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1.
A protocol that adopts aqueous hydrogen peroxide as a terminal oxidant and [(Me3tacn)(CF3CO2)2RuIII(OH2)]CF3CO2 ( 1 ; Me3tacn=1,4,7‐trimethyl‐1,4,7‐triazacyclononane) as a catalyst for oxidation of alkenes, alkynes, and alcohols to organic acids in over 80 % yield is presented. For the oxidation of cyclohexene to adipic acid, the loading of 1 can be lowered to 0.1 mol %. On the one‐mole scale, the oxidation of cyclohexene, cyclooctene, and 1‐octanol with 1 mol % of 1 produced adipic acid (124 g, 85 % yield), suberic acid (158 g, 91 % yield), and 1‐octanoic acid (129 g, 90 % yield), respectively. The oxidative C?C bond‐cleavage reaction proceeded through the formation of cis‐ and trans‐diol intermediates, which were further oxidized to carboxylic acids via C? C bond cleavage.  相似文献   

2.
The facile one‐pot reaction of the stable N‐heterocyclic silylene LSi: 1 (L?(ArN)C(?CH2) CH?C(Me)(NAr), Ar=2,6‐iPr2C6H3) with Me2Zn, Me3Al, H3Al‐NMe3, and MeLi has been investigated. The silicon(II) atom in 1 is capable of insertion into the corresponding M? C and Al? H bonds under very mild reaction conditions. Thus, Me2Zn furnishes the bis(silyl) zinc complex LSi(Me)ZnSi(Me)L 2 as the sole product, irrespective of the molar ratio of the starting materials applied. Moreover, the reactions of 1 with Me3Al, H3Al‐NMe3, and MeLi lead directly to the 1,1‐addition products LSi(Me)(Al(thf)Me2) 3 , LSi(H)(AlH2(NMe3)) 4 , and LSi(Me)Li(thf)3 5 , respectively. All new compounds 2 – 5 were fully characterized by multinuclear NMR spectroscopy, mass spectrometry, elemental analyses, and single‐crystal X‐ray diffraction analyses.  相似文献   

3.
Mixed-ligand Complexes of Rhenium. IX. Reactions on the Nitrido Ligand of [ReN(Me2PhP)(Et2dtc)2]. Synthesis, Characterization, and Structures of [Re(NBCl3)(Me2PhP)(Et2dtc)2], [Re(NGaCl3)(Me2PhP)(Et2dtc)2], and [Re(NS)Cl(Me2PhP)2(Et2dtc)] BCl3, GaCl3 and S2Cl2 react with the well-known [ReN(Me2PhP)(Et2dtc)2] by attack of the nucleophilic nitrido ligand. Final products of these reactions are [Re(NBCl3)-(Me2PhP)(Et2dtc)2], [Re(NGaCl3)(Me2PhP)(Et2dtc)2], and [Re(NS)Cl(Me2PhP)2Et2dtc)] which have been studied by mass spectrometry, IR spectroscopy and X-ray diffraction. [Re(NBCl3)(Me2PhP)(Et2dtc)2] crystallizes in the triclinic space group P1 , Z = 2, a = 8.151(6), b = 9.935(8), c = 18.67(1) Å; α = 94.42(4), β = 97.09(1), γ = 101.35(4)°. The coordination geometry is a distorted octahedron. The equatorial coordination sphere is occupied by one phosphorus and three sulphur atoms. The fourth sulphur atom is in trans position to the Re?N? B moiety. The almost linear Re?N? B unit has an Re?N? B angle of 170.5(3)° with a Re? N bond length of 1.704(3) Å. The analogous [Re(NGaCl3)(Me2PhP)(Et2dtc)2] crystallizes in P21/c with a = 8.138(3), b = 18.279(2), c = 19.880(6) Å; β = 99.81(2)°; Z = 4. Rhenium has a distorted octahedral environment. The Re? N? Ga bond is slightly bent with an angle of 154.5(4)° and a Re? N bond length of 1.695(6) Å. [Re(NS)Cl(Me2PhP)2(Et2dtc)] crystallizes in the triclinic space group P1 , Z = 4, a = 9.514(2); b = 16.266(5); c = 18.388(3) Å; α = 88.75(2), β = 76.59(2), γ = 85.50(2)° with two crystallographically independent molecules in the asymmetric unit. Rhenium has a distorted octahedral environment with the chloro ligand in trans position to the almost linear thionitrosyl group. The Re?N bond lengths are 1.795(6) and 1.72(1) Å, respectively, and the N?S distances are 1.55(1) and 1.59(1) Å, respectively.  相似文献   

4.
Mixed-ligand Complexes of Rhenium. VI. Synthesis and X-Ray Structures of the Rhenium Thionitrosyl Complexes mer-[Re(NS)Cl2(Me2PhP)3] · CH2Cl2 and trans-[Re(NS)Cl3(Me2PhP)2] mer-Dichlorotris(dimethylphenylphosphine)(thionitrosyl)rhenium(I), mer-[Re(NS)Cl2(Me2PhP)3], and trans-Trichlorobis(dimethylphenylphosphine)(thionitrosyl)rhenium(II), trans-[Re(NS)Cl3(Me2PhP)2], are formed during the reaction of rhenium(V) mixed-ligand complexes of the general formula [ReN(Cl)(Me2PhP)2(R2tcb)] with disulphur dichloride (HR2tcb = N-(N,N-dialkylthiocarbamoyl)benzamidine). The chelating ligands are substituted during the reaction. mer-[Re(NS)Cl2(Me2PhP)3] crystallizes monoclinic in the space group P21/n. The dimensions of the unit cell are a = 8.854(2); b = 31.295(3); c = 11.981(3) Å; β = 108.14(1)°; Z = 4. A final R value of 0.033 was achieved on the basis of 5 387 reflections with I ≥ 3σ(I). The rhenium atom is coordinated in a distorted octahedral environment. The Me2PhP ligands are arranged meridionally cis to the linear thionitrosyl group. trans-[Re(NS)Cl3(Me2PhP)2] crystallizes in the monoclinic space group C2/c with an unit cell of the dimensions a = 33.320(9); b = 8.446(1); c = 17.28(5) Å; β = 116.09(1)°, Z = 8. The R value converged at 0.026 on the basis of 5 460 independent reflections. The metal is octahedrally coordinated with the phosphine ligands in trans position to each other. The angle Re? N? S is 175.7(3)°.  相似文献   

5.
Mixed-ligand Complexes of Technetium. XV. The Reaction of [TcNCl2(Me2PhP)3] with Dialkyldithiocarbamates and N,N-Dialkylthio-carbamoylbenzamidines [TcN(Cl)(Me2PhP)2(Et2dtc)], [TcN(Me2PhP)(Et2dtc)2], and [TcN(Et2dtc)2] can be prepared by stepwise ligand exchange reactions starting from dichlorotris(dimethylphenylphosphine)nitridotechnetium(V), [TcNCl2(Me2PhP)3], and diethyldithiocarbamate. In contrast to this, only one intermediate, [TcN(Cl)(Me2PhP)2(HEt2tcb)], could be isolated during the reaction with N,N-Diethlthiocarbamoylbenzamidine, which yields the bis chelate [TcN(HEt2tcb)2]. [TcN(Me2PhP)(Et2dtc)2] crystallizes in the monoclinic space group P21/c; a = 17.369(5) Å, b = 15.024(1) Å, c = 9.906(3) Å, β = 76.47(1)º, Z = 4. The phosphine is coordinated equatorially. The multiply bonded nitrogen ligand (Tc? N(1) 1.624(3) Å) strongly labilizes the trans positioned donor atom (distance Tc? S(4) 2.826(1) Å). [TcN(HEt2tcb)2] crystallizes in the triclinic space group P1 with a = 9.749(4) Å, b = 11.264(4) Å, c = 12.359(4) Å, α = 75.34(2)º, β = 79.69(2)º, γ = 87.55(2)º, Z = 2. The metal is five-coordinate with the nitrido donor atom occupying the apex of a square pyramid. It's basal plane is formed by the cis-coordinated chelate ligands. The technetium is situated over the basal plane by about 0.6 Å. The Tc?N distane was found to be 1.610(5) Å.  相似文献   

6.
A series of WIV alkyne complexes with the sulfur-rich ligand hydridotris(2-mercapto-1-methylimidazolyl) borate) (TmMe) are presented as bio-inspired models to elucidate the mechanism of the tungstoenzyme acetylene hydratase (AH). The mono- and/or bis-alkyne precursors were reacted with NaTmMe and the resulting complexes [W(CO)(C2R2)(TmMe)Br] (R=H 1 , Me 2 ) oxidized to the target [WE(C2R2)(TmMe)Br] (E=O, R=H 4 , Me 5 ; E=S, R=H 6 , Me 7 ) using pyridine-N-oxide and methylthiirane. Halide abstraction with TlOTf in MeCN gave the cationic complexes [WE(C2R2)(MeCN)(TmMe)](OTf) (E=CO, R=H 10 , Me 11 ; E=O, R=H 12 , Me 13 ; E=S, R=H 14 , Me 15 ). Without MeCN, dinuclear complexes [W2O(μ-O)(C2Me2)2(TmMe)2](OTf)2 ( 8 ) and [W2(μ-S)2(C2Me2)(TmMe)2](OTf)2 ( 9 ) could be isolated showing distinct differences between the oxido and sulfido system with the latter exhibiting only one molecule of C2Me2. This provides evidence that a fine balance of the softness at W is important for acetylene coordination. Upon dissolving complex 8 in acetonitrile complex 13 is reconstituted in contrast to 9 . All complexes exhibit the desired stability toward water and the observed effective coordination of the scorpionate ligand avoids decomposition to disulfide, an often-occurring reaction in sulfur ligand chemistry. Hence, the data presented here point toward a mechanism with a direct coordination of acetylene in the active site and provide the basis for further model chemistry for acetylene hydratase.  相似文献   

7.
Treatment of pyridine‐stabilized silylene complexes [(η5‐C5Me4R)(CO)2(H)W?SiH(py)(Tsi)] (R=Me, Et; py=pyridine; Tsi=C(SiMe3)3) with an N‐heterocyclic carbene MeIiPr (1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) caused deprotonation to afford anionic silylene complexes [(η5‐C5Me4R)(CO)2W?SiH(Tsi)][HMeIiPr] (R=Me ( 1‐Me ); R=Et ( 1‐Et )). Subsequent oxidation of 1‐Me and 1‐Et with pyridine‐N‐oxide (1 equiv) gave anionic η2‐silaaldehydetungsten complexes [(η5‐C5Me4R)(CO)2W{η2‐O?SiH(Tsi)}][HMeIiPr] (R=Me ( 2‐Me ); R=Et ( 2‐Et )). The formation of an unprecedented W‐Si‐O three‐membered ring was confirmed by X‐ray crystal structure analysis.  相似文献   

8.
Mixed-Ligand Complexes of Rhenium IV. The Reaction of [ReNCl2(Me2PhP)3] with Dithiocarbamates. X-Ray Crystal Structures of trans-Chloro-dimethyldithiocarbamato-bis(dimethylphenylphosphine) nitridorhenium(V), [ReN(Cl)(Me2PhP)2(Me2dtc)], and Bis(diethyldithiocarbamato)(dimethylphenylphosphine)nitridorhenium(V), [ReN(Cl)(Me2PhP)(Et2dtc)2] [ReNCl2(Me2PhP)3] reacts with dialkyldithiocarbamates, R2dtc?, under a stepwise ligand exchange. Final products of these reactions are the well-known [ReN(R2dtc)2] bischelates. Intermediatelly, however, complexes of the general formulae [ReN(Cl)(Me2PhP)2(R2dtc)] and [ReN(Me2PhP)(R2dtc)2] can be isolated. Representatives have been structurally characterized. [ReN(Cl)(Me2PhP)2(Me2dtc)] crystallizes monoclinic in the space group P21/c, Z = 4. The dimensions of the unit cell are a = 13.071(3); b = 11.622(1); c = 15.667(3) Å; β = 97.09(1)°. The rhenium atom has a distorted octahedral environment; the Re≡N bond length is 1.71(1) Å. The Re? Cl bond distance is markedly lengthened (2.665(2) Å) as a consequence of the strong trans labilizing influence of the coordinated nitrido ligand. [ReN(Me2PhP)(Et2dtc)2] crystallizes monoclinic in the space group P21/c, Z = 4, a = 17.262(3); b = 14.915(2); c = 9.888(2); β = 76.35(8)°. The equatorial coordination sphere is occupied by one phosphorus atom and three sulphur atoms. One of the dithiocarbamate ligands is coordinated bidentately; the second one with two distinct Re? S bond lengths. The Re? S(4) distance is 2.7983(2) Å which can be discussed as a weak interaction with the metal.  相似文献   

9.
Ruthenium(II) complexes, [RuCl(L)(CO)(PPh3)2] {where L?=?N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives}, are prepared from reaction between [RuHCl(CO)(PPh3)3] and N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives in toluene and characterized by elemental analysis and spectral data (electronic, infrared, 1H NMR, and 31P NMR). The combination of [RuCl(L)(CO)(PPh3)2] (0.01?mmol) and N-methylmorpholine-N-oxide (NMO) (3?mmol) is an active catalyst for the oxidation of primary, secondary, cyclic, allylic, aliphatic, and benzylic alcohols to their corresponding aldehydes and ketones at room temperature. The oxidation protocol is simple to operate and gives the corresponding carbonyl compounds good to excellent yields.  相似文献   

10.
The enantioselective reduction of prochiral ketones with NaBH4/Me2SO4/(S)-Me-CBS is described. Borane is generated in situ via the reaction of NaBH4 with Me2SO4 in tetrahydrofuran, which is as efficient as the commercial one. Such in situ–generated borane reagent was applied to reduce prochiral ketones in the presence of chiral oxazaborolidine catalyst directly. The corresponding chiral secondary alcohols were obtained with excellent enantiomeric excesses (93–99% ee) and good to excellent yield (80–99%).  相似文献   

11.
Investigations of the Reaction between the [Lithium(trimethylsilyl)amido]-methyl-trimethyl-silylamino-silane Me(Me3SiNLi)(Me3SiNH)SiH and different Electrophiles The lithium silylamide Me(Me3SiNLi)(Me3SiNH)SiH 1 reacts with chlorotrimethylsilan in the nonpolar solvent n-hexane to the N-substitution product Me[(Me3Si)2N](Me3SiNH)SiH 2 and to the cyclodisilazane [Me(Me3SiNH)Si—N(SiMe3)]2 3 nearly in same amounts. The reaction of 1 with chlorotrimethylstannane gives besides small amounts of the cyclodisilazane 3 the N-substitution product Me[(Me3Si)(Me3Sn)N](Me3SiNH)SiH 4 . By the reaction of 1 with trimethylsilyltriflate the cyclodisilazane 3 is obtained as the main product. Furthermore 2 and the cyclodisilazane 5 are formed. Ethylbromide shows no reaction with 1 under the same conditions. These results indicate the existence of an equilibrium of the lithium silylamide 1 , the silanimine Me(Me3SiNH)Si?N(SiMe3) and lithium hydride.  相似文献   

12.
Reaction of [RuCl(CNN)(dppb)] ( 1‐Cl ) (HCNN=2‐aminomethyl‐6‐(4‐methylphenyl)pyridine; dppb=Ph2P(CH2)4PPh2) with NaOCH2CF3 leads to the amine‐alkoxide [Ru(CNN)(OCH2CF3)(dppb)] ( 1‐OCH2CF3 ), whose neutron diffraction study reveals a short RuO ??? HN bond length. Treatment of 1‐Cl with NaOEt and EtOH affords the alkoxide [Ru(CNN)(OEt)(dppb)] ? (EtOH)n ( 1‐OEt?n EtOH ), which equilibrates with the hydride [RuH(CNN)(dppb)] ( 1‐H ) and acetaldehyde. Compound 1‐OEt?n EtOH reacts reversibly with H2 leading to 1‐H and EtOH through dihydrogen splitting. NMR spectroscopic studies on 1‐OEt?n EtOH and 1‐H reveal hydrogen bond interactions and exchange processes. The chloride 1‐Cl catalyzes the hydrogenation (5 atm of H2) of ketones to alcohols (turnover frequency (TOF) up to 6.5×104 h?1, 40 °C). DFT calculations were performed on the reaction of [RuH(CNN′)(dmpb)] ( 2‐H ) (HCNN′=2‐aminomethyl‐6‐(phenyl)pyridine; dmpb=Me2P(CH2)4PMe2) with acetone and with one molecule of 2‐propanol, in alcohol, with the alkoxide complex being the most stable species. In the first step, the Ru‐hydride transfers one hydrogen atom to the carbon of the ketone, whereas the second hydrogen transfer from NH2 is mediated by the alcohol and leads to the key “amide” intermediate. Regeneration of the hydride complex may occur by reaction with 2‐propanol or with H2; both pathways have low barriers and are alcohol assisted.  相似文献   

13.
Reactions of tBu(Me3Si)P? P(Li)? P(tBu)2 with CH3Cl and 1,2-Dibromoethane tBu(Me3Si)P? P(Li)? P(tBu)2 · 0.95 THF 1 with CH3Cl (?70°C) yields tBu(Me3Si)P? P = P(Me)(tBu)2 2 at ?70°C, with 1,2-Dibromoethane tBu(Me3Si)P? PBr? P(tBu)2 3 (main product) and tBu(Me3Si)P? P?P(Br)tBu2 4. 3 eliminates Me3SiBr yielding the cyclotetraphosphane {tBuP? P[P(tBu)2]}2 5 .  相似文献   

14.
The 3-(N,N-Dimethylamino)prop-1-enyl Group as a Chelate Ligand in Indium Organyls InBr3 reacts with Me2NCH2CH?CHMgCl (molar ratio 1 : 2) to form (Me2NCH2CH?CH)2InBr ( 1 ) as the first indium alkenyl compound with amino-functionalized alkenyl groups. The X-ray structure determination shows the formation of a chelate complex. 1 crystallizes in the orthorhombic space group Fddd with the unit cell parameters a = 14.904(2) Å, b = 17.140(1) Å and c = 21.035(2) Å. By reaction of Me2InBr with Me2NCH2CH?CHMgCl (molar ratio 1 : 1) (Me2NCH2CH?CH)InMe2 ( 2 ) is formed as a colorless, at room temperature liquid, monomeric compound. The n.m.r. and mass spectra are discussed.  相似文献   

15.
The new triphosphine (Me2P)2N? N(Me)(PMe2) ( 1 ), has been synthesized in pure form by the reaction of methylhydrazine with dimethylchlorophosphine in the presence of triethylamine. This triphosphine represents a bridge between phosphinoamine (>P? N(R)? P<) and phosphanyl hydrazide (>P? N(R)? N(R)? P<) backbones. Reaction of 1 with cis-[W(CO)4(NHC5H10)2] proceeds via two coordination modes to give four-membered M? P? N? P and five-membered M? P? N? N? P metallacyclic frameworks. The tungsten complex cis-[W(CO)4{(Me2P)2NN(Me)(PMe2)}] ( 2 ) possessing an uncoordinated phosphine moiety to prepare multimetallic organometallic compounds. For example, reactions of 2 with PdCl2(PhCN)2 and PtCl2(COD) produced the trimetallic complexes consisting of W(0)? Pt(II) and W(0)? Pd(II) centers respectively in good yields. The different isomers of these trinuclear complexes have been clearly identified by 31P NMR spectroscopy.  相似文献   

16.
Four binuclear Co(Ⅱ), Ni(Ⅱ) and Cu(Ⅱ) complexes bridged by oxamidate (oxd) group have been synthesized, namely Co2(byp)2(oxd)(ClO4)2 (1), Co2(Me2bpy)2(oxd)(ClO4)2.H2O (2), Ni2(bpy)2(oxd)(ClO4)2.2H2O (3) and Cu2(Me2bpy)2(oxd)(NO3)2 (4). (bpy=2,2'-bipyridyl, Me2-bpy=4,4'-dimethylbipyridyl, oxd=oxamidate) The complexes are characterized by IR, UV spectra, EPR and variable-temperature magnetic susceptibility (4-300 K). The susceptibility data for. complexes 1 and 3 were least-squares fit to the susceptibility equation derived from the spin Hamiltonian H=-2J . S1 . S2. The exchange integral, J, was found to be equal to -3.62 cm-1 in 1 and -1.82 cm-1 in 3. This indicates a weak antiferromagnetic spin exchange interaction between the metal ions.  相似文献   

17.
An oxygen atom is selectively inserted into the P?B bond of a borylphosphine ( L1 ) by reaction with Me3NO to afford the corresponding borylphosphinite ( L2 ). This transformation can also be effected when L1 is coordinated to rhodium. The ν(CO) values for trans‐[RhCl(CO)(L)2] reveal very different electronic properties for coordinated L1 and L2 which translate into the strikingly different performances of the complexes [RhCl(L)(cod)] (L= L1 or L2 , cod=1,5‐cyclooctadiene) in hydrosilylation and hydroboration catalysis.  相似文献   

18.
Alternative Ligands. XXII. Rhodium(I) complexes with Donor/Acceptor Ligands of the Typs Me2PCH2CH2SiXnMe3?n(X = F, Cl, OMe) Donor/acceptor ligand of the type Me2PCH2SiXnMe3?n react with [Rh(CO)2Cl]2 ( 1 ) to give the mononuclear complexes RhCl(CO)(PMe2CH2CH2SiXnMe3?n)2 ( 2-6 , Table 1) with planar geometry of the donor atoms, one exception being Me2PCH2CH2CH2SiCl3, yielding the crystalline RhIII-complex RhCl2(CO)(PMe2CH2CH2SiCl2)(PMe2CH2CH2SiCl3) ( 7 ) by oxidative addition of one of the SiCl bonds to the Rh1 precursor. Structures with Rh → Si interaction between the basic central atoms and the acceptor group SiXnMe3?n could be detected in the isolated products neither spectroscopically nor by X-ray diffraction of the two representatives RhCl(CO)(PMe2CH2CH2SiF3)2 ( 2 ) and RhCl(CO)[PMe2CH2CH2siF3]2 ( 2 ) and RhCl(CO) [PMe2CH2CH2Si(OMe3]2 ( 6 ). The presence of such acid/base adducts in the reaction mixture is indicated for the more acidic acceptor groups SiXnMe3?n byvco values near 1990cm?1, (see Table 3). The complex RhCl(CO)PMe3)(PMe2CH2CH2SiF3 ( 8 ) is obtained by the reaction of RhCl(CO)(PMe3)2 ( 9 ) with Me2PCH2SiF3 and has been identified spectroscopically in a mixture with 2 and 9 .  相似文献   

19.
Catalytic Carbonylation of Acetone Oxime at Bisoximatodiruthenium Complexes: A Simple Access to Anhydrous Acetonine. Isolation and Molecular Structure of [Ru2(CO)5(Me2CNO)2(Me2CNOH)] In the presence of catalytic amounts of [Ru2(CO)4(Me2CNO)2(Me2CNOH)2] ( 1 ), acetone oxime reacts with carbon monoxide to give 2,3,4,5-tetrahydro-2,2,4,4,6-pentamethylpyrimidine (‘acetonine’). CO2, and NH3. The reaction proceeds presumably via carbonylation of Me2C?NOH to the unstable intermediate Me2C?N? OCHO which undergoes decarboxylation to give the corresponding imine Me2C?NH. The final product is assumed to result from the cyclotrimerisation of Me2C?NH with elimination of NH3. Evidence for the intermediacy of the imine comes from the analogous reaction of acetophenone oxime, PhMeC?NOH, which gives the corresponding imine PhMeC?NH as a stable product. The isolation of the complex [Ru2(CO)5(Me2CNO)2(Me2CNOH)] ( 2 ) suggests the carbonylation to take place at the bridging oximato ligand of 1 .  相似文献   

20.
The rare‐earth‐metal? hydride complexes [{(1,7‐Me2TACD)LnH}4] (Ln=La 1 a , Y 1 b ; (1,7‐Me2TACD)H2=1,7‐dimethyl‐1,4,7,10‐tetraazacyclododecane, 1,7‐Me2[12]aneN4) were synthesized by hydrogenolysis of [{(1,7‐Me2TACD)Ln(η3‐C3H5)}2] with 1 bar H2. The tetrameric structures were confirmed by 1H NMR spectroscopy and single‐crystal X‐ray diffraction of compound 1 a . Both complexes catalyze the dehydrogenation of secondary amine? borane Me2NH ? BH3 to afford the cyclic dimer (Me2NBH2)2 and (Me2N)2BH under mild conditions. Whilst the complete conversion of Me2NH ? BH3 was observed within 2 h with lanthanum? hydride 1 a , the yttrium homologue 1 b required 48 h to reach 95 % conversion. Further reactions of compound 1 a with Me2NH ? BH3 in various stoichiometric ratios gave a series of intermediate products, [{(1,7‐Me2TACD)LaH}4](Me2NBH2)2 ( 2 a ), [(1,7‐Me2TACDH)La(Me2NBH3)2] ( 3 a ), [(1,7‐Me2TACD)(Me2NBH2)La(Me2NBH3)] ( 4 a ), and [(1,7‐Me2TACD)(Me2NBH2)2La(Me2NBH3)] ( 5 a ). Complexes 2 a , 3 a , and 5 a were isolated and characterized by multinuclear NMR spectroscopy and single‐crystal X‐ray diffraction studies. These intermediates revealed the activation and coordination modes of “Me2NH ? BH3” fragments that were trapped within the coordination sphere of a rare‐earth‐metal center.  相似文献   

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