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The reactions of 2-cyano-3-ferrocenylacrylonitrile (1) with malononitrile (2) in a MeOH/H2O or 2-PrOH/H2O medium in the presence of Na2CO3 afforded 6-alkoxy-2-amino-4-ferrocenylpyridine-3,5-dicarbonitriles 3a,b (multi-component condensation) and 6-alkoxy-2-amino-4-ferrocenyl-3-ferrocenylmethyl-3,4-dihydropyridine-3,5-dicarbonitriles 4a,b (multi-component cyclodimerization). Analogous reactions of 1 with 2 in an MeOH/H2O medium in the presence of NaOH, piperidine, or morpholine gave compounds 3a, 4a and 2-amino-4-ferrocenyl-6-hydroxy-, 6-piperidino- and 6-morpholinopyridine-3,5- dicarbonitriles 3c-e, respectively. The structures of the compounds 3b, 4a and 4b were established by the spectroscopic data and X-ray diffraction analysis. The electrochemical behaviour of compounds 3b, 3d and 4b was investigated by means of cyclic voltammetry. [ABSTRACT FROM AUTHOR]

A new method of synthesis of 2-( Z -1,2-diferrocenylvinyl)-4,5-dihydrooxazoles 3a-f and 5 , 2-( Z- 1,2-diferrocenylvinyl)-4,5-dihydrooxazol-3-ium salts 4a-f , 4g , h , and 9h-j by reactions of 2,3-diferrocenylcyclopropenylium salts 1a,b with 1,2-amino- and 1,2-N-alkylaminoalcohols in the presence of Et 3 N is described. The interactions of the salts 4a,d,f and 9h-j with morpholine and piperidine results in the corresponding ( E )-2-[( N -2′,3'-diferrocenylacryloyl-2-( N -alkyl)amino]ethylmorpholines and piperidines. The characterization of the new compounds was done by IR, 1 H and 13 C NMR spectroscopy, mass-spectrometry, elemental analysis, and X-ray diffraction studies. Electrochemical properties of the compounds 3a-d and 4a-d were investigated using cyclic square voltammetry. One adsorption process and two electrochemical processes II and III , attributed to the oxidations of the ferrocene moieties, E 0 ′ ( II ), E 0 ′ ( III ), and comproportionation constant K com are reported. [ABSTRACT FROM AUTHOR]

Abstract: 2,3-Diferrocenyl-1-methylthiocyclopropenylium iodide reacts with water, metal alkoxides, phenolates and with alcohols in the presence of Et3N to give E-1,2-diferrocenyl-3-methylthioprop-2-enone or its ketals. Their structures were established based on data from 1H and 13C NMR spectroscopy and X-ray diffraction analysis. The mechanistic aspects of these reactions are discussed. Electrochemical properties of 8 and 13b have been studied. The compounds present two oxidation processes (I–II), attributed to the oxidations of the ferrocenes groups, E 0′(I), E 0′(II), ΔE 0′(II–I) and comproportionation constant K com are reported. [Copyright &y& Elsevier]

The reaction of E -2-ferrocenylmethylidenetetralones and E , E -2,6- bis -(ferrocenylmethylidene)-cyclohexanone with 2-aminothiophenol proceed with high diastereoselectivity, forming the ~ 4.5:1 mixture of trans - and cis -isomers of polycyclic ferrocenylthiazepines, respectively. The reactions of E , E -2,5- bis -(ferrocenylmethylidene)cyclopentanone and E , E -3,5- bis -(ferrocenylmethylidene)-1-methyl-4-piperidone with 2-aminothiophenol take place stereo specifically to form the diastereomeric tricyclic thiazepines of cis - and trans -configuration, respectively. The structures of the obtained compounds were established by IR, 1 H and 13 C NMR spectroscopy and mass-spectrometry. The structures of the trans -tetralino[1,2 a ]-, trans -5,7-dimethyltetralino[1,2 a ]-2-ferrocenyl [1,5]benzo-2,3-dihydrothiazepines and cis -5-ferrocenyl-methylidenecyclopentano[1,2 a ]-2-ferrocenyl- [1,5]benzo-2,3-dihydrothiazepine were confirmed by X-ray diffraction analysis. An electrochemical study reveals that the diferrocenyl derivatives belong to a Class I compounds of the Robin-Day classification. This behavior is explained by the analysis of frontier orbitals as calculated by density functional theory, showing that only one ferrocenyl unit participates in the generation of HOMO and LUMO orbitals. Compounds 4a and 4c showed similar capacity to inhibit the proliferation of HM1: IMSS trophozoite cultures than the first choice drug for human amoebiasis treatment, metronidazole. Morphological changes induced in the trophozoites after drug exposure suggest a redox in balance as the probable mechanism of the parasite death. [ABSTRACT FROM AUTHOR]

Abstract: A new method of synthesis of 2-(1,2-diferrocenylvinyl)imidazolines 3a,b and 4a,b, 1,2-diferrocenyl-4,7-diazaspiro[2.4]hept-1-enes 5a–d and 2-(1,2-diferrocenylvinyl)-2-imidazolidinium iodides 6a–d by reactions of diferrocenyl(methylthio)cyclopropenylium iodide 1 with diamines 2a–c and piperazine 2d in the presence of Et3N (80–82 °C) is described. The structure of one of the 2-(1,2-diferrocenylvinyl)-2-imidazolidinium iodide 6c is confirmed by X-ray diffraction analysis. Electrochemical properties of the compounds 3a, 3b, 6b and 6c were investigated using cyclic square voltammetry. One adsorption process (I) and two electrochemically reversible processes II and III, associated with oxidations of the ferrocene moieties, , , and comproportionation constant K com are reported. [Copyright &y& Elsevier]

Abstract: The effect of the structure of three different redox mediators on the oxidation of tetrabutylammonium acetate was studied in acetonitrile on glassy carbon and HOPG electrodes. The direct oxidation of acetate ion is essentially a carbocation process which allows in many instances the formation of products in solution. However a covalent modification of the carbon surface was possible when the oxidation process is mediated by ferrocene derivatives. The redox catalysis process occurs at lower potential values than the direct oxidation process, which triggers a radical chemistry allowing the grafting of carbon surfaces with methyl groups. Depending on the redox potential of the mediator as well as on the number of ferrocene redox centers present in its structure, the efficiency of the electrode modification process can be significantly increased. Atomic force microscopy images of HOPG modified surfaces, by using either a mediator containing one or two redox centers, were obtained to show the formation of aggregates distributed in a highly compact layer. [ABSTRACT FROM AUTHOR]

Abstract: Diethyl 2-(ferrocenylmethylidene)malonate undergoes linear dimerization with formation of tetraethyl 2,3-diferrocenylbutane-1,1,4,4-tetracarboxylate when treated with EtMgBr in the presence of Ti(OiPr)4. Under similar conditions, ethyl (E)-2-(ferrocenylmethylidene)benzoylacetate and ethyl (E,Z)-2-(ferrocenylmethylidene)acetoacetate afford linear dimerization products (3,4-diferrocenyladipic acid derivatives) and intramolecular cyclization products of the latter (3,4-diferrocenylcyclopentanol derivatives). No products of the Kulinkovich reaction (hydroxycyclopropanation of the ester groups) were observed. The structures of the compounds obtained were established based on data from IR, 1H and 13C NMR spectroscopy, mass spectrometry and X-ray diffraction analysis. The mechanistic aspects of these reactions are discussed. Electrochemical properties of the compounds 7a, 10 and 12 were investigated using cyclic voltammetry, one step potential chronoamperometry and square wave voltammetry. Two electrochemical processes (I–II), attributed to the oxidations of the ferrocenes moieties, E 0′(I), E 0′(II), ΔE 0′(II–I) and comproportionation constant K com are reported. [ABSTRACT FROM AUTHOR]

Abstract: A simple method of synthesis of 5-aryl-1-ferrocenylpenta-1,4-dien-3-ones 5a–e is described. It consists of the condensation of 3-ferrocenylmethylidenepentane-2,4-dione with arenecarboxaldehydes in the presence of an aqueous alkali. Electrochemical and optical properties of the obtained ferrocenyl-containing dienones were studied. It was found that a reversible electron transfer Fc/Fc+ takes place in all compounds. In addition, a particular redox behavior of the pyridine moiety Py−/Py was detected in the molecule trans-/trans-1-ferrocenyl-5-p-pyridylpenta-1,4-diene-3-one 5c. The cubic nonlinear behavior of the synthesized compounds was tested in solid state at the wavelength range of 1100–1800nm (telecommunications window). The third-order nonlinear susceptibility χ (3)(−3ω,ω,ω,ω), measured for polymer films doped with 30wt.% of aryl(ferrocenyl)penta-1,4-dien-3-ones, was in the range of 1 and 2×10−12 esu. Compounds 5a, 5b, 5d and 5e showed, within the experimental error, very similar values for χ (3), which means that the phenyl (compound 5a), the p-methoxyphenyl (p-anisyl) (compound 5b), the ferrocenyl (compound 5d), and the p-fluorophenyl (compound 5e) groups give similar behavior for the third-order nonlinearities independently of the electronic effects of these substituents. On the other hand, the nonlinearities were partially enhanced by three-photon resonance. [Copyright &y& Elsevier]