Beiträge zur Koordinationschemie von Rhenium(III)chlorid in nichtwäßrigen Lösungen

Coordination reactions of solutions of Re₃Cl₉ in acetonitrile, propanediol-1,2-carbonate, acetone and dimethylsulfoxide yield compounds with unchanged metal-cluster structures. The following compounds were isolated and characterised: [Et ₄N]₃[Re₃Cl₉(N₃)₃], [Et ₄N]₃[Re₃Cl₆(N₃)₆], [Et ₄N]₃[Re₃Cl₃(N₃)₉], [Et ₄N]₃[Re₃Cl₉(CN)₃], [Et ₄N]₃[Re₃Cl₃(CN)₉],Et ₄N]₃[Re₃Cl₉(NCS)₃], [Et ₄N]₃[Re₃Cl₆(NCS)₆], [Et ₄N]₃[Re₃Cl₃(NCS)₉], Re₃Cl₉·(DMSO)₃, Re₃Cl₉·(HMPT)₃.     

Darstellung und Konfiguration von Tricarbonylchromat-Anionen mit SnCl3− und GeCl3− als Liganden

B₃N₃Me₆Cr(CO)₃ reacts with [AsPh₄] [SnCl₃] and [AsPh₄] [GeCl₃] in tetrahydrofuran to give [AsPh₄]₃[Cr(CO)₃(SnCl₃)₃] and [AsPh₄]₃[Cr(CO)₃(GeCl₃)₃], respectively. According to IR. and ¹³C-NMR.-data, the tricarbonylate anions possess a meridional configuration. The donor-acceptor properties of SnCl₃^? and GeCl₃^? in the anions [Cr(CO)₃(ECl₃)₃]^3? (E = Sn, Ge) are very similar. A similar synthesis of [AsPh₄]₃[Cr(CO)₃(SnF₃)₃] was not successful.     

Zur Kenntnis des Aluminiumchlorids. Die Umsetzung von AlCl3 mit PCl5 und Methylamin

Aluminium trichloride forms the adducts AlCl₃ · NH₂CH₃, AlCl₃ · 2NH₂CH₃, AlCl₃ · 4NH₂CH₃; AlCl₃ · NH₃CH₃Cl, AlCl₃ · 2NH₃CH₃Cl. The interaction between AlCl₃, PCl₅ and NH₃CH₃Cl in the molar ratio 1:3:2 proceeds according to the reaction equation in “Inhaltsübersicht”. On applying other stoichiometric amounts, [Cl₂(NHCH₃)P? N(CH₃)? AlCl₃] · HCl and [Cl₃P? N(CH₃)? AlCl₃] · HCl are obtained; the latter reacts as [Cl₃P? NHCH₃][AlCl₄]. At the molar ratio AlCl₃:PCl₅:NH₃CH₃Cl = 1:2:4 a compound is formed being presumably the six-membered heterocycle formulated in “Inhaltsübersicht”. With [Cl₃P?N? PCl₃] and aluminium chloride [Cl₃P?N? PCl₃][AlCl₄] is formed.     

Molecular Nitrides with Titanium and Group 13–15 Elements

Several heterometallic nitrido complexes were prepared by reaction of the imido–nitrido titanium complex [{Ti(η⁵‐C₅Me₅)(μ‐NH)}₃(μ₃‐N)] ( 1 ) with amido derivatives of Group 13–15 elements. Treatment of 1 with bis(trimethylsilyl)amido [M{N(SiMe₃)₂}₃] derivatives of aluminum, gallium, or indium in toluene at 150–190 °C affords the single‐cube amidoaluminum complex [{(Me₃Si)₂N}Al{(μ₃‐N)₂(μ₃‐NH)Ti₃(η⁵‐C₅Me₅)₃(μ₃‐N)}] ( 2 ) or the corner‐shared double‐cube compounds [M(μ₃‐N)₃(μ₃‐NH)₃{Ti₃(η⁵‐C₅Me₅)₃(μ₃‐N)}₂] [M=Ga ( 3 ), In ( 4 )]. Complexes 3 and 4 were also obtained by treatment of 1 with the trialkyl derivatives [M(CH₂SiMe₃)₃] (M=Ga, In) at high temperatures. The analogous reaction of 1 with [{Ga(NMe₂)₃}₂] at 110 °C leads to [{Ga(μ₃‐N)₂(μ₃‐NH)Ti₃(η⁵‐C₅Me₅)₃(μ₃‐N)}₂] ( 5 ), in which two [GaTi₃N₄] cube‐type moieties are linked through a gallium–gallium bond. Complex 1 reacts with one equivalent of germanium, tin, or lead bis(trimethylsilyl)amido derivatives [M{N(SiMe₃)₂}₂] in toluene at room temperature to give cube‐type complexes [M{(μ₃‐N)₂(μ₃‐NH)Ti₃(η⁵‐C₅Me₅)₃(μ₃‐N)}] [M=Ge ( 6 ), Sn ( 7 ), Pb ( 8 )]. Monitoring the reaction of 1 with [Sn{N(SiMe₃)₂}₂] and [Sn(C₅H₅)₂] by NMR spectroscopy allows the identification of intermediates [RSn{(μ₃‐N)(μ₃‐NH)₂Ti₃(η⁵‐C₅Me₅)₃(μ₃‐N)}] [R=N(SiMe₃)₂ ( 9 ), C₅H₅ ( 10 )] in the formation of 7 . Addition of one equivalent of the metalloligand 1 to a solution of lead derivative 8 or the treatment of 1 with a half equivalent of [Pb{N(SiMe₃)₂}₂] afford the corner‐shared double‐cube compound [Pb(μ₃‐N)₂(μ₃‐NH)₄{Ti₃(η⁵‐C₅Me₅)₃(μ₃‐N)}₂] ( 11 ). Analogous antimony and bismuth derivatives [M(μ₃‐N)₃(μ₃‐NH)₃{Ti₃(η⁵‐C₅Me₅)₃(μ₃‐N)}₂] [M=Sb ( 12 ), Bi ( 13 )] were obtained through the reaction of 1 with the tris(dimethylamido) reagents [M(NMe₂)₃]. Treatment of 1 with [AlCl₂{N(SiMe₃)₂}(OEt₂)] affords the precipitation of the singular aluminum–titanium square‐pyramidal aggregate [{{(Me₃Si)₂N}Cl₃Al₂}(μ₃‐N)(μ₃‐NH)₂{Ti₃(η⁵‐C₅Me₅)₃(μ‐Cl)(μ₃‐N)}] ( 14 ). The X‐ray crystal structures of 5 , 11 , 13 , 14 , and [AlCl{N(SiMe₃)₂}₂] were determined.     

Tricarbonyl Derivatives of Manganese(I) with Diphosphinite Chelating Ligands

Reaction of [MnBr(CO)₃L] [L = Ph₂POCH₂CH₂OPPh₂, L¹ , {(CH₃)₂CH}₂POCH₂CH₂OP{CH(CH₃)₂}₂, L² ] with AgO₃SCF₃ and AgO₂CCF₃ in dichloromethane afforded the new complexes [Mn(O₃SCF₃)(CO)₃L] and [Mn(O₂CCF₃)(CO)₃L], respectively. Substitution of O₃SCF₃ resulted in the new species [Mn(SCN)(CO)₃L], [Mn(NCCH₃)(CO)₃L](O₃SCF₃) and, in the case of L² , [Mn(CN)(CO)₃L²]. By contrast, any attempt to displace the O₂CCF₃ ligand in the same way was unsuccessful. After maintaining for some days the complex [Mn(CH₃CN)(CO)₃L¹](O₃SCF₃) in dichloromethane at room temperature, the new complex [MnCl(CO)₃L¹] was formed. All the new complexes were characterized by elemental analysis, mass spectrometry and IR and NMR spectroscopies. In the case of [Mn(O₃SCF₃)(CO)₃L¹], [Mn(O₂CCF₃) (CO)₃L¹], [MnCl(CO)₃L¹], [Mn(CH₃CN) (CO)₃L²] (O₃SCF₃), [Mn(CN)(CO)₃L²] and [Mn(O₂CCF₃)(CO)₃L²], together with the previously synthesized complex [MnBr(CO)₃L²], suitable crystals for X‐ray structural analysis were isolated. In all of them the Mn atom adopts six‐coordination by bonding to the three CO ligands, the two P atoms of L and either one C atom (CN), one oxygen atom (O₂CCF₃, O₃SCF₃), one N atom (CH₃CN, SCN) or the halogen atom (Cl, Br).     

A Design Strategy for Single‐Stranded Helicates using Pyridine‐Hydrazone Ligands and PbII

The reactions of py‐hz ligands ( L1–L5 ) with Pb(CF₃SO₃)₂?H₂O resulted in some rare examples of discrete single‐stranded helical Pb^II complexes. L1 and L2 formed non‐helical mononuclear complexes [Pb L1 (CF₃SO₃)₂]?CHCl₃ and Pb L2 (CF₃SO₃)₂][Pb L2 CF₃SO₃]CF₃SO₃?CH₃CN, which reflected the high coordination number and effective saturation of Pb^II by the ligands. The reaction of L3 with Pb^II resulted in a dinuclear meso‐helicate [Pb₂ L3 (CF₃SO₃)₂Br]CF₃SO₃?CH₃CN with a stereochemically‐active lone pair on Pb^II. L4 directed single‐stranded helicates with Pb^II, including [Pb₂ L4 (CF₃SO₃)₃]CF₃SO₃?CH₃CN and [Pb₂ L4 CF₃SO₃(CH₃OH)₂](CF₃SO₃)₃?2 CH₃OH?2 H₂O. The acryloyl‐modified py‐hz ligand L5 formed helical and non‐helical complexes with Pb^II, including a trinuclear Pb^II complex [Pb₃ L5 (CF₃SO₃)₅]CF₃SO₃?3CH₃CN?Et₂O. The high denticity of the long‐stranded py‐hz ligands L4 and L5 was essential to the formation of single‐stranded helicates with Pb^II.     

Über Umsetzungen von weißem Phosphor mit Metallorganylen

Reactions of White Phosphorus with Lithium Alkyls The reaction of white phosphorus with Lime (me = CH₃) (molar ratio P₄: Lime = 1:1) in DME or THF via insoluble lithium polyphosphides yields Li₃P₇ 1 , Li₂P₇me 2 and LiP₇me₂ 3 , which react with me₃SiCl or meBr to form P₇(Sime₃)₃, P₇(Sime₃)₂me and P₇me₃, respectively. All of these compounds were characterized by ³¹P-n.m.r. By higher amounts of Lime (molar ratio P₄:Lime = 1:2) Li₂P₇me is decomposed. The analogous reaction of P₄ with LiCme₃ yields Li₃P₇, LiP₇(Cme₃)₂, Li₂P₇Cme₃, and additionally LiP₄(Cme₃)₃ and LiP₃(Cme₃)₂. Again insoluble lithium polyphosphides were observed as intermediates. Addition of me₃SiCl to the reaction mixture affords P₇(Sime₃)₃, P₇(Sime₃)₂(Cme₃), P₇(Sime₃)(Cme₃)₂ P₄(Sime₃)(Cme₃)₃, and P₃(Sime₃)(Cme₃)₂. In n-hexane/THF the reaction of P₄ with LiCme₃ in the molar ratio of 1:2 predominantly yields the fourmembered ring LiP₄(Cme₃)₃ besides some of the three-membered ring LiP₃(Cme₃)₂, which with me₃SiCl yield P₄(Sime₃)(Cme₃)₃ and P₃(Sime₃)(Cme₃)₂. In addition to the mentioned main products are found: all compounds of the group P₈(Sime₃)₅(Cme₃) to P₈(Sime₃)(Cme₃)₅, the five-membered rings P₅(Sime₃)₂(Cme₃)₃ and P₅(Sime₃)₃(Cme₃)₂ as well as P(Sime₃)₂Cme₃ and P(Sime₃)₃.     

Synthese und Röntgenstrukturanalyse von S4N4-Derivaten mit drei- und vierfach koordinierten Schwefelatomen

CF₃SO₂N?SCl₂ reagiert mit (CH₃)₂S[NSi(CH₃)₃]₂, (C₄H₈)S[NSi(CH₃)₃]₂ oder (C₅H₁₀)S[NSi(CH₃)₃]₂ unter Trimethylchlorsilanabspaltung zu den achtgliedrigen S₄N₄-Derivaten S₄N₄(NSO₂CF₃)₂(CH₃)₄ 3 , S₄N₄(NSO₂CF₃)₂(C₄H₈)₂ 4a und S₄N₄(NSO₂CF₃)₂(C₅H_{1 0})₂ 4b . In den achtgliedrigen SN-Ringen haben die Schwefelatome die Koordinationszahl 3 und 4. Die Röntgenstrukturanalyse von 4a ergab eine Sessel-Konformation. 4a kristallisiert orthorhombisch in der Raumgruppe Pna2₁ mit a = 17,641(4), b = 6,406(2), c = 19,130(4) Å, d_x = 1,815 g cm^?3 und Z = 4. Die mittleren S? N-Abstände betragen an den vierfach koordinierten Schwefelatomen 1,597 Å und an den Schwefelatomen mit der Koordinationszahl 3 1,650 Å. CF₃SO₂N? SCl₂ reagiert mit trimethylzinnhaltigen S? N-Verbindungen zum bekannten CF₃SO₂N[Sn(CH₃)₃]S(CH₃)NSO₂CF₃ und Dimethylzinndichlorid. Synthesis and X-Ray Structure Analysis of S₄N₄-Derivatives with Threefold and Fourfold Coordinated Sulfur Atoms CF₃SO₂N?SCl₂ reacts with (CH₃)₂S[NSi(CH₃)₃]₂, (C₄H₈)S[NSi(CH₃)₃]₂ or (C₅H₁₀S[NSi(CH₃)₂]₂ under elimination of (CH₃)₃SiCl to yield the eight-membered S₄N₄ derivatives S₄N₄?NSO₂CF₃)₂(CH₃)₄, 3 , S₄N₄(NSO₂CF₃)₂(C₄H₈)₂ 4a und S₄N₄(NSO₂CF₃)₂(C₅H_{1 0})₂ 4b . In the eight-membered SN-rings the sulfur atoms have the coordination number 3 and 4. The X-ray structure analysis of 4a revealed a chair conformation. 4a crystallizes in the orthorhombic space group Pna2₁ with a = 17.641(4), b = 6.406(2), c = 19.130(4) Å, d_x = 1.815 g cm^?3, and Z = 4. The average S? N distance was found to be 1.597 Å at fourfold coordinated sulfur atoms and 1.650 Å at sulfur with coordination number 3. CF₃SO₂N=SCl₂ reacts with trimethyl tin-containing S? N compounds to the known CF₃SO₂N[Sn(CH₃)₃]S(CH₃)NSO₂CF₃ and dimethyl tin dichloride.     

Untersuchungen zur Reaktionsfähigkeit der höheren Silylphosphane (me3Si)4P2, [(me3Si)2P]2PH, [(me3Si)2P]2P–Sime3 und (me3Si)3P7

Investigations Concerning the Reactivity of the Higher Silylphosphanes (me₃Si)₄P₂, [(me₃Si)₂P]₂PH, [(me₃Si)₂P]₂P—Sime₃, and (me₃Si)₃P₇ The reaction of (me₃Si)₂P? P(Sime₃)₂ 1 in ether solutions (THF, monoglyme) with t-buLi (me ? CH₃; t-bu ? (CH₃)₃C) yields (me₃Si)₃P, (me₃Si)₂PLi and Li₃P₇ via (me₃Si)₂P? P(Li) (Sime₃) 4 . Already at ?40° (me₃Si)₃P₂Li 4 decomposes yielding (me₃Si)₂PLi, Li₃P₇ and (me₃Si)₃P. The metallation of (me₃Si)₃P₂H with t-buLi leads to the same results. t-buLi with [(me₃Si)₂P]₂PH 2 in pentane forms [(me₃Si)₂P]₂PLi, which reacts on with meCl or me₃SiCl to [(me₃Si)₂P]₂Pme or [(me₃Si)₂P]₂PSime₃, resp. On addition of monoglyme to a suspension of [(me₃Si)₂P]₂PLi in pentane, or by treating [(me₃Si)₂P]₂PH in ethers with t-buLi (me₃Si)₂PLi, Li₃P₇, (me₃Si)₃P, are formed. The same compounds are generated by reacting [(me₃Si)₂P]₂P—Sime₃ in ethers with t-buLi. The metallation of (me₃Si)₃P₇ in ethers with t-buLi yields (me₃Si)₂PLi, (me₃Si)₃P, (t-bu)₃P₄?(Sime₃), Li₃P₇ and a red solid. The formation of (me₃Si)₂P₇Li is the first step of this reaction.     

Fluordiazadiphosphetidine, 5. Mitt.

Reaction of (CH₃NPF₃)₂ with equimolar amounts of N-methylhexamethyldisilazane yields a reaction product, which can be separated in a polymer and a crystalline fraction. High-vacuum sublimation of the crystalline part yields the already known compound (CH₃N)₄P₃F₇, the new spiro-isomer F₃P(CH₃N)₂PF(CH₃N)₂PF₃ and the spiro-compound F₃P(CH₃N)₂PF(CH₃N)₂PF(CH₃N)₂PF₃, an isomer of the known compound (CH₃N)₆P₄F₈.     

Cuboidal oxalate cluster complexes with the Mo<Subscript>3</Subscript>CuQ<Subscript>4</Subscript><Superscript>5+</Superscript> cluster core (Q = S or Se): synthesis,structure, and electrochemical properties

The reactions of the [Mo₃(μ₃-Q)(μ₂-Q)₃(H₂O)₃(C₂O₄)₃]²⁻ complex (Q = S or Se) with CuX salts (X = Cl, Br, I, or SCN) in water produce the cuboidal heterometallic clusters [Mo₃(CuX)(μ₃-Q)₄(H₂O)₃(C₂O₄)₃]²⁻, which were isolated as the potassium and tetraphenylphosphonium salts. Two new compounds, K₂[Mo₃(CuI)(μ₃-S)₄(H₂O)₃(C₂O₄)₃]·6H₂O and (PPh₄)₂[Mo₃(CuBr)(μ₃-S)₄(H₂O)₃(C₂O₄)₃]·7H₂O, were structurally characterized. All compounds were characterized by elemental analysis and IR spectroscopy. The K₂[Mo₃(CuI)(μ₃-Se)₄(H₂O)₃(C₂O₄)₃] compound was characterized by the ⁷⁷Se NMR spectrum; the (PPh₄)₂[Mo₃(CuI)(μ₃-S)₄(H₂O)₃(C₂O₄)₃], (PPh₄)₂[Mo₃(CuI)(μ₃-Se)₄(H₂O)₃(C₂O₄)₃] and K₂[Mo₃(CuSCN)(μ₃-S)₄(H₂O)₃(C₂O₄)₃]·7H₂O compounds, by electrospray mass spectra. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1639–1644, September, 2007.     

Silicium-stickstoff-fluorverbidungen: V. Darstellung neuer silylaminofluorsilane

Compounds of the composition RR′SiFNR″Si(CH₃)₃ (R = H, F, CH₃, C₂H₅, C₃H₇, C₂H₃, C₆H₅, C(CH₃)₃; R = F, CH₃, C₆H₅; R″ = CH₃, C(CH₃)₃, Si(CH₃)₃) are obtained by the reaction of silicontetrafluoride or organo-substituted silicon-fluorides with the lithium salts of alkylsilylamines in a molar ratio of $\text{1}\text{1}$. The disubstituted compounds RSiF(NR′Si(CH₃)₃)₂ (R = H, F, CH₃, C₂H₃, C₆H₅; R′ = CH₃, C(CH₃)₃) result when the reactants are in a $\text{1}\text{2}$ molar-ratio. Likewise the unsymmetrical siliconfluorsilylamines of the formulae F₂Si(NRSi(CH₃)₃) (NR′Si(CH₃)₃) (R = CH₃, R′ = C(CH₃)₃), as well as the trisubstituted compounds FSi(NCH₃Si(CH₃)₃)₃ and FSi(NCH₃Si(CH₃)₃)₂(N(Si(CH₃)₃)₂) were made. By reacting phenyltrifluorsilane with dialkylamines ($\text{1}\text{2}$) C₆H₅SiF₂NR₂(R = CH₃, C₂H₅) was obtained. The IR-, mass-, ¹H and ¹⁹F NMR spectra of the above-mentioned compounds are reported.     

Acid-base properties and catalytic activity of ABO3 (perovskite-type) oxides consisting of rare earth and 3d transition metals

The surface acidity/basicity of perovskite-type mixed oxides (LaCrO₃, PrCrO₃, SmCrO₃, LaMnO₃, PrMnO₃, SmMnO₃, LaFeO₃, PrFeO₃, SmFeO₃, LaCoO₃, PrCoO₃, SmCoO₃, LaNiO₃, PrNiO₃ and SmNiO₃) are reported. These properties have been correlated with the catalytic activity of these oxides towards esterification of acetic acid usingn-butanol.     

Untersuchung der Phasengleichgewichte in den Systemen Sb2O3?SO3?H2O und Bi2O3?SO3?H2O

Investigation of Phase Equilibria in the Systems Sb₂O₃? SO₃? H₂O and Bi₂O₃? SO₃? H₂O Phase equilibria in the systems Sb₂O₃? SO₃? H₂O and Bi₂O₃? SO₃? H₂O within the concentration range of 1 up to 98.5% H₂SO₄ at 100°C are studied. In the system Sb₂O₃? SO₃? H₂O crystallization fields of five compounds depending on the H₂SO₄ concentration were determined: 5Sb₂O₃ · Sb₂(SO₄)₃ · 3H₂O; 7Sb₂O₃ · 2Sb₂(SO₄)₃; 2Sb₂O₃ · Sb₂(SO₄)₃; Sb₂O₃ · Sb₂(SO₄)₃ and Sb₂(SO₄)₃. The obtained compounds are identified by chemical and derivatographic analysis.     

Untersuchungen zur Metallierung der Cyclophosphane P4(Cme3)3(Sime3), P4(Cme3)2(Sime3)2, P4(Sime3)4

Investigations Concerning the Metallation of the Cyclotetraphosphanes P₄(Cme₃)₃(Sime₃), P₄(Cme₃)₂(Sime₃)₂, and P₄(Sime₃)₄ The reaction of white phosphorus with LiCme₃ and me₃SiCl yields P₄(Sime₃)(Cme₃)₃ 1 . With n-buLi this crystalline cyclotetraphosphane forms the crystalline LiP₄(Cme₃)₃. In the same manner, n-buLi, with trans-P₄(Sime₃)₂(Cme₃)₂ 2 to yields LiP₄(Sime₃)(Cme₃)₂, which in contrast to LiP₄(Cme₃)₃ decomposes within a few hours yielding P(Sime₃)₂n-bu 6 , P(Sime₃)₃ 8 , LiP(Sime₃)₂ 9 and also the cyclic compounds P₄(Sime₃)(Cme₃)₃ 10 , LiP₄(Cme₃)₃ 11 and LiP₃(Cme₃)₂ 12 . The composition of the product mixture depends on the molar ratio of 2 to LiC₄H₉. At a molar ratio of 1:1 11 and 12 are not jet observed. At molar ratios of 1:1.5 and 1:2 P(Sime₃)₃ is not found. The amount of 11 and 12 grows with increasing concentration of n-buLi. On addition of n-buLi the solution of P₄(Sime₃)₄ immediately turns red. Li₃P₇ and Li₂P₇(Sime₃) (among others) are formed so fast that the first intermediates in the lithiation sequence so far could not be elucidated. These results demonstrate clearly that replacement of two me₃Si groups in P₄(Sime₃)₄ by two me₃C groups excludes the rearrangement of LiP₄(Sime₃)(Cme₃)₂ to a P₇-molecule.     

Spektroskopische Untersuchungen an Siliciumverbindungen. XXXI. Schwingungsverhalten von p-substituierten N,N-Bistrimethylsilylanilinen

The following p-substituted N,N-bis-trimethlsilyl anilines p-X? C₆H₄? N[Si(CH₃)₃]₂ are prepared by silylation of free amines: X = H, CH₃, C₂H₅, CH₃O, CH₃CO, F, Cl, Br, J, CN, C₆H_S, (CH₃)₃SiO, and [(CH₃)₃Si]₂N, and the isotopic derivatives C₆H₅? ¹⁵N[Si(CH₃)₃]₂ and C₆D₅N[Si(CH₃)₃]₂. The vibrational spectra are reported and assigned. The molecular symmetry of p-[(CH₃)₃Si]₂N? C₆H₄? N[Si(CH₃)₃]₂ is determined. The influence of the mass of the substituents X on the positions of the ν_sSiNSi vibrational frequencies is discussed.     

Theoretical study of the decomposition mechanism of a series of group III triazides X(N3)3 (X = B,Al, Ga)

Density functional theory method is used to examine a series of group III triazides X(N₃)₃ (X = B, Al, Ga). These compounds, except for the C_3h planar B(N₃)₃ and Al(N₃)₃, are first reported here. C_3h planar structures are the most energetically favored for all singlet X(N₃)₃ systems. Potential‐energy surfaces for unimolecular decompositions of the C_3h and C_S planar X(N₃)₃ species have been investigated. Results show that decomposition of B(N₃)₃ obeys sequential fashion and follows a four‐step mechanism: (1) B(N₃)₃ → NB(N₃)₂ + N₂; (2) NB(N₃)₂ → cyc‐N₂BN₃ + N₂; (3) cyc‐N₂BN₃ → trigonal‐BN₃ + N₂; (4) trigonal‐BN₃ → linear‐NBNN. Decomposition of Al(N₃)₃ follows a two‐step mechanism: (1) Al(N₃)₃ → NAl(N₃)₂ + N₂; (2) NAl(N₃)₂ → linear‐AlN₃ + 2N₂. The dissociation of Ga(N₃)₃ follows only one‐step mechanism: Ga(N₃)₃ → angular‐GaN₃ + 3N₂. These findings may be helpful in understanding the decomposition mechanisms of group III triazides as well as the possible mechanism for XN film generation. © 2014 Wiley Periodicals, Inc.     

Fluorinated peroxides derived from hexafluoroacetone. II. Insertion of (CF3) 2CO into alkali-metal peroxides and subsequent reaction with active halogen compounds

The novel alkali metal peroxide derivatives (CH₃) ₃COOC(CF₃) ₂ONa, NaOC(CF₃) ₂OOC(CF₃) ₂ONa and CF₃C(O) OOC(CF₃) ₂ONa have been prepared through reactions of hexafluoroacetone, (CF₃) ₂CO, with the sodium salts of various organic hydroperoxides. These new salts are soluble in water and polar organic solvents and have been used to prepare the new covalent fluorocarbon/hydrocarbon peroxides [(CH₃₃COOC(CF₃) ₂OC(O)C₆H₅, (CH₃) ₃SiOC(CF₃) _2-OOC(CF₃) ₂OSi(CH₃) ₃, and (CH₃₃COOC(CF₃) ₂C(O)CF₃] through reaction with compounds having active halogen. Although the new peroxides are apparently less flammable and explosive than their hydrocarbon analogs, they also exhibit shorter half-lives than the parent compound (i.e., the peroxide without hexafluoroacetone insertion).     

Darstellung und Eigenschaften von Chromtricarbonyl-Komplexen strukturisomerer Borazin-Derivate

The new hexaalkylborazine chromium tricarbonyls (n-Pr)₃B₃N₃Me₃Cr(CO)₃ (V), Me₃B₃N₃(n-Pr)₃Cr(CO)₃ (VI), (i-Pr)₃B₃N₃Me₃Cr(CO)₃ (VII) and Me₃B₃N₃(i-Pr)₃Cr(CO)₃ (VIII) have been prepared from fac-Cr(CO)₃(MeCN)₃ and the corresponding borazine in dioxane or without solvent. They are much more labile than the isomeric complex Et₃B₃N₃Et₃Cr(CO)₃ (IV) which can be readily obtained from Et₃B₃N₃Me₃Cr(CO)₃ and Et₃B₃N₃Et₃ by ring ligand exchange. The NMR., IR., UV. and Mass spectroscopic data of the complexes IV–VIII will be briefly discussed. The preparation of the borazine derivatives (n-Pr)₃B₃N₃Me₃ (IX) and Me₃B₃N₃(n-Pr)₃ (X) is also reported.     

Crystal structure,thermal decomposition mechanism and catalytic performance of hexaaquaaluminum methanesulfonate

Hexaaquaaluminum methanesulfonate crystals, [Al(H₂O)₆][CH₃SO₃]₃ were synthesized by a hydrothermal reaction of Al(OH)₃ with methanesulfonic acid. Single-crystal diffraction determination revealed that Al³⁺ was coordinated by six water molecules in octahedral geometry, while the CH₃SO₃^– anion connected with Al³⁺ through coordinated water molecules by hydrogen bonds. The six-coordinate environment of Al was also determined by ²⁷Al MAS NMR measurement. Thermogravimetric analysis and Fourier transform infrared spectroscopy showed that the decomposition intermediate at 265–365 °C was Al₂(μ-OH)(CH₃SO₃)₅ and the final product was amorphous Al₂O₃ residue with about 0.8 wt% SO₃ at 520–800 °C. A pure phase of [Al(H₂O)₆][CH₃SO₃]₃ was confirmed by powder X-ray diffraction analysis. Esterification of n-butyric acid with n-butanol and ketalization of cyclohexanone with glycol catalyzed by [Al(H₂O)₆][CH₃SO₃]₃ and Al₂(μ-OH)(CH₃SO₃)₅, respectively, proceeded in 100% yield by continuously removing the produced water. In the case of tetrahydropyranylation of n-butanol at room temperature in dichloromethane, the catalytic activity of [Al(H₂O)₆][CH₃SO₃]₃ was much lower than that of Al₂(μ-OH)(CH₃SO₃)₅. Furthermore, both [Al(H₂O)₆][CH₃SO₃]₃ precursor and Al₂(μ-OH)(CH₃SO₃)₅ catalysts could be recycled.