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1.
Hydrocarbon solutions of Mo2(O—t-Bu)6 and PF3 (2 equiv) yield Mo4F4(O—t-Bu)8, I, and PF2(O—t-Bu). Compound I contains a bisphenoid of molybdenum atoms with two short MoMo distances, 2.26 Å, and four long MoMo distances, 3.75 Å, corresponding to localized MoMo triple bonding and non-bonding distances, respectively. The tetranuclear compound may be viewed as a dimer, [Mo22-F)2(O-t-Bu)4]2, and addition of PMe3 to hydrocarbon solutions of I yields Mo2F2(O—t-Bu)4(PMe3)2, II, which contains an unbridged MoMo triple bond of distance 2.27 Å. Each molybdenum atom is coordinated to two oxygen atoms, one fluorine atom and the phosphorus atom of the PMe3 ligand in a roughly square planar manner. The overall central Mo2O4F2P2 skeleton has C2 symmetry and NMR studies (1H, 19F and 31P) are consistent with the maintenance of this type of structure in solution. Infrared and electronic absorption spectral data are reported. These are the first compounds containing fluorine ligands attached to the (MoMo)6+ unit.  相似文献   

2.
Summary The compoundtrans-[MoCl2(PMe2Ph)4] has been prepared by the reduction of MoCl5 (by Mg) or of [MoCl3(PMe2Ph)3] (by LiBun) in the presence of PMe2Ph in tetrahydrofuran (THF). It has eff=2.84 B.M. and crystallises in space group P1 witha=11.591(3),b=12.931(3),c=12.703(3) Å, = 95.28(2), =105.97(2), =103.54(2)°. Refinement of the structure gave R=0.036. The Mo-Cl and Mo-P distances average 2.443(6) and 2.534(8) Å, respectively.Low-valent phosphine complexes of the Group VI metals continue to attract much attention because of their involvement in studies of the catalytic activation of dinitrogen(1), dihydrogen(2, 3), alkenes and alkynes(4). As a by-product during our studies of dinitrogen(1) and hydride(2) complexes of molybdenum and tungsten, we obtainedtrans-[MoCl2- (PMe2Ph)4] as yellow, paramagnetic crystals (eff= 2.84 B.M.). We first obtained the compound during the attempted synthesis ofcis-[Mo(N2)2(PMe2Ph)4] by reduction of MoCl5 with Mg in the presence of PMe2Ph (see Experimental). Upon identification of the compound we found that it could be readily synthesised by treatment of [MoCl3(PMe2Ph)3](5) with LiBun in THF in the presence of PMe2Ph (experimental).The complex was shown to have thetrans structure by x-ray analysis (Figure). Analogues oftrans-[MoCl2(PMe2Ph)4] have been prepared, namely [CrCl2(Me2PCH2CH2PMe2)2](6),trans- [MoCl2(PMe3)4](7), [WCl2(PMe2Ph)4](8) and [WCl2(PMe3)4](4), of which onlytrans-[MoCl2(PMe3)4] has been examined by X-rays(7). Its principal structural parametersi.e. d(Mo-Cl)= 2.420(6), d(Mo-P)av=2.496(3) Å(6) are close to those found here fortrans-[MoCl2(PMe2Ph)4].  相似文献   

3.
The reactions of [M2Cl2(μ-Cl)2(PMe2Ph)2] with mercapto-o-carboranes in the presence of pyridine afforded mono-nuclear complexes of composition, [MCl(SCb°R)(py)(PMe2Ph)] (M = Pd or Pt; Cb° = o-C2B10H10; R = H or Ph). The treatment of [PdCl2(PEt3)2] with PhCb°SH yielded trans-[Pd(SCb°Ph)2(PEt3)2] (4) which when left in solution in the presence of pyridine gave another substitution product, [Pd(SCb°Ph)2(py)(PEt3)] (5). The structures of [PdCl(SCb°Ph)(py)(PMe2Ph)] (1), [Pd(SCb°Ph)2(PEt3)2] (4) and [Pd(SCboPh)2(py)(PEt3)] (5) were established unambiguously by X-ray crystallography. The palladium atom in these complexes adopts a distorted square-planar configuration with neutral donor atoms occupying the trans positions. Thermolysis of [PdCl(SCb°)(py)(PMe2Ph)] (2) in TOPO (trioctylphosphine oxide) at 200 °C gave nanocrystals of TOPO capped Pd4S which were characterized by XRD pattern and SEM.  相似文献   

4.
The compounds [MoCl(NAr)2R] (R=CH2CMe2Ph (1) or CH2CMe3(2); Ar=2,6-Pri2C6H3) have been prepared from [MoCl2(NAr)2(dme)] (dme=1,2-dimethoxyethane) and one equivalent of the respective Grignard reagent RMgCl in diethyl ether. Similarly, the mixed-imido complex [MoCl2(NAr)(NBut)(dme)] affords [MoCl(NAr)(NBut)(CH2CMe2Ph)] (3). Chloride substitution reactions of 1 with the appropriate lithium reagents afford the compounds [MoCp(NAr)2(CH2CMe2Ph)] (4) (Cp=cyclopentadienyl), [MoInd(NAr)2(CH2CMe2Ph)] (5) (Ind=Indenyl), [Mo(OBut)(NAr)2(CH2CMe 2Ph)] (6), [MoMe(NAr)2(CH2CMe2Ph)] (7), [MoMe(PMe3)(NAr)2(CH2CMe 2Ph)] (8) (formed in the presence of PMe3) and [Mo(NHAr)(NAr)2(CH2CMe2P h)](9). In the latter case, a by-product {[Mo(NAr)2(CH2CMe2Ph) ]2(μ-O)}(10) has also been isolated. The crystal structures of 1, 4, 5 and 10 have been determined. All possess distorted tetrahedral metal centres with cis near-linear arylimido ligands; in each case (except 5, for which the evidence is unclear) there are α-agostic interactions present.  相似文献   

5.
Three new tetrahedral rhenium cluster compounds [Re4Se4(PMe2Ph)4Br8]·1.5CH2Cl2 (1), [Re4Te4(PMe2Ph)4Br8]·CH2Cl2 (2), and [Re4Te4(PMe2Ph)4Cl8]·CH2Cl2 (3) have been synthesized by the reaction of the corresponding precursor chalcohalide complexes [Re4Q4(TeX2)4X8] (X = Br, Q = Se (for 1), Te (for 2); X = Cl, Q = Te (for 3)) with dimethylphenylphosphine in CH2Cl2. All compounds have been characterized by X-ray single-crystal diffraction and elemental analyses, IR and 31P NMR spectroscopy. 31P NMR spectroscopy indicates the formation of isomers in solution, confirmed by single-crystal X-ray analysis.  相似文献   

6.
Novel tetrameric rhenium(V) complexes have been prepared from [ReNCl2(PPh3)2] and [ReN(PMe2Ph)(S2CNEt)2], respectively. [ReNCl2(PPh3)2] reacts with 1.5 equivalents of KS2CNEt2 in methanol to yield the unusual dark red species [{cyclo-ReN}4(S2CNEt2)6(MeOH)2(PPh3)2][BPh4]2 · CH2Cl2 · 2 H2O ( 1 ). The crystal structure of the tetramer (triclinic, space group P1, a = 13.842(2), b = 15.213(2), c = 16.796(3) Å, α = 67.88(1), β = 70.90(1), γ = 88.05(1)°, U = 3080.2(8) Å3, Z = 1) shows four rhenium atoms in a square configuration which are bridged via linear asymmetric Re≡N–Re groups with bond lengths of about 169 and 203 pm. The molecule contains a centre of symmetry with two distinct octahedral rhenium environments. The first rhenium environment contains two bidentate dithiocarbamate ligands which complete the octahedral geometry and the second contains a bidentate dithiocarbamate ligand, coordinated methanol and has retained a single phosphine coligand. A symmetric compound containing the {cyclo-ReN}4 core is obtained from the reaction of [ReN(PMe2Ph)(S2CNEt2)2] with Al2Cl6 in acetone. [{cyclo-ReN}4(S2CNEt2)4Cl4(PMe2Ph)4] · 2 acetone ( 2 ) forms red crystals (monoclinic, space group C2/c, a = 21.432(6), b = 13.700(3), c = 28.060(9) Å, β = 102.37(1)°, U = 8048(4) Å3, Z = 4) with each rhenium atom coordinated by a bidentate dithiocarbamato, a phosphine and a chloro ligand. The non-planar 8-membered {ReN}4 ring contains asymmetric Re≡N–Re bridges (mean values: 1.69 Å and 2.029 Å, respectively). In contrast, reaction of [ReNCl(S2CNEt2)(PMe2Ph)2] with one equivalent of K[S2CN(Me)CH2CH2NMe3]I gave the mixed dithiocarbamato-cation [ReN(S2CNEt2)(S2CN(Me)CH2CH2NMe3)(PMe2Ph)]+ ( 3 ) which was isolated as a tetraphenylborate salt.  相似文献   

7.
The reactions of PhCboSeNa (Cbo = o-C2B10H10), prepared by reductive cleavage of Se-Se bond in (PhCboSe)2 by NaBH4 in methanol, with Na2PdCl4, MCl2(PR3)2 and [M2Cl2(μ-Cl)2(PR3)2] afforded a variety of complexes, viz., [Pd(SeCboPh)Cl] (1), [M(SeCboPh)2(PR3)2], [M2Cl2(μ-SeCboPh)(μ-Cl)(PR3)2] (M = Pd, Pt) and [Pd2Cl(SeCb0Ph)(μ-Cl)(μ-SeCboPh)(PEt3)2] (7) have been isolated. These complexes were characterized by elemental analyses and NMR (1H, 31P, 77Se, 195Pt) spectroscopy. The structures of [Pd(SeCboPh)2(PEt3)2] (2), [Pt(SeCboPh)2(PMe2Ph)2] (3), [Pd2Cl2(μ-SeCboPh)(μ-Cl)(PMe2Ph)2] (5) and [Pd2Cl(SeCboPh)(μ-Cl)(μ-SeCboPh)(PEt3)2] (7) were established by X-ray crystallography. The latter represents the first example of asymmetric coordination of selenolate ligands in binuclear bis chalcogenolate complexes of palladium and platinum. Thermolysis of [Pd(SeCboPh)2(PEt3)2] (2) in HDA (hexadecylamine) at 330 °C gave nano-crystals of Pd17Se15.  相似文献   

8.
Five complexes of type cis-[PtCl2(PR3)Q] (PR3 =PMe3, PMe2Ph, PEt3; Q = CH2 CHOCOCH3 or CH2=CHCH2OCOCH3) have been prepared. The crystal structure of cis-[PtCl2[PME2Ph)(CH2=CHOCOCH3)] is described. Crystals of cis-[PtCl2(PME2Ph)(CH2-CHOCOCH3)] are triclinic, with a 8.441(4), b 13.660(5), c 7.697(3) Å, a 101.61(3)°, β 111.85(3)° γ 95.22(3)°, pP1, Z = 2. The structure was determined from 2011 reflections I σ 3σ (I) and refined to R = 0.037. The CH3COO grouping is syn to the cis-PMe2Ph ligand, with bond lengths of PtCl (trans to P) 2.367(3), PtCl (trans to olefin) 2.314(3), PtP 2.264(2), and PtC of 2.147(12) and 2.168(11) Å. The complexes cis-[PtCl2- (PR3)Q] were studied by variable temperature 1H and 31P NMR spectroscopy. Spectra of the vinyl acetate complexes were temperature dependent as a result of rotation about the platinum—olefin bond. The rotation was “frozen out” at ca. 240 K; for cis-[PtCl2(PME2Ph)(CH2=CHOCOCH3] ΔG≠ (rotation) 15.0 ± 0.2 kcal mol-1. NMR parameters for the rotamers are reported. NMR studies of the interaction between chloro-bridged complexes of type [Pt2Cl2(PR3)2] (PR3 = P-N-Pr3 or PMe2Ph) and vinyl acetate shows that even at low temperatures (213 K) equilibrium favours the bridged complex and the proportion of trans-[PtCl2(PR3)CH2=CHOCOCH3)] is very small e.g. 2%. The allyl acetate complexes cis-[PtCl2(PR3)(CH2=CHCH2OCOCH3)] showed only one rotamer over the range 333–213 K. Reversible dissociation of cis-[PtCl2(PMe2Ph)- (CH2=CHCH2OCOCH3)] to [Pt2Cl4(PMe2Ph)2] + allyl acetate was studied at ambient temperature. At low temperatures e.g. 213–190 K addition of allyl acetate to a CDCl3 solution of [Pt2Cl2(P-n-Pr3)2] reversibly gave some olefin complex trans-[PtCl2(P-n-Pr3)(CH2=CHCH2OCOCH3)] and some O-bonded complex trans-[PtCl2(P-n-Pr3)(CH2=CHCH2OCOCH3)].  相似文献   

9.
Trimethylsilyldiethylamine Me3SiNEt2 and MoOCl4 (1:1) undergo a free radical redox reaction in CH2Cl2 or Et2O to form MoCl3O(HNEt2). Reduction occurs even in aprotic media like CCl4 and CS2 to give MoV complexes Mo2Cl6O2(N2Et4) and Mo2Cl6O2[(SCNEt2)2S2], respectively. A 2:1 reaction in nonionizing protic solvents undergoes redox cum cleavage to provide MoCl2O(NEt2) (HNEt2) but a reaction at reflux temperature in 1,2-dichloroethane leads to diethylammonium salt, [Et2NH2][MoCl4O(HNEt2)]. Higher molar reactions (3:1, 4:1) in CH2Cl2 or Et2O are associated with redox reaction as well as oxygen atom abstraction to form de-oxo MoIV complex MoCl3(NEt2)(HNEt2)2, whereas, a 3:1 reaction in CS2 forms Mo2Cl4O(S2CNEt2)4. Compounds have been characterized by elemental analyses, redox titration, magnetic moment, conductance, infrared, electronic absorption and 1H-NMR measurements.  相似文献   

10.
[CpRu(dppf)Cl] (Cp=η5-C5H5) (1) and [(HMB)Ru(dppf)Cl]PF6 ((HMB)=η6-C6Me6) (3) react with different donor ligands to give rise to N-, P- and S-bonded complexes. The stoichiometric reactions of 1 and 3 with NaNCS give the mononuclear complexes [CpRu(dppf)(NCS)] (2) and [(HMB)Ru(dppf)(NCS)]PF6 (4), respectively, in yields above 80%, while 3 also gives a dppf-bridged diruthenium complex [(HMB)Ru(NCS)2]2(μ-dppf) (5) in 67% yield from reaction with four molar equivalents of NaNCS. Compound 5 is also obtained in 70% yield from the reaction of 4 with excess NaNCS. With CH3CN in the presence of salts, both 1 and 3 give their analogous solvento derivatives [CpRu(dppf)(CH3CN)]BPh4 (6) and [(HMB)Ru(dppf)(CH3CN)] (PF6)2 (7). With phosphines, the reaction of 1 gives chloro-displaced complexes [(CpRu(dppf)L]PF6 (L =PMe3 (8), PMe2Ph(9)), whereas the reaction of 3 with PMe2Ph leads to substitution of dppf, giving [(HMB)Ru(PMe2Ph)2Cl] PF6 (10). The reaction of 1 with NaS2CNEt2 gives a dinuclear dppf-bridged complex [{CpRu(S2CNEt2)}2(μ-dppf)] (11), whereas that of 3 results in loss of the HMB ligand giving a mononuclear complex [Ru(dppf)(S2CNEt2)2] (12). With elemental sulfur S8, 1 is oxidized to give a dinuclear CpRuIII dppf-chelated complex [{CpRu(dppf)}2(μ-S2)](BPh4)Cl (13), whereas 3 undergoes oxidation at the ligand, giving a dppf-displaced complex [(HMB)Ru(CH3CN)2Cl]PF6 (14) and free dppfS2. The structures of 1, 2, 5-9, 11, 13 and 14 were established by X-ray single crystal diffraction analyses. Of these, 5 and 11 both contain a dppf-bridge between RuII centers, while 13 is a dinuclear CpRuIII disulfide-bridged complex; all the others are mononuclear. All complexes obtained were also spectroscopically characterized.  相似文献   

11.
The reaction of [Rh2(acac)2{μ-C(p-tol)2}2(μ-SbiPr3)] (1) with PMe3 led to the displacement of the stibine by phosphine and afforded the highly labile intermediate [Rh2(acac)2(PMe3){μ-C(p-tol)2}2] (2) in which the PMe3 ligand possibly occupies a terminal position. Treatment of 2 with CO at low temperatures gave the unsymmetrical dinuclear complex [Rh2(acac)2(PMe3){μ-C(p-tol)2}2(μ-CO)] (3), the molecular structure of which was determined crystallographically.  相似文献   

12.
A controlled polymerisation of styrene has been achieved under ATRP conditions by using a phosphine-containing MoIII/MoIV system. Linearity of the Mn vs conversion plot and low PDI’s are observed in bulk, in a 30% (v/v) PhCl solution, and in a chain extension experiment when using MoCl3(PMe3)3/BIB. Controlled polymerisation is also observed for a reverse ATRP experiment starting from MoCl4(PMe3)3/AIBN. The absence of chain transfer and termination is confirmed by NMR and MALDI–TOF analyses of polymers obtained by employing BEB and BIB as initiators. To cite this article: F. Stoffelbach et al., C. R. Chimie 5 (2002) 37–42  相似文献   

13.
New Phosphido-bridged Multinuclear Complexes of Ag and Zn. The Crystal Structures of [Ag3(PPh2)3(PnBu2tBu)3], [Ag4(PPh2)4(PR3)4] (PR3 = PMenPr2, PnPr3), [Ag4(PPh2)4(PEt3)4]n, [Zn4(PPh2)4Cl4(PRR′2)2] (PRR′2 = PMenPr2, PnBu3, PEt2Ph), [Zn4(PhPSiMe3)4Cl4(C4H8O)2] and [Zn4(PtBu2)4Cl4] AgCl reacts with Ph2PSiMe3 in the presence of tertiary Phosphines (PnBu2tBu, PMenPr2, PnPr3 and PEt3) to form the multinuclear complexes [Ag3(PPh2)3(PnBu2tBu)3] 1 , [Ag4(PPh2)4(PR3)4] (PR3 = PMenPr2 2 , PnPr3 3 ) and [Ag4(PPh2)4(PEt3)4]n 4 . In analogy to that ZnCl2 reacts with Ph2PSiMe3 and PRR′2 to form the multinuclear complexes [Zn4(PPh2)4Cl4(PRR′2)2] (PRR′2 = PMenPr2 5 , PnBu3 6 , PEt2Ph 7 ). Further it was possible to obtain the compounds [Zn4(PhPSiMe3)4Cl4(C4H8O)2] 8 and [Zn4(PtBu2)4Cl4] 9 by reaction of ZnCl2 with PhP(SiMe3)2 and tBu2PSiMe3, respectively. The structures were characterized by X-ray single crystal structure analysis. Crystallographic data see “Inhaltsübersicht”.  相似文献   

14.
[C4H9)4N]2[Mo2O7] reacts with a variety of organic species containing α-diketone groups to give tetranuclear complexes of general composition [RMo4O15X]3−. The complexes [(C4H9)4N]3[(C9H4O)Mo4O15(OCH3)] (I), [(C4H9)4N]3[(C14H10)Mo4O15(C6H5CO2)] (11) and [(C4H9)4N]3[(C14H8)Mo4O15(OH)] (III) were synthesized from the reactions of dimolybdate with ninhydrin, benzil and phenanthraquinone, respectively. Complex II may also be prepared from dimolybdate and benzoin in acetonitrile-methanol solution, from which it co-crystallizes with the binuclear species [(C4H9)4N]2[Mo2O5(C6H5C(O)C(O)C6H5)2] · CH3CN · CH3OH (IV). Complexes I–III exhibit the tetranuclear core, previously described for the α-glyoxal derivatives [(C4H9)4N]3[(HCCH)Mo4O15X], where X = F or HCO2. The ligands may be formally described as diketals, formed by insertion of ligand carbonyl subunits into molybdenum-oxygen bonds. The structures I–III differ most dramatically in the identity and coordination mode of the anionic ligand X which occupies a position opposite the diketal moiety relative to the [Mo4O11]2+ central cage. Thus, I exhibits a doubly bridging methoxy group in this position, while II possesses a benzoate ligand with an unusual μ3-O,O′coordination mode. Complex III presents a hydroxy-group unsymmetrically bonded to three of the molybdenum centres. The stereochemical consequences of the various coordination modes are discussed. Crystal data: Compound I, monoclinic space group Pc, a = 24.888(2), b = 12.897(3), c = 24.900(3) Å, β = 101.94(2)°, Dcalc = 1.28 g cm−1 for Z = 4. Structure solution and refinement based on 8695 reflections with Fo 6σ(Fo) (Mo-Kα, λ = 0.71073 Å) converged at a conventional discrepancy factor of 0.060. Compound II, orthorhombic space group Pbca, a = 20.426(6), b = 26.916(6), c = 32.147(7) Å, V = 17673.2(20) Å3, Dcalc = 1.33 g cm−3 for Z = 8; 5224 reflections, R = 0.076. Compound III, tetragonal space group I41/a, a = b = 48.129(6), c = 13.057(2) Å, V = 30246.2(12) Å3, Dcalc = 1.35 g cm−3 for Z = 16; 5554 reflections, R = 0.053. Compound IV, orthorhombic space group Pnca, a = 16.097(4), b = 16.755(4), c = 25.986(7) Å, V = 7008.1(13) Å3, Z = 4, Dcalc = 1.18 g cm−3 ; 2944 reflections, R = 0.061.  相似文献   

15.
The mechanism of the reactions of aryl/heteroaryl halides with aryl Grignard reagents catalyzed by [FeIII(acac)3] (acac=acetylacetonate) has been investigated. It is shown that in the presence of excess PhMgBr, [FeIII(acac)3] affords two reduced complexes: [PhFeII(acac)(thf)n] (n=1 or 2) (characterized by 1H NMR and cyclic voltammetry) and [PhFeI(acac)(thf)]? (characterized by cyclic voltammetry, 1H NMR, EPR and DFT). Whereas [PhFeII(acac)(thf)n] does not react with any of the investigated aryl or heteroaryl halides, the FeI complex [PhFeI(acac)(thf)]? reacts with ArX (Ar=Ph, 4‐tolyl; X=I, Br) through an inner‐sphere monoelectronic reduction (promoted by halogen bonding) to afford the corresponding arene ArH together with the Grignard homocoupling product PhPh. In contrast, [PhFeI(acac)(thf)]? reacts with a heteroaryl chloride (2‐chloropyridine) to afford the cross‐coupling product (2‐phenylpyridine) through an oxidative addition/reductive elimination sequence. The mechanism of the reaction of [PhFeI(acac)(thf)]? with the aryl and heteroaryl halides has been explored on the basis of DFT calculations.  相似文献   

16.
The new pyrazine-pillared solids, AgReO4(C4H4N2) (I) and Ag3Mo2O4F7(C4H4N2)3 (C4H4N2=pyrazine, pyz) (II), were synthesized by hydrothermal methods at 150 °C and characterized using single crystal X-ray diffraction (IP21/c, No. 14, Z=4, a=7.2238(6) Å, b=7.4940(7) Å, c=15.451(1) Å, β=92.296(4)°; IIP2/n, No. 13, Z=2, a=7.6465(9) Å, b=7.1888(5) Å, c=19.142(2) Å, β=100.284(8)°), thermogravimetric analysis, UV-Vis diffuse reflectance, and photoluminescence measurements. Individual Ag(pyz) chains in I are bonded to three perrhenate ReO4- tetrahedra per layer, while each layer in II contains sets of three edge-shared Ag(pyz) chains (π-π stacked) that are edge-shared to four Mo2O4F73- dimers. A relatively small interlayer spacing results from the short length of the pyrazine pillars, and which can be removed at just slightly above their preparation temperature, at >150-175 °C, to produce crystalline AgReO4 for I, and Ag2MoO4 and an unidentified product for II. Both pillared solids exhibit strong orange-yellow photoemission, at 575 nm for I and 560 nm for II, arising from electronic excitations across (charge transfer) band gaps of 2.91 and 2.76 eV in each, respectively. Their structures and properties are analyzed with respect to parent ‘organic free’ silver perrhenate and molybdate solids which manifest similar photoemissions, as well as to the calculated electronic band structures.  相似文献   

17.
The reaction of NbCl4(THF)2 with an excess of PMe3 in toluene solution afforded a 70% isolated yield of green NbCl4(PMe3)3. When a slurry of TaCl5 in toluene containing a slight excess of PMe3 was reduced with sodium amalgam overnight, a 60% yield of orange to red (depending on crystal size) Ta2Cl8(PMe3)4 was obtained. Both compounds have been fully characterized by X-ray crystallography. NbCl4(PMe3)3 forms monoclinic crystals (P21/c) with unit cell dimensions a = 15.061(3) Å, b = 11.677(4) Å, c = 11.583(4) Å, β = 91.71(3)°, V = 2036(2) Å3, and Z = 4. It is isomorphous with its TaCl4(PMe3)3 homolog, and the bond lengths and angles are very similar. Ta2Cl8(PMe3)4 forms cubic crystals (Im3) with a = 16.377(2), V = 4392(2) Å3 and Z = 6. It is thus isomorphous with its niobium homolog, and the internal dimensions are quite comparable. The Ta-Ta distance is 2.830(1) Å, consistent with the existence of a single bond.  相似文献   

18.
Electron-impact-induced mass spectra of MoO2(C5H7O2)2, 1, and Mo2O3(C5H7O2)4, 2, recorded at an ion-source temperature of 100°C show the molecular ion signals at m/z 328 and at m/z 636, respectively, indicating that they do not undergo association in the vapour state. The parent ion of 1, unlike bis(acetylacetonato)metalates of the first-row transition metals, loses (CH2CO followed by C3H5O to produce [MoO2(C5H7O2)]+ at m/z 229, the base peak, which ultimately fragments to [MoO2]+. The molecular ion of 2, [Mo2O3(C5H7O2)4]+, undergoes fragmentation following two different, but equally probable, pathways with one involving the loss of C5H7O2 and C5H7O groups producing the ion [Mo2O4(C5H7O2)2]+, and the other involving the formation of the ion [MoO(acac)2]+ directly from the parent ion. The signal at m/z 312 owing to the ion [MoO(C5H7O2)2]+ constitutes the base peak in the spectrum of 2. Metastable transitions were studied, and the most probable fragmentation schemes for the compounds 1 and 2 are suggested. There is evidence for CH3 shift from the ligand to the oxygen atoms bound to the metal centres or to form metal-carbon bonds.  相似文献   

19.
[C5Me5Rh(μ-co)]2 reacts with phosphines (PMe2H, PMe3) and trimethylphosphite to give the binuclear complexes C5Me5(L)Rh(μ-CO)2RhC5Me5 which have been characterised by elemental analyses, mass spectra,1H and 31P NMR data. They are surprisingly inert toward an excess of L and do not react to give the mononuclear compounds C5Me5Rh(CO)L. These are obtained in good yields from C5Me5Rh(CO)2 and L where L is PMe2H, P(OMe)3, PEt3, P(OEt)3 and PMe2Ph.  相似文献   

20.
Sodium amalgam reduction of the complexes [MCl3(PMe3)3] (M = Mo, W) in tetrahydrofuran, under dinitrogen, yields dark red-brown suspensions from which red-orange crystals of composition trans-[MCl(N2)· (PMe3)4] can be collected. Spectroscopic and chemical evidence indicate the compounds are best formulated as mixtures of trans-[M(N2)2(PMe3)4] and trans-[MCl2(PMe3)4] species, but attempts to isolate the pure bis(dinitro derivatives have proved unsuccessful. Single crystals of analytical composition [MCl(N2)(PMe3)4] have been studied by X-ray crystallography, and the structure of trans-[MoCl2(PMe3)4] has been determined for comparison. trans-[MCl(N2)(PMe3)4] (M = Mo, W) and trans-[MoCl2(PMe3)4] are all isostructural, crystallizing in the tetragonal space group I42 trans-[MoCl(N2)(PMe3)4] has a = 9.597(5), b = 12.294(6) Å, Dc = 1.36g cm?3 Z = 2 and was refined to a final R value of 0.021 based on 319 independent observed reflections. The tungsten analogue has a = 9.573(4), b = 12.278(5) Å, Dc = 1.63g cm?3 for Z = 2 and was refined to R = 0.19 with 322 independent observed reflections. trans-[MoCl2(PMe3)4] has cell parameters a = 9.675(5), b = 12.311(6) Å Dc = 1.36 g cm?3 for Z = 2 and was refined to R = 0.043 with 316 independent observed reflections. In each case the metal atom resides on a crystallographic 42m position. For trans-[MoCl(N2)(PMe3)4] (M = Mo, W) the chlorine and dinitrogen ligands are disordered. M-N distances of 2.08(1) ? (M = Mo) and 2.04(2) ? (M = W) and M-Cl bond lengths of 2.415(8) Å (M = Mo) and 2.46(1) Å (M = W) are observed. In trans-[MoCl2(PMe3)4], where there is no disorder, the Mo-Cl distance is 2.420(6) Å.  相似文献   

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