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1.
[Mo2(OAc)4] reacts with three or more equivalents of lithium chloride and PMe3 in thf to give [Mo2Cl3(μ-OAc)(PMe3)3]0.75thf (1). The IR spectrum of the complex shows Mo---O and Mo---Cl stretches at 350 and 300 cm−1 respectively and the 1H and 13C NMR spectra suggest several species are present in solution. [Mo2Cl3(μ-OAc)(PMe3)3] converts slowly in thf to [Mo2Cl4(PMe3)4] and [Mo2(OAc)4]. The structure of [Mo2Cl3(μ-OAc) (PMe3)3]0.5C6H5Me (2) has been determined by single-crystal X-ray diffraction methods. Crystals of the toluene solvate are tetragonal with a = 20.726(2), c = 11.776(2) Å, space GROUP = I4cm. The structure was solved by Patterson and Fourier methods and refined to R of 0.035 for the 539 observed data. The molecule contains two metal centres each of which shows 5-fold coordination. The two molybdenum atoms are linked by an acetate bridge and a short Mo---Mo bond of 2.121(3) Å. Remaining coordination sites are occupied on Mo(1) by two Cl and one PMe3 and on Mo(2) by one Cl and two PMe3 groups.  相似文献   

2.
Reaction of C5H4(SiMe3)2 with Mo(CO)6 yielded [(η5-C5H3(SiMe3)2)Mo(CO)3]2, which on addition of iodine gave [(η5-C5H3(SiMe3)2Mo(CO)3I]. Carbonyl displacement by a range of ligands: [L = P(OMe)3, P(OPri)3,P(O-o-tol)3, PMe3, PMe2Ph, PMePh2, PPh3, P(m-tol)3] gave the new complexes [(η5-C5H3(SiMe3)2 MO(CO)2(L)I]. For all the trans isomer was the dominant, if not exclusive, isomer formed in the reaction. An NOE spectral analysis of [(η5-C5H3(SiMe3)2)Mo(CO)2(L)I] L = PMe2Ph, P(OMe)3] revealed that the L group resided on the sterically uncongested side of the cyclopentadienyl ligand and that the ligand did not access the congested side of the molecule. Quantification of this phenomenon [L = P(OMe)3] was achieved by means of the vertex angle of overlap methodology. This methodology revealed a steric preference with the trans isomer (less congestion of CO than I with an SiMe3 group) being the more stable isomer for L = P(OMe)3.  相似文献   

3.
Treatment of ruthenium complexes [CpRu(AN)3][PF6] (1a) (AN=acetonitrile) with iron complexes CpFe(CO)2X (2a–2c) (X=Cl, Br, I) and CpFe(CO)L′X (6a–6g) (L′=PMe3, PMe2Ph, PMePh2, PPh3, P(OPh)3; X=Cl, Br, I) in refluxing CH2Cl2 for 3 h results in a triple ligand transfer reaction from iron to ruthenium to give stable ruthenium complexes CpRu(CO)2X (3a–3c) (X=Cl, Br, I) and CpRu(CO)L′X (7a–7g) (L′=PMe3, PMe2Ph, PMePh2, PPh3, P(OPh)3; X=Br, I), respectively. Similar reaction of [CpRu(L)(AN)2][PF6] (1b: L=CO, 1c: P(OMe)3) causes double ligand transfer to yield complexes 3a–3c and 7a–7h. Halide on iron, CO on iron or ruthenium, and two acetonitrile ligands on ruthenium are essential for the present ligand transfer reaction. The dinuclear ruthenium complex 11a [CpRu(CO)(μ-I)]2 was isolated from the reaction of 1a with 6a at 0°C. Complex 11a slowly decomposes in CH2Cl2 at room temperature to give 3a, and transforms into 7a by the reaction with PMe3.  相似文献   

4.
The complexes (Hal)Nb(CO)3(PR3)3 (PR3 = PEt3, Hal = I; PR3 = PMe2Ph, Hal = Cl, Br, I) and (Hal)Nb(CO)4/2(dppe)1/2 (Hal = Br, I) have been prepared by oxidative halogenation of carbonylniobate with pyridinium halides (Hal = Cl, Br) or iodine (Hal = I). In the tricarbonyls, one CO and one PR3 are labile and can be displaced by a four-electron donating alkyne to give all-trans-[(Hal)Nb(CO)2(RCCR′)(PR3)2] (PR3 = PMe2Ph; Hal = Cl, Br, I: R, R′ = H, Et, Ph; R = H, R′ = Ph. PR3 = PEt3, Hal = I: R, R′ = Pr; R = H, R′ = Bu, Ph; R = Me, R′ = Et). In the case of acetylene, INb(CO)(HCCH)2(PEt3)2 is also formed. PR3 can be displaced by P(OMe) 3. In the tetracarbonyls, two CO ligands are replaced by two isonitriles to form INb(CO)2(CNR)2dppe (R = tBu, Cy), or by one alkyne to form (Hal)Nb(CO)2(PhCCPh)dppe (Hal = Br, I). In these complexes, the remaining CO ligands occupy cis positions. The structure of BrNb(CO)2(dppe)2·THF, INb(CO)2(dppe)2·hexane and INb(CO)2(PEt3)2(MeCCEt) have been determined by a single crystal X-ray diffraction study. The alkyne complexes are best regarded as octahedral with the centre of the alkyne ligand occupying the positions trans to the halide and the CC axis aligned with the OC---Nb---CO axis. The complexes (Hal)Nb(CO)2(dppe)2 adopt a trigonal prismatic structure with the halide capping the tetragonal face spanned by the four phosphorus functions. The crystal structure of a by-product, Br2Nb(CO)(H2CPhPCH2CH2PPh2)2·1/2THF has also been determined. The geometry is pentagonal bipyramidal, with one of the bromine atoms and the CO on the axis. Some 93 Nb NMR data for the NbI complexes are presented, and preliminary observations on the reactions between the π-alkyne complexes and H2 or H− are reported.  相似文献   

5.
The binuclear molybdenum(II) complexes [Mo2(O2CCF3)4(PR3)2] (R = Ph, Et) act as templates for the self-condensation of 2-aminobenzaldehyde to give a new class of complexes in which a hydride ion bridges two molybdenum(III) centres, each of which carries a tetradentate macrocyclic ligand (C). The new hydrido complexes [Mo2(C)2 (H)(O2CCF3)3(PPh3)2] (I), [Mo2(C)2(H)2(O2CCF3)2(PPh3)2] (II), and [Mo2(C)2 (H)2(O2CCF3)2(PEt3)2]2 (V) exist in two or more isomeric forms as shown by their IR, 1H, 31P and 19F NMR spectra. Substitution with thiocyanate, nitrate and tetraphenylborate anions gives the new products [Mo2(C)2(H)(CO)(NCS)3(PPh3)2] (III), [Mo2(C)2 (H)2(O2CCF3)(NO3)(PPh3)2] (IV), [Mo2(C)2(H)(O2CCF3)(PPh3)2](BPh4)2 (VI) and [Mo2(C)2(H)2(O2CCF3)(PEt3)2](BPh4) (VII), which also exist in isomeric forms.  相似文献   

6.
The reaction of the labelled carborane ligand [3-Et-7,8-Ph2-7,8-nido-C2B9H8]2− with a source of {Pt(PMe2Ph)2}2+ affords non-isomerised 1,2-Ph2-3,3-(PMe2Ph)2-6-Et-3,1,2-closo-PtC2B9H8 (1). The analogous reaction between [3-F-7,8-Ph2-7,8-nido-C2B9H8]2− and {Pt(PMe2Ph)2}2+ yields 1,8-Ph2-2,2-(PMe2Ph)2-4-F-2,1,8-closo-PtC2B9H8 (3). Compound 1 has a heavily slipped structure (Δ 0.72 Å), which to some degree obviates the need for C atom isomerisation. However, that it is a kinetic product of the reaction is evident from the fact that it reverts to isomerised 1,8-Ph2-2,2-(PMe2Ph)2-4-Et-2,1,8-closo-PtC2B9H8 (2) slowly at room temperature but more rapidly with gentle warming. The heteroatom and labelled-B atom positions in the isomerised compounds 2 and 3 may be explained most simply by the rotation of a CB2 face of an intermediate based on the structure of 1. Compounds 1–3 were characterised by a combination of spectroscopic and crystallographic techniques.  相似文献   

7.
The complexes [WI2(CO)L2(η2-RC2R)] (L = PEt3 or PMe2Ph; R = Me or Ph) react with an equimolar quantity of Ag[BF4] in acetonitrile at room temperature to give good yields of the new purple cationic alkyne complexes [WI(CO)(NCMe)L2(η2-RC2R)][BF4]. 31P NMR spectroscopy indicates that the phosphines are trans to each other in these compounds. 13C NMR spectroscopy suggests that the alkyne ligands are donating four electrons to the tungsten in these complexes.  相似文献   

8.
Photochemical reaction of (CO)2(dppe)Fe(H)(SiR3) with HSiR3 (SiR3 = Si(OMe)3, Si(OEt)3, SiMe3, SiMe2Ph, SiPh3) yields the trihydrido silyl complexes (CO)(dppe)FeH3(SiR3 ). The analogous complexes (PR′Ph2)3 FeH3(ER3) are prepared by reaction of the H2 -complexes (PR′Ph2)3FeH2(H2) with HER3 (ER3 = SiMe3, SiMC2Ph, SiMePh2, SiPh3, Si(Me2)OSi(Me2)H, SnPh3, SnEt3). Additional derivates of (CO) (dppe)FeH3(SiR3) (SiR3 = SiMePh2) and (PR′Ph2)3FeH3(SiR3) (SiR3 = Si(OMe)3, SiH2Ph, SiHPh2, Si(OEt)3, SiMePhCl) are accessible by silane exchange starting from (CO)(dppe)FeH3(SiMe3) and (PR′Ph2) 3FeH3(SiMe3). (PBuPh2)3FeH3(SiMePh2) was also prepared from (PBuPh2)3FeH2(N2) and HSiMePh2, and (PBuPh2)3FeH3(SnMe3) from (PBuPh2)3FeH2(H2) and Me3SnCl. The complex (PBuPh2) 3FeH3(SnMe3) crystallizes as a toluene solvate in the cubic space group I 3d and shows crystallographically imposed C3-symmetry. The complexes (CO)2 (dppe)Fe(H)(SiR3) and (PR′Ph2)3FeH3(ER3) are highly dynamic in solution. Low temperature NMR measurements and the E, Fe, H coupling constants strongly indicate that the exchange mechanism involves η2-HER3 ligands.  相似文献   

9.
The heats of reaction of tolueneMo(CO)3 with a series of phosphines and phosphites have been measured by solution calorimetry. The order of stability toward formation of fac-(PR3)3Mo(CO)3 in THF solution is: P(OCH3)3s> PMe3 > PnBu3 > PMe2Ph> PEt3 > triphos> P(OPh)3 > PMePh2 > PPh3 > PCl3 and spans a range of 25 kcal/mol reflecting individual bond strength differences up to 8 kcal/mol. The bulky phosphines PCy3 and PtBu3 react with tolueneMo(CO)3 in THF, but 30–40 kcal/mol less heat is evolved in these reactions than with the other phosphines and phosphites. The coordinately unsaturated five-coordinate complexes (PR3)2Mo(CO)3 are proposed as the reaction products. The importance of both steric and electronic factors in the Mo---P bond is discussed.  相似文献   

10.
The excited state geometries of the metal-metal quadruply bonded compounds Mo2X4(PMe3)4 (X = Cl, Br or I) have been studied by means of resonance Raman and absorption spectroscopy. A fit of the parameters of a simple theoretical model to the experimental data indicates that the metal-metal bond increases some 10 pm on excitation to the 1B2 (δδ*) state, whereas other geometric changes are small. Furthermore, the phenomenological lifetime factor of the excited state, Γ, is found to be dependent on the vibrational quantum number, ν, of this state.  相似文献   

11.
The reaction of Ln(NO3)3·6H2O (Ln=La, Ce, Pr or Nd) with a sixfold excess of Ph3PO in acetone formed [Ln(Ph3PO)4(NO3)3]·Me2CO. The crystal structure of the La complex shows a nine-coordinate metal centre with four phosphine oxides, two bidentate and one monodentate nitrate groups, and PXRD studies show the same structure is present in the other three complexes. In CH2Cl2 or Me2CO solutions, 31P NMR studies show that the complexes are essentially completely decomposed into [Ln(Ph3PO)3(NO3)3] and Ph3PO. Similar reactions in ethanol gave [Ln(Ph3PO)3(NO3)3] only. In contrast for Ln=Sm, Eu or Gd, only the [Ln(Ph3PO)3(NO3)3] are formed from either acetone or ethanol solutions. For the later lanthanides Ln=Tb–Lu, acetone solutions of Ln(NO3)3·6H2O and Ph3PO gave [Ln(Ph3PO)3(NO3)3] only, even with a large excess of Ph3PO, but from cold ethanol [Ln(Ph3PO)4(NO3)2]NO3 (Ln=Tb, Ho–Lu) were obtained. The structure of [Lu(Ph3PO)4(NO3)2]NO3 shows an eight-coordinate metal centre with four phosphine oxides and two bidentate nitrate groups. In solution in CH2Cl2 or Me2CO the tetrakis-complexes show varying amounts of decomposition into mixtures of [Ln(Ph3PO)3(NO3)3], [Ln(Ph3PO)4(NO3)2]NO3 and Ph3PO as judged by 31P{1H} NMR spectroscopy. The [Ln(Ph3PO)3(NO3)3] also partially decompose in solution for Ln=Dy–Lu, forming some tetrakis(phosphine oxide) species.  相似文献   

12.
The compounds (π-C5H5)(CO)2LM-X (L = CO, PR3; M = Mo, W; X = BF4, PF6, AsF6, SbF6) react with H2S, p-MeC6H4SH, Ph2S and Ph2SO(L′) to give ionic complexes [(π-C5H5)(CO)2LML′]+ X−. Also sulfur-bridged complexes, [(π-C5H5)(CO)3W---SH---W(CO)3(π-C5H5)]+ AsF6− and [(π-C5H5)(CO)3M-μ-S2C=NCH2Ph-M(CO)3(π-C5H5)], have been obtained. Reactions with SO2 and CS2 have been examined.  相似文献   

13.
The neutral nitrogen-bidentate ligand, diphenylbis(3,5-dimethylpyrazol-1-yl)methane, Ph2CPz′2, can readily be obtained by the reaction of Ph2CCl2 with excess HPz′ in a mixed-solvent system of toluene and triethylamine. It reacts with [Mo(CO)6] in 1,2-dimethoxyethane to give the η2-arene complex, [Mo(Ph2CPz′2)(CO)3] (1). This η2-ligation appears to stabilize the coordination of Ph2CPz′ 2 in forming [Mo(Ph2CPz′2)(CO)2(N2C6H4NO2-p)][BPh4] (2) and [Mo(Ph2CPz′2)(CO)2(N2Ph)] [BF4] (3) from the reaction of 1 with the appropriate diazonium salt but the stabilization seems not strong enough when [Mo{P(OMe)3} 3(CO)3] is formed from the reaction of 1 with P(OMe)3. The solid-state structures of 1 and 3 have been determined by X-ray crystallography: 1-CH2Cl2, monoclinic, P21/n, a = 11.814(3), b = 11.7929(12), c = 19.46 0(6) Å, β = 95.605(24)°, V = 2698.2(11) Å3, Z = 4, Dcalc = 1.530 g/cm3 , R = 0.044, Rw = 0.036 based on 3218 reflections with I > 2σ(I); 2 (3)-1/2 hexane-1/2 CH3OH-1/2 H2O-1 CH2Cl2, monoclinic, C2/c, a = 41.766(10), b = 20.518(4), c = 16.784(3) Å, β = 101.871(18)°, V = 14076(5) Å3, Z = 8, Dcalc = 1.457 g/cm3, R = 0.064, Rw = 0.059 based on 5865 reflections with I > 2σ(I). Two independent cations were found in the asymmetric unit of the crystals of 3. The average distance between the Mo and the two η2-ligated carbon atoms is 2.574 Å in 1 and 2.581 and 2.608 Å in 3. The unfavourable disposition of the η2-phenyl group with respect to the metal centre in 3 and the rigidity of the η2-arene ligation excludes the possibility of any appreciable agostic C---H → Mo interaction.  相似文献   

14.
Reaction of Hg(S7N)2 with cis- PtCl2(PR3)2 (PR3 = PPh3, PPh2Me, PPHMe2, PEt3) in the presence of Na[PF6] gives [Pt(S3N)(PR3)2][PF6] in 32–46% yield. The complexes have been characterized by IR, NMR and microanalyses. The X-ray crystal structures of two examples (PR3 = PPh2Me and PEt3) show that the S3N− ligand coordinates in a bidentate fashion via two sulphur atoms.  相似文献   

15.
The complexes [(η6-arene)Ru=C(OMe)CH2R′)Cl(PR3)]PF6 (R′ = Ph; ARENE = Me4C6H2, iPr3C6H3, Et3C6H3; PR3 = PMe3, PPh3, P(OMe)3) have been made from RuCl2(PR3)(arene) precursors by activation at room temperature of phenylacetylene in methanol containing NaPF6. The complex with R′ = nBu, ARENE = Me4C6H2, and PR3 = PMe3 is similarly formed from hex-1-yne but much more slowly, and a complex of the type [(p-cymene)Ru=C(OMe)CH2R′)Cl(PR3)]+PF6− could be obtained only when the phosphine was the bulky PPh3 (10b). It has been shown that the steric hindrance by both arene and phosphine ligands contributes to the stabilization of the carbeneruthenium complexes.  相似文献   

16.
Reaction of the bis(dihydrogen) ruthenium complex RuH2(H2)2(PCy3)2 (1) with an excess of 9-borabicyclononane yields Ru[(μ-H)2BC8H14]2(PCy3) (6) and the phosphine adduct PCy3·HBC8H14. The new complex is characterized by NMR spectroscopy and X-ray diffraction. New X-ray data on 9-BBN dimer, from a measurement at 180 K, are also reported. DFT calculations (B3LYP) on Ru[(μ-H)2BC8H14]2(PMe3) (7), the PMe3 analogue of 6, confirm the ruthenium (II) formulation with two dihydroborate ligands. The data obtained using PH3 or PMe3 as models for PCy3 in PR3·HBC8H14 are also discussed.  相似文献   

17.
Addition of H2 to CH2Cl2 solutions of [(diene)Rh(L)2][closo-CB11H12] (diene=norbornadiene, cyclooctadiene, L=PCy3, P(OMe)3, 1/2dppe) results in the formation of the exo-closo complexes [(PR3)2Rh(closo-CB11H12)]. These have been characterised in solution by 1H- and 11B-NMR spectroscopy, and for L=PCy3 by a single crystal X-ray diffraction study. This suggests that the metal fragment is bound with the cage through the 7,8- and not the 7,12-{BH} vertices. DFT calculations on a model system where L=PMe3 show that there is only a negligible energy difference between these two isomers (1 kcal mol−1), suggesting that both represent stable structures. The salient spectroscopic markers that indicate an interaction of [closo-CB11H12]− with a metal fragment are discussed and compared across a range of metal complexes. Large upfield shifts in the 11B-NMR spectrum and a small downfield shift of the CH vertex in the 1H-NMR spectrum are shown to the most reliable indicators of borane interaction in solution.  相似文献   

18.
The complexes [Ru(S,S)2(PPh3)2] [S,S = EtCOCS2−, (CH2)4NCS2−] react with a variety of tertiary phosphines with the substitution of triphenylphosphine and the formation of [Ru(S,S)2(PR3)2]. The reaction occurs with the formation ofthe cis isomer, except for the complex with PMe2Ph that gives rise to the trans isomer as the crystal structure shows. The effect of the different phosphines on the ruthenium complex is analysed in terms of the spectroscopic and electrochemical properties of the isolated compounds. The cyclic voltammetric studies of the cis complexes show that isomerization to the trans isomer occurs on oxidation. This isomerization is not observed in the trans-[Ru(S,S)2(PMe2Ph)2] complexes that give rise to stable trans-ruthenium(II)/ruthenium(III) couples. In a similar way the diphosphine complexes afford a quasi-reversible cis-ruthenium(II)/ruthenium(III) process.  相似文献   

19.
The reaction of Ru(CO)4(C2H4) or Ru(CO)5 with 1,5-Ph4P2N4S2 in CH2Cl2/hexane at 23°C produces the dimer [Ru(CO)2(Ph4 P2N4S2)]2 (2), which was shown by X-ray crystallography to have a centrosymmetric structure in which the P2N4S2 ring is attached to one ruthenium atom through two (geminal) nitrogen atoms and the remote sulfur atom and serves as a bridge to the other ruthenium atom via the second sulfur atom. Crystals of 2 ·2(CH2Cl2) are triclinic, space group P (No. 2), a = 12.901(1) Å, b = 13.072(1) Å, c = 10.123(1) Å, = 100.88(1)°, β = 98.90(1)°, γ = 67.50(1)°, V = 1542.4(3) Å, Z = 1 with final R and Rw values of 0.040 and 0.027, respectively.  相似文献   

20.
13C and 31P{1H} NMR data at low temperature prompted us to characterize cis-[Rh(CO)2(PR3)Cl] (3) (3a, PR3 = PPh3; 3b, PR3 = PMe2Ph), as surprisingly stable products of the reaction between [{Rh(CO)2(μ-Cl)}2] (1) and tertiary phosphines in toluene (P : Rh = 1). Every attempt to isolate solid 3a led to the cis- and trans- halide-bridged dimers [{Rh(CO)2(μ-Cl)}2] (5a) and 6a which are formed from 3a by slow decarbonylation, a process which is greatly accelerated by the evaporation of the solvent under vacuum.

The analogous reaction of 1 with dimethylphenylphosphine follows a similar pathway; in this case, however, low temperature NMR spectra allowed us to characterize the pentacoordinated dinuclear species [{Rh(CO)2(μ-Cl)}2] (2b) as the unstable intermediate of the bridge-splitting process.

The reaction of 3 with a second equivalent of phosphine (P : Rh = 2) leads, at room temperature, to the well known product trans-[Rh(CO)(PR3)2Cl] (8) accompanied by evolution of CO; however our data show that when the reaction is performed at 200 K, decarbonylation is prevented and spectroscopic evidence of trigonal bipyramidal pentacoordinate [Rh(CO)2(PR3)2Cl] (7), stable only at low temperature, can be obtained.  相似文献   


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