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1.
Enda Bergin David L. Hughes Christopher J. Richards 《Tetrahedron: Asymmetry》2010,21(11-12):1619-1623
Reaction of (η5-cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt with Hg(OAc)2 (2.3 equiv) in 1:1 MeOH/CH2Cl2 followed by the addition of LiCl resulted in the formation of (η5-1,2-dichloromercuricyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt (33%) and its 1,3-isomer (6%). Following conversion into their corresponding diiodides these compounds were desymmetrised by Suzuki reactions with ArB(OH)2 employing [(R)-BINAP]PdCl2, with the highest ee of 24% being obtained for (η5-1-iodo-3-(2-methoxyphenyl)cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt. 相似文献
2.
Rajkumar Jana 《Journal of organometallic chemistry》2008,693(25):3780-3786
(η5-methylcyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt (1) and its derivatives, [(1-acetyl-2-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene)cobalt (2) [(1-acetyl-3-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene)cobalt (3) [(1-carbomethoxy-2-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene)cobalt (4) and [(1-carbomethoxy-3-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene) cobalt (5) have been prepared in yields varying from 11% to 28% by introducing the substituents on the cyclopentadienyl ring of methylcyclopentadienyl sodium and then reacting with diphenylacetylene and CoCl(PPh3)3. The carboxylic acids [(1-carboxy-2-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene)cobalt (6), [(1-carboxy-3-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene)cobalt (7) have been prepared after ester hydrolysis of compounds 4 and 5 using KOH/ethanol. [(1-dimethylaminomethyl-3-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene) cobalt (8), was prepared selectively by direct substitution on the cyclopentadienyl ring of (η5-methylcyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt in 65% yield. The 1,2-isomer was formed only in traces in this reaction. Reactivity of (η5-methylcyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt and its carbomethoxy derivative have been compared with (η5-cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt. All new compounds were characterized by 1H and 13C NMR, FT-IR, mass spectra and CHN analysis. Compounds 2, 4, 6 and 8 have also been structurally characterized by single crystal X-ray structural analysis. 相似文献
3.
The reaction of diarylacetylenes with CoCl(PPh3)3 and sodium cyclopentadienylide or sodium carbomethoxycyclopentadienylide gave (η4-tetra-arylcyclobutadiene)(η5-cyclopentadienyl)cobalt and (η4-tetra-arylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt, respectively, where aryl = para-XC6H4 (X = CF3, F, MeO). The reaction was unsuccessful for the synthesis of (η4-tetra(para-methoxyphenyl)cyclobutadiene)(η5-cyclopentadienyl)cobalt, which was synthesised instead from dicarbonyl(η5-cyclopentadienyl)cobalt. In all of the examples starting with CoCl(PPh3)3 an intermediate (η5-cyclopentadienyl)- or (η5-carbomethoxycyclopentadienyl)(triphenylphosphine)-2,3,4,5-tetraarylcobaltacyclopentadiene complex was isolated, and two examples were characterised by X-ray crystallography. Heating the (η5-cyclopentadienyl)- or (η5-carbomethoxycyclopentadienyl)(triphenylphosphine)-2,3,4,5-tetraarylcobaltacyclopentadiene complexes resulted in clean conversion to the corresponding metallocenes. The influence of the para-aryl substituents on the 1H NMR of the cyclopentadienyl moiety is tabulated, together with the influence of a range of R substituents in (η4-tetraphenylcyclobutadiene)(η5-RC5H4)cobalt (R = CO2Me, CH2OH, Me, CHO, CCH, CO2H, CN, CONHR1, 2-oxazolinyl, NH2, NHAc, HgCl, Br, I, SiMe3, SnMe3, Ph). 相似文献
4.
Planar chiral alkenylferrocene phosphanes, viz. (Sp)-[Fe(η5-C5H3-1-PPh2-2-CHCR2)(η5-C5H5)] (R = H, (Sp)-2; Ph, (Sp)-5) and (Sp)-[Fe(η5-C5H3-1-PPh2-2-(E)-CHCHR)(η5-C5H5)] (R = Ph, (Sp)-3; C(O)CH3, (Sp)-6; and CO2CH2CH3, (Sp)-7) have been prepared by alkenylation of (Sp)-2-(diphenylphosphanyl)ferrocenecarboxaldehyde and tested as ligands for enantioselective palladium-catalysed allylic alkylation of 1,3-diphenyprop-2-en-1-yl acetate with dimethyl malonate. All phosphanylalkenes formed active catalysts. However, the induced enantioselectivity was only poor to moderate [12-43% ee after 20 h at room temperature], with the ee’s and configuration of the preferred product strongly depending on the ligand structure. The catalytic results have been related to solution properties (NMR, ESI MS) and the solid-state structural data (X-ray diffraction) of [Pd(η3-1,3-Ph2C3H3){(Sp)-2-η2:κP}]ClO4 ((Sp)-12), which represent a model of the plausible reaction intermediate. 相似文献
5.
Pangbu Hong Katsuyuki Aoki Hiroshi Yamazaki 《Journal of organometallic chemistry》1978,150(2):279-293
The diphenylacetylene-cobalt complex, η5-C5H5Co(PPh3)(PhCCph) (I) reacted with alkyl diazoacetates (II, alkyl = methyl, ethyl, and t-butyl) at room temperature to give two isomers of the mononuclear cobalt complex, η5-C5H5Co- (PhC2Ph)(CHCO2R)2 (III and IV) and two isomers of the dinuclear cobalt complex [η5-C5H5Co(PhC2Ph)(CHCO2R)]2 (V and VI).The complexes III and IV are diene complexes, syn,syn- and syn,anti- (dialkyl 2,3-diphenylmuconate)-η5-cyclopentadienylcobalt, respectively. The structure of Vb (R = C2H5) was determined by X-ray diffraction as η-[1–3-η3 : 1,4,5-μ3- 1,6-bis(ethoxycarbonyl)-2,3,4,5-tetraphenylhexa-2,4-diene-1,1-diyl]bis(η5-cyclopentadienylcobalt)(CoCo. The complex VI is the bis(η3-allyl)cobalt complex, μ-[1–3-η3 : 4–6η3-1,6-anti,anti-bis(alkoxycarbonyl)-2,3,4,5,-tetraphenylhexa- 1,3,5-triene]bis(η5-cyclopentadienylcobalt)(CoCo) according to its 1H NMR spectrum.The formation of these products was rationalizes in terms of a cobaltacyclobutene intermediate. 相似文献
6.
The structure of (η5-trimethylsilylcyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt, ((CH3)3SiC5H4)Co((C6H5)4C4), has been determined by single crystal X-ray diffraction techniques using three-dimensional data collected on an automatic diffractometer. The crystals are monoclinic, space group P21/c, with lattice parameters a 11.551(1), b 16.352(6), c 18.324(2) », β 122.85(1)° with four molecules in the unit cell. The structure consists of discrete molecules in which a cobalt atom is sandwiched between the η5-cyclopentadienyl (Cp) and the η4-cyclobutadience (Cb) ligands bonded to the metal in the hapto mode. The perpendicular distances Co?(Cp) and Co?(Cb) of 1.688 and 1.699 », respectively, as well as the dihedral angle of 6.9° between the two rings and the distortions of their side groups, indicate steric interactions within the molecule. The Cb ring is planar within 0.015 » and has a rectangular shape with edges of 1.480(5) and 1.463(3) ». The Cp ring, which is planar to within 0.005 », appears to be highly distorted by the trimethylsilyl group, which induces a lengthening of the C—C distances involving the substituted carbon atom (1.440(7) ») and a narrowing of the corresponding bond angle (105.3(2)°). 相似文献
7.
《Tetrahedron: Asymmetry》2000,11(9):1849-1858
The first synthesis of (R)- and (S)-4-hydroxyisophorone by catalytic transfer hydrogenation of ketoisophorone is reported. Ruthenium catalysts containing commercially available chiral amino alcohols afforded 4-hydroxyisophorone in up to 97% selectivity and 97% ee. (R)- or (S)-4-Hydroxyisophorones with >99% ee were isolated by crystallization. The catalyst precursors [RuCl2((S,R)-ADPE)(η6-p-cymene)] ((S,R)-ADPE=(1S,2R)-amino-1,2-diphenylethanol-N) and (RRu)-[RuCl((S,R)-ADPE−1)(η6-p-cymene)] (ADPE−1=amino-1,2-diphenylethanolato-N,O) were isolated for the first time and the X-ray crystal structure of the latter determined. 相似文献
8.
Daniel Carmona Roberto Medrano Isabel T. Dobrinovich Fernando J. Lahoz Joaquina Ferrer Luis A. Oro 《Journal of organometallic chemistry》2006,691(26):5560-5566
Half-sandwich complexes of formula [(ηn-ring)MClL]PF6 [L = (S)-2-[(Sp)-2-(diphenylphosphino)ferrocenyl]-4-isopropyloxazoline; (ηn-ring)M = (η5-C5Me5)Rh; (η5-C5Me5)Ir; (η6-p-MeC6H4iPr)Ru; (η6-p-MeC6H4iPr)Os] have been prepared and spectroscopically characterised. The molecular structures of the rhodium and iridium compounds have been determined by X-ray crystallography. The related solvate complexes [(η5-C5Me5)ML(Me2CO)]2+ (M = Rh, Ir) are active catalysts for the Diels-Alder reaction between methacrolein and cyclopentadiene. 相似文献
9.
《Tetrahedron: Asymmetry》1998,9(22):4035-4041
The resolution of cycloplatinated ferrocenylketimines was carried out by using S-leucine as chiral auxiliary and a pair of diastereomers was obtained. The optically active derivatives of the cycloplatinated ferrocenylketimines have been prepared and characterized. The structures and absolute configurations of (−)-(Sp,S)-[Pt{(η5-C5H3CMeNC6H4-4-CH3)Fe(η5-C5H5)}(S-leu)] and (−)-(Sp)-[Pt{(η5-C5H3CMeNC6H4-4-Br)Fe(η5-C5H5)}(PPh3)Cl] were determined by X-ray diffraction, on the basis of which the absolute configurations of other optically active compounds studied were ascertained. 相似文献
10.
Sven Dabek 《Journal of organometallic chemistry》2007,692(11):2216-2226
Five different (η4-tetraarylcyclobutadiene)(η5-formylcyclopentadienyl)cobalt(I) complexes (1a-1e) were synthesized in reasonable yields in a one-pot reaction of CoCl(PPh3)3, formylcyclopentadienyl sodium and the appropriate diarylethyne. The aryl groups of the ethyne were modified by various para-substituents X (X = Cl, H, Me, OMe, NMe2), which were intended to alter the redox potentials of the synthesized cobalt sandwich complexes. A cyclic voltammetry study revealed a linear dependence of the first oxidation potential to the Hammett parameter σp. X-ray structure analyses performed for two complexes (X = Me and NMe2) demonstrate only subtle changes in the solid state structure despite the large differences in electrochemical properties. A theoretical analysis by the density functional theory method has been performed on the geometries and electronic structures of the complex (η4-cyclobutadiene)(η5-cyclopentadienyl)Co(I), its cation and dication. 相似文献
11.
《Journal of organometallic chemistry》2002,641(1-2):90-101
Arene ruthenium(0) complexes with carbonyl side chain functionalities like [Ru(η6-C6H5COR)(η4-COD)] or [Ru(η6-o-C6H4{R1}COR)(η4-COD)] (COD=1,5-cyclooctadiene; R=H, CH3; R1=H, CH3, OCH3) are easily accessible by replacing the naphthalene ligand of [Ru(η6-naphthalene)(η4-COD)] (1) through an arene exchange reaction. These carbonyl species are susceptible to standard organic reactions of the carbonyl function, thus allowing the introduction of dangling side chains bearing highly polar functions like hydroxyl or amino groups. Aldol reaction of [Ru(o-C6H4{CH3}COCH3)(COD)] (3) with (−)-menthylchloroformate in the presence of LDA (LDA=lithium diisopropylamide) leads to a diastereomeric mixture of [Ru(menthyl-{3-oxo-3-η6-o-tolyl}propionate)(COD)] (10). However, treatment of 3 with LDA and o-tolylaldehyde or benzaldehyde affords the unexpected products [Ru(1-η6-o-tolyl-3-o-tolylpropan-1-one)(COD)] (11) and [Ru(1-η6-o-tolyl-1-phenylpropan-1-one)(COD)] (12). A diastereoselective addition (88% de) of deprotonated menthylacetate to [Ru(o-tolylaldehyde)(COD)] (4) results in the formation of [Ru(menthyl 3-η6-o-tolyl-3-hydroxypropionate)(COD)] (13). Racemic planar-chiral aldehyde complexes 2 and 4 react with amines giving the imination products in good yield. In case of reaction between 2 and (R)-N-amino-2-(methoxymethyl)-pyrrolidine (RAMP), diastereomeric [Ru(N-[[η6-(2-methylphenyl]methylene]-(R)-2-(methoxymethyl)-1-pyrrolidinamine)(COD)] (17) is formed. The diastereomers (R,R)-17 and (S,R)-17 have been separated by fractional crystallisation. Asymmetric arene ruthenium complexes with a defined planar-chiral configuration are thus accessible. Reduction of [Ru(3-η6-phenyl-(R)-methylbutyrate)(COD)] (7) with LiAlH4 yields the chiral γ-alcohol [Ru(3-η6-phenyl-(R)-1-butanol)(COD)] (18). A Wittig olefination converts the aldehyde complex 4 into a mixture of E- and Z-isomeric [Ru(1-η6-o-tolyl-2-phenylethylene)(COD)] 21a and 21b, which were separated again by fractional crystallisation. 相似文献
12.
Doyle J. Cassar Dr. Gennadiy Ilyashenko Dr. Muhammad Ismail James Woods Dr. David L. Hughes Dr. Christopher J. Richards 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(52):17951-17962
The reaction of (η5‐(N,N‐dimethylaminomethyl)cyclopentadien‐yl)(η4‐tetraphenylcyclobutadiene)cobalt with sodium tetrachloropalladate and (R)‐N‐acetylphenylalanine gave planar chiral palladacycle di‐μ‐chloridebis[(η5‐(Sp)‐2‐(N,N‐dimethylaminomethyl)cyclopentadienyl,1‐C,3′‐N)(η4‐tetraphenylcyclobutadiene)cobalt]dipalladium [(Sp)‐Me2‐CAP‐Cl] in 92 % ee and 64 % yield. Enantiopurity (>98 % ee) was achieved by purification of the monomeric (R)‐proline adducts and conversion back to the chloride dimer. Treatment with AgOAc gave (Sp)‐Me2‐CAP‐OAc which was applied to asymmetric transcyclopalladation (up to 78 % ee). The (R)‐N‐acetylphenylalanine mediated palladation methodology was applicable also to the corresponding N,N‐diethyl (82 % ee, 39 % yield) and pyrrolidinyl (>98 % ee, 43 % yield) cobalt sandwich complexes. A combination of 5 mol % of the latter [(Sp)‐Pyrr‐CAP‐Cl] and AgNO3 (3.8 equiv) is a catalyst for the allylic imidate rearrangement of an (E)‐N‐aryltrifluoroacetimidate (up to 83 % ee), and this catalyst system is also applicable to the rearrangement of a range of (E)‐trichloroacetimidates (up to 99 % ee). This asymmetric efficiency combined with the simplicity of catalyst synthesis provides accessible solutions to the generation of non‐racemic allylic amine derivatives. 相似文献
13.
Martin Steinbeck Wolfgang W. Schoeller Wolfgang A. Herrmann 《Journal of organometallic chemistry》2011,696(25):3945-3954
Different chiral mono-substituted N-heterocyclic carbene complexes of rhodium were prepared, starting from [Rh(COD)Cl]2 (COD = cyclooctadiene) by addition of free N-heterocyclic carbenes (NHC), or an in-situ deprotonation of the corresponding iminium salt. All new complexes were characterized by spectroscopy methods. In addition, the structures of chloro(η4-1,5-cyclooctadiene)(1,3-di-[(1R,2R,3R,5S)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl] imidazolin-2-ylidene)rhodium(I) (5a), chloro(η4-1,5-cyclooctadiene)(1,3-di-[(1R,2S,5R)-2-isopropyl-5-menthylcyclohex-1-yl]imidazol-2-ylidene)rhodium(I) (5b) and chloro(η4-1,5-cyclooctadiene)(1,3-di-[(2R,4S,5S)-2-methyl-4-phenyl-1,3-dioxacyclohex-5-yl]imidazolin-2-ylidene)rhodium(I) (5i) were analyzed by DFT-calculations. The enantioselective hydrosilylation of acetophenone, ethylpyruvate and n-propylpyruvate with diphenylsilane and hydrolysis was carried out with chiral C2-symmetrical mono-substituted N-heterocyclic carbene rhodium complexes giving for the first time an enantioselective excess of up to 74% ee in the case of the n-propylpyruvate. 相似文献
14.
《Journal of organometallic chemistry》1991,402(3):C56-C58
Complete self-recognition of chirality is observed in the Michael addition of the enolate derived from R,S-[η5-C5H5Fe(CO)(PPh3-COCH3] to the acryloyl complex R,S-[(η5-C5H5Fe(CO)(PPh3)-COCHCH2)] to generate exclusively the single diastereoisomer of the glutaroyl complex RR,SS-[(η5-C5H5)Fe(CO)(PPh3)COCH2]2CH2. 相似文献
15.
The reactions of arenediazomolybdenum(II) complexes such as [(η-C5H5)Mo(N2C6H4CH3-p)I2]2, (η-C5H5)Mo(CO species with neutral and anionic monodentate or chelating ligands have been investigated. The new arenediazo complexes isolated from these reactions include neutral species such as (η-C5H5)Mo(PPh3)(N2C6H4CH3-p)I2 and (η-C5H5)Mo(N2C6H4CH3-p) cations of the type [η-C5H5)Mo(bipy)(N2C6H4CH3-p)I]+ and the anion [(η-C5H5)Mo(N2C6H4CH3-p)I3]?. The structures of the new complexes are discussed. 相似文献
16.
The Friedel-Crafts reaction of (η(4)-tetraphenylcyclobutadiene)(η(5)-carbomethoxycyclopentadienyl)cobalt with acid chlorides/aluminum chloride resulted exclusively in para-phenyl acylation. Both monoacylated (1.1 equiv of RCOCl/AlCl(3)) and tetraacylated products (>4 equiv of RCOCl/AlCl(3)) were synthesized. Reaction of PhCC(o-RC(6)H(4)) (R = Me, i-Pr) with Na(C(5)H(4)CO(2)Me) and CoCl(PPh(3))(3) gave predominantly (η(4)-1,3-diaryl-2,4-diphenylcyclobutadiene)(η(5)-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Conformational control of Friedel-Crafts reactions on the major isomers gave exclusively para-acylation of the unsubstituted phenyl groups. 相似文献
17.
《Tetrahedron: Asymmetry》2000,11(13):2765-2779
The ligands 6-[(diphenylphosphanyl)methoxy]-4,8-di-tert-butyl-2,10-dimethoxy-5,7-dioxa-6-phosphadibenzo[a,c]cycloheptene, 1, (S)-4-[(diphenylphosphanyl)methoxy]-3,5-dioxa-4-phosphacyclohepta[2,1-a;3,4a′]dinaphthalene, (S)-2, and (S)-4-[(diphenylphosphanyl)methoxy]-2,6-bis-trimethylsilanyl-3,5-dioxa-4-phosphacyclohepta[2,1-a;3,4-a′]dinaphthalene, (S)-3, (S)-2-(3,5-dioxa-4-phosphacyclohepta[2,1-a;3,4-a′]dinaphthalen-4-yloxymethyl)pyridine, (S)-4, and (S)-2-(3,5-dioxa-4-phosphacyclohepta[2,1-a;3,4-a′]dinaphthalen-4-yloxy)pyridine, (S)-5, have been easily prepared.The cationic complexes [Pd(η3-C3H5)(L-L′)]CF3SO3 (L–L′=1–(S)-5) and [Pd(η3-PhCHCHCHPh)(L–L′)]CF3SO3 (L–L′=(S)-2–(S)-4) were synthesized by conventional methods starting from the complexes [Pd(η3-C3H5)Cl]2 and [Pd(η3-PhCHCHCHPh)Cl]2, respectively. The behavior in solution of all the π-allyl- and π-phenylallyl-(L–L′)palladium derivatives 6–14 was studied by 1H, 31P{1H}, 13C{1H} NMR and 2D-NOESY spectroscopy. As concerns the ligands (S)-4 and (S)-5, a satisfactory analysis of the structures in solution was possible only for palladium–allyl complexes [Pd(η3-C3H5)((S)-4)]CF3SO3, 11, and [Pd(η3-C3H5)((S)-5)]CF3SO3, 12, since the corresponding species [Pd(η3-PhCHCHCHPh)((S)-4)]CF3SO3, 13, and [Pd(η3-PhCHCHCHPh)((S)-5)]CF3SO3, 14, revealed low stability in solution for a long time. The new ligands (S)-2–(S)-5 were tested in the palladium-catalyzed enantioselective substitution of (1,3-diphenyl-1,2-propenyl)acetate by dimethylmalonate. The precatalyst [Pd(η3-C3H5)((S)-2)]CF3SO3 afforded the allyl substituted product in good yield (95%) and acceptable enantioselectivities (71% e.e. in the S form). A similar result was achieved with the precatalyst [Pd(η3-C3H5)((S)-3)]CF3SO3. The nucleophilic attack of the malonate occurred preferentially at allylic carbon far from the binaphthalene moiety, namely trans to the phosphite group. When the complexes containing ligands (S)-4 and (S)-5 were used as precatalysts, the product was obtained as a racemic mixture in high yield. The number of the configurational isomers of the Pd-allyl intermediates present in solution in the allylic alkylation and the relative concentrations are considered a determining factor for the enantioselectivity of the process. 相似文献
18.
Gabriele Albertin Stefano Antoniutti Stefano Paganelli 《Journal of organometallic chemistry》2010,695(18):2142-169
p-Cymene complexes MCl2(η6-p-cymene)L [M = Ru, Os; L = P(OEt)3, PPh(OEt)2, (CH3)3CNC] were prepared by allowing [MCl(μ-Cl)(η6-p-cymene)]2 to react with phosphites or tert-butyl isocyanide. Treatment of MCl2(η6-p-cymene)L complexes with 1,3-ArNNN(H)Ar triazene and an excess of NEt3 gave the cationic triazenide derivatives [M(η2-1,3-ArNNNAr)(η6-p-cymene)L]BPh4 (Ar = Ph, p-tolyl). Neutral triazenide complexes MCl(η2-1,3-ArNNNAr)(η6-p-cymene) (M = Ru, Os) were also prepared by allowing [MCl(μ-Cl)(η6-p-cymene)]2 to react with 1,3-diaryltriazene in the presence of triethylamine. p-Cymene complexes MCl2(η6-p-cymene)L reacted with equimolar amounts of 1,3-ArNNN(H)Ar triazene to give both triazenide complexes [M(η2-1,3-ArNNNAr)(η6-p-cymene)L]BPh4 and amine derivatives [MCl(ArNH2)(η6-p-cymene)L]BPh4. A reaction path for the formation of the amine complex is also reported. The complexes were characterised by spectroscopy and X-ray crystallography of RuCl2(η6-p-cymene)[PPh(OEt)2] and [Ru(η2-1,3-p-tolyl-NNN-p-tolyl)(η6-p-cymene){CNC(CH3)3}]BPh4. Selected triazenide complexes were studied as catalysts in the hydrogenation of 2-cyclohexen-1-one and cinnamaldehyde. 相似文献
19.
The reactions of [Co(η-C5H5)(L)I2] with Na[S2CNR2] (R = alkyl or phenyl) give [Co(η-C5H5)(I)(S2CNR2)] (I) when L = CO and [Co(η-C5H5)(L)(S2CNR2)]I (II) when L is a tertiary phosphine, phosphite or stibine, or organo-isocyanide ligand. In similar reactions [Co(η-C5H5)(CO)(C3F7)I] gives [Co(η-C5H5)(C3F7)(S2CNMe2)] and [Mn(η-MeC5H4)(CO)2(NO)]PF6 forms [Mn(η-MeC5H4)(NO)(S2CNR2)]. The iodide ligands in I may be displaced by L, to give II, or by other ligands such as [CN]?, [NCS]?, H2O or pyridine whilst SnCl2 converts it to SnCl2I. The iodide counter-anion in II may be replaced by others to give [BPh4]?, [Co(CO)4]? or [NO3]? salts. However [CN]? acts differently and displaces (PhO)3P from [Co(η-C5H5){P(OPh)3}(S2CNMe)]I to give [Co(η-C5H5)(CN)(S2CNMe2)] which may be alkylated reversibly by MeI and irreversibly by MeSO3F to [Co(η-C5H5)(CNMe)(S2CNMe2)]+ salts. Conductivity measurements suggest that solutions of I in donor solvents are partially ionized with the formation of [Co(η-C5H5)(solvent)(S2CNR2)]+ I? species. The IR and 1H NMR spectra of the various complexes are reported. They are consistent with pseudo-octahedral “pianostool” molecular structures in which the bidentate dithiocarbamate ligands are coordinated to the metal atoms through both sulphur atoms. 相似文献
20.
Javier A. Cabeza Ignacio del Río Robert A. Gossage Lorena Martínez-Méndez Daniel Miguel 《Journal of organometallic chemistry》2007,692(20):4346-4352
The synthesis and characterisation of three novel mononuclear ruthenium(II) complexes containing one of the following chiral auxiliary ligands: 2-amino-(4R)-phenyl-2-oxazoline (amphox), indanyl-2-amino-(4R,5S)-2-oxazoline (aminox) or indanyl-(2′-anilinyl)-(4R,5S)-2-oxazoline (aninox) is described using [Ru2Cl4(η6-p-cym)2] (p-cym = 1-isopropyl-4-methylbenzene) as the Ru starting material. The new complexes have been identified as the neutral derivatives [RuCl2(η6-p-cym)(amphox-κ1Nox)] (1), [RuCl2(η6-p-cym)(aminox-κ1Nox)] (2) and the salt [RuCl(η6-p-cym)(aninox-κ2N,N′)]Cl (3). These materials have been fully characterised (elemental analysis, NMR, IR, conductance, MS, etc.) and, in the case of 2 and 3, structurally elucidated in the solid-state using single crystal X-ray diffraction methods. All three complexes show good catalytic activity (max. conversion >99%, TOF = 424 h−1) but only modest enantio-selectivity (max. ee = 40%) for the transfer hydrogenation reaction of acetophenone with isopropyl alcohol. The complexes were also tested in an asymmetric Diels-Alder reaction involving cyclopentadiene and acrolein (max. conversion >99%, TOF = 42 h−1). In this case, the diastereo-selectivity was good to moderate (max. de = 84%), but the ee values were poor (max. ee = 12%). 相似文献