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1.
The thermal and photochemical reactions of CpRe(PPh3)2H4 and CpRe(PPh3)H4 (Cp = η5-C5H5) with PMe3, P(p-tolyl)3, PMe2Ph, DMPE, DPPE, DPPM, CO, 2,6-xylylisocyanide and ethylene have been examined. While CpRe(PPh3)2H2 is thermally inert, it will undergo photochemical substitution of one or two PPh3 ligands. With ethylene, substitution is followed by insertion of the olefin into the C-H bond of benzene, giving ethylbenzene. CpRe(PPh3)H4 undergoes thermal loss of PPh3, which leads to substituted products of the type CpRe(L) H4. Photochemically, reductive elimination of dihydrogen occurs preferentially. The complex trans-CpRe(DMPE)H2 was structurally characterized, crystallizing in the monoclinic space group P21/n (No. 14) with a = 6.249(6), b = 16.671(8), c = 13.867(7) Å, β = 92.11(6)°, V = 1443.7(2.9) Å and Z = 4. The complex trans-CpRe(PMe2Ph)2H2 was structurally characterized, crystallizing in the monoclinic space group P21/n (No. 14) with a = 7.467(3), b = 23.874(14), c = 11.798(6) Å, β = 100.16(4)°, V = 2070.2(3.4) Å3 and Z = 4.  相似文献   

2.
Metathetical exchange between carbon dioxide and the tin(II) dimer, {Sn[N(SiMe3)2](μ-OBu1)}2 (3) has been observed to cleanly produce the two new heteroleptic tin(II) dimers, Sn[N(SiMe3)2](μ-OBut)2Sn(OSiMe3) (6) and [Sn(OSiMe3)](μ-OBut)]2 (7]). In addition, reaction of 3 with I equiv, of tert-butylisocyanate (8), at 25°C, quantitatively provides 6, and with 2 equiv., quantitatively provides 7. Likewise 6 reacts with 1 equiv, of 8 to quantitatively provide 7. The mechanism for these latter processes has been investigated by low temperature 1H NMR spectroscopy which reveals that metathetical exchange does not involve the tri-coordinate tin(II) centers of the dimeric structures, but rather, it occurs, in each case, via the transient monomeric tin(II) species, Sn[N(SiMe3)2](μ-OBut) (4), that undergoes metathesis to produce, initially the open dimer intermediate, Sn(OCNBut)(OSiMe3)(μ-OBut)Sn(OBut) (OSiMe3) (12), that is observed at −10°C. Subsequent redistribution reactions then generate the final products that are observed. Together, these mechanistic details provide additional support for the ‘monomeric tin(II)’ hypothesis proposed earlier for metathetical exchange between XCO and Sn[N (SiMe3)2]2 (1).  相似文献   

3.
The reaction of TiCl4 with Li2[(SiMe2)25-C5H3)2] in toluene at room temperature afforded a mixture of cis- and trans-[(TiCl3)2{(SiMe2)25-C5H3)2}] in a molar ratio of 1/2 after recrystallization. The complex trans-[(TiCl3)2{(SiMe2)25-C5H3)2}] was hydrolyzed immediately by the addition of water to THF solutions to give trans-[(TiCl2)2(μ-O){(SiMe2)25-C5H3)2}] as a solid insoluble in all organic solvents, whereas hydrolysis of cis-[(TiCl3)2{(SiMe2)25-C5H3)2}] under different conditions led to the dinuclear μ-oxo complex cis-[(TiCl2)2)(μ-O){(SiMe2)25-C5H3)2}] and two oxo complexes of the same stoichiometry [(TiCl)2(μ-O){(SiMe2)25-C5H3)2}]2(μ-O)2 as crystalline solids. Alkylation of cis- and trans-[(TiCl3)2{(SiMe2)25-C5H3)2}] with MgCIMe led respectively to the partially alkylated cis-[(TiMe2Cl)2{(SiMe2)25-C5H3)2}] and the totally alkylated trans-[(TiMe3)2{(SiMe2)25-C5H3)2}] compounds. The crystal and molecular structure of the tetranuclear oxo complex [(TiCl)2(μ-O){(SiMe2)25-C5H3)2}]2(μ-O)2 was determined by X-ray diffraction.  相似文献   

4.
(η3-Cyclooctenyl)Co(bisphosphine) compounds react with HBF4 in the presence of alkenes with oxidation of the metal to give the novel, paramagnetic organocobalt(II) species [(η3-cyclooctenyl)Co(bisphosphine)]+BF4, (η3-2-RC3H4)Co(bisphosphine) complexes react similarly. The Co(II) compounds form adducts with CO and NO (the latter being diamagnetic) and undergo facile chemical and electrochemical reduction.  相似文献   

5.
Kinetic results are reported for intramolecular PPh3 substitution reactions of Mo(CO)21-L)(PPh3)2(SO2) to form Mo(CO)22-L)(PPh3)(SO2) (L = DMPE = (Me)2PC2H4P(Me)2 and dppe=Ph2PC2H4PPh2) in THF solvent, and for intermolecular SO2 substitutions in Mo(CO)32-L)(η2-SO2) (L = 2,2′-bipyridine, dppe) with phosphorus ligands in CH2Cl2 solvent. Activation parameters for intramolecular PPh3 substitution reactions: ΔH values are 12.3 kcal/mol for dmpe and 16.7 kcal/mol for dppe; ΔS values are −30.3 cal/mol K for dmpe and −16.4 cal/mol K for dppe. These results are consistent with an intramolecular associative mechanism. Substitutions of SO2 in MO(CO)32-L)(η2-SO2) complexes proceed by both dissociative and associative mechanisms. The facile associative pathways for the reactions are discussed in terms of the ability of SO2 to accept a pair of electrons from the metal, with its bonding transformations of η2-SO2 to η1-pyramidal SO2, maintaining a stable 18-e count for the complex in its reaction transition state. The structure of Mo(CO)2(dmpe)(PPh3)(SO2) was determined crystallographically: P21/c, A=9.311(1), B = 16.344(2), C = 18.830(2) Å, ß=91.04(1)°, V=2865.1(7) Å3, Z=4, R(F)=3.49%.  相似文献   

6.
The preparation and structural characterization of {Ru3(CO)11}2(1,4-bis(diphenylphosphino)benzene), a modified synthesis of 1,4-bis(diphenylphosphino)benzene, and the structural characterization of {Ru3(CO)11}2(bis(diphenylphosphino)ethane) are reported. In both compounds two metal cluster units are connected through ditertiary-phosphine ligands. Both molecules consist of centrosymmetric units in which the diphosphine ligands are largely covered by the triangular ruthenium clusters. No direct interaction between the two cluster units occurs within individual molecules. Molecular packing in the solid state is dominated by interactions between sets of carbon monoxide ligands in motifs that were previously identified in the solid state structure of the parent cluster, Ru3(CO)12.  相似文献   

7.
The bis(oxazoline) ligand, 2,2-bis[4(R)-phenyl-1,3-oxazolon-2-yl]propane (bpop), was introduced to the η6-benzenemthenium(II) moiety on treatment with [Ru(η6-C6H6)Cl2]2 to give [Ru(η6-C6H6)(bpop)Cl]+. Aquo and amine complexes [Ru(η6-C6H6)(bpop)(L)]2+ (L = H2O (1), NH2R; R = H (2) , Me (3) , and n-Bu (4) ) were prepared by treating the chloride complex with AgBF4 in the presence of L. X-ray structure determinations of 1 and 3 were carried out. Both complexes possessed a three-leg piano stool structure with the N or O donors located at the three comers of a pseudo octahedron. The aquo complex 1 exhibited a dynamic NMR feature in which two magnetically nonequivalent oxazoline parts observed at lower temperatures were interchanged with each other at higher temperatures. This observation was ascribed to the formation of a C2-symmetric 16-electron intermediate via Ru-OH2 cleavage, which is slower in acetone than in dichloromethane owing to more effective solvation by acetone around hydrogens of the coordinated water molecule. The two diastereotopic N-hydrogens of 4 underwent deuterium exchange with CD3OD with greatly different rates from each other owing to different energy of NHO (D) (CD3) interaction. Carboxylate and sulfonate ions (A) formed second sphere complexes with 4 by means of NHA hydrogen bonding, as evidenced by continuous shift of NH2 resonances with increasing amounts of the anions added.  相似文献   

8.
Reactions of Cr(CO)36-BT), in which the Cr is π-coordinated to the benzene ring of benzo[b]thiophene (BT), with Cp′(CO)2Re(THF), where Cp′ = η5-C5H5 or η5-C5Me5, give the products Cp′(CO)2Re(η262-BT)Cr(CO)3 in which the Cr remains coordinated to the benzene ring and Re is bound to the C(2)=C(3) double bond. An X-ray diffraction study of Cp(CO)2Re(η262-BT)Cr(CO)3 (3) provides details of the geometry. This structure contrasts with that of the Cp′(CO)2Re(BT) complexes that exist as mixtures of isomers in which the BT is coordinated to the Re through either the double bond (2,3-η2) or the sulfur (η1(S)). Thus, the electron-withdrawing Cr(CO)3 group in 3 stabilizes the 2,3-η2 mode of BT coordination to the Cp′(CO)2Re fragment. Implications of these results for catalytic hydrodesulfurization of BT are discussed. Crystal data for 3: triclinic, space group .  相似文献   

9.
The complex [Ru(H2)(H)(PMe2Ph)4]PF6 (1) has been prepared by reaction of [Ru(H)(PMe2Ph)5] FP6 (2) in THF with 1 atm H2 and characterised by variable temperature 31P and 1H NMR. It undergoes four distinct fluxional processes listed in order of decreasing activation energy: (i) exchange of H2 in solution with the dihydrogen ligand above 273 K; (ii) isomerisation of cis and trans isomers of 1 above 230 K; (iii) exchange of H atoms between H2 and hydride in trans-1 above 180 K; (iv) rapid H2/hydride exchange in cis-1 to below 180 K. A single crystal X-ray diffraction study of 1 at 173 K shows that the complex has the cis geometry in the solid state but does not clearly reveal the positions of the hydrogen ligands. Complex 1 starts out as a catalyst of high activity for the selective hydrogenation of 1-alkynes to 1-alkenes (RC≡CH; R=11Bu, Ph) but it is rapidly deactivated, possibly because of formation of the enynyl complex [Ru(η3RC3CHR)(PMe2Ph)4]+. Complex 1 efficiently catalyzes the hydrogenation of internal alkynes (3-hexyne, 2-pentyne) to internal cis-alkenes with little deactivation, although some isomerisation of the alkene produced is observed. These observations are consistent with those of Nkosi, Coville, Albers and Singleton who reported that complex 2 must dissociate one PMe2Ph ligand to produce the species active for alkyne hydrogenation. Complex 2 catalyses these hydrogenations with slower initial rates than complex 1 but deactivates less readily. In contrast to 1, complex 2 does not appear to cause the isomerisation of internal alkenes.  相似文献   

10.
The Pt2 (II) isomeric terminal hydrides [(CO)(H)Pt(μ-PBu2)2Pt(PBu2H)]CF3SO3 (1a), and [(CO)Pt(μ-PBu2)2Pt(PBu2H)(H)]CF3SO3 (1b), react rapidly with 1 atm of carbon monoxide to give the same mixture of two isomers of the Pt2 (I) dicarbonyl [Pt2(μ-PBu2)(CO)2(PBu2H)2]CF3SO3 (3-Pt); the solid state structure of the isomer bearing the carbonyl ligands pseudo-trans to the bridging phosphide was solved by X-ray diffraction. A remarkable difference was instead found between the reactivity of 1a and 1b towards carbon disulfide or isoprene. In both cases 1b reacts slowly to afford [Pt2(μ-PBu2)(μ,η22-CS2)(PBu2H)2]CF3SO3 (4-Pt), and [Pt2(μ-PBu2)(μ,η22-isoprene) (PBu2H)2]CF3SO3 (6-Pt), respectively. In the same experimental conditions, 1a is totally inert. A common mechanism, proceeding through the preassociation of the incoming ligand followed by the P---H bond formation between one of the bridging P atoms and the hydride ligand, has been suggested for these reactions.  相似文献   

11.
The reactions of [(H5C6)3P]2ReH6 with (CH3CN)3Cr(CO)3, (diglyme)Mo(CO)3 or (C3H7CN)3W(CO)3 led to the formation of [(H5C6)3P]2ReH6M(CO)3 (M = Cr, Mo, W) complexes. These have been characterized by IR and NMR spectroscopies, as well as elemental analyses. A single crystal X-ray diffraction study has also been carried out for the M = Cr complex as a K(18-crown-6)+ salt. The complex crystallizes as a THF monosolvate in the monoclinic space group P21/n with a = 22.323(6), B = 9.523(2), C = 27.502(5) Å, β = 104.98(2)0 and V = 5648 Å3 for Z = 4. The Re---Cr separation is 2.5745(12) Å, and the two phosphine ligands are oriented unsymmetrically. Although the hydride ligands were not found, the presence of three bridging hydrides and a dodecahedral coordination geometry about rhenium could be inferred. Low temperature 1H and 31P NMR spectroscopic studies did not reveal the low symmetry of the solid state structure.  相似文献   

12.
The reactions of various proton donors (phenol, hexafluoro-2-propanol, perfluoro-2-methyl-2-propanol, monochloroacetic acid, and tetrafluoroboric acid) with the rhenium (I) hydride complex [(triphos)Re(CO)2H] (1) have been studied in dichloromethane solution by in situ IR and NMR spectroscopy. The proton donors from [(triphos)Re(CO)2H…HOR] adducts exhibiting rather strong H…H interactions. The enthalpy variations associated with the formation of the H-bonds (−ΔH = 4.4–6.0 kcal mol−1) have been determined by IR spectroscopy, while the H…H distance in the adduct [(triphos)Re(CO)2H…HOC(CF3)3] (1.83 Å) has been calculated by NMR spectroscopy through the determination of the T1min relaxation time of the Re---H proton. It has been shown that the [(triphos)Re(CO)2H…HOR] adducts are in equilibrium with the dihydrogen complex [(triphos)Re(CO)22-H2)]+, which is thermodynamically more stable than any H-bond adduct.  相似文献   

13.
The reactions of the polysulfur and selenium cationic clusters S82+ and Se82+ with various iron carbonyls were investigated. Several new chalcogen containing iron carbonyl cluster cations were isolated, depending on the nature of the counteranion. In the presence of SbF6 as a counterion, the cluster [Fe3(E2)2(CO)10] [SbF6]2·SO2 (E = S, Se) could be isolated from the reaction of E82+ and excess iron carbonyl. The cluster is a picnic-basket shaped molecule of two iron centers linked by two Se2 groups, with the whole fragment capped by an Fe(CO)4 group. Crystallographic data for C10O12Fe3Se4Sb2F12S (I): space group monoclinic P21/c, A = 11.810(9), b = 24.023(6), c = 10.853(7) Å, β = 107.15(5)°, V = 2942(3) Å3, Z = 4, R = 0.0426, Rw = 0.0503. When Sb2F11 is present as the counterion, or Se4[Sb2F11]2 is used as the cluster cation source, a different cluster can be isolated, which has the formula [Fe4(Se2)3(CO)12] [SbF6]2·3SO2. The dication contains two Fe2Se2 fragments bridged by an Se2 group. Crystallographic data for C12O18Fe4Se6Sb2F12S3 (III): space group triclinic , b = 18.400(9), C = 10.253(4) Å, = 93.10(4), β = 103.74(3), γ = 93.98(3)°, V = 1995(1) Å3, Z = 2, R = 0.0328, Rw = 0.0325. The CO stretches in the IR spectrum all show a large shift to higher wavenumbers, suggesting almost no τ backbonding from the metals. This also correlates with the observed bond distances. All the compounds are extremely sensitive to air and water, and readily lose SO2 when removed from the solvent. Thus all the crystals were handled at −100°C. The clusters seem to be either insoluble or unstable in all solvents investigated.  相似文献   

14.
New mixed metal complexes SrCu2(O2CR)3(bdmap)3 (R = CF3 (1a), CH3 (1b)) and a new dinuclear bismuth complex Bi2(O2CCH3)4(bdmap)2(H2O) (2) have been synthesized. Their crystal structures have been determined by single-crystal X-ray diffraction analyses. Thermal decomposition behaviors of these complexes have been examined by TGA and X-ray powder diffraction analyses. While compound 1a decomposes to SrF2 and CuO at about 380°C, compound 1b decomposes to the corresponding oxides above 800°C. Compound 2 decomposes cleanly to Bi2O3 at 330°C. The magnetism of 1a was examined by the measurement of susceptibility from 5–300 K. Theoretical fitting for the susceptibility data revealed that 1a is an antiferromagnetically coupled system with g = 2.012(7), −2J = 34.0(8) cm−1. Crystal data for 1a: C27H51N6O9F9Cu2Sr/THF, monoclinic space group P21/m, A = 10.708(6), B = 15.20(1), C = 15.404(7) Å, β = 107.94(4)°, V = 2386(2) Å3, Z = 2; for 1b: C27H60N6O9Cu2Sr/THF, orthorhombic space group Pbcn, A = 19.164(9), B = 26.829(8), C = 17.240(9) Å, V = 8864(5) Å3, Z = 8; for 2: C22H48O11N4Bi2, monoclinic space group P21/c, A = 17.614(9), B = 10.741(3), C = 18.910(7) Å, β = 109.99(3)°, V = 3362(2) Å3, Z = 4.  相似文献   

15.
The reaction of RuCl3(H2O), with C5Me4CF3J in refluxing EtOH gives [Ru25-C5Me1CF2)2 (μ-Cl2] (20 in 44% yield. Dimer 2 antiferromagnetic (−2J=200 cm1). The crystal structures of 2 (rhombohedral system, R3 space group, Z=9, R=0.0589) and [Rh25-C5Me4CF3(2Cl2(μ-Cl)2] (3) (rhombohedral system. space group, Z = 9, R = 0.0641) were solved; both complexes have dimeric structures with a trans arrangement of the η5-C5Me4CF4 rings. Comparison of the geometry of 2 and 3 with those of the corresponding η5-C5Me5 complexes shows that lowering the ring symmetry causes significant distortion of the M2(μ-Cl)2 moiety. The analysis of the MCl3 fragment conformations in 2 and 3 and in the η5-C5ME5 analogues shows that they are correlated with the M---M distances. The Cl atoms are displaced by Br on reaction of 2 with KBr in MeOH to give the diamagnetic dimer [Ru25-C5Me4CF3)2Br2 (μ-Br2] (4). Complex 2 reacts with O2 in CH2Cl2 solution at ambient temperature to form a mixture of isomeric η6-fulvene dimers [Ru26-C5Me3CF3 = CH2)2Cl2(μ-Cl)2] (5). Reactions of 5 with CO and allyl chloride give Ru(η5-C5Me3CF3CH2Cl)(CO)2Cl (6) and Ru(η5-C5Me3CF3CF3CH2Cl)(η3-C3H5)Cl2 (7) respectively.  相似文献   

16.
The preparation of a novel mononuclear complex of zirconium having an η8-bonded pentalene ligand and two η3-allyl groups is described. Its structure has been determined by 1H and 13C NMR spectroscopy. At room temperature some of the NMR signals are broadened, revealing that the compound is structurally dynamic. It is shown that the compound has C2 symmetry with the enantiomeric forms undergoing racemisation.  相似文献   

17.
Four complexes of the type [Cu4I4(CH3CN)2(L)2], L = aniline derivative: Cu4I4(CH3CN)2(2,6-dimethylaniline)2 (I), triclinic, , a = 12.449(3), B = 14.108(6), C = 10.606(4) Å, = 73.46(3), β = 95.00(2), γ = 73.42(3)°, V = 1682.3(10) Å3; Cu4I4(CH3CN)2(o-ethylaniline)2 (II), triclinic, , V = 1734.0(8) Å3; Cu4I4(CH3CN)2(6-ethyl-o-toluidine)2 (III), orthorhombic, Pnam, a = 14.976(6), b = 21.187(6), C = 12.545(2) Å, V = 3980.7(2) Å3; Cu4I4(CH3CN)2(p-anisidine)2 (IV), monoclinic, A2/a, A = 20.032(10), B = 7.863(1), C = 18.715(9) Å, β = 101.56(4)°, V = 2888.0(2) Å3; were examined by single crystal X-ray diffraction. Complexes I and II have no internal symmetry elements, III has an internal mirror and IV has a two-fold axis. Ab initio calculations based on the atomic positional parameters of complexes containing the three types of symmetry elements reveal HOMO orbitals to be dominated by the p orbitals of the iodine atoms whereas the LUMO orbitals contain major contributions from copper based p orbitals.  相似文献   

18.
In a synthetic route that varies from the standard procedure requiring irradiation, the (η6-C6H5Cl)Cr(CO)2PPh3 complex is obtained upon reacting (η6-C6H5Cl)Cr(CO)3 with tetrakis(triphenylphosphine)palladium(0), CuI, and trimethylsilylphenylacetylene in triethylamine. The X-ray crystal structure of the yellow–orange crystals of (η6-C6H5Cl)Cr(CO)2PPh3 allows structural comparisons to related (arene)Cr(CO)2PR3 complexes.  相似文献   

19.
Manganese tricarbonyl complexes (η5-C5H4CH2CH2Br)Mn(CO)3 (3) and (η5-C5H4CH2CH2I)Mn(CO)3 (4), with an alkyl halide side chain attached to the cyclopentadienyl ligand, were synthesized as possible precursors to chelated alkyl halide manganese complexes. Photolysis of 3 or 4 in toluene, hexane or acetone-d6 resulted in CO dissociation and intramolecular coordination of the alkyl halide to manganese to produce (η51-C5H4CH2CH2Br)Mn(CO)2 (5) and (η51-C5H4CH2CH2I)Mn(CO)2 (6). Low temperature NMR and IR spectroscopy established the structures of 5 and 6. Photolysis of 3 in a glass matrix at 91 K demonstrated CO release from manganese. Low temperature NMR spectroscopy established that the coordinated alkyl halide complexes are stable to approximately −20°C.  相似文献   

20.
The synthesis and characterization of a ferrocenyl-derived tridentate ligand, ferrocenyltris((methylthio)methyl)borate (FcTtP), and its representative metal complexes, [(FcTt)Cu]4 and [FcTt]2M (M = Fe, Co and Ni), are reported. The M = Fe complex exhibits spin-crossover behavior with a μeff = 1.19 μB at 25°C. The low-spin Co(II) derivative (1.88 μB) exhibits a characteristic axial electron paramagnetic resonance (EPR) spectrum, gav = 2.13, A = 53 G and A¦ = 43 G. The [FcTt]2M complexes display reversible two-electron redox processes assigned to ligand-centered events about 200 mV negative of the ferrocene-ferrocenium couple. [(FcTt)Cu]4 and [FcTt]2Ni have been characterized by X-ray diffraction. X-ray data for [(FcTt)Cu]4: monoclinic space group C2/c, with a = 24.3747(3) Å, b = 20.0857(2) Å, c = 17.2747(4) Å, β = 95.843(1)°, V = 8413.5(3) Å3, and Z = 4; [FcTt]2Ni: monoclinic space group C2/c, with a = 12.6220(3) Å, b = 11.6002(3) Å, c = 25.0125(7) Å, β = 94.067(1)°, V = 3653.1(2) Å3, and Z = 4.  相似文献   

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