Sodium magnesium amidoborane: the first mixed-metal amidoborane

The first example of a mixed-metal amidoborane Na(2)Mg(NH(2)BH(3))(4) has been successfully synthesized. It forms an ordered arrangement in cation coordinations, i.e., Mg(2+) bonds solely to N(-) and Na(+) coordinates only with BH(3). Compared to ammonia borane and monometallic amidoboranes, Na(2)Mg(NH(2)BH(3))(4) can release 8.4 wt% pure hydrogen with significantly less toxic gases.     

Synthesis and X-Ray Crystal Structure of an Optically Pure Tripodal C3-Symmetric Tritertiary Phosphine Bearing Chirality on Phosphorus

The preparation of the optically pure tritertiary phosphine (RRR)-MeSi(CH2P(t-Bu)Ph)3 (2) is reported. The route followed involves deprotonation of optically pure (R)-P(BH3)Me(t-Bu)PH (2) the reaction of the resulting carbanion with MeSiCl3, followed by removal with morpholine of the BH3-protecting groups from the triertiary phosphine-borane 3 . The latter's X-ray crystal structure and that of [Rh(NBD)((RRR)- 1 ]TOf)( 4 ), are also rported. Furthermore, it is shown that the separation of the racemic phosphine-borane 2 can be conveniently carried out using medium-pressure liquid chromatgrapy with cellulose-riacetate as a chiral stationary phase.     

Stoichiometric reactivity of dialkylamine boranes with alkaline earth silylamides

Reactions of β-diketiminato group 2 silylamides, [HC{(Me)CN(2,6-(i)Pr(2)C(6)H(3))}(2)M(THF)(n){N(SiMe(3))(2)}] (M = Mg, n = 0; M = Ca, Sr, n = 1), and an equimolar quantity of pyrrolidine borane, (CH(2))(4)NH·BH(3), were found to produce amidoborane derivatives of the form [HC{(Me)CN(2,6-(i)Pr(2)C(6)H(3))}(2)MN(CH(2))(4)·BH(3)]. In reactivity reminiscent of analogous reactions performed with dimethylamine borane, addition of a second equivalent of (CH(2))(4)NH·BH(3) to the Mg derivative induced the formation of a species, [HC{(Me)CN(2,6-(i)Pr(2)C(6)H(3))}(2)Mg{N(CH(2))(4) BH(2)NMe(2)BH(3)}], containing an anion in which two molecules of the amine borane substrate have been coupled together through the elimination of one molecule of H(2). Both this species and a calcium amidoborane derivative have been characterised by X-ray diffraction techniques and the coupled species is proposed as a key intermediate in catalytic amine borane dehydrocoupling, in reactivity dictated by the charge density of the group 2 centre involved. On the basis of further stoichiometric reactions of the homoleptic group 2 silylamides, [M{N(SiMe(3))(2)}(2)] (M = Mg, Ca, Sr, Ba), with (CH(3))(2)NH·BH(3) and (i)Pr(2)NH·BH(3) reactivity consistent with successive amidoborane β-hydride elimination and [R(2)N[double bond, length as m-dash]BH(2)] insertion is described as a means to induce the B-N dehydrocoupling between amine borane substrates.     

Ammine magnesium borohydride complex as a new material for hydrogen storage: structure and properties of Mg(BH4)2.2NH3

The ammonia complex of magnesium borohydride Mg(BH4)2.2NH3 (I), which contains 16.0 wt % hydrogen, is a potentially promising material for hydrogen storage. This complex was synthesized by thermal decomposition of a hexaaammine complex Mg(BH4)2.6NH3 (II), which crystallizes in the cubic space group Fm3 m with unit cell parameter a=10.82(1) A and is isostructural to Mg(NH3) 6Cl2. We solved the structure of I that crystallizes in the orthorhombic space group Pcab with unit cell parameters a=17.4872(4) A, b=9.4132(2) A, c=8.7304(2) A, and Z=8. This structure is built from individual pseudotetrahedral molecules Mg(BH4)2.2NH3 containing one bidentate BH4 group and one tridentate BH4 group that pack into a layered crystal structure mediated by N-H...H-B dihydrogen bonds. Complex I decomposes endothermically starting at 150 degrees C, with a maximum hydrogen release rate at 205 degrees C, which makes it competitive with ammonia borane BH 3NH3 as a hydrogen storage material.     

Synthesis and characterization of methylammonium borohydride

A new borohydride, [CH(3)NH(3)](+)[BH(4)](-), has been synthesized through the metathesis of CH(3)NH(3)F and NaBH(4) in methylamine. Room-temperature X-ray diffraction studies have shown that [CH(3)NH(3)](+)[BH(4)](-) adopts a tetragonal unit cell with considerable hydrogen mobility similar to that observed in NH(3)BH(3). The kinetics and thermodynamics of hydrogen release have been investigated and were found to follow a similar pathway to that of [NH(4)](+)[BH(4)](-). Decomposition of [CH(3)NH(3)](+)[BH(4)](-) occurred slowly at room temperature and rapidly at ca. 40 °C to form [BH(2)(CH(3)NH(2))(2)](+)[BH(4)](-), the methylated analogue of the diammoniate of diborane. The decomposition has been investigated by means of in situ X-ray diffraction and solid state (11)B NMR spectroscopy and occurred in the absence of any detectable intermediates to form crystalline [BH(2)(CH(3)NH(2))(2)](+)[BH(4)](-). [(CH(3))(2)NH(2)](+)[BH(4)](-) and [BH(2){(CH(3))(2)NH}(2)](+)[BH(4)](-) have also been synthesized through analogous routes, indicating a more general applicability of the synthetic method.     

A new ammine dual-cation (Li, Mg) borohydride: synthesis, structure, and dehydrogenation enhancement

A new ammine dual-cation borohydride, LiMg(BH(4))(3)(NH(3))(2), has been successfully synthesized simply by ball-milling of Mg(BH(4))(2) and LiBH(4)·NH(3). Structure analysis of the synthesized LiMg(BH(4))(3)(NH(3))(2) revealed that it crystallized in the space group P6(3) (no. 173) with lattice parameters of a=b=8.0002(1) ?, c=8.4276(1) ?, α=β=90°, and γ=120° at 50 °C. A three-dimensional architecture is built up through corner-connecting BH(4) units. Strong N-H···H-B dihydrogen bonds exist between the NH(3) and BH(4) units, enabling LiMg(BH(4))(3)(NH(3))(2) to undergo dehydrogenation at a much lower temperature. Dehydrogenation studies have revealed that the LiMg(BH(4))(3)(NH(3))(2)/LiBH(4) composite is able to release over 8 wt% hydrogen below 200 °C, which is comparable to that released by Mg(BH(4))(3)(NH(3))(2). More importantly, it was found that release of the byproduct NH(3) in this system can be completely suppressed by adjusting the ratio of Mg(BH(4))(2) and LiBH(4)·NH(3). This chemical control route highlights a potential method for modifying the dehydrogenation properties of other ammine borohydride systems.     

Magnesium borohydride complexed by tetramethylethylenediamine

A complex of magnesium borohydride, Mg(BH4)2.Me2NC2H4NMe2, has been synthesized and structurally characterized. This monomer complex has a pseudotetrahedral geometry around the Mg atom with tridentate BH4 groups and short Mg...B distances.     

Reactivity of cyclooligophosphanes: synthesis and structural characterisation of cyclo-1,4-(BH3)2(P4Ph4CH2) and cyclo-1,2-(BH3)2(P5Ph5)

The borane complexes cyclo-1,4-(BH3)2(P4Ph4CH2) (3) and cyclo-1,2-(BH3)2(P5Ph5) (4) were prepared by reaction of cyclo-(P4Ph4CH2) and cyclo-(P5Ph5) with BH3(SMe2). Only the 2:1 complexes 3 and 4 were isolated, even when an excess of the borane source was used. In solution, 3 exists as a mixture of the two diastereomers (R(P)*,S(P)*,S(P)*,R(P)*)-(+/-)-3 and (R(P)*,R(P)*,R(P)*,R(P)*)-(+/-)-3. However, in the solid state the (R(P)*,S(P)*,S(P)*,R(P)*)-(+/-) diastereomer is the major stereoisomer. Similarly, while only one isomer of 4 is observed in its X-ray structure, NMR spectroscopic investigations reveal that it forms a complex mixture of isomers in solution. 3 may be deprotonated with tBuLi to give the lithium salt cyclo-1,4-(BH3)2(P4Ph4CHLi) (3 x Li), though this could not be isolated in pure form.     

Binuclear magnesium amidoborane complexes: characterization of a trinuclear thermal decomposition product

The bis-β-diketimine with a meta-phenylene bridge (META-H(2): DIPPN(H)CMeCHCMeN-C(6)H(4)-NCMeCHCMeN(H)DIPP; DIPP = 2,6-iPr-C(6)H(3)) reacted with two equivalents of nBu(2)Mg to give the bis-β-diketiminate complex META-(MgnBu)(2). The latter binuclear magnesium complex was converted to META-[MgNH(iPr)BH(3)](2) by reaction with H(2)N(iPr)BH(3). The thermal decomposition of this binuclear iPr-substituted magnesium amidoborane complex has been investigated. In benzene it starts to eliminate H(2) at 90 °C. Two decomposition products could be obtained by fractional crystallization of the residue. The first product is the trinuclear magnesium complex META-Mg(3)[iPrNB(H)N(iPr)BH(3)](2) and the second product is (META-Mg)(2). These products have been formed by ligand exchange reactions of the expected complex META-Mg(2)[iPrNB(H)N(iPr)BH(3)] and were characterized by single crystal X-ray diffraction. The central Mg(2+) ion in META-Mg(3)[iPrNB(H)N(iPr)BH(3)](2) is not connected to the ligand system and its coordination geometry could be representative of that in a solid-state magnesium salt containing the RNB(H)N(R)BH(3)(2-) ion.     

Improved dehydrogenation properties of Ca(BH4)2-LiNH2 combined system

Ca(BH(4))(2)-LiNH(2) combined system is shown to release hydrogen at much lower temperature compared to the pure Ca(BH(4))(2). The improved dehydrogenation in this system can be ascribed to a combination reaction between [BH(4)] and [NH(2)] based on the reaction mechanism of positive H and negative H.     

In situ hybridization of LiNH2-LiH-Mg(BH4)2 nano-composites: intermediate and optimized hydrogenation properties

Nano-composites of LiNH(2)-LiH-xMg(BH(4))(2) (0 ≤ x ≤ 2) were prepared by plasma metal reaction followed by a nucleation growth method. Highly reactive LiNH(2)-LiH hollow nanoparticles offered a favorable nucleus during a precipitation process of liquid Mg(BH(4))(2)·OEt(2). The electron microscopy results suggested that more than 90% of the obtained nano-composites were in the range 200-400 nm. Because of the short diffusion distance and ternary mixture self-catalyzing effect, this material possesses enhanced hydrogen (de)sorption attributes, including facile low-temperature kinetics, impure gases attenuation and partial reversibility. The optimal hydrogen storage properties were found at the composition of LiNH(2)-LiH-0.5Mg(BH(4))(2), which was tentatively attributed to a Li(4)(NH(2))(2)(BH(4))(2) intermediate. 5.3 wt% hydrogen desorption could be recorded at 150 °C, with the first 2.2 wt% release being reversible. This work suggests that controlled in situ hybridization combined with formula optimization can improve hydrogen storage properties.     

Transition metal-catalyzed formation of boron-nitrogen bonds: catalytic dehydrocoupling of amine-borane adducts to form aminoboranes and borazines

A mild, catalytic dehydrocoupling route to aminoboranes and borazine derivatives from either primary or secondary amine-borane adducts has been developed using late transition metal complexes as precatalysts. The adduct Me(2)NH.BH(3) thermally eliminates hydrogen at 130 degrees C in the condensed phase to afford [Me(2)N-BH(2)](2) (1). Evidence for an intermolecular process, rather than an intramolecular reaction to form Me(2)N=BH(2) as an intermediate, was forthcoming from "hot tube" experiments where no appreciable dehydrocoupling of gaseous Me(2)NH.BH(3) was detected in the range 150-450 degrees C. The dehydrocoupling of Me(2)NH.BH(3) was found to be catalyzed by 0.5 mol % [Rh(1,5-cod)(mu-Cl)](2) in solution at 25 degrees C to give 1 quantitatively after ca. 8 h. The rate of dehydrocoupling was significantly enhanced if the temperature was raised or if the catalyst loading was increased. The catalytic activity of various other transition metal complexes (Ir, Ru, Pd) for the dehydrocoupling of Me(2)NH.BH(3) was also demonstrated. This new catalytic method was extended to other secondary adducts RR'NH.BH(3) which afforded the dimeric species [(1,4-C(4)H(8))N-BH(2)](2) (2) and [PhCH(2)(Me)N-BH(2)](2) (3) or the monomeric aminoborane (i)Pr(2)N=BH(2) (4) under mild conditions. A new synthetic approach to the linear compounds R(2)NH-BH(2)-NR(2)-BH(3) (5: R = Me; 6: R = 1,4-C(4)H(8)) was developed and subsequent catalytic dehydrocoupling of these species yielded the cyclics 1 and 2. The species 5 and 6 are postulated to be intermediates in the formation of 1 and 2 directly from the catalytic dehydrocoupling of the adducts R(2)NH.BH(3). The catalytic dehydrocoupling of NH(3).BH(3), MeNH(2).BH(3), and PhNH(2).BH(3) at 45 degrees C to give the borazine derivatives [RN-BH](3) (10: R = H; 11: R = Me; 12: R = Ph) was demonstrated. TEM analysis of the contents of the reaction solution for the [Rh(1,5-cod)(mu-Cl)](2) catalyzed dehydrocoupling of Me(2)NH.BH(3) together with Hg poisoning experiments suggested a heterogeneous catalytic process involving Rh(0) colloids.     

Cu(I) and Zn(II) complexes of 7-azaindole-containing scorpionates: structures, luminescence and fluxionality

A new scorpionate borate ligand K[HB(7-azain)3](1, 7-azain = 7-azaindolyl) has been obtained from the reaction of KBH4 with excess 7-azaindole. The scorpionate ligand 1 was found to be able to form complexes with Zn(II) and Cu(I) ions. Complex 2 with the formula [BH(7-azain)3](ZnCl) has been obtained from the reaction of ZnCl2 with 1. Complex 3 with the formula [BH(7-azain)3][Cu(PPh3)] has been obtained from the reaction of [Cu(PPh3)2(CH3CN)2][BF4] with . The crystal structures of 1-3 have been determined by single-crystal X-ray diffraction analyses which revealed that has a dimeric structure linked together by two K+ ions, 2 has a symmetric tripodal structure with all three 7-azaindolyl groups being coordinated to the Zn(II) center, and 3 has an asymmetric structure with two of the 7-azaindolyl groups being coordinated to the Cu(I) center and the third 7-azaindolyl group uncoordinated. Variable temperature 1H NMR experiments established that 3 is highly dynamic in solution involving a rapid exchange between the coordinated and the non-coordinated 7-azaindolyl groups. All three compounds display blue emission in the solid state at ambient temperature. However, in solution at ambient temperature, compounds 1 and 2 display bright blue emission while compound 3 has no emission at all. At 77 K, solutions of all three compounds display blue-green phosphorescent emission with a long decay lifetime (> 2 ms).     

Synthesis, coupling, and condensation reactions of 1,2-diborylated benzenes: an experimental and quantum-chemical study

1,2-Bis(pinacolboryl)benzene (1,2-C(6) H(4) (Bpin)(2) , 2) was synthesized in preparatively useful yields from 1,2-C(6) H(4) Br(2) , iPrO?Bpin, and Mg turnings in the presence of 1,2-C(2) H(4) Br(2) as an entrainer. Compound 2 is a versatile starting material for the synthesis of (un)symmetrically substituted benzenes (i.e., 1,2-C(6) H(4) (Ar(1) )(Ar(2) )) through sequential Suzuki-Miyaura coupling reactions. Alternatively, it can be transformed into bis-borate Li(2) [1,2-C(6) H(4) (BH(3) )(2) ] (3) through reduction with Li[AlH(4) ]. In the crystal lattice, the diethyl ether solvate 3?OEt(2) establishes a columnar structure that is reinforced by an intricate network of B?(μ-H)?Li interactions. Hydride-abstraction from compound 3 with Me(3) SiCl leads to the transient ditopic borane 1,2-C(6) H(4) (BH(2) )(2) , which can either be used in situ for subsequent hydroboration reactions or trapped as its stable NMe(2) Et diadduct (6). In SMe(2) solution, the putative diadduct 1,2-C(6) H(4) (BH(2) ?SMe(2) )(2) is not long-term stable but rather undergoes a condensation reaction to give 9,10-dihydro-9,10-diboraanthracene, HB(μ-C(6) H(4) )(2) BH, and BH(3) . 9,10-Dihydro-9,10-diboraanthracene was isolated from the reaction mixture as its SMe(2) monoadduct (7), which dimerizes in the solid state through two B?H?B bridges ((7)(2) , elucidated by X-ray crystallography). In contrast, hydride-abstraction from compound 3 in THF or CH(2) Cl(2) provides the unique exo-adduct H(2) B(μ-H)(2) B(μ-C(6) H(4) )(2) B(μ-H)(2) BH(2) (8, elucidated by X-ray crystallography). Quantum-chemical calculations on various conceivable isomers of [1,2-C(6) H(4) (BH(2) )(2) ](2) revealed that compound 8 was the most stable of these species. Moreover, the calculations confirmed the experimental findings that the NMe(2) Et diadduct of 1,2-C(6) H(4) (BH(2) )(2) is significantly more stable than the corresponding SMe(2) complex and that the latter complex is not able to compete successfully with borane-dimerization and -condensation. The reaction cascade in SMe(2) , which proceeds from 1,2-C(6) H(4) (BH(2) )(2) to the observed adducts of HB(μ-C(6) H(4) )(2) BH, has been elucidated in detail and the important role of B?C?B-bridged intermediates has been firmly established.     

Reversible dehydrogenation of magnesium borohydride to magnesium triborane in the solid state under moderate conditions

Thermal decomposition of magnesium borohydride, Mg(BH(4))(2), in the solid state was studied by a combination of PCT, TGA/MS and NMR spectroscopy. Dehydrogenation of Mg(BH(4))(2) at 200 °C en vacuo results in the highly selective formation of magnesium triborane, Mg(B(3)H(8))(2). This process is reversible at 250 °C under 120 atm H(2). Dehydrogenation at higher temperature, >300 °C under a constant argon flow of 1 atm, produces a complex mixture of polyborane species. A borohydride condensation mechanism involving metal hydride formation is proposed.     

Role of NH3 in the dehydrogenation of calcium amidoborane ammoniate and magnesium amidoborane ammoniate: a first-principles study

First-principles calculations show that [NH(3)] molecules play crucial roles as both activator for the break-up of B-H bond and supplier of protic H for the establishment of dihydrogen bonding, which could facilitate the dehydrogenation of Ca(NH(2)BH(3))(2)·2NH(3) or Mg(NH(2)BH(3))(2)·NH(3) occurring at lower temperatures compared to those of Ca(NH(2)BH(3))(2) and Mg(NH(2)BH(3))(2). Moreover, the calculations of Helmholtz Free energy and [NH(3)] molecule removal energy evidence that coordination between [NH(3)] and Mg cation is stronger than that between [NH(3)] and Ca cation; therefore, Mg(NH(2)BH(3))(2)·NH(3) will undergo directly dehydrogenation rather than deammoniation at lower temperatures.     

Syntheses and structural characterizations of anionic borane-capped ammonia borane oligomers: evidence for ammonia borane H2 release via a base-promoted anionic dehydropolymerization mechanism

Studies of the activating effect of Verkade's base, 2,8,9-triisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane (VB), on the rate and extent of H(2) release from ammonia borane (AB) have led to the syntheses and structural characterizations of three anionic aminoborane chain-growth products that provide direct support for anionic dehydropolymerization mechanistic steps in the initial stages of base-promoted AB H(2) release reactions. The salt VBH(+)[H(3)BNH(2)BH(2)NH(2)BH(3)](-) (1) containing a linear five-membered anionic aminoborane chain was produced in 74% yield via the room-temperature reaction of a 3:1 AB/VB mixture in fluorobenzene solvent, while the branched and linear-chain seven-membered anionic aminoborane oligomers VBH(+)[HB(NH(2)BH(3))(3)](-) (2a) and VBH(+)[H(3)BNH(2)BH(2)NH(2)BH(2)NH(2)BH(3)](-) (2b) were obtained from VB/AB reactions carried out at 50 °C for 5 days when the AB/VB ratio was increased to 4:1. X-ray crystal structure determinations confirmed that these compounds are the isoelectronic and isostructural analogues of the hydrocarbons n-pentane, 3-ethylpentane, and n-heptane, respectively. The structural determinations also revealed significant interionic B-H···H-N dihydrogen-bonding interactions in these anions that could enhance dehydrocoupling chain-growth reactions. Such mechanistic pathways for AB H(2) release, involving the initial formation of the previously known [H(3)BNH(2)BH(3)](-) anion followed by sequential dehydrocoupling of B-H and H-N groups of growing borane-capped aminoborane anions with AB, are supported by the fact that 1 was observed to react with an additional AB equivalent to form 2a and 2b.     

Synthesis and structural diversity of barium (N,N-dimethylamino)diboranates

The reaction of a slurry of BaBr(2) in a minimal amount of tetrahydrofuran (THF) with 2 equiv of Na(H(3)BNMe(2)BH(3)) in diethyl ether followed by crystallization from diethyl ether at -20 °C yields crystals of Ba(H(3)BNMe(2)BH(3))(2)(Et(2)O)(2) (1). Drying 1 at room temperature under vacuum gives the partially desolvated analogue Ba(H(3)BNMe(2)BH(3))(2)(Et(2)O)(x) (1') as a free-flowing white solid, where the value of x varies from <0.1 to about 0.4 depending on whether desolvation is carried out with or without heating. The reaction of 1 or 1' with Lewis bases that bind more strongly to barium than diethyl ether results in the formation of new complexes Ba(H(3)BNMe(2)BH(3))(2)(L), where L = 1,2-dimethoxyethane (2), N,N,N',N'-tetramethylethylenediamine (3), 12-crown-4 (4), 18-crown-6 (5), N,N,N',N'-tetraethylethylenediamine (6), and N,N,N',N",N"-pentamethylethylenetriamine (7). Recrystallization of 4 and 5 from THF affords the related compounds Ba(H(3)BNMe(2)BH(3))(2)(12-crown-4)(THF)·THF (4') and Ba(H(3)BNMe(2)BH(3))(2)(18-crown-6)·2THF (5'). In addition, the reaction of BaBr(2) with 2 equiv of Na(H(3)BNMe(2)BH(3)) in the presence of diglyme yields Ba(H(3)BNMe(2)BH(3))(2)(diglyme)(2) (8), and the reaction of 1 with 15-crown-5 affords the diadduct [Ba(15-crown-5)(2)][H(3)BNMe(2)BH(3)](2) (9). Finally, the reaction of BaBr(2) with Na(H(3)BNMe(2)BH(3)) in THF, followed by the addition of 12-crown-4, affords the unusual salt [Na(12-crown-4)(2)][Ba(H(3)BNMe(2)BH(3))(3)(THF)(2)] (10). All of these complexes have been characterized by IR and (1)H and (11)B NMR spectroscopy, and the structures of compounds 1-3, 4', 5', and 6-10 have been determined by single-crystal X-ray diffraction. As the steric demand of the Lewis bases increases, the structure changes from polymers to dimers to monomers and then to charge-separated species. Despite the fact that several of the barium complexes are monomeric in the solid state, none is appreciably volatile up to 200 °C at 10(-2) Torr.     

Synthesis and characterization of boranate ionic liquids (BILs)

Straightforward access to hydridoborate-based ionic liquids (BILs) is provided. They fall into a barely developed area of research and are of interest as, for example, reagents for organic synthesis. A series of pure [BH(4)](-) ILs with 1-butyl-2,3-dimethylimidazolium (BMMIM), 1-ethyl-3-methylimidazolium (EMMIM), 1-propyl-1-methylpiperidinium (PropMPip), and1-butyl-1-methylpyrrolidinium (BMP) cations were prepared. All synthesized ILs are well soluble in CH(2)Cl(2). We developed a procedure that gives clean products with correct elemental analyses. In contrast to earlier reports, which when conducted by us yielded only mixtures of the boranate anion with major halide contamination (maximum [BH(4)](-) content: 77.5?%). These materials can be viewed as the starting material for the (hypothetical) hydrogen-storage redox shuttling sequence between [BH(4)](-) and [B(12)H(12)](2-), in which the triboranate anion [B(3)H(8)](-) is a formal intermediate. Here we also developed a facile route to [B(3)H(8)](-) ILs with [BMMIM](+), [EMMIM](+), [PropMPip](+), and [NBu(4)](+), in which Na[BH(4)] reacts in situ (enhanced by ultrasound) with the solvent CH(2)Cl(2) as the oxidizing agent to give the triboranate IL in high yield and purity according to the equation: 3?[BH(4)](-)+2?CH(2)Cl(2)+[Cat](+)→[B(3)H(8)](-)[Cat](+)+H(2)+2?CH(3)Cl+2?Cl(-). We further investigated this reaction path by additional NMR spectroscopic experiments, powder-XRD analysis, and quantum chemical DFT calculations.     

The preparation of WMeCl3Y (Y = S OR Se) and some coordination compounds of WMeCl3Y (Y = O,S OR Se)

The reaction of WCl₄Y (Y = S or Se) with Me₂Mg leads to the formation of WMeCl₃Y. The compounds WMeCl₃Y (Y = O, S or Se) are very reactive and attempts to isolate them in pure form failed. However, a range of complexes which they form with some nitrogen and oxygen donors have been isolated and characterised.