Reaction between cis-[Mo(CO)2(dmpe)2] (dmpe =Me2PCH2CH2PMe2) and organic π-acids tetracyanoethene (TCNE), 1,2,4,5-tetracyanobenzene (TCNB) and 1,3,5-trinitrobenzene (TNB) proceeds via electron transfer from the metal complex, which is oxidised to the 17-electron trans-[Mo(CO)2(dmpe)2]+ ion, to the organic acceptor which is reduced to the radical anion. The final products of the reactions are characterised ascis-[Mo{C2(CN)3} (CO)2(dmpe)2] [CN], cis-[Mo{C6H2(CN)4} (CO)2(dmpe)2] [C6H2(CN)4]8 and [Mo(CO)2(dmpe)2 · 2 C6H3(NO2)3] by analysis and spectroscopic (IR, NMR, ESR) measurements which are compared with those of cis-[MoX(CO)2(dmpe)2]X (X = Cl, Br, I) and fac, fac-[Mo2Cl4(CO)4(dmpe)3]. The reaction of cis-[Cr(CO)2(dmpe)2] with TCNE gives trans-[Cr(CO)2(dmpe)2]+ [TCNE]? only. 相似文献
The first 4d/4f polyphosphides were obtained by reaction of the divalent metallocenes [Cp*2Ln(thf)2] (Ln = Sm, Yb) with [{CpMo(CO)2}2(μ,η2:2-P2)] or [Cp*Mo(CO)2(η3-P3)]. Treatment of [Cp*2Ln(thf)2] (Ln = Sm, Yb) with [{CpMo(CO)2}2(μ,η2:2-P2)] gave the 16-membered bicyclic compounds [(Cp2*Ln)2P2(CpMo(CO)2)4] (Ln = Sm, Yb) as the major products. From the reaction involving samarocene, the cyclic P4 complex [(Cp*2Sm)2P4(CpMo(CO)2)2] and the cyclic P5 complex [(Cp*2Sm)3P5(CpMo(CO)2)3] were also obtained as minor products. In each reaction, the P2 unit is reduced and a rearrangement occurred. In dedicated cases, a P–P bond formation takes place, which results in a new aggregation of the central phosphorus scaffold. In the reactions of [Cp*2Ln(thf)2] (Ln = Sm, Yb) with [Cp*Mo(CO)2P3] a new P–P bond is formed by reductive dimerization and the 4d/4f hexaphosphides [(Cp*2Ln)2P6(Cp*Mo(CO)2)2] (Ln = Sm, Yb) were obtained. 相似文献
Pure cis and trans isomers of CpMo(CO)2(L)X (Cp = η5-C5H5, L = PPh3 or PBu3, X = Br, or I) have been separated by chromatography and characterized by infrared and proton NMR spectroscopy. The reactions of trans-CpMo(CO)2(L)CH3 with HgX2 (X = Cl, Br, I, SCN) afford cis-CpMo(CO)2(L)X in high yield. Both linkage isomers are obtained in the reaction with Hg(SCN)2, L = PPh3. The mercuric halides react with CpMo(CO)2(L)COCH3 to form the metalmetal bonded derivatives trans-CpMo(CO)2(L)HgX. Reactions of CpMo(CO)2(L)CH3 or CpMo(CO)2(L)COCH3 with bromine or iodine yield the halide complexes CpMo(CO)2(L)X (X = Br and I, respectively), the product mixtures containing high proportions of the trans isomers. 相似文献
The preparation of the complexes [M(CO)n(dcpe)] [M Cr, Mo, W; n 4, 5; dcpe is ((cyclo-C6H11)2PCH2)2] is reported. Attempts to prepare [M(CO)2(dcpe)2] by many different methods gave only cis-[M(CO)4(dcpe)] and [M(CO)5(dcpe)]. Heating cis-[M(CO)4(dcpe)] with (Me2PCH2)2(dmpe) gives cis-[M(CO)2(dmpe)2] only. These observations are explained in terms of unfavourable intramolecular non-bonded interactions between substituents at phosphorus. The rate of chelation of [M(CO)5(dcpe)] to give cis-[M(CO)4(dcpe)] has been measured at various temperatures in the range 360–420 K. The activation parameters indicate the dominance of a dissociative process leading to the observed steric acceleration in the chelation step. The rate of chelation is correlated satisfactorily with the ligand cone angle; the operation of an apparent saturation effect is noted. 相似文献
Synthesis and Crystal Structure of (C5H5)Mo(CO)3(AuPPh3) and [(C5H5)Mo(CO)2(AuPPh3)4]PF6 CpMo(CO)3(AuPPh3) is obtained by the reaction of Li[CpMo(CO)3] with Ph3PAuCl at ?95°C in CH2Cl2. It crystallizes in the monoclinic space group C2/c with a = 2625.1(7), b = 883.2(1), c = 2328.4(7) pm, β = 116.39(1)° und Z = 8. In the complex the AuPPh3 group is coordinated to the CpMo(CO)3 fragment with a Au? Mo bond of 271,0 pm. The Mo atom thus achieves a square pyramidal coordination with the center of the Cp ring in apical position. CpMo(CO)3(AuPPh3) reacts under uv irradiation with an excess of Ph3PAuN3 to afford the cluster cation [CpMo(CO)2(AuPPh3)4]+. It crystallizes as [CpMo(CO)2(AuPPh3)4]PF6 · 2 CH2Cl2 in the orthorhombic space group P212121 with a = 1553.9(1), b = 1793.8(2), c = 2809.8(7) pm und Z = 4. The five metal atoms form a trigonal bipyramidal cluster skeleton with the Mo atom in equatorial position. The Mo? Au distances range from 275.5 to 280.8 pm, and the Au? Au distances are between 281.2 and 285.6 pm. 相似文献
Polynuclear organometallic compounds [CpMo(CO)3]2BiCl and [CpMo(CO)3]BiCl2 were prepared by reaction of bismuth with tricarbonylcyclopentadienylmolybdenum chloride in dimethyl sulfoxide (DMSO). [CpMo(CO)3]2BiCl is reduced with magnesium or indium in tetrahydrofuran to give bismuth, [CpMo(CO)3]3Bi, and magnesium or indium chloride. In the presence of DMSO, the reaction of [CpMo(CO)3]2BiCl with magnesium or indium yields bismuth and the organomolybdenum derivative of magnesium or lithium, respectively. 相似文献
Microcalorimetric measurements at elevated temperatures of the heats of thermal decomposition and of iodination of a number of [M(CO)nL6-n] complexes (M = Cr, Mo, W; n = 3, 4; L = py, MeCN) have led to values for the standard enthalpies of formation of the following crystalline compounds (values given in kJ mol?) at 25°C: fac-[Mo(CO)3py3](275 ± 12), fac-[Mo(CO)3(NCCH3)3] (410 ± 12), fac-[W(CO)3py3](250 ± 12), fac-[W(CO)3(NCCH3)3](405 ± 12) and cis-[Cr(CO)4py2](505 ± 20). From these and other data, including estimated heats of sublimation, the bond enthalpy contributions of the various metalligand bonds in the gaseous metal complexes were evaluated as follows (values in kJ mol?): D(Crpy) 102, D(Mopy) 146, DWPy) 173, D(Mo7z.sbnd;NCMe) 135 and D(WNCMe) 169. For a given metal the bond enthalpy contribution decreased in the order D(MCO) > D(Mpy) > D(Mz.sbnd;NCMe). This order is related to the σ- and π-bonding character of the ligand. 相似文献
The reactions of several mono- and poly-nuclear carbonyl metallates with nitrosonium ion have been studied. Besides simple substitution of a carbon monoxide with NO+ some reactions yielded products containing other nitrogeneous ligands. When [CoRu3(CO)13]? reacts with NO+, low yields of the new nitrido cluster CoRu3N(CO)12 are formed. Prior conversion of [CoRu3(CO)13]? to the new hydrido cluster [H2CoRu3(CO)12]? under hydrogen, followed by nitrosylation, forms the new imido cluster H2Ru3(NH)(CO)9 in very low yield. The reaction of [FeCO3(CO)12]? with NO+ also generates an imido cluster, FeCo2(NH)(CO)9, in 15% yield. This cluster has been characterized by X-ray crystallography and was found to be similar to the tricobalt alkylidyne clusters. (Triclinic crystal system, P space group, Z=2, a 6.787(1), b 8.016(1), c 13.881(2) Å, α 95.50(1), β 100.77(1), γ 107.93(1)°. Modifications of the nitrosylations using NO+ were studied. In particular, the addition of triethylamine or N-t-butylbenzaldimine allowed the use of NO+ in THF without solvent decomposition. With [CpMo(CO)3]? and [CpFe(CO)2]? the N-nitrosoiminium species appears to form transient alkylmetals which further react to give the dimers [CpMo(CO)3]2 and [CpFe(CO)2]2. 相似文献
The new complexes [Et4N]2 [Mo(CO)4(SR)2] (R = Ph, Bz) have been prepared by reaction of [Et4N] [SR] with (norbornadiene)Mo(CO)4 at low temperature. The IR spectra and electrochemical behavior of these two species are different, perhaps implicating different conformational isomers with respect to the thiolate ligands. These complexes may prove to be valuable reagents for the synthesis of new heterometallic compounds, by virtue of their cis-monodentate thiolate ligands. 相似文献
The cyclopentadienyl molybdenum hydride compounds, CpRMo(PMe3)3–x(CO)xH (CpR = Cp, Cp*; x = 0, 1, 2 or 3), are catalysts for the dehydrogenation of formic acid, with the most active catalysts having the composition CpRMo(PMe3)2(CO)H. The mechanism of the catalytic cycle is proposed to involve (i) protonation of the molybdenum hydride complex, (ii) elimination of H2 and coordination of formate, and (iii) decarboxylation of the formate ligand to regenerate the hydride species. NMR spectroscopy indicates that the nature of the resting state depends on the composition of the catalyst. For example, (i) the resting states for the CpMo(CO)3H and CpMo(PMe3)(CO)2H systems are the hydride complexes themselves, (ii) the resting state for the CpMo(PMe3)3H system is the protonated species [CpMo(PMe3)3H2]+, and (iii) the resting state for the CpMo(PMe3)2(CO)H system is the formate complex, CpMo(PMe3)2(CO)(κ1-O2CH), in the presence of a high concentration of formic acid, but CpMo(PMe3)2(CO)H when the concentration of acid is low. While CO2 and H2 are the principal products of the catalytic reaction induced by CpRMo(PMe3)3–x(CO)xH, methanol and methyl formate are also observed. The generation of methanol is a consequence of disproportionation of formic acid, while methyl formate is a product of subsequent esterification. The disproportionation of formic acid is a manifestation of a transfer hydrogenation reaction, which may also be applied to the reduction of aldehydes and ketones. Thus, CpMo(CO)3H also catalyzes the reduction of a variety of ketones and aldehydes to alcohols by formic acid, via a mechanism that involves ionic hydrogenation. 相似文献
The compound Ph2PN(H)PPh2 (I) reacts under special conditions with M(CO)6 (M Cr, Mo), Fe(NO)2(CO)2 and Co(NO)(CO)3 to give the new complexes cis-M(CO)2[Ph2PN(H)PPh2]2 (III, IV), [Fe(NO)2(CO)Ph2P]2NH (V), [Fe(NO)2Ph2-PN(H)PPh2]2 (VI) and Co(NO)(CO)2Ph2PN(H)PPh2 (VII). Compound VI can also be prepared reacting V with I. For III and IV proton NMR spectra indicate some interaction between o-protons of the phenyl rings and cis-M(CO)2 groups. VI exists an eight-membered ring complex without a metal-metal bond. On the basis of spectroscopic data VII seems to exist in two conformers. 相似文献
The mixed ligand tetracarbonyl derivatives, cis-M(CO)4(PPh2H)(PPh3) (M Cr, Mo, W) and cis-W(CO)4(PPh2H)(L) (L PEt3, PEt2Ph, PEtPh2) have been prepared from the reaction of M(CO)5PPh2H with L in THF in the presence of potassium t-butoxide. These reactions are accompanied in most instances by the formation of [W(CO)5PPh2]−, [(OC)5M(μ-PPh2)M(CO)5]−, [(OC)5M(μ-PPh2)-M(CO)4(PPh2H)]−, [(OC)4M(μ-PPh2)2M(CO)4]2−, (OC)4M(μ-PPh2)2M(CO)4, and cis-M(CO)4(PPh2H)2. 相似文献
The carbonylation of Cp2MoH2 proceeds through the intermediates Cp2MoCO, [Cp2Mo(H)CO] [CpMo(CO)3] (I) and CpMo(CO)3 to the final products [CpMo(CO)3]2 and CpMo(η3-C5H7)(CO)2. The formation of I in the carbonylation reaction has been shown to involve net hydride transfer, but an alternate synthesis has demonstrated the considerable proton basicity of Cp2MoCO. Since the net hydride transfer between Cp2MoH2 and [CpMo(CO)3]2 can be accelerated by production of metal centered radicals, the actual mechanism is not a simple two-electron process (H? transfer, but rather a sequence of one-electron steps. 相似文献
New complexes {M(CO)4[Ph2P(S)P(S)Ph2]} (M = Cr, Mo and W), (1a)–(3a), [(1a), M = Cr; (2a), M = Mo; (3a), M = W] and {M2(CO)10[-Ph2P(S)P(S)Ph2]} (M = Cr, Mo, W), [(1b)–(3b) [(1b), M = Cr; (2b), M = Mo; (3b), M = W]] have been prepared by the photochemical reaction of M(CO)6 with Ph2P(S)P(S)Ph2 and characterized by elemental analyses, f.t.-i.r. and 31P-(1H)-n.m.r. spectroscopy and by FAB-mass spectrometry. The spectra suggest cis-chelate bidentate coordination of the ligand in {M(CO)4[Ph2P(S)P(S)Ph2]} and cis-bridging bidentate coordination of the ligand between two metals in (M = Cr, Mo and W). 相似文献
Reduction of cis / trans-CpMo(CO)2(CNtBu)I (1a/1b) (Cp η5C5H5) with an excess of sodium gives the Mo0-metallate Na[CpMo(CO)2(CNtBu)] (2) in quantitative yield. Complex 2 is alkylated by Et3OBF4 at both the metal center and the isocyanide nitrogen. Reaction at the metal center leads to a mixture of the MoII, isomers cis- and trans-CpMo(CO)2(CNtBu)(Et) (3a, 3b), while reaction at the isocyanide nitrogen gives the aminocarbyne complex Cp(CO)2MoCN(Et)tBu (4). The ethyl complexes 3a and 3b rearrange in refluxing THF to give a mixture of the iminoacyl complex Cp(CO)2Mo[η2C(NtBu)Et] (5) and the 1-azaallyl complex Cp(CO)2MO[η3-CH(Me)CHNtBu] (6). A comparison of the product distribution obtained in the reaction of the metallates Na[CpMo(CO)2(CNR)] (R Et, tBu) with Et3OBF4 shows a strong effect of the isocyanide substituent R on the orientation of electrophilic attack in these compounds. 相似文献
Summary Reinvestigation of the reaction of M(CO)6 (M=Cr, Mo or W) with KOH has been found to provide a very convenient route to the K[M2H(CO)10] compounds (M=Cr, Mo or W). The reaction involving Cr(CO)6 yields new potassium derivatives containing [Cr2(CO)10]2– and [HCr(CO)5]– species; also K[Cr2D(CO)10] is produced from the Cr(CO)6/KOD interaction in C2D5OD. The reaction involving two different group 6 metal carbonyls yields [MM(CO)10(-H)]– (MM=CrMo, CrW or WMo) species as their K+ and PPN+ [bis(triphenylphosphine)iminium] salts. 相似文献
Attempts to synthesize complexes of group 6 carbonyl compounds [M(CO)6] (M = Cr, Mo, W) with the carbone C(PPh3)2 ( 1 ) via the photo chemically created adducts [(CO)5M(THF)] lead to quantitative formation of the salts [HC(PPh3)2]2[M2(CO)10] ( 2 , Cr; 3 , Mo; 4 , W). Alternatively, a long-time thermal reaction of [Mo(CO)6] performed with 1 in THF generates a series of products initiated by a Wittig-type reaction. In addition to 3 , minor amounts of [(CO)5MoCCPPh3] ( 8 ), [(CO)5MoO2CC{PPh3}2] ( 5 ), and the carbonate complexes [HC(PPh3)2]2[(CO)5Mo(CO3)Mo(CO)4] ( 6 ) and [HC(PPh3)2]2[(CO)4Mo(CO3)Mo(CO)4] ( 7 ) were found. Compounds 2 , 3 , 5 , 6 , and 7 were characterized by X-ray analyses, 31P NMR, and IR spectroscopy. The water, necessary for the formation of the carbonate, stems from decomposition of THF. 相似文献
The reaction between η5-C5H5M(CO)3I (M Mo, W) and isonitriles, RNC, (RNC PhCH2NC, t-BuNC and 2,6-dimethylphenylisocyanide (XyNC)) is catalysed by the dimer [η5-C5H5M(CO)3]2 (M = Mo, W) to yield η5-C5H5M(CO)3?n(RNC)nI (n = 1–3) and [η5-C5H5Mo(RNC)4]I. The complexes (η5-C5H5)2Mo2(CO)6?n(RNC)n (n = 1, RNC = MeNC, PhCH2NC, XyNC, t-BuNC; n = 2, RNC = t-BuNC) have been prepared in moderate yield from the direct reaction between [η5-C5H5Mo(CO)3]2 and RNC, and also catalyse the above reaction. A reaction pathway involving a fast non-chain radical mechanism and a slower chain radical mechanism is proposed to account for the catalysed reaction. 相似文献
Reaction of [Mo(CO)4(diene)] with 4,4′-bipyridine (44′B), trans-1,2-bis(2-pyridyl)ethene (2-bpe) and trans-1,2-bis(4-pyridyl)-ethene (4-bpe) gives polymeric [Mo(CO)4(44′B)]n, mononuclear cis-[Mo(CO)4(2-bpe)2] and binuclear [Mo(CO)4(4-bpe)]2 respectively. Reaction of the same ligands with [Mo(CO)4(bpy)] (bpy is 2,2′-bipyridine) produces the bridged binuclear complexes [{Mo(CO)3(bpy)}2(44′B)] and [{Mo(CO)3(bpy)}2(4-bpe)]. Products are characterised by microanalysis and spectroscopy (IR, 1H NMR, UV/vis). Reduction of [{Mo(CO)3(bpy)}2(44′B)] produces an anion in which the unpaired electron is localised on the chelating bpy ligand. 相似文献
The reaction of BrMn(CO)5 with dppm in refluxing toluene gives the neutral compunds cis-cis-BrMn(CO)2(dppm)2 which has been shown by 31P NMR spectroscopy to have one dppm monodentate and the other bidendate. This complex reacts with TIPF6 in dichloromethane solution to give the salt cis-[Mn(CO)2-(dppm)2]PF6 or, if the reaction is carried out in the presence of CO, the salt mer-[Mn(CO)3(dppm)2]PF6 which also has one monodentate dppm (by 31P NMR). The cationic complex cis-[Mn(CO)2(dppm)2]+ isomerizes to the transisomer when irradiated with UV light, while heating of the latter gives back the cis-isomer. The perchlorate salts of the cation cis-[Mn(CO)2(dppm)2+ can be prepared by reacting fac-O3ClOMn(CO)3(dppm) withdppm in refluxing toluene, and trans-[Mn(CO)2(diphos)(diphos)′]+, diphos or diphos′ being dppm or dppe, by treating the fac-O3ClMn(CO)3(diphos) with dppm or dppe under UV irradiation. 相似文献
