = 6.937(4), b = 6.877(5), c = 17.11(1) Å, β = 95.65(6)[ddot], Z = 2; crystals of 2 are monoclinic, space group P21/c, with a = 10.389(2), b = 11.580(3), c = 11.198(2) Å, β = 95.96(2)[ddot], Z = 2. The R values for 1 and 2 are 0.0617 and 0.0681, respectively. The solid state structures of 1 and 2 consist of chloride-bridged dimers.

Temperature programmed desorption study of gallium chloride adsorbed on GaAs surfaces

Adsorption of gallium chloride (GaCl) on GaAs (100), (111)A and (111)B surfaces is studied by temperature programmed desorption (TPD). A GaCl molecular beam is produced by a newly designed GaCl cell. TPD measurements are carried out for (100) 2×4, (100) 4×6, (111)B √19×√19 and (111)A 2×2 reconstructed surfaces. GaCl desorption is observed from these surfaces, while the desorption of GaCl x ( x=2, 3), AsCl x ( x=1≁3) and Cl 2 is not detected. Two GaCl peaks appear at 220 and 330°C for (100) 2×4, 4×6 and (111)A 2×2 surfaces, and a single peak appears at 330°C for the (111)B surface. The GaCl peaks at 220 and 330°C are assigned to the adsorption on Ga and As sites, respectively. The adsorption energy of GaCl is calculated to be 38 kcal/mol for the As sites and 32 kcal/mol for the Ga sites. The self-limiting process in chloride atomic layer epitaxy (ALE) is discussed.

A simple method for the preparation of gallium chloride from the citrate solution

A simple method for the preparation of gallium chloride from the citrate solution

Neue metallorganische Platin–Indium und Cobalt–Gallium Komplexe

Oxidative addition of one indium–carbon bond of InR 3 (R = CH 2Si(CH 3) 3) to the highly reactive, coordinatively unsaturated platinum fragment [Cy 2P(CH 2CH 2)PCy 2]Pt (Cy = cyclo-C 6H 11) gives the novel platinum–indium complex [Cy 2P(CH 2CH 2)Pcy 2]Pt(InR 2)(R) ( 3) in high yield. A single-crystal X-ray diffraction study reveals a PT–In bond distance of 260.12(2) pm. Salt elimination between Na[Co(CO) 4] and bis(neopentyl)gallium chloride constitutes a surprisingly facile access to the novel halide-free, volatile cobalt–gallium complexes of type (CO) 4Co–GaR 2(thf) ( 4; R = CH 2C(CH 3) 3).

Molten lithium nitrate-potassium nitrate eutectic: the reactions of aluminium, gallium and thallium

Aluminium(III) chloride and sulphate reacted with the alkali nitrate eutectic forming alumina, with intermediate formation of two immiscible, oxide-containing layers in the case of aluminium(III) sulphate. Both chloride and sulphate anions stabilised aluminium cations by coordination. Aluminium nitride (A1N) was unreactive in pure melt, but reacted in both basic (NaOH) and acidic (K 2S 2O 7) melts. Gallium(III) chloride and nitrate reacted with pure nitrate melts at temperatures which increased as chloride was added. However, additions of bromide and nitrite caused reaction at lower temperatures. In each case the product was gallium(III) oxide, but in various crystal modifications. Thallium(I) nitrate did not react in the pure melt below 500 ° C, following the expected trend with increase in cation size and decrease in oxidation state. Both thallium and gallium cations were stabilised by coordination with nitrate when dissolved in the melt.

Epitaxial Growth and Selectivity of AlxGa1 − xAs Using Novel Metalorganic Precursors

Diethyl aluminum chloride and diethyl gallium chloride were successfully employed as precursors for the epitaxial growth of . The composition, thickness, and compositional uniformity of these layers were strong functions of the growth temperature, as determined with double‐crystal x‐ray diffraction and photoluminescence measurements. A thermodynamic model based on the free energy minimization of the expected gas and solid phase constituents is presented to explain these trends and other growth chemistry effects. Selective epitaxy was also investigated. was selectively grown on wafers masked with or under certain conditions. In contrast, growth was not selective. Selectivity of improved with increasing diethyl gallium chloride mole fraction and with increasing temperature, in accordance with thermodynamic considerations. Thermodynamic analysis of this growth chemistry indicates that various multinary semiconductors can be grown selectively using related metalorganic‐chloride precursors.

Thermodynamics of aqueous gallium chloride. Heats of solution and dilution at 25°C

The heat of solution of GaCl3 and heats of dilution of single GaCl3 solutions in water and of mixed GaCl3−HCl solutions in HCl solutions (with a fixed HCl concentration of 0.1337 mol-kg−1 HCl) up to 4 mol-kg−1 GaCl3 were measured at 25°C. While in the acid solutions hydrolysis is suppressed to below 0.5% of total gallium concentration, the measurements in water allow evaluation of the effect of hydrolysis on the relative enthalpy. The Pitzer interaction model for excess properties of aqueous electrolytes was used to interpret the change in relative enthalpy with concentration. Pitzer parameters were derived by statistical inference using ridge regression. Their physical significance is supported by the heat of solution data. The measurements yield the following results for standard heats of formation and Pitzer parameters for the relative molar enthalpy at 25°C: $$\begin{gathered} H_{GaCl_3 }^ \circ = - 722 kJ - mol^{ - 1} ; \beta _{L,GaCl_3 }^0 = - 1.52 \times 10^{ - 3} kg - mol^{ - 1} - K^{ - 1} ; \hfill \\ \beta _{L,GaCl_3 }^1 = 1.21 \times 10^{ - 2} kg - mol^{ - 1} - K^{ - 1} ; C_{L,GaCl_3 } = - 1.42 \times 10^{ - 4} kg^2 - mol^{ - 2} - K^{ - 1} ; \hfill \\ H_{GaOHCl_2 }^ \circ = - 492 kJ - mol^{ - 1} ; H_{Ga(OH)_2 Cl}^0 = - 706 kJ - mol^{ - 1} ; \hfill \\ \end{gathered} $$ With these parameters the overall variance in the partial molar heat of solution at infinite dilution, extrapolated from the present experiments, is minimized to 0.35 kJ2-mol−2, while the experimental apparent molar heats of dilution are reproduced on average within 2.7 kJ-mol−1.

Alteration in protein synthesis in primary cultures of rat kidney proximal tubule epithelial cells by exposure to gallium, indium, and arsenite

Patterns of protein synthesis in primary cultures of rat kidney proximal epithelial tubule cells were examined following exposure to gallium (Ga) chloride, indium (In) chloride, and sodium arsenite. After incubation with these chemicals for 20 hr, newly synthesized proteins were labeled with [ 35S]methionine. 35S-labeled proteins in the cells were separated by SDS/polyacrylamide gel and two-dimensional gel electrophoresis and detected by fluorography. A protein with molecular weight ( M r) of 30,000 was markedly induced by exposure to 300 μ m Ga or 10 μ m arsenite, and synthesis of proteins with M r of 85,000, 71,000, 65,000, 51,000, 38,000, and 28,000 was also increased by Ga or arsenite. Arsenite exposure increased synthesis of eight different proteins, which were not induced by Ga. No significant changes in protein synthesis were observed with 300 μ m In exposure. Release of lactate dehydrogenase from the cells was not significantly increased by exposure to concentrations of 300 μ m Ga and 3 μ m arsenite or less. In the absence of overt cell injury, the induction of these proteins may be useful as an early indicator for assessing exposure to Ga.

Thermodynamics of aqueous gallium chloride. Apparent molar volumes and heat capacities at 25°C

Apparent molar volumes and heat capacities of aqueous GaCl3 have been measured at 25°C in binary GaCl3 solutions up to 3 mol-kg−1, and in ternary GaCl3-HCl solutions, containing 0.1345 mol-kg−1 HCl to suppress hydrolysis, up to a concentration of 1 mol-kg−1 GaCl3. Using the Pitzer interaction model for the excess properties, and using ridge regression for the derivation of physically meaningful regression parameters, the measurements yield the following results for the standard molar properties and Pitzer parameters at 25°C: V0(GaCl3)=12.85 cm3-mol−1;β 0 v (GaCl3)=1.10×10−4 kg-mol−1−J−1−cm−3; β v 1 (GaCl3)=2.12×10−3 kg−mol−1−J−1−cm3; Cv(GaCl3)=1.34×10−5 kg2−J−1−cm3; Vo(GaOHCl2)=13.84 cm3−mol−1; C o p (GaCl3)=−480.8 J−K−1−mol−1; β J 0 (GaCl3)=−8.02×10−6 kg−mol−1−K−2; β J 1 (GaCl3)=0.73×10−4 kg−mol−1−K−2; CJ(GaCl3)=−2.52×10−6 kg2-mol−2-K−2; C p 0 (GaOHCl2)=20.4 J-K−1-mol−1. The latter parameter has only mathematical significance, its physical meaning is unclear. Comparison of the present experimental results for the standard molar properties of Ga3+ with semi-empirical correlations casts doubt upon the general validity of these correlation methods for trivalent cations.