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1.
The complexation reactions of monoaryl- and diaryl-substituted [2.2]paracyclophanes with (NH3)3Cr(CO)3 have been studied. The aromatic rings of [2.2]paracyclophane are more favorable for coordination than aryl substituents. This leads to the regioselective formation of the corresponding mono- or binuclear tricarbonylchromium complexes. In some cases, the tricarbonylchromium group is coordinated to the aryl ring of the substituent to form (in low yields) the corresponding mononuclear complex or binuclear complexes with both the aromatic ring of paracyclophane and the aryl ring of the substituent involved in coordination. The structure of such complex, namely, [4-(η6-2,4,6-trimethylpheny)-11-16-η6-[2,2]paracyclophane]bis[tricarbonylchromium(0)] was confirmed by X-ray diffraction study. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 142–150, January, 1998.  相似文献   

2.
E. Langer  H. Lehner 《Tetrahedron》1973,29(2):375-383
Concerning the question of transanular II-II-interactions in [2.2]metacyclophane, [2.2]paracyclophane and 2,2′-spirobiindane.From the quotient of the two dissociation constants (K1/K2) of [2.2]metacyclophane-bis-chromtricarbonyl (9·0 ± 1·9) it was concluded that there are no transanular II-II-interactions between the two benzene rings. The corresponding values for the bis-chromtricarbonyl-complexes of 2,2′-spirobiindane and [2.2]paracyclophane are 8·0 ± 1·5 and 104, resp. These results are supported by IR-spectroscopical data of the CO-frequencies of the Cr(CO)3-complexes of [2.2]metacyclophane and some derivatives, of 2,2′-spirobiindane and [2.2]paracyclophane.Moreover, UV-spectroscopic studies of tetracyanoethylene complexes of arenes are shown to be insignificant with regard to transanular II-II-interactions.  相似文献   

3.
S. Hirano  H. Hara  T. Hiyama  S. Fujita  H. Nozaki 《Tetrahedron》1975,31(18):2219-2227
A new preparative sequence from 2,3-polymethylene-2-cyclopentenone 5 to 2,6-polymethylenebromobenzenes 3 (n = 6, 7, 10) and 2,6-polymethylenephenyllithiums 6 has been found. The reaction of 6 with various electrophiles produces a number of new compounds to disclose the unique reactivity of the aryl C-Li moiety surrounded by the polymethylene chain. Photolysis of 3a and 3b provides transannular products 8, 10 and 11, all arising from the proximity between the aromatic bromine and the aliphatic hydrogen intraannularly opposed to be removed as HBr. Spectrometric study gives quantitative data of the dependence of the molecular geometry upon the chain length and the aromatic substituents. The energy barriers ΔGc of the conformational flipping are 17·4 kcal/mol (Tc 76·5°) for [6]metacyclophane (7a), 11·5 kcal/mol (Tc ?28°) for [7]metacyclophane (7b), ·8 kcal/mol for [10]metacyclophane (7c). The lower-energy process of the aliphatic chain in [6]metacyclophane derivatives is the pseudorotation with substituent-dependent barrier ΔGc 11·1 kcal/mol (Tc ?31·5°) for 7a, 12·4 kcal/mol (Tc ?4·5°) for 3a and 12·7 kcal/mol (Tc 1·0°) for 12a. The rather large rotational barrier is attributed to the compressed structure of each system. The benzene ring distortion of the cyclophanes is deduced from the bathochromic shift of the B-band and the diamagnetic shift of the benzene proton signals in the PMR.  相似文献   

4.
Unlike benzene(tricarbonyl)chromium which displays two carbonyl stretching vibrations bands in the IR spectrum, analogous tricarbonylchromium complexes of the general formula (C6H5ZMe)Cr(CO)3 [Z = O, CH(OH), N(Pr), CH=CH] are characterized by three carbonyl bands, one of which is displaced to the low-frequency region. The appearance of that band was rationalized in terms of intramolecular interaction between hydrogen atoms in the substituent on the benzene ring and carbonyl groups.  相似文献   

5.
The hydrolysis of 8-bromomethyl[2.2]metacyclophanes 3 to the corresponding 8-hydroxymethyl derivatives 4 was carried out in 83% aqueous dioxane solution at 25°C. Substituent effect through space on the rate of the hydrolysis of bromomethyl groups attached on the opposite aromatic ring was first found in this investigation. Interestingly, the introduction of the substituents at the internal position 16 tends to enhance the hydrolysis reaction rate 10–100 times. It was found also that the stabilization by both the direct through-space cation-π-interaction and the interaction through the intra-annular 8,16-position are possible in the [2.2]metacyclophane 8-benzyl cations. The good correlation with log(K/KH) and σp + was observed for the hydrolysis of internally unsubstituted 5-bromomethyl[2.2]MCPs 7, in which the direct through-space cation-π-interactions are not possible. TiCl4 and Nafion-H, a perfluorinated resinsulfonic acid, catalysed Friedel-Crafts benzylation of benzene and substituted benzenes with 8-bromomethyl- and 8-hydroxymethyl[2.2]metacyclophanes to afford 8-benzyl[2.2]metacyclophanes is described. A high substrate and positional selectivity were observed in the present benzylation reaction quite different from those obtained from the benzyl bromide and benzyl alcohol. The benzyl cation intermediate stabilized by the through-space electronic interaction among the opposite benzene ring was first demonstrated in the benzylation of [2.2]metacyclophane systems. The mild and selective transannular reaction attributable to the highly strained character of [2.2]metacyclophane skeleton and the increased stabilization of the 5-benzyl cation intermediate arising from the electronic interactions among the opposite benzene ring through the intra-annular 8,16-positions was also observed.  相似文献   

6.
MNDO calculations on [n]metacyclophanes and a variety of related compounds are reported. An analysis of the strain, imposed by the oligomethylene bridge, and its distribution over the distorted benzene ring and the oligomethylene bridge is presented. The effect of strain and bending of the benzene ring on aromatic delocalization is investigated by a comparison of ΔHof of the bent benzene systems with that of a correspondingly bent, but localized 1,3,5-cyclohexatriene. The results indicate that, even in the case of the highly bent [4]metacyclophane ( 1a ), localization is unfavorable by about 10 kcal/mol.  相似文献   

7.
Treatment of [η6-(bicyclo[4.2.0]octa-1,3–5 triene)]tricarbonylchromium(0) ( 2 ) with BuLi or lithium 2,2,6,6-tetramethylpiperidinide (TMPLi) gives rise to a highly regioselective deprotonation at C(2). Subsequent reaction with electrophiles (6 examples) gives [η6-(2-R-bicyclo[4.2.0]octa-1,3,5-triene)]tricarbonylchromiurn complexes 3 and 5 – 9 in moderate (R?I, 50%; R?CHO, 67%) to good (R?Me, D, SiMe3, CO2Me, > 80%) yield (Scheme 1). Analogous reactions with tricarbonyl (η6-indane)chromium ( 10 ) give mixtures of complexes substituted at C(4) and C(5) (Scheme 2). In 10 , deprotonation β to the ring junction is strongly favoured with the bulky base TMPLi. Double lithiation/electrophile additions to 2 give access to [η6-(2-R′-5-R″-bicyclo[4.2.0]octa-1,3,5-triene)]tri-carbonylchromium complexes (e.g. 13 (R′?R″?Me3Si) and 14 (R′?Me3Si, R″?CHO)) as single products. The Cr(CO)3 group can be easily removed by oxidation (I2, Ce(IV), O2/light; 2 examples each) to give the free arenes. Base-catalyzed (CsF, DMF/D2O) deuterodesilylation of 13 yields the [(2,5-2H2)bicyclo[4.2.0]octa-1,3,5-triene]chromium complex 15 , and treatment of 2,5-bis(trimethylsilyl) compound 16 with CF3COOD gives the 2,4-dideuterated 17 . Compound 16 is also accessible more directly via reductive silylation/oxidation of bicyclo[4.2.0]octa-1,3,5-triene ( 1 ). Stereoselective base-catalyzed (t-BuOK.) H/D exchange of the benzylic H-atoms. opposite to the Cr(CO)3 moiety in 2 takes place rapidly in (D6)DMSO, but benzylic functionalization via this route remains elusive.  相似文献   

8.
Three novel aspects emerge for the reaction of [5]metacyclophane ( 1 ) with the (intermediate) phenylphosphinidene complex 2 to give the 7-phosphanorbornadiene 3 . It is the first 1,4-addition of a phosphinidene complex to an unsaturated system, the first addition of a phosphinidene complex to a benzene ring, and the first [4+1] cycloaddition to an aromatic compound.  相似文献   

9.
Benzo[8,9]bicyclo[5.2.0]nona-2,4,8-triene (I) isomerizes to benzo[7,8]bicyclo[4.2.1]nona-2,4,7-triene (II) in the presence of L3M(CO)3 complexes (L = CO, NH3, CH3CN; M = Cr, Mo, W). In THF at 40°C with (CH3CN)3CrCO3 the uncomplexed II is formed together with smaller amounts of the corresponding η6-tricarbonylchromium complex, TCC-II. In n-butyl ether at 120°C with (NH3)3Cr(CO)3 the main product is the latter complex. The structure of TCC-II has been determined by NMR and X-ray analysis.  相似文献   

10.
Electron attachment reactions of a series of (η6-arene)tricarbonylchromium(O) complexes have been examined in the gas phase. The electron capture process has been shown to be influenced by the structure of the η6-arene ligand and its substituents. Whereas (η6-benzene)- and (η6-mesitylene)tricarbonylchromium(O) undergo dissocative electron capture, or reductive decarbonylation, yielding [M? CO]?˙ ions of highest abundance in their negative ion mass spectra, [η6-(2,2-dimethylindan-1,3-dione)]tricarbonylchromium(O) forms a molecular negative ion which undergoes sequential CO eliminations and finally a demetallation to give the arene radical ion. A localization of charge on the coordinated arene ligand is proposed for the formation of [M]?˙ in this case. (η6-Methylbenzoate)tricarbonylchromium(O) also forms a molecular negative ion by secondary electron attachment which decomposes by simultaneous and consecutive eliminations of up to four CO molecules. The elucidation of a mechanism and sequence for these CO eliminations has been achieved by synthesizing and examining the negative ion mass spectrum of [η6-(C6H5·13CO2Me)]Cr(CO)3. The first CO loss in the principal fragmentation pathway occurs solely from the –Cr(CO)3 group of [M]?˙. The effect of para substituent groups on the stabilities of molecular negative ions and their fragmentations has been ascertained using a series of para-substituted (η6-methylbenzoate)tricarbonylchromium(O) compounds containing the groups NH2, OH, OCH3, CL and COOMe. The stabilities of the [M]?˙ ions have been rationalized in terms of the Hammett and Taft parameters σP, σI, σRP, σPO and σRO. The overall electronic substituent effect transmitted to the carbonyl groups of the –Cr(CO)3 unit involves both resonance and inductive components. In this series of compounds the stability of [M]?˙ decreases as the electron withdrawing capacities of the para substituents increase.  相似文献   

11.
The anionic [MeSeFe(CO)4] and [MeSeCr(CO)5] complexes were synthesized by reaction of [PPN][HFe(CO)4] and [PPN][HCr(CO)5] with MeSeSeMe respectively via nucleophilic cleavage of the Se-Se bond. The ease of cleavage of the Se-Se bond follows the nucleophilic strength of metal-hydride complexes. Methylation of [RSeCr(CO)5?] by the soft alkylating agent MeI resulted in the formation of neutral (MeSeMe)Cr(CO)5 in THF at 0°C. In contrast, the [ICr(CO)5?] was isolated at ambient temperature. Reaction of [MeSeFe(CO)4?] or [MeSeCr(CO)5?] with HBF4 yielded (CO)3Fc(μ-SeMe)2Fe(CO)3 dimer and anionic [(CO )5Cr (μ-SeMe)Cr(CO)5?] respectively, and no neutral (HSeMe)Fe(CO)4 and (HSeMe)Cr(CO)5 were detected spectrally (IR) even at low temperature. Reaction of NOBF4 or [Ph3C][BF4] and [MeSeCr(CO)5?] resulted in the neutral monodentate (MeSeSeMe)Cr(CO)5 complex. Addition of 1 equiv CpFe(CO)2I to 2 equiv [MeSeCr(CO)5?] gave CpFe(CO)2(SeMe) and the anionic [(CO)5Cr(μ-SeMe)Cr(CO)5?] in THF at ambient temperature.  相似文献   

12.
In the presence of large amounts of [Me4N]Cl, the reaction of ortho-chloromercurated 2-[(eta6-phenyl)tricarbonylchromium]pyridine with mu-chloro cyclopalladated aromatic compounds yields a series of new heteroleptic heterodinuclear cis-(C--N)2Pd(II) complexes, which are valuable precursors of planar chiral cyclopalladated (eta6-arene)Cr(CO)3 complexes.  相似文献   

13.
The spiro-compound 3′H-spiro[indole-3,2′-[1,3]benzothiazole-2(1H)-one (IBTH2) was synthesized and its structure was determined using spectroscopic techniques (FTIR, 1H NMR and mass) and X-ray crystallography. This ligand possesses different centers for coordination. Reactions of [M(CO)6], M = Cr, Mo or W with IBTH2 in THF under reduced pressure were studied. For chromium a complex with molecular formula [Cr(ITP)2] was isolated; where ITP is the opened form of the ligand which occurred through Cspiro–S bond, while [Mo(CO)5(IBTH2)] and [W(CO)5(IBTH2)] were isolated from the reaction of IBTH2 with molybdenum and tungsten carbonyls, respectively. All complexes were characterized by elemental analysis, IR, mass and 1H NMR spectroscopy. The biological activity of the ligand and its complexes were studied and compared with the parent compound isatin.  相似文献   

14.
In the complex salt [η6‐1‐chloro‐2‐(pyrrolidin‐1‐yl)benzene](η5‐cyclopentadienyl)iron(II) hexafluoridophosphate, [Fe(C5H5)(C10H12ClN)]PF6, (I), the complexed cyclopentadienyl and benzene rings are almost parallel, with a dihedral angle between their planes of 2.3 (3)°. In a related complex salt, (η5‐cyclopentadienyl){2‐[η6‐2‐(pyrrolidin‐1‐yl)phenyl]phenol}iron(II) hexafluoridophosphate, [Fe(C5H5)(C16H17NO)]PF6, (II), the analogous angle is 5.4 (1)°. In both complexes, the aromatic C atom bound to the pyrrolidine N atom is located out of the plane defined by the remaining five ring C atoms. The dihedral angles between the plane of these five ring atoms and a plane defined by the N‐bound aromatic C atom and two neighboring C atoms are 9.7 (8) and 5.6 (2)° for (I) and (II), respectively.  相似文献   

15.
The reactions of [Re(CO)6]+, [FeCp(CO)2CS]+ and [FeCp(CNPh)3]+ with the metallo nitrile ylides [M{C+=N–C(H)CO2Et}(CO)5] (M = Cr, W) and the chromio nitrile imine [Cr{C+=N–NH}(CO)5] (generated by mono‐α‐deprotonation of the parent isocyanide complexes) to give neutral 5‐metallated 1,3‐oxazolin‐ ( 1 ), 1,3‐thiazolin‐ ( 2 ), imidazolin‐ ( 3 , 4 ), 1,3,4‐oxdiazolin‐ ( 5 ), 1,3,4‐thiadiazolin‐ ( 6 ) and 1,3,4‐triazolin‐2‐ylidene ( 8 ) chromium and tungsten complexes represent the first all‐organometallic versions of Huisgen’s 1,3‐dipolar cycloadditions. The formation of 6 and 8 is accompanied by partial decomposition to (OC)5Cr–C≡N–FeCpL2 {L = CO ( 7 ), CNPh ( 9 )}. The structures of 4a and 5 have been characterized by X‐ray diffraction.  相似文献   

16.
Kinetic acidities of aryl and benzyl CH-bonds for complexes of benzene and its methoxy and alkyl derivatives with tricarbonylchromium are determined in a solution of lithium tert-butoxide in N,N-dimethylacetamide. Complexation of alkyl-aromatic compounds to the Cr(CO)3 group increases the lability of the aryl CH-bond by 107–109 times and that of the benzyl bond by 5·104–5·105 times. The Cr(CO)3 group in arene complexes neutralizes the effect of other substituents regardless of their nature and position in the molecule.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2458–2461, November, 1989.  相似文献   

17.
The arene complexes, (η6-C6H6)Cr(CO)2(CX) (X = S, Se), react with excess CO gas under pressure in tetrahydrofuran at about 60° C to produce the Cr(CO)5(CX) complexes in high yield. The IR and NMR (13C and 17O) spectra of these complexes are in complete accord with the expected C4v molecular symmetry. Like the analogous W(CO)5(CS) complex, both compounds react with cyclohexylamine to give Cr(CO)5(CNC6H11). However, while W(CO)5(CS) undergoes stereospecific CO substitution with halide ions (Y? to form trans-[W(CO)4(CS)Y]?, the two chromium chalcocarbonyl complexes apparently undergo both CO and CX substitution to afford mixtures of [Cr(CO)5Y]? and trans-[Cr(CO)4(CX)Y]?.  相似文献   

18.
A comparative molecular orbital study of [2.2]paracyclophane and simple arenes as ligands toward a Cr(CO)3 group was performed with the aim of accounting for the observed coordination patterns. While the inter-ring repulsion is an important factor in [2.2]paracyclophane activation, it is not the only one. The molecular orbitals of two arene rings stacked parallel to each other were analyzed in some detail. The inward hybridization (toward the other ring) of the (arene)2 HOMO was shown to reduce the strength of consequent bonding with the Cr(CO)3 is fragment. The overall stabilization of [2.2]paracyclophane complex with Cr(CO)3 is enhanced by a reduction of the inter-ring repulsion and strengthening of the Ar−Cr bond, and reduced by weakening of the intra-ring carbon-carbon bonds. The inter-ring repulsion increases with approach of the arenes to each other, as appears to happen in the structure of [2.2]paracyclophane complex with Cr(CO)3. This explains the high donor ability of the free ring of the (arene)2Cr(CO)3 complex toward another Cr(CO)3 fragment. It was proposed that the stabilization of the [2.2]paracyclophane complex with Cr(CO)3 results ultimately from the relaxation of the strained framework of [2.2]paracyclophane. The kinetic factor in Cr(CO)3 complexation was also studied by analyzing the charges on competing arene rings in monoaryl-substituted derivatives of [2.2]paracyclophanes. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 151–157, January, 1998.  相似文献   

19.
Daniel Krois  Harald Lehner 《Tetrahedron》1982,38(22):3319-3324
While in [3.3]metacyclophane (19) the aromatic rings preferentially adopt the syn arrangement, its lower and higher homologues, i.e. [2,2]-, [3.2]-, [4.2], and [4.3]-metacyclophane (1, 6, 26 and 30), adopt the anti conformation. Substituted [m,n]metacyclophanes do not necessarily behave similarly to the parent hydrocarbons. Substituted compounds exhibiting a different conformation are [3.2]metacyclophane-1,11-dione (7) (syn), [3.3]metacyclophane-2,11-dione (24) and the corresponding bis[propylene thioacetal] (25) (anti), [4.2]metacyclophane-2,12-dione (27) (syn), and [4.3]metacyclophane-2,13-dione (31) (syn). Thus, the solution conformation of an [m.n]metacyclophane is sensitive both to chain length [m.n.] of the bridges and substitution. The ring inversion barriers determined by variable temperature 1H NMR decrease with increasing length of the bridges and qualitatively correlate with the transanular strain present in the pertinent system.  相似文献   

20.
Reaction of lithium diisopropylamide (LDA) with (η4-1,3-cyclohexadiene)Fe(CO)3 complexes bearing functionalized side chains at C-5, under an atmosphere of carbon monoxide, gives bridged bicyclo[3,2,1]octene and bicyclo[3,3,1]nonene systems after electrophilic quenching. Under the same reaction conditions, intramolecular cyclization of acyclic (η4- 1,3-butadiene)Fe(CO)3 complexes with functionalized side chains at the terminal position of the diene ligands furnishes fused bicyclo[3.3,0]octanone and bicyclo[4.3.0]nonanone derivatives after acid quenching. The addition of a variety of the highly functionalized zinc-copper reagents RCu(CN)ZnI to the (η7-cycloheptatrienyl)Cr(CO) gives (η6-cyclohepta-1,3,5-triene)Cr(CO)3 complexes with a functionalized side-chain at the C-7 position of the ring. Intramolecular cyclization of ester-subsbtuted adducts using lithium diisopropylamide generates fused bicyclo[5.3.0]decane and bicyclo[5.4.0]undecane derivatives. The addition of a variety of the highly functionalized zinc-copper reagents RCu(CN)Znl to the (η4-cyclohexa-1,3-diene)Mo(CO)2(Cp) at the terminus of the coordinated diene ligand gives [Mo(π-allyl)(CO)2(Cp)](Cp = cyclopentadienyl) complexes with the functionalized side-chain at the C-4 position of the ring. Intramolecular cyclization of the (π-allyl)molybdenum complex containing a pendant propanoic acid unit generates the δ-lactone derivative.  相似文献   

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