共查询到20条相似文献,搜索用时 31 毫秒
1.
1,1,3,3-Tetrakis(trifluoromethyl)allene reacts with π-C 5H 5Fe(CO) 2- and Re(CO) 5- to give σ-complexes. The iron σ-complex, when refluxed in decalin or exposed to UV radiation, is transformed to the π-allylidene analogue. Structures of the σ-complexes are determined from IR, Raman, 19F NMR and X-ray spectral data. 相似文献
2.
Treatment of ruthenium complexes [CpRu(AN) 3][PF 6] (1a) (AN=acetonitrile) with iron complexes CpFe(CO) 2X (2a–2c) (X=Cl, Br, I) and CpFe(CO)L′X (6a–6g) (L′=PMe 3, PMe 2Ph, PMePh 2, PPh 3, P(OPh) 3; X=Cl, Br, I) in refluxing CH 2Cl 2 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′=PMe 3, PMe 2Ph, PMePh 2, PPh 3, P(OPh) 3; X=Br, I), respectively. Similar reaction of [CpRu(L)(AN) 2][PF 6] (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 CH 2Cl 2 at room temperature to give 3a, and transforms into 7a by the reaction with PMe 3. 相似文献
3.
(η 4-Cycloheptatriene)Ru(CO) 3 reacts with tetracyanoethylene (TCNE), 4-phenyltriazoline-3,5-dione (PTAD) and (carbomethoxy)maleic anhydride (CMA) to give stable 3 + 2 σ,π-allylic adducts. The 3 + 2 adduct with TCNE equilibrates via a [4,4]-sigmahaptotropic rearrangement with the less stable 6 + 2 adduct, which decomposes under the reaction conditions to the demetallated 6 + 2 adduct. It is concluded that σ,π-allylic adducts are in general more stable than their isomeric η 4-π counterparts. The structure of the 3 + 2 TCNE adduct was determined by a single-crystal X-ray diffraction study. 相似文献
4.
The main product of the thermal reaction between the title oxatetraene (I) and Fe 2(CO) 9 in ether/pentane is the bimetallic complex (C 10H 10O)Fe 2(CO) 6- diexo (II), which has C2υ symmetry both in the solid state (X-ray analysis) and in solution. Whereas the protonation of the free ligand leads usually to polymerisation, the addition of a protic acid such as CF 3CO 2H to II proceeds cleanly at 0°C giving first a (η 3-allyl)Fe(CO) 3O 2CCF 3 complex (III). The intermediate III adds a second equivalent of acid in a slower step ( k2/ k1 = 0.1, CF 3CO 2D/CHCl 3, 0°C) giving the trans-bis(η 3-allyl) isomer IV with high regioselectivity. The addition of CF 3CO 2D yields the corresponding deuteriomethylallyliron tricarbonyl trifluoroacetates III′ and IV′. No further deuterium incorporation is observed at 0°C, thus confirming the kinetic control of the regioselective double addition of protic acid to II. 相似文献
5.
The complex (DMPP)Fe 2(CO) 7 in which DMPP (1-phenyl-3,4-dimethylphosphole) is η 4-coordinated with Fe(CO) 3 through its diene and η 1-coordinated with Fe(CO) 4 through its phosphorus atom is selectively decomplexed at phosphorus to give (DMPP)Fe(CO) 3 by reaction with AlCl 3 followed by NH 4OH. This new η 4-complex (DMPP)Fe(CO) 3 can be oxidized, sulfurized and quaternized at phosphorus by H 2O 2, S 8, and PhCH 2Br and MeI, respectively, as an ordinary phosphine without decomplexation of the diene. As a free phosphole, this complex also gives a ring-expanded product by reaction with benzoyl chloride, water and Et 3N. In the presence of some metallic salts such as (PhCN) 2PdCl 2, it loses CO to give the bimetallic sandwich [(DMPP)Fe(CO) 2] 2. It can also give some new bimetallic complexes such as [(DMPP)Fe(CO) 3]W(CO) 5 by complexation of the phosphorus lone pair by W(CO) 5(THF). 相似文献
6.
In the reaction of cis-(CO) 4(SnPh 3)Re[C(OEt)NR 2] (R = ipr (isopropyl), chex (cyclohexyl)) with BI 3 the Lewis acid attacks the triphenylstannyl ligand. Substitution of a phenyl for a iodine group leads to equilibrium mixtures of rhenium carbene complexes of general formula cis-(CO) 4(SnPh 3−χI χ)Re[C(OEt)NR 2] (χ = 1−3; R = ipr, chex). By changing the solvent and ratio of can be shifted such that only one major product is formed. Thus this reaction pathway can be used for the preparation of cis-(CO) 4(SnPhI 2)Re[C(OEt)NR 2] (R = ipr, chex). Even when a large excess of BI 3 is present electrophilic attack by the Lewis acid on the carbene ligand is not observed. Synthesis of cis-(CO)4(SnPh3−χIχ)Re[C(OEt)NR2] (χ = 1−3; R --- ipr, chex) can be achieved in high yield by reaction of cis-(CO)4(SnPh3)Re[C(OEt)NR2] (R = ipr, chex) with one, two or three equivalents of HI. This reaction, with successive rupture of the tin-carbon bonds in the triphenylstannyl ligand and the simultaneous formation of benzene, affords the desired substitution product irreversibly. Reaction of cis-(CO)4(SnPh3)Re[C(OEt)NR2] (R = ipr, chex) with I2 gives the compounds, cis-(CO)4(SnI3)Re[C(OEt)NR2] (R = ipr, chex), in relatively low yields. 相似文献
7.
The strong π-acid ligand Ph 2PN( iBu)PPh 2 reacts with Co 2(CO) S (1:1) to give Co 2[μ-Ph 2PN( iBu)PPh 2] (μ-CO) 2(CO) 4 (1); however, when the ratio is 2:1 a novel species [Co{Ph 2PN( iBu)PPh 2- P, P′} 2(CO)][Co(CO) 4] (2) has been obtained. Crystal data for 2: Mr = 1140.83; triclinic, space group P
, a = 12.330(2), b = 13.340(2), c = 18.122(3) Å, = 86.63(1), β = 80.75(1), γ = 84.24(1)°, V = 2924 Å 3, Z = 2; R = 0.060 for 3711 reflections having I 3σ( I). The results of X-ray diffraction, ESR, variable-temperature magnetic susceptibility, conductivity, and XPS analysis support that the species 2 is a d 9-d 9 cage molecule-pair. The mechanism for the formation of the species 2 has been investigated initially by 31P NMR. 相似文献
8.
The d2/d3 redox pair [WF2(PhC identical to CPh)Tp']z [z = +1 or 0, Tp' = hydrotris(3,5-dimethylpyrazolyl)borate] is the missing link in a 'redox family tree' relating the d6 tricarbonyls [M(CO)3L]- to the d2 trihalides [MX3L] (M = Mo or W, L = Cp or Tp') by a series of stepwise reactions involving sequential one-electron oxidation followed by ligand substitution. 相似文献
9.
Reaction of (μ 3-CCH 3)CO 3(CO) 9 (I) with dppm (dppm = bis-(diphenylphosphino)methane) affords the cluster (μ 3-CCH 3)Co 3(CO) 7-dppm (II). The crystal and molecular structure of II have been determined at −160°C. The dppm ligand bridges one of the three metal—metal edges in the equatorial plane to give a five-membered ring, which adopts an envelope conformation. Cluster II functions as a catalyst for the hydroformylation of 1-pentene (80 bar of H2/CO (1/1); 110°C). The results indicate that the dppm bridging ligand stabilizes and activates the cluster for catalysis, and open the way to the synthesis of chiral clusters. 相似文献
10.
Reactions between benzo [h]quinoline (BqH) and M(CO) 5Me (M = Mn, Re), M 3(CO) 12 (M = Ru, Os) and [Rh(CO) 2Cl] 2 have given the complexes M(CO) 4Bq (M = Mn, Re), M(CO) 2Bq 2 (M = Ru, Os), and Bq 2RhCl 2Rh(CO) 2, respectively; Cr(CO) 3 (π-BqH) is metallated on reaction with Mn(CO) 5Me, affording [π-BqMn(CO) 4]Cr(CO) 3. Spectroscopic evidence was obtained for the formation of Mo(CO) 2Bq(π-C 5H 5). Reactions of some complexes to give bi(benzo [h]quinolyl) are also reported. Characteristic changes in the IR and NMR spectra which occur as a result of metallation of the ligand are reported. 相似文献
11.
Summary Tetraazaadamantane (taad) reacts with group VI metal hexacarbonyls to give mononuclear (taad)M(CO) 5 (M=Cr, Mo and W) derivatives. Mixed ligand metal tricarbonyls, cis- (L-L)(taad)M(CO) 3 (L-L=o-phenanthroline or 2,2-bipyridine; M=Cr and Mo) have also been synthesised. Bromine or iodine reacts with (taad)M(CO) 5 (M=Cr and Mo) to give [(taad)M(CO) 5X] +X – (X=Br or I). Nitrosyl chloride reacts with (taad)M(CO) 5 at room temperature to yield mer- (taad)M(CO) 3NOCl while with the mixed (L-L)(taad)-Mo(CO) 3 complex, a mixture of (L-L)Mo(NO) 2Cl 2 and (L-L)Mo(CO) 2NOCl was obtained. An analogous reaction with (L-L)(taad)Cr(CO) 3, gave only (L-L)Cr(NO) 2Cl 2 derivatives. The products have been characterised by elemental analysis, i.r. spectra, conductivity data and magnetic measurements. 相似文献
12.
Treatment of the diene-Fe(CO) 3 complex (2) with dehydrated ferric chloride on silica gel support results in oxidative cyclisation of the alcohol function onto the diene ligand to give (3). This contrasts with the normal behaviour of both diene-Fe(CO) 3 complexes and alcohols toward ferric chloride. 相似文献
13.
As a model for non-classical metal carbonyls, we investigate CO in presence of a unit positive charge placed at different distances along the bond axis. We use the force approach, to look into the nature of the individual molecular orbitals. We find that in free CO the HOMO (σ(3)) is antibinding. As the positive charge approaches form carbon side, σ(1) and degenerate π orbitals become more binding, while σ(2) and σ(3) become more antibinding. The overall effect is more binding resulting in a shorter C–O bond. If the charge approaches from oxygen side, then σ(1), σ(3) and degenerate π orbitals become less binding, while σ(2) becomes slightly more binding, resulting in a lengthening of C–O bond. 相似文献
14.
Acylation of diene Fe(CO) 3 complexes using the Perrier complexes RCOCl/AlCl 3 in methylene chloride at 0°C gives dienone complexes in high yield. Substitution occurs only at unsubstituted terminal carbons of the diene unit. Quenching the reaction mixtures in cold aqueous ammonia gives cis dienone complexes only. Trans dienone complexes are prepared by subsequent isomerization in methanolic sodium methoxide. Formylation of diene Fe(CO) 3 complexes proceeds in modest yield using dichloromethylmethyleter/AlCl 3 in methylene chloride to give trans-dienal complexes. Reduction of the dienone and dienal complexes as well as those of dienols and dienoic esters with 4 : 1 AlCl 3/LiAlH 4 results in complete removal of the oxygen function to give trans-diene complexes in good yield. 相似文献
15.
1-Methoxy-3-trimethylsiloxy-1,3-butadiene (Danishefsky's diene) is recognized as a synthetically useful diene due to its high reactivity in the Diels-Alder reaction with electron-deficient alkenes to give oxygen-functionalyzed cyclohexenes and substituted cyclohexenones, which are important building blocks for the total synthesis of natural products. However, the development of catalytic enantioselective versions of Diels-Alder reactions using Danishefsky type dienes with electron-deficient alkenes has been difficult because of the instability of the dienes under Lewis acidic conditions. Only highly reactive CO and CN double bonds are employed in a hetero-Diels-Alder reaction which proceeds under catalysis of chiral Lewis acids. We have developed a new chiral ligand, BINAMIDE, which is easily prepared from 1,1'-binaphtyl-2,2'-diamine by acylation. The highly diastereo- and enantioselective Diels-Alder reaction of Danishefsky type dienes with electron-deficient alkenes in the presence of an Yb(III)-BINAMIDE complex has been developed. The reaction proceeded in an exoselective mode and gave chiral highly functionalized cyclohexene derivatives in good yields. 相似文献
16.
The compounds (π-C 5H 5)(CO) 2LM-X (L = CO, PR 3; M = Mo, W; X = BF 4, PF 6, AsF 6, SbF 6) react with H 2S, p-MeC 6H 4SH, Ph 2S and Ph 2SO(L′) to give ionic complexes [(π-C 5H 5)(CO) 2LML′] + X −. Also sulfur-bridged complexes, [(π-C 5H 5)(CO) 3W---SH---W(CO) 3(π-C 5H 5)] + AsF 6− and [(π-C 5H 5)(CO) 3M-μ-S 2C=NCH 2Ph-M(CO) 3(π-C 5H 5)], have been obtained. Reactions with SO 2 and CS 2 have been examined. 相似文献
17.
An unprecedented, intramolecular metal-to-metal silyl ligand migration reaction has been discovered in a series of phosphido-bridged iron-platinum complexes and which may be triggered by an external nucleophile. Thus, reaction of solutions of [(OC)3-(R1/3Si)Fe(mu-PR2R3)Pt(1,5-COD) (1a R1 = OMe, R2 = 3 = Ph; 1b R1 = OMe, R2 = R3 = Cy; 1c R1 = Ph, R2 = R3 = Ph; 1d R1 = Ph, R2 = R3 = Cy; 1e R1 = Ph, R1 = H, R3 = Ph) in CH2Cl2 with CO rapidly afforded the corresponding complexes [(OC)4Fe(mu-PR2R3)Pt(SiR1/3)-(CO)] (2a-e) in which the silyl ligand has migrated from Fe to Pt, while two CO ligands have been ligated, one on each metal. When 1a or 1c was slowly treated with two equivalents of tBuNC at low temperature, quantitative displacement of the COD ligand was accompagnied by silyl migration from Fe to Pt and coordination of an isonitrile ligand to Fe and to Pt to give [(OC)3-(tBuNC)Fe(mu-PPh2)Pt[Si(OMe)3](CNtBu)] (3a) and [(OC)3(tBuNC)-Fe(mu-PPh2)Pt[SiPh3](CNtBu)] (3c). Reaction of 2a with one equivalent of tBuNC selectively led to substitution of the Pt-bound CO to give [(OC)4-Fe(mu-PCy2)Pt[Si(OMe)3](CNtBu)] (4b), which reacted with a second equivalent of tBuNC to give [(OC)4Fe(mu-PCy2)-Pt[Si(OMe)3](CNtBu)2] (5b) in which the metal-metal bond has been cleaved. Opening of the Fe-Pt bond was also observed upon reaction of 3a with tBuNC to give [(OC)3(tBuNC)-Fe(mu-PPh2)Pt[Si(OMe)3](CNtBu)2] (6). The silyl ligand migrates from Fe, in which it is trans to mu-PR2R3 in all the metal-metal-bonded complexes, to a position cis to the phosphido bridge on Pt. However, in 5a,b and 6 with no metal-metal bond, the Pt-bound silyl ligand is trans to the phosphido bridge. The intramolecular nature of the silyl migration, which may be formally viewed as a redox reaction, was established by a cross-over experiment consisting of the reaction of 1a and 1d with CO; this yielded exclusively 2a and 2d. The course of the silyl-migration reaction was found to depend a) on the steric properties of the -SiR1/3 ligand, and for a given mu-PR2R3 bridge (R2 = R3 = Ph), the migration rate decreases in the sequence Si(OMe)3> SiMe2Ph> SiMePh2>SiPh3; b) on the phosphido bridge and for a given silyl ligand (R1 = OMe), the migration rate decreases in the order mu-PPh2 > mu-PHCy; c) on the external nucleophile since reaction of 1c with two equivalents of P(OMe)3, P(OPh)3 or Ph2PCH2C(O)Ph led solely to displacement of the COD ligand with formation of 11a-c, respectively, whereas reaction with two equivalents of tBuNC gave the product of silyl migration 3c. Reaction of [(OC)3-[(MeO)3Si]Fe(mu-PPh2)Pt(PPh3)2] (7a) with tBuNC (even in slight excess) occurred stereoselectively with replacement of the PPh3 ligand trans to mu-PPh2, whereas reaction with CO led first to [(OC)3((MeO)3Si)Fe(mu-PPh2)Pt(CO)-(PPh3)] (8a), which then isomerized to the migration product [(OC)4Fe(mu-PPh2)Pt[Si(OMe)3](PPh3)] (9a). Most complexes were characterized by elemental analysis, IR and 1H, 31P, 13C, and 29Si NMR spectroscopy, and in five cases by X-ray diffraction. 相似文献
18.
Conclusions The reaction of Cr(CO) 6, (NH 3) 3Cr(CO) 3, and Py 3Cr(CO) 3 with arenes that contain -functional groups in the side shain gave a number of new arenechromium tricarbonyls.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2824–2827, December, 1978. 相似文献
19.
Thiacalix[3]pyridine (Py3S3) reacted with [Rh(diene)(mu-Cl)]2(diene = 1,5-cyclooctadiene (cod), 2,5-norbornadiene (nbd)) to give amphiphilic trigonal bipyramidal complexes, [Rh(Py3S3)(diene)]Cl. Sulfur bridges of the Py3S3 ligand in these complexes were selectively oxygenated by m-chloroperoxybenzoic acid in dichloromethane to give sulfinylcalix[3]pyridine complexes, [Rh(Py3(SO)3)(diene)]+, in which all three oxygen atoms of the SO groups occupy the equatorial positions. Structures of the complexes were analysed by X-ray crystallography and the oxidation reaction was investigated using 1H NMR spectroscopy and electrospray ionisation mass spectrometry showing that the oxygenation of the sulfur atoms in the ligand proceeded stepwise and further oxygenation of the SO moiety occurred only for the nbd complex having the smaller diene ligand resulting in [Rh(Py3(SO)2(SO2))(nbd)]+. On the other hand, the oxidation of [Rh(Py3S3)(cod)]+ by H2O2 in water did not result in oxygenation of the sulfur bridges but the cod ligand is hydroxygenated to give 1,4,5,6-eta4-2-hydroxycycloocta-4-ene-1,6-di-yl. 相似文献
20.
A wide range of aryl and vinylic halides react with 1,1-dimethylallene (2a) and potassium carbonate in the presence of Pd(dba)(2) (dba = dibenzylideneacetone) in N,N-dimethylacetamide (DMA) at temperature 100-120 degrees C to give the corresponding dienes CH(2)C(CH(3))CRCH(2) (3a-o), where R is aryl or vinylic, in good to excellent yields. Higher yields of diene products were obtained for aryl bromides than for the corresponding aryl iodides and chlorides. Under similar reaction conditions, tetramethylallene (2b), 1-methyl-1-phenylallene (2c), 1-methyl-3-phenylallene (2d), and 1-cyclohexylallene (2e) also react with aryl and vinylic halides to give diene products (3p-w). For 2d, both E and Z isomers 3t and 3u of the diene product were observed. For 2e, two regioisomers 3vand 3w were isolated with 3w likely from alkene isomerization of 3v. Various palladium systems were tested for the catalytic activity of diene formation. In addition to Pd(dba)(2)/PPh(3), Pd(OAc)(2)/PPh(3), PdCl(2)(PPh(3))(2), and PdCl(2)(dppe) are also very effective as catalysts for the reaction of 2a with p-bromoacetophenone (1a) to give 3a. Studies on the effect of solvents and bases show that DMA and K(2)CO(3) are the solvent and base that give the highest yield of diene 3a. Possible mechanisms for this catalytic diene formation are proposed. 相似文献
|