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1.
Reactions of Co 3(μ 3-CBr)(μ-dppm)(CO) 7 with {Au[P(tol) 3]} 2{μ-(CC) n} ( n=2–4) have given {Co 3(μ-dppm)(CO) 7}{μ 3:μ 3-C(CC) nC} [ n=2 (1), 3 (2), 4 (3)] containing carbon chains capped by the cobalt clusters. Tetracyanoethene reacts with 2 to give {Co 3(μ-dppm)(CO) 7} 2{μ 3:μ 3-C(CC) 2C[=C(CN) 2]C[=C(CN) 2]C} (4). X-ray structural characterisation of 1, 3 and 4 are reported, that for 3 being the first of a cluster-capped C 10 chain. 相似文献
2.
The synthesis and reactivity of {(η 5-C 5H 4SiMe 3) 2Ti(CCSiMe 3) 2} MCl 2 (M = Fe: 3a; M = Co: 3b; M = Ni: 3c) is described. The complexes 3 are accessible by the reaction of (η 5-C 5H 4SiMe 3) 2Ti(CSiMe 3) 2 (1) with equimolar amounts of MCl 2 (2) (M = Fe, Co, Ni). 3a reacts with the organic chelat ligands 2,2′-dipyridyl (dipy) (4a) or 1,10-phenanthroline (phen) (4b) in THF at 25°C to afford in quantitative yields (η 5-C 5H 4SiMe 3) 2Ti(CSiMe 3) 2 (1) and [Fe(dipy) 2]Cl 2 (5a) or [Fe(phen) 2]Cl 2 (5b). 1/ n[Cu IHal] n (6) or 1/ n[Ag IHal] n (7) (Hal = Cl, Br) react with {(η 5 -C 5H 4SiMe 3) 2Ti(CCSiMe 3) 2}FeCl 2 (3a), by replacement of the FeCl 2 building block in 3a, to yield the compounds {(η 5-C 5H 4SiMe 3) 2Ti(C CSiMe 3) 2}Cu IHal (8) or {(η 5-C 5H 4SiMe 3) 2Ti(CSiMe 3) 2}Ag IHal (9) (Hal = Cl, Br), respectively. In 8 and 9 each of the two Me 3SiCC-units is η 2-coordinated to monomeric Cu I Hal or Ag IHal moieties. Compounds 8 and 9 can also be synthesized by the reaction of (η 5-C 5H 4SiMe 3) 2 Ti(CSiMe 3) 2 (1) with 1/ n[Cu IHal] n (6) or 1/ n [Ag IHal] n (7) in excellent yields. All new compounds have been characterized by analytical and spectroscopic data (IR, 1H-NMR, MS). The magnetic moments of compounds 3 were measured. 相似文献
3.
Polycrystalline octa-nuclear copper(I) O, O′-di- i-propyl- and O, O′-di- i-amyldithiophosphate cluster compounds, {Cu 8[S 2P(OR) 2] 6(μ 8-S)} where R = iPr and iAm, were synthesized and characterized by 31P CP/MAS NMR at 8.46 T and static 65Cu NMR at multiple magnetic field strengths (7.05, 9.4 and 14.1 T). The symmetries of the electronic environments around the P sites were estimated from the 31P chemical shift anisotropy (CSA) parameters, δaniso and η. Analyses of the 65Cu chemical shift and quadrupolar splitting parameters for these compounds are presented with the data being compared to those for the analogous octa-nuclear cluster compounds with R = nBu and iBu. The 65Cu transverse relaxation for the copper sites in {Cu 8[S 2P(O iPr) 2] 6(μ 8-S)} and {Cu 8[S 2P(O iAm) 2] 6(μ 8-S)} was found to be very different, with a relaxation time, T2, of 590 μs (Gaussian) and 90 μs (exponential), respectively. The structures of {Cu 4[S 2P(O iPr) 2] 4} and {Cu 8[S 2P(O iPr) 2] 6(μ 8-S)} cluster compounds in the liquid- and the solid-state were studied by Cu K-edge EXAFS. The disulfide, [S 2P(O iAm) 2] 2, was obtained and characterized by 31P{ 1H} NMR. The interactions of the disulfide and of the potassium O, O′-di- i-amyldithiophosphate salt with the surfaces of synthetic chalcocite (Cu 2S) were probed using solid-state 31P NMR spectroscopy and only the presence of copper(I) dithiophosphate species with the {Cu 8[S 2P(O iAm) 2] 6(μ 8-S)} structure was observed. 相似文献
4.
Ab initio molecular orbital theory was used to determine the equilibrium structure and vibrational frequencies of Fe 2Cl 6 and FeAlCl 6. The equilibrium structure the Fe 2Cl 6 dimer has D2h symmetry with a planar arrangement of the four membered {FeCl brFeCl br} ring, similar to the Al 2Cl 6 dimer. The calculated bond distances and vibrational frequencies are in good agreement with experiment. The potential energy surface for the puckering of the {FeCl brFeCl br} ring is extremely flat. This prevents an unambiguous assignment of either D2h or C2v symmetry to the Fe 2Cl 6 structure in electron diffraction measurements. The FeAlCl 6 molecule is found to have a C2v structure similar to Fe 2Cl 6 with vibrational frequencies in good agreement with experiment. 相似文献
5.
A series of novel diphosphinoazine rhodium amido carbonyl complexes [{R 2PCHC(Bu t)–NNC(Bu t)CH 2PR 2}Rh(CO)] ( R = Ph, Pr i, c-C 6H 11, Bu t) was prepared by deprotonation of cationic diphosphinoazine rhodium amino carbonyl complexes. The complexes were characterized by NMR as were also their precursors. The crystal structures of two cationic and one neutral deprotonated complex were determined by X-ray diffraction showing the complexes to be essentially planar with mutual trans arrangement of phosphine groups and nitrogens trans to carbonyl ligands. Measurement of valence vibration frequencies of carbonyl groups in the complexes allowed to estimate the electron density on the rhodium centre. The ene-hydrazone ligand backbone (nitrogen covalently bonded) is more electron donating than the azine backbone (nitrogen bonded by electron pair donation) as expected. In the neutral series of complexes electron donation increases with phosphine substitution in the order Ph < Pr i = c-C 6H 11 < Bu t with the corresponding decrease of carbonyl valence vibration frequency. The tert-butyl cationic complex undergoes in a low yield an unusual diphosphinoazine bond cleavage with simultaneous oxidation of the metal resulting in a binuclear bis(iminophosphine)dirhodium complex [{(Bu t) 2PCH 2C(Bu t)NH}Rh(Cl) 2(μ-Cl)] 2 the structure of which was also determined by X-ray diffraction. 相似文献
6.
Reaction between 5,5′-methylenebis(salicylaldehyde) or 5,5′-dithiobis(salicylaldehyde) and 1,2-diaminocyclohexane in equimolar ratio leads to the formation of new polymeric chelating ligands [–CH 2(H 2sal-dach)–] n (I) and [–S 2(H 2sal-dach) 2–] n (II). These ligands react with [VO(acac) 2] in DMF to give coordination polymers [–CH 2{VO(sal-dach)·DMF}–] n (1) and [–S 2{VO(sal-dach)·DMF}–] n (2). Both complexes are insoluble in common solvents and exhibit a magnetic moment value of 1.74 and 1.78 μB, respectively. IR spectral studies confirm the coordination of ligands through the azomethine nitrogen and the phenolic oxygen atoms to the vanadium. These complexes exhibit good catalytic activity towards the oxidation of styrene, cyclohexene and trans-stilbene using tert-butylhydroperoxide as an oxidant. Concentration of the oxidant and reaction temperature has been optimised for the maximum oxidation of these substrates. Under the optimised conditions, oxidation of styrene gave a maximum of 76% (with 1) or 85% (with 2) conversion having following products in order of selectivity: benzaldehyde > styreneoxide > 1-phenylethane-1,2-diol > benzoic acid. A maximum of 98% conversion of cyclohexene was obtained with both the catalysts where selectivity of cyclohexeneoxide varied in the order: 2 (62%) > 1 (45%). With the conversion of 33% (with 1) and 47% (with 2), oxidation of trans-stilbene gives benzaldehyde, benzil and trans-stilbeneoxide as major products. 相似文献
7.
Some aspects of the theory of LASIN (laser assisted surface ion neutralization) are discussed, with emphasis on the physical origins of the so-called double-peak structures found in some calculations of the charge-transfer (neutralization) probability, P, as a function of the laser frequency η. These two peaks have been called the first peak at η ≈ η m = O − m (in a.u.), where o( m) is the electronic energy level of the ion/atom (middle of the solid's valence band) and the second peak, a much larger peak at η ≈ 1.3 η m, respectively. We show that these double-peak structures are all special cases of multiple-peak structures which result from quantum interference effects, and that, in fact, the second peak is to be regarded as the main resonance peak. This result is interesting in itself, because it is the first peak which has heretofore been considered the main resonance peak. To simplify the discussion, a two-level model is adapted, which represents the solid valence band by a single level at m. Clarification of the physical reason for the multiple peaks is based on the semiclassical theory of nonadiabatic transitions, in which the peaks are due to the phase difference between the two adiabatic paths that arise from the diagonalization of the two-level hamiltonian. With the electronic hopping potential modelled by V(t) = Vosech(λt), and the laser potential by W(t) = Wosech(λt) cos(πt + δ), in the usual notation, an approximate analytical expression for P(η) is presented for the case Wo/Vo < 1, which covers most of the previous treatments, and is in good agreement with the exact results. 相似文献
8.
A performance evaluation of Density Functional Tight Binding (DFTB) in the two-layer ONIOM method is presented in an effort to estimate DFTB effectiveness as an inexpensive low level quantum mechanical layer. Ground state geometries, geometry error, S-values and energy error for: (H 2O) x(MeOH) y, [(η 5-C 5Me nH 5−n) 2Ti] 2(μ 2, η 2,η 2-N 2), n = 4, and complexes of Cu + with tyrosine, were compared to target calculations at B3LYP level of theory for all three of the systems and second order Moller-Plesset (MP2) target level of theory for the first two systems. The calculated root-mean-square errors (RMS) of the ONIOM optimized geometries relative to the target are found to be small. The DFTB level of theory was unable to reproduce the target geometry structure for one of the isomers of tyrosine–Cu + complex, while the ONIOM combinations were able to reproduce all target structures. The absolute value of the geometry error was determined to be smaller then the corresponding energy error except for the (H 2O) x(MeOH) y system at the ONIOM(MP2/6-31G(d,p):DFTB) level of theory. The S-values were relatively small and close in value contributing to relatively small energy errors. Both method combinations ONIOM(MP2:DFTB) and ONIOM(DFT:DFTB) show similar performance compared to the corresponding target level of theory. The results also suggest that it is safe to use ONIOM(DFT:DFTB) for investigations of [(η 5-C 5Me nH 5−n) 2Ti] 2(μ 2, η 2,η 2-N 2) complexes. 相似文献
9.
Three interpenetrated polymeric networks, {[Co(bpp)(OH-BDC)] · H 2O} n (1) [Ni(bpp) 1.5(H 2O)(OH-BDC)] n (2) and {[Cd(bpp)(H 2O)(OH-BDC)] · 2H 2O} n (3), have been prepared by hydrothermal reactions of 1,3-bis(4-pyridyl)propane (bpp), 5-hydroxyisophthalic acid (OH-H 2BDC), with Co(NO 3) 2 · 6H 2O, Ni(NO 3) 2 · 6H 2O and Cd(NO 3) 2 · 4H 2O, respectively. Single-crystal X-ray diffraction analyses reveal that the three compounds all exhibit interpenetrated but entirely different structures. Compound 1 is a fourfold interpenetrated adamantanoid structure with water molecules as space fillers, in which bpp adopts a TG conformation ( T = trans, G = gauche). Compound 2 is an interdigitated structure from the interpenetrated long arms of one-dimensional molecular ladders, while bpp in 2 adopts both TT and TG conformations. Compound 3 is a twofold interpenetrated three-dimensional network from a one-dimensional metal-carboxylate chain bridged by TG conformational bpp. The hydrogen bonding interactions in 1–3 further stabilize the whole structural frameworks and play critical roles in their constructions. 相似文献
10.
The title complex Mn 2(CO) 6(μ-H){μ-S(SC 3H 5)C=C(PP r3i)S} was synthesized by allyation of the homobinuclear anion [Mn 2(CO) 6(μ-H){μ-S(SC 3H 5)C=C(PP r3i)S}] −1, and characterized by elemental analysis, IR, 1H NMR and 31P NMR spectra. The molecular structure shows that it contains a novel fairly planar ligand S(S)C=C(PPr 3i)S, and the two Mn(CO) 3 fragments are symmetrically placed at both sides of the plane of the ligand. 相似文献
11.
Two polymeric mercury(II) halide adducts of an olefinic double betaine, cis-( p-Me 2NC 5H 4N +) 2C 2(COO −) 2 (L), have been prepared and characterized by X-ray crystallography. [{Hg 2L 2Cl 4·6HgCl 2} n] (1) crystallizes in the monoclinic space group C2/ c with Z = 4, and [{Hg 2L 2Br 4·HgBr 2} n] (2) in the triclinic space group P
with Z = 1. Complexes 1 and 2 are structurally similar, being composed of centrosymmetric fourteen-membered rings and nearly linear HgX 2 (X = Cl, Br) moieties that are further inter-linked by weak HgX [HgCl = 2.930–3.136(9) Å, HgBr = 3.057–3.310(6) Å] and HgO [2.64, 2.75(3) Å] bonds to generate a two-dimensional polymeric network. 相似文献
12.
Two cobalt(II) coordination polymers formed from bte (bte = 1,2-bis(1,2,4-triazol-1-yl)ethane), namely [Co(bte) 2(dca) 2] n (1) and {[Co(bte)(dca) 2] · H 2O} n (2), have been synthesized and characterized by elementary analyses, IR, thermogravimetric analyses, X-ray diffraction analyses and magnetic measurements. Compound 1 is a double-chain with Co(II) centers bridged by bte, containing metallocycles of [Co 2(bte) 2] and trans dca as termination ligands. In 2, each Co(II) center is bonded by two bridging bte ligands and four dca as μ-1,5-dca in different orientations in the 3D network. 相似文献
13.
Reaction of potassium 3{5}-(3′,4′-dimethoxyphenyl)pyrazolide with 2-bromopyridine in diglyme at 130°C for 3 days followed by an aqueous quench, affords 1-{pyrid-2-yl}-3-{3′,4′-dimethoxyphenyl}pyrazole (L 2) in 69% yield after recrystallization from hot hexanes. Complexation of [Cu(NCMe) 4]BF 4 by 2 molar equivalents of 1-{pyrid-2-yl}-3-{2′,5′-dimethoxyphenyl}pyrazole (L 1) or L 2 in MeCN at room temperature, followed by concentration and crystallisation with Et 2O, gives [Cu(L) 2]BF 4 L = L 1, L 2) in good yields. Treatment of AgBF 4 with L 1 or L 2 in MeNO 2 similarly gives [Ag(L) 2]BF 4 L = L 1, L 2); reaction of AfBF 4 with L 2 in MeCN gives a product of stoichiometry [Ag(L 2)(NCMe)]BF 4. The 1H NMR spectra of the [M(L) 2]BF 4 complexes show peaks arising from a single coordinated environment. The single crystal X-ray structure of [Cu(L 1) 2]BF 4 shows a tetrahedral complex cation with Cu---N = 2.011(8), 2.036(8), 2.039(8), 2.110(8) Å. The Cu I centre is close to tetrahedral, the dihedral angle between the least-squares planes formed by the Cu atom and the N donor atoms of the two ligands being 88.3(3)°. Complexation of hydrated Cu(BF 4) 2 by L 2 in MeCN at room temperature yields [Cu(L 2) 2](BF 4) 2. The cyclic voltammograms of the three Ag I complexes in MeCN/0.1 M Bu 4n NPF 6 are suggestive of extensive ligand dissociation in this solvent. 相似文献
14.
Trifunctional primary phosphines of the type 1,3,5-[PH 2(CH 2) n] 3C 6H 3 (3b–d) were obtained via an Arbusov reaction between the 1,3,5-tris(bromoalkyl)benzenes 1b–d and P(OEt) 3 followed by a reaction of the trisphosphonates 1,3,5-[(EtO) 2P(O)(CH 2) n] 3C 6H 3 (2b–d) with LiAlH 4. A straightforward conversion of these sensitive key phosphines 3b–d to the corresponding water-soluble ligands 1,3,5-tris[bis(hydroxymethyl)phosphinylalkyl]benzenes 4b–d and 1,3,5-tris[bis(2′-diethylphosphonatoethyl)phophinylalkyl]benzenes 5b–d was achieved by formylation with formaldehyde and hydrophosphonation with diethyl vinylphosphonate, respectively. A five component self-assembly consisting of three equivalents of the platinum(II) complex Cl 2Pt(NCPh) 2 and two equivalents of the ligands 5b–d under high dilution conditions resulted in the formation of the nanoscaled, water-soluble triplatinacyclophanes 6b–d in high yields. However, comparable reactions with the ligands 4b–d led only to polymeric materials, which are insoluble in all organic solvents and water. The structures of the metallacyclophanes 6b–d were elucidated by 31P{ 1H}-, 13C{ 1H}-, and 195Pt{ 1H}-NMR spectroscopic investigations. 相似文献
15.
In this paper some synthetic procedures to obtain (η 6-arene)metal derivatives are reviewed. The metal-atom-arene-vapor co-condensation technique is the most appropriate to generate complexes of polycyclic aromatic hydrocarbons or heterocycles. As far as the aluminium halide-mediated synthesis is concerned, two classes of reaction are observed. When AlX 3 is used with a metal halide in the presence of an aromatic hydrocarbon in the absence of any reducing agent, AlX 3 can function as a dehalogenating agent, to give ionic compounds of general formula [M(η 6-arene) n](AlX 4) m, or it can add across the M---X bond with formation of M(μ-X) nAlX 4−n systems. In both cases the metal displays its typical oxidation state. However, the use of AlX 3 in combination with aluminium (the Fischer-Hafner reducing system) affords ionic or covalent low-oxidation-state metal(η 6-arene) complexes. Attention is focused on our most recent results concerning the synthesis, properties and reactivity of η 6-arene derivatives of Group 4 and 5 elements, showing, inter alia, the first example of a tetraarylborate anion behaving as a 12-electron donor to one metal atom and low-valent η 6-arene compounds as useful reagents in the inorganic and coordination chemistry of the corresponding metal in nonaqueous systems. 相似文献
16.
To examine the steric effects on the stability of Ln(0) π-arene compounds, molecular mechanics (MMP2) calculations are performed on Gd(η-C 6H 6) 2 and Ln(η-Bu t3C 6H 3) 2 (where Ln is Gd, Yb and Y ). The small potential-well depth ( ≈ 2 kcal mol −1) and the large Gd-C equilibrium distance ( > 3.3 Å) explains the instability of Gd(η-C 6H 6) 2, while the difference in the stability between Gd(η-Bu t3C 6H 3) 2 and Yb(η-Bu t3C 6H 3) 2 can be attributed to the difference in the van der Waalsradii of the two metals and the more contracted 5d orbitals on the Yb atom. 相似文献
17.
The reaction of [ R-( R, R)]-(+) 589-[(η 5-C 5H 5){1,2-C 6H 4(PMePh) 2}Fe(NCMe)]PF 6 with (±)-AsHMePh in boiling methanol yields crystalline [ R-[( R)-( R, R)]-(+) 589)-[(η5-C5H5){1,2-C6H4(PMePh)2}Fe(AsHMePH)PF 6, optically pure, in ca. 90% yield, in a typical second-order asymmetric transformation. This complex contains the first resolved secondary arsine. Deprotonation of the secondary arsine complex with KOBu t at −65°C gives the diastereomerically pure tertiary arsenido-iron complex [ R-[( R),( R, R)]]-[((η 5-C 5H 5){1,2-C 6H 4(PMePh) 2}FeAsMePh] · thf, from which optically pure [ R-[( S),( R, R)]]-(+) 589-[(η 5-C 5H 5){1,2-C 6H 4(PMePh) 2}Fe(AsEtMePh)PF 6 is obtained by reaction with iodoethane. Cyanide displaces ( R)-(−) 589-ethylmethylphenylarsine from the iron complex, thereby effecting the asymmetric synthesis of a tertiary arsine, chiral at arsenic, from (±)-methylphenylarsine and an optically active transition metal auxiliary. 相似文献
18.
The new diphenolato complexes [{Mo(NO){HB(dmpz) 3}Cl} 2Q] where dmpz = 3,5-dimethylpyrazolyl and Q = OC 6H 4(C 6H 4O ( n = 1 or 2), OC 6H 4CR=CRC 6H 4O (R = H or Et), and OC 6H 4CH=CHC 6H 4CH=CHC 6H 4O have been prepared and their electrochemical properties (cyclic and differential pulse voltammetry) compared with previously reported analogues where Q = OC 6H 4O, OC 6H 4EC 6H 4O (E = SO 2, CO and S), OC 6H 4 (CO)C 6H 4 C 6H 4(CO)C 6H 4O and 1,5- and 2,7-O 2C 10H 6. The electrochemical interaction between the redox centres in the new complexes is very weak, in contrast to that in the 1,4-benzenediolato and naphthalendiolato species. The EPR spectra of the reduced mixed-valence species [{Mo(NO){HB(dmpz) 3}Cl} 2Q] − where Q = 1,3- and 1,4-OC 6H 4O and OC 6H 4SC 6H 4O shows that they are valence-trapped at room temperature, whereas those of the dianions [{Mo(NO){HB(dmpz) 3}Cl} 2Q] 2− where Q = 1,4-OC 6H 4O, OC 6H 4EC 6H 4O (E = CO or S) and OC 6H 4CH=CHC 6H 4CH=CHC 6H 4O shows that the unpaired spins on each molybdenum centre are strongly correlated ( J, the spin exchange integral A Mo, the metal-hyperfine coupling constant). The electrochemical properties and the comproportionation constants for the reaction [{Mo(NO){HB(dmpz) 3} Cl} 2Q] + [{Mo(NO){HB(dmpz) 3}Cl}O] 2] 2−2[{Mo(NO) {HB(dmpz) 3}Cl} 2Q] − where Q = diphenolato bridge, are compared with related compounds containing benzenediamido and dianilido bridges. 相似文献
19.
Reaction of Na[MCl 4] (M=Pd or Pd) with the azo-containing phosphines Ph 2P{1-(4-RC 6H 4N 2)-2-OR′-C 10H 5} {R=Me (I), NMe 2 (II); R′=C(O)Me} affords the complexes [MCl 2L 2] (1–4) in good yield. Complexes 1–4 have all been fully characterised by elemental analysis, 1H-, 13C{ 1H}-, and 31P{ 1H}-NMR spectroscopy and UV–visible spectroscopy. The use of 1 in the Heck reaction has been investigated and shown to effect up to 1000 turnovers. 相似文献
20.
Novel isonitrile derivatives of a diruthenium carbonyl complex, (μ 2,η 3:η 5-guaiazulene)Ru 2(CO) 5 (2), were synthesized by substitution of a CO ligand by an isonitrile, and were subjected to studies on thermal and photochemical haptotropic interconversion. Treatment of 2 (a 45:55 mixture of two haptotropic isomers, 2-A and 2-B) with RNC at room temperature resulted in coordination of RNC and alternation of the coordination mode of the guaiazulene ligand to form (μ 2,η 1:η 5-guaiazulene)Ru 2(CO) 5(CNR), 5d–5f, [5d; R= tBu, 5e; 2,4,6-Me 3C 6H 2, or 5f; 2,6- iPr 2C 6H 3] in moderate to good yields. Thermal dissociation of a CO ligand from 5 at 60 °C resulted in quantitative formation of a desirable isonitrile analogue of 2, (μ 2,η 3:η 5-guaiazulene)Ru 2(CO) 4(CNR), 4d–4f, [4d; R= tBu, 4e; 2,4,6-Me 3C 6H 2, or 4f; 2,6- iPr 2C 6H 3], as a 1:1 mixture of the two haptotropic isomers. A direct synthetic route from 2 to 4d–4f was alternatively discovered; treatment of 2 with one equivalent of RNC at 60 °C gave 4d–4f in moderate yields. All of the new compounds were characterized by spectroscopy, and structures of 5d (R= tBu) and 4d-A (R= tBu) were determined by crystallography. Thermal and photochemical interconversion between the two haptotropic isomers of 4d–4f revealed that the isomer ratios in the thermal equilibrium and in the photostatic state were in the range of 48:52–54:46. 相似文献
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