Reaction Of Trimethylgallium Research Articles

Dimethyl-Gallium/-Indium Complexes Derived from Bis(2-Hydroxy Benzylidene)-1,4-Phenylenediamine and Bis(2-Hydroxybenzylidene)-4,4’-Methylene Dianiline: Synthesis and Structural Characterization

Reactions of trimethyl-gallium/-indium etherate with bis(2-hydroxybenzylidene)-1,4-phenylenediamine and bis(2-hydroxybenzylidene)-4,4’-methylene dianiline in benzene at room temperature afford complexes of compositions [1,4-{Me2MOC6H4CH=N}2-C6H4] (M=Ga (1), In (2)) and [{Me2MOC6H4CH=NC6H4}2-CH2] (M=Ga (3), In (4)), respectively. These complexes were characterized by elemental analysis, IR and NMR (1H, 13C) spectroscopy. The complexes [1,4-{Me2GaOC6H4CH=N}2-C6H4] (1) and [{Me2GaOC6H4CH=NC6H4}2-CH2]·[Me2Ga(μ-OH)]3.C6H6 (5b) (formed by partial hydrolysis during crystallization) have been structurally characterized. The gallium atom in these complexes adopts a distorted tetrahedral configuration. The fragment [Me2Ga(μ-OH)]3 in 5b acquires a trimeric structure rather than the tetrameric form as described earlier.

Computational Study on the Growth of Gallium Nitride and a Possible Source of Oxygen Impurity

The reaction pathways for the gallium nitride GaN growth by gas phase reaction of trimethylgallium (TMG) with ammonia is studied theoretically. Water is the most important impurity in ammonia, therefore its reaction with TMG is investigated as a possible source of oxygen impurity in GaN. Gallium oxide (GaO) formed by the reaction between TMG and H(2)O is predicted to be one of the possible source of oxygen impurity in GaN. The mechanisms and energetics of these reactions in the gas phase have been investigated by density functional B3LYP/[LANL2DZ-ECP + 6-31G(d,p)] method and ab initio MP2/[LANL2DZ-ECP + 6-31G(d,p)], CCSD(T)/[LANL2DZ-ECP + 6-31G(d,p)]//B3LYP/[LANL2DZ-ECP + 6-31G(d,p)], CCSD(T)/[LANL2DZ-ECP + 6-31G(d,p)]//MP2/[LANL2DZ-ECP + 6-31G(d,p)], and CCSD(T)/[LANL2DZ-ECP + Ahlrichs-VTZP]//MP2/[LANL2DZ-ECP + Ahlrichs-VTZP] methods. Both the reactions of TMG with NH(3) and H(2)O are modeled using pre-equilibrium charge-transfer complexes (CH(3))(3)Ga:NH(3) (C1) and (CH(3))(3)Ga:OH(2) (C2) having binding energies of 18.8 and 12.4 kcal/mol, respectively. The first step of the methane elimination reaction from the complexes proceeds through the saddle points TS1 and TS1a having activation barriers 37.0 and 22.6 kcal/mol for C1 and C2, respectively. The first CH(4) elimination step is exothermic for both the cases, but the exothermicity is 15.0 kcal/mol greater for CH(4) elimination from C2. The next step of methane elimination from the stable reaction intermediates (CH(3))(2)GaNH(2) and (CH(3))(3)GaOH has a very high activation barrier of 76.0 and 67.8 kcal/mol via saddle points TS2 and TS2a, respectively. The calculated reaction rates at 298.15 K for both the reactions are low but are comparable to each other. The total rate constant k(tot) for GaN formation is 2.07 x 10(-60) cm(3) molecule(-1) s(-1), and that for GaO formation is 6.85 x 10(-62) cm(3) molecule(-1) s(-1).

Multiscale Model of the GaAs MOVPE Process for the Fast Numerical Simulation

As a successive work to clarify the film growth kinetics of GaAs, a new lumped model for computer simulation of film growth during MOCVD process is proposed. The film growth process in a horizontal reactor using trimethylgallium (TMGa) and tertiarybutylarsine (TBAs) is considered. Analyzing methodologies at two different scales have been used to revise our previous simulation model. One is the micro-scale analysis using a selective-area growth method and the other is the reactor-scale macro analysis using numerical simulation. Species concentration profiles are obtained from the macro-scale computational fluid dynamics study incorporated with chemical reactions. Surface reaction rate constants are extracted from the selective-area growth experiments. From the multi-scale analysis that combined the two-scale analyses, surface formation from the source gas, TMGa, is included to the previous model. The kinetic data for the surface reaction of TMGa are deduced from the quantitative analysis for the species concentrations from both of the analyses. Simulation results using the new model show that monomethylgallium is the major source of film deposition, but deposition from TMGa is important in the upstream region of the reactor.

Synthesis, characterization and luminescence study of dimethyl[2-(arylmethyleneimino)phenolato]gallium complexes. Crystal structure of dimethyl[3,4-dimethoxyphenylmethyleneiminophenolato]gallium

Three dimethylgallium complexes of type Me 2GaL [L = 3,4-dimethoxyphenylmethyleneiminophenolato ( 1), 4-butoxylphenyl methyleneiminophenolato ( 2), 2-pyridylphenolato ( 3)] have been synthesized by the reaction of trimethylgallium with appropriate N-arylmethyleneiminophenol. The complexes obtained have been characterized by elemental analysis, 1H NMR, FT-IR and mass spectroscopy, respectively. The solid structure of 1 has been determined by X-ray single crystal analysis. The gallium atom was bonded by an oxygen atom and coordinated by an imine nitrogen atom forming one five-membered ring. The stable dimmer was formed by the coordination of bridging oxygen atom of phenolate to another gallium atom. The photoluminescence of complexes 1– 3 were studied. The maximum emission wavelengths of 1– 3 are between 338 and 362 nm upon radiation by UV light. The Electroluminescent properties of diodes using 1– 3 as emitters were measured. The blue/green electroluminescence has been observed.

Synthesis, characterization and luminescence study of dimethyl[2-(arylmethyleneimino)phenolato]gallium complexes: Crystal structure of dimethyl[ N-(4- N, N′-dimethylamino) phenylmethyleneiminophenolato]gallium

Three dimethylgallium complexes of type Me 2GaL [L = 2-methoxylphenylmethyleneiminophenolato ( 1), N-(4- N, N′-dimethylamino)phenylmethyleneiminophenolato ( 2), N-(2-naphthyl)methyleneiminophenolato ( 3)] have been synthesized by the reaction of trimethylgallium with appropriate N-arylmethyleneiminophenol. The complexes obtained have been characterized by elemental analysis, 1H, 13C{ 1H} NMR, IR and mass spectroscopy, respectively. The solid structure of 2 has been determined by X-ray single crystal analysis. The gallium atom was bonded by an oxygen atom and coordinated by an imine nitrogen atom forming one five-membered ring. The stable dimmer was formed by the coordination of bridging oxygen atom of phenolate to another gallium atom. The photoluminescence of complexes 1– 3 were studied. The maximum emission wavelengths of 1– 3 are between 305 and 320 nm upon radiation by UV light. The electroluminescent properties of diodes using 1– 3 as emitting material were measured. The blue/green electroluminescence has been observed.

Simulation of growth rate and deposition profile on the periodically patterned substrate

The growth of GaN on the patterned substances has proven favorable to achieve thick, crack-free GaN layers. Based on these methods, we specially designed periodically patterned Si substrate process, which is referred to as lateral epitaxy on patterned Si substrate (LEPS). High crystalline quality GaN are obtained by using this technique. In this paper, numerical modeling of transport and reaction of species is performed to estimate the growth rate of GaN from the reaction of trimethyl gallium (TMG) and ammonia. The effect of fabricated structure of feature scale model will be predicted by using the topography simulator, and deposition profile of the GaN on the pattern will be discussed. The effect of flow conditions and pattern shape and periodicity will also be addressed, which can be critical for the quality of crystal growth. The dependency of step coverage and conformality of patterned mask will also be discussed.

Formation of Digallium Sites in the Reaction of Trimethylgallium with Silica

The room-temperature, gas−solid reaction of volatile GaMe3 with a nonporous silica was studied by elemental and gas-phase analysis, in situ IR and 1H, 13C, and 29Si solid-state NMR, and extended X-ray absorption fine structure (EXAFS) spectroscopy. Most of the grafting (∼85%) occurred on Q3 sites, O3SiOH, but a small amount (∼15%) of siloxane (O3SiO−SiO3) bond cleavage was also observed. The major, if not the only, gallium product has the empirical formula ⋮SiOGaMe2, but it is not an “isolated” site. The Ga K-edge EXAFS of GaMe3-modified silica, recorded at 10 K, reveals that each Ga has a Ga neighbor at 2.97−2.99 Å. The sites are best described as [GaMe2(μ-OSi⋮)]2. To strengthen this assignment, a molecular analogue, [GaMe2(μ-OSiPh3)]2, was characterized by both single-crystal X-ray diffraction and EXAFS. The Ga2O2 rings in the molecular complex and the silica-supported gallium dimer have very similar dimensions. The gallium dimer is formed on the silica surface regardless of the extent of partial dehydroxylation (varied by pretreatment in vacuo at 100 and 500 °C). This result is interpreted in terms of a vicinal disposition for the majority of Q3 grafting sites.

Synthesis, characterization and luminescence study of dimethyl(β-ketoiminato)gallium (-indium) complexes: crystal structure of dimethyl[1-phenyl-3- N-(4-methoxyphenylimino)-1-butanonato]gallium

Six dimethylgallium (indium) complexes of type Me 2ML [M = Ga, L = 1-phenyl-3- N-(phenylimino)-1-butanonato ( 1), 1-phenyl-3- N-( p-methoxyphenylimino)-1-butanonato ( 2), 1-phenyl-3- N-( o-chloro phenylimino)-1-butanonato ( 3); M = In, L = 1-phenyl-3- N-(phenyl imino)-1-butanonato ( 4), 1-phenyl-3- N-( p-methoxyphenylimino)-1-butanonato ( 5), 1-phenyl-3- N-( o-chlorophenylimino)-1-butanonato ( 6)] have been synthesized by reaction of trimethylgallium (indium) with appropriate 1-phenyl-3- N-(arylimino)-1-butanones. The complexes obtained have been characterized by elemental analysis, 1H NMR, IR and mass spectroscopy. Structure of 2 has been determined by X-ray single-crystal analysis, in which Ga atom is four coordinated. Complexes 1– 6 emit colors from blue to green (463–491 nm) when irradiated by UV light. The electroluminescent (EL) properties of 1– 6 were examined by fabricating EL devices using 1– 6 as emitter, respectively. The EL bands are located in the green region (509–522 nm).

Synthesis and asymmetric catalytic activities of chiral organogallium and indium complexes with ephedrine derivatives as ligands. The crystal structure of [(1 R, 2 S)-(Me 2Ga-μ-OCH(C 6H 5)CH(CH 3)-μ-NHCH 3)] 2

Reactions of trimethylgallium or trimethylindium with (1 R, 2 S)-(−)-ephedrine derivatives afford compounds [(1 R, 2 S)-(Me 2E-μ-OCH(C 6H 5)CH(CH 3)-μ-NRCH 3)] 2 [E=Ga, R=H ( 1), CH 3 ( 2), CH 2Ph ( 3); E=In, R=H ( 4), CH 3 ( 5), CH 2Ph ( 6)] in high yields. The resulting complexes 1– 6 have been characterized by 1H-NMR spectroscopy and elemental analysis. Structure of the compound 1 determined by single-crystal X-ray analysis shows a dimeric feature containing a standard parallelogram Ga 2O 2 core bridging through the oxygen atom of ephedrine group. The catalytic asymmetric isocyanosilylation of meso cyclohexene oxide with trimethylsilyl cyanide has been realized with complexes 1– 6 as catalysts.

Synthesis, structural characterization and electroluminescence study of alkylgallium derivatives of thiobenzhydrazones

Six dimethylgallium complexes of type Me 2GaL [L= N-benzylidenethiobenzahydrazonato ( 1), N-(4-methoxy)benzylidenethiobenzahydrazonato ( 2), N-(3,4-dimethoxy)benzylidenethiobenzahydrazonato ( 3), N-(4- N, N-dimethylamino)benzylidenethiobenzahydrazonato ( 4), N-(2-naphthyl)methylenethiobenzahydrazonato ( 5) and N-(9-anthryl)methylenethiobenzahydrazonato ( 6)] have been synthesized by reaction of trimethylgallium with appropriate N-arylmethylenethiobenzahydrazones. The complexes obtained have been characterized by elemental analysis, 1H-NMR, IR and mass spectroscopy. Structure of 2 has been determined by X-ray single-crystal analysis, in which Ga atom is four-coordinated. Compounds 2– 4 emit blue colors at λ max=432–479 nm when irradiated by UV light. The electroluminescent (EL) properties of 2, 3 and 4 were examined by fabricating EL devices using 2, 3 and 4 as emitter, respectively. The EL bands are located in the blue region (451, 454 and 479 nm for complexes 2, 3 and 4, respectively).

Synthese und Charakterisierung chiraler Organogallium- und -aluminiumalkoholate mit intramolekularer Stickstoffstabilisierung. Röntgenstrukturanalyse von Dimethylgallium-( S)-2-dimethylamino-3-methyl-1-butanolat, Dimethylgallium-( S)-2-dimethylamino-3-phenyl-1-propanolat und Dimethylgallium-( R)-2-dimethylamino-1-butanolat

The reactions of trimethylgallium and trimethylaluminium with optically active alcohols yield [Me 2GaOCH 2CHRNMe 2] 2 [R=Me ( S) 6, i Pr ( S) 7, i Bu ( S) 8, Bz ( S) 9, Et ( R: S>90:10) 10] and [Me 2AlOCH 2CHRNMe 2] 2 [R= i Bu ( S) 11, Et ( R: S>90:10) 12], respectively. The compounds have been characterized by 1H-, 13C-NMR and mass spectroscopy. They undergo a dynamic process with respect to the dissociation and association of the GaN or AlN dative bond resulting in equilibria between four- and five-coordinate metal atoms. The structures of 7, 9 and 10 were determined by single crystal X-ray diffraction. The molecules exist as dimers containing a M 2O 2 four-membered ring. 6– 11 exclusively consist of dimers with enantiomerically equal ligands; 12, on the contrary contains diastereomeric dimers featuring different NMR spectra.

Synthesis and characterization of dialkylgallium (dialkylindium) complexes of N-salicylidene 2-aminopyridine and N-salicylidene 2-methoxyaniline: crystal structure of dimethyl[ N-salicylidene 2-aminopyridine]gallium

Reaction of trimethylgallium (trimethylindium) and triethylgallium (triethylindium) with N-salicylidene 2-aminopyridine or N-salicylidene 2-methoxyaniline in benzene solution yields seven intramolecular coordinated Group 13 metal Schiff-base complexes. All complexes obtained were characterized by elemental analysis, 1H-NMR, IR and mass spectrometry. The structure of dimethyl[ N-salicylidene 2-aminopyridine]gallium ( 1) was determined by X-ray single crystal analysis. The Ga atom is four coordinate in the structure. Photoluminescent emission spectra of complexes dimethyl[ N-salicylidene 2-aminopyridine]gallium ( 1), diethyl[ N-salicylidene 2-aminopyridine]gallium ( 3), diethyl[ N-salicylidene 2-aminopyridine]indium ( 4) and dimethyl[ N-salicylidene 2-methoxylaniline]gallium ( 5) were measured. The maximum emission wavelength is between 503 and 511 nm, respectively on radiation by UV light.

Gas Phase Studies of Trimethylgallium with Ammonia, Propylamine and Water at Elevated Temperatures: Towards an Understanding of GaN Growth and Oxygen Incorporation

The reactions between trimethylgallium (TMG) and three reactants were studied to provide some insight into the reaction mechanism of gallium nitride growth and oxygen incorporation. All reactions were studied in a flow reactor. The gas phase was analyzed by molecular beam sampling mass spectrometry. Ammonia is a widely used precursor for the deposition of GaN films. In the gas phase, different gallium- and nitrogen-containing species were detected as a function of temperature. Propylamine is pyrolyzed at lower temperatures than ammonia and could therefore provide a low-temperature route towards GaN. In the reaction of TMG with propylamine, a different behavior was found; only simple adducts with one gallium atom per molecule were detected, which were instable at higher temperatures. The reaction of TMG with water is an important side reaction, because water is the main impurity of ammonia and could thus be the main reason for the high oxygen levels found in GaN films.

Breaking the Ga–CH3 bond at cryogenic temperatures using atomic hydrogen. Adsorbed trimethylgallium reactivity

The chemical interaction of adsorbed trimethylgallium and atomic hydrogen was investigated on a powdered silicon dioxide substrate containing various coverages of hydroxyl groups. The adsorption of trimethylgallium occurs nondissociatively at 128 K. Desorption of trimethylgallium occurs near 160 K by a nondissociative route. Atomic hydrogen, produced on a hot tungsten filament, reacts with adsorbed trimethylgallium at 128 K. This reaction produces infrared absorbances characteristic of dimethylgalliumhydride dimers or higher polymers, with Ga–H–Ga bridge bonds with a broad absorbance centered at 1690 cm−1. These hydrogenated species are much more resistant to subsequent reaction with atomic hydrogen than trimethylgallium. Variations of the surface hydroxyl coverage on the silicon dioxide had no effect on the reaction of trimethylgallium with atomic hydrogen. Surface hydroxyl groups do not react with trimethylgallium below 173 K. The highly dehydroxylated silicon dioxide surface also does not react with trimethylgallium below 173 K.

A study of the mechanism of the reaction of trimethylgallium with hydrogen selenide

A study of the pre-deposition room temperature gas-phase reactions involved in the growth of Ga 2 Se 3 (and/or GaSe) using trimethylgallium (GaMe 3 ) and hydrogen selenide (H 2 Se) was undertaken, using a simple mass spectrometric sampling system on a conventional atmospheric pressure MOCVD reactor. The experimental studies were complemented by theoretical quantum chemical calculations which were used to predict the reaction thermochemistry and kinetics of the proposed reaction scheme. We have shown that the gas phase reaction of the GaMe 3 –H 2 Se mixture can be described by a simple reaction mechanism with no need for the participation of a stable Lewis acid–base adduct, although a transient adduct type species may be involved. The effect of the room temperature reaction of GaMe 3 with H 2 Se on the growth mechanism of Ga 2 Se 3 /GaSe and its role in determining epilayer morphology and microstructure are also discussed.

A Ga4N8 cage structure formed by reaction of trimethylgallium with phenylhydrazine

Methane elimination during thermolysis of GaMe3 with PhHNNH2 yields sequentially dimeric [Me2Ga{µ-N(H)N(H)Ph}]2, tetrameric [MeGa{µ-N(H)NPh}]4 and, ultimately, GaN; the X-ray structure of the tetramer shows a novel Ga4N8 cage.

Metallacycles of the imidoylamidinato compounds HNC(R)NC(R)NH and Group 13 elements. Crystal structure of the complex [GaMe2{HNC(CF3)NC(CF3 )NH}

Reaction of trimethylgallium with trifluoroacetamidine [H 2 NC(CF 3 )NH] resulted in an unusual elimination reaction, and yielded the air-stable volatile metallacycle [GaMe 2 {HNC(CF 3 )NC(CF 3 )NH}] which shows a planar six-membered (GaNCNCN) ring; a related aluminium system [AlMe 2 {HNC(Ph)NC(Ph)NH}] was formed using benzamidine [H 2 NC(Ph)NH].

High Temperature Gas Phases Reactions Of Trimethylgallium with Ammonia and Trimethylamine

AbstractThe use of trimethylgallium-trimethylamine (TMG:TMN) adduct as alternative cation precursor for MOVPE of GaN was studied by means of in-situ mass spectroscopy in an isothermal flow tube reactor. The temperature, pressure and reaction time were chosen to emulate the gas phase environment typical of the metal-organic vapor phase: epitaxy (MOVPE) of GaN. Dynamic changes in the mass spectra are reported for the gas phase reactions between trimethylgallium (TMG) and TMN in hydrogen (H2/D2) and ammonia (NH3/ND3) ambients. Evidence presented for the high temperature TMG:TMN adduct formation, followed by ethane elimination. The strength of the adduct bonding is comparable to that of TMG:NH3 and thus suppresses TMN displacement by ammonia. The thermal stability of TMG:TMN was found to be higher in ammonia ambient than it is in hydrogen. Kinetic parameters for some of the decomposition processes are given.

Synthesis and characterization of Me 3Ga and Me 3In: Adducts of secondary amines

The reactions of trimethylgallium and trimethylindium with a variety of secondary amines [HNMe 2, HNEt 2, HNPr 2 n, HNPr 2 i, HNBu 2 i, HNBu 2 s, HN(CH 2Ph) 2, HN( c-C 6H 11) 2, HNC 4H 8, HNC 5H 10, HNC 6H 12 and HN(CH 2CH 2) 2NMe], produce a series of room-temperature stable liquid or solid adducts. These were characterized by 1H and 13C NMR, IR, mass spectrometry and elemental analysis. Spectroscopic comparisons are made between these and the corresponding trimethylaluminum derivatives. 1H and 13C NMR data for all three series of adducts indicate a correlation between the chemical shifts of the methyl groups on the metal and the relative steric requirements of the amines. The data show a general downfield movement of these chemical shifts with increasing steric bulk.

Synthesis and Molecular Structure of [Me2Ga-PPh2]3

The trimeric phosphinogallane [Me2Ga-PPh2]3 was prepared by the room temperature reaction of trimethylgallium with diphenylphosphine in toluene. The title compound, characterized by 1H NMR, 31P NMR, elemental analyses, and single-crystal x-ray diffraction, crystallizes in the monoclinic space group P21/n (No. 14) with one trimeric phosphinogallane and two toluene solvent molecules per asymmetric unit. The unit cell parameters were a = 14.455(3) A; b = 22.541 (4) A; c = 16.847 (4) A, β = 105.53 (2)°, D calcd = 1.30 g cm−3, and V = 5289 (2) A3, for Z = 4. Refinement converged at R = 0.039, R w = 0.054. The crystal structure reveals that the title compound resides about a Ga3P3 six-membered ring in a chair conformation with a mean Ga-P bond distance of 2.433 (1) A.