N-aryl-and N-vinyldiaza-18-crown-6: Synthesis and complexing ability

The nucleophilic aromatic and vinyl substitution using diaza-18-crown-6 as nucleophile afforded a number of its N,N’-diaryl-[aryl = 2,4-(NO₂)₂C₆H₃, 4-C₅F₄N, 4-CF₃C₆F₄] and N,N’-dialkenyl-substituted derivatives [alkenyl = PhC(O)CH=CH, MeOCOCH=CH, (EtO₂C)₂C=C(Ph), etc.]. Arylation of diaza-18-crown-6 with nonactivated aryl bromides, such as 4-Me₂NC₆H₄Br, 4-MeOC₆H₄Br, C₆H₅Br, and 4-CF₃C₆H₄Br, was effected under catalysis by palladium complexes. N,N’-Diaryldiaza-18-crowns-6 having electron-acceptor substituents in the aromatic rings turned out to be incapable of forming complexes with metal cations, while their analogs containing electron-donor para-methoxy and para-dimethylamino groups gave complexes with barium perchlorate.     

Anions of Transition Metals Carbonyls in Nucleophilic Vinyl Substitution: VII.2* Carbonylates Reaction with 1-Chloro-2-(trifluoromethyl)- and 1-Chloro-2-(perfluoro-tert-butyl)hexafluorocyclopent-1-enes,and with Z and E Isomers of ββ-Chloro-αα,ββ-difluorostyrenes. Halophilic and/or Nucleophilic Reaction mechanism2*2*

Reactions were studied between 1-chloro-2-(trifluoromethyl)-hexafluorocyclopent-1-ene with anions [CpFe(CO)₂]^-, [Re(CO)₅]^-, [Mn(CO)₅]^-, [CpMo(CO)₃]^-, and [CpW(CO)₃]^-. The effect of proton donors on the composition of reaction products was established. The reactions with [Re(CO)₅]^- and [Mn(CO)₅]^- were shown to proceed quantitatively along nucleophilic route (S_N2Vin) resulting in -vinyl complexes of rhenium and manganese. The [CpMo(CO)₃]^- and [CpW(CO)₃]^- anions turned out to be 10⁴ times less nucleophilic than [Mn(CO)₅]^-. In this case the main course of the reaction is the metal-halogen exchange with concurrent nucleophilic substitution. In reaction of [CpMo(CO)₃]^- and [CpW(CO)₃]^- with 1-chloro-2- (trifluoromethyl)-hexafluorocyclopent-1-ene the -vinyl complexes arise along an unusual autocatalytic mechanism: the reaction of carbonyl occurs not with the initial substrate but with pentafluoromethylcyclopent-1-ene that forms from the substrate under the action of a fluoride ion. In an extremely fast reaction of the same substrate with [CpFe(CO)₂]K the main process is carbonylate oxidation along unestablished mechanism. The reaction between carbonylates and 1-chloro-2-(perfluoro-tert-butyl)hexafluorocyclopent-1-ene proceeds exclusively as metal-halogen exchange that with [Re(CO)₅]^- furnishes anionic acyl complex cis[C₉F_{1 5}C(O)Re(CO)₄Cl]^-. The reaction of Z and E isomers of -chloro-,-difluorostyrenes with [CpFe(CO)₂]^- in the presence of proton donors confirmed the previously assumed (S_N2Vin) mechanism of nucleophilic substitution and also the intermediate formation of alkenyl carbanions in the parallel redox process.     

Stability and structure in solution of potassium and barium complexes with N,N’-diaryldiaza-18-crown-6: Crystal structure of N,N’-Bis(4-dimethylaminophenyl)diaza-18-crown-6 and its complex with barium perchlorate

It has been shown that N,N’-diaryldiaza-18-crown-6 ethers with p-dimethylamino-and p-methoxy groups in the benzene ring (aryl is 4-Mc₂NC₆H₄) (I) and 4-MeOC₆H₄ (II) form complexes with potassium and barium salts. The influence of these salts on the UV and ¹H NMR spectra of crown ethers I and II has been studied. The stability constants (logβ) of the complexes increase in the series II · Ba(ClO₄)₂ (2.0), I · Ba(ClO₄)₂ (2.3), II · KBr (2.8), I · KBr (3.0). N,N’-bis(4-dimethylphenylamine)diaza-18-crown-6 (L, I) and its complex with barium perchlorate Ba(ClO₄)₂ · L (III) are characterized by X-ray crystallography. The crystals of I are monoclinic: a = 13.778(2) Å, b = 5.9731(9) Å, c = 17.542(3) Å, β = 106.65(1)°, V = 1383.1(4) ų, Z = 2, space group P2₁/n, R = 0.0374 for 990 reflections with I > 2σ(I). The crystals of III are monoclinic: a = 17.275(4) Å, b = 8.017(2) Å, c = 26.935(4) Å, β = 100.47(2)°, V = 3669(1) ų, Z = 4, space group C2/c, R = 0.0320 for 1897 reflections with I > 2σ(I). The molecules of I and III are centrosymmetric. In III, the Ba atom is in the center of substituted diaza-18-crown-6 (DA18C6). The Ba atom is coordinated by all six donor atoms of diaza-18-crown-6 (av. Ba-O, 2.779(3) Å; Ba-N, 3.004(4) Å) and four oxygen atoms of two asymmetrically bound perchlorate groups (Ba-O, 2.832(4) and 3.031(4) Å) arranged below and above the plane of substituted diaza-18-crown-6. The conformations of the macrocycle in free and coordinated L are different.     

1H,13C,and19F NMR study of products of the interaction of the η5-cyclopentadienyldicarbonyliron(ii) anion,CpFe(CO)2 −, with pentafluorobenzoyl chloride

Interaction of the ⁵-cyclopentadienyldicarbonyliron(II) anion with pentafluorobenzoyl chloride affords C₆F₅COFe(CO)₂Cp, CpFe(CO)₂C₆F₄COFe(CO)₂Cp, and CpFe(CO)₂C₆F₄C₆F₄Fe(CO)₂Cp. The reaction products are characterized by¹H,¹³C and¹⁹F NMR spectra.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 935–937, May, 1994.     

Arylation of Substituted Anilines Catalyzed by Palladium

Arylation catalyzed by palladium complexes of substituted anilines obtained by modification of 2,4,6-trinitrotoluene makes possible preparation of various diaryl- and arylheterylamines in high yields.