Ferrocenyl-containing compounds

Ferrocenyl-containing zinc complexes 64 and 65 were analyzed by El mass spectrome-try57"58 For 64, the intact M+ has been recorded at 70 eV gj mass spectra for the other heterometallic compounds, such as Zn F. containing mixed-valence Mn Fjy[n( 7... 

Interaction of ferrocene and diazonium compounds, which is followed by loss of nitrogen, leads to a large number of derivatives 17, HI, 1, 14s, 30S) most of them, naturally, are aryl-substituted compounds. Ferrocene cannot only be mercuriated, but can also be metalled by lithium butyl or similar compounds such as sodium phenyl. A great variety of pt ibilities for substitution is afforded by the interaction of ferrocenyl lithium and halogen-containing compounds 5, 128, 143, 162). Carboxylic acids, in particular, may easily be obtained by formation of the lithium derivative of ferrocene and treatment with carbon dioxide. 

Ferrocene has been by far the most nsed redox-active gronp in a molecular redox sensor dne to its stability, its ease of functionalization, and its well-nnderstood and reversible redox chemistry. A whole host of ferrocene-containing compounds are now known that bind cations, anions, and neutral molecules. Indeed some of the first examples of redox-active receptors, for which the complexation of other species was demonstrated, were ferrocenyl crown-ether compounds, as reported in the late 1970s and in 1980. Initial progress in this area has been reviewed extensively. Representative examples of such compounds are 1, 2, 3 23 4 24 525 (pigufe 1) which all bind and electro-... 

Ferrocenyl-containing Complexes. - A collection of compounds derived from ferrocenyl-substituted acetylide Ti-based tweezer molecules have been prepared and characterised." The crystal structure of the cyclohexadienyl-containing complex 168 has been reported." A series of multimetallic complexes have been prepared by addition of enolates of bis-(ferrocenyl)-1,3-diketones to a range of p -ethene-, riCcydohexatriene-, p -cycloheptatrienyl- and pCcyclo-heptatrienyl-containing complexes." The crystal structure of 169 has been described." Compounds 170 and 171 were obtained from the reaction between... 

The bis-benzo-15-crown-5 ferrocene compound [7] containing two vinylic linkages was formed in a mixture of three isomeric components, the cis-cis, cis-trans and trans-trans isomers, which proved inseparable. However, the precedent of insignificant differences found between the magnitudes of the metal cation-induced anodic shifts in the ferrocenyl redox potentials of the respective separated cis and trans isomers [2a] and [2b] led us to use the same isomeric mixture of [7] throughout the subsequent FABMS and electrochemical group 1 and 2 metal cation complexation experiments,... 

The first iron-containing silsesquioxanes which appeared in the literature were compounds containing ferrocenyl units as side-groups.However, these are not within the scope of this review as iron is not part of the metallasilsesquioxane skeleton. Meanwhile, several ferrasilsesquioxane complexes have been synthesized. The first iron(III) compound of this type was prepared in our laboratory according to Scheme 56. ° In 161, the coordination sphere of iron is completed by TMEDA (N,N,N, N -tetramethylethylenediamine) as a chelating amine ligand. Pale yellow, crystalline 161 was isolated in 80% yield and structurally characterized by X-ray diffraction. This compound was later used by Maxim et to prepare iron... 

The reaction of ferrocene and formaldehyde in either concentrated sulfuric acid or liquid hydrogen fluoride, followed by reduction, produces a compound containing two ferrocenyl and two methylene groups (57, 98, 123). After several incorrect assignments had been proposed for the structure of this condensation product, Rinehart and coworkers showed by an unequivocal synthesis that the product was 1,2-diferrocenylethane (XIX) (104). The mechanism of the reaction presumably involves the initial formation of ferrocenylcarbinol (XX) followed by ionization in the strongly acidic medium to the ferrocenylmethyl-carbonium ion (XXI). Conversion to radical ion XXII followed by dimerization and subsequent reduction produces the product. 

Using a chiral 4-dimethylaminopyridine-ferrocenyl catalyst, acyclic silyl ketene acetals react with anhydrides to furnish 1,3-dicarbonyl compounds containing allcarbon quaternary stereocentres in good yield and ee.144 Evidence for dual activation (anhydride -> acylpyridinium, and acetal -> enolate) is presented. 

Apart from these complexes, a number of heterodinuclear neutral compounds containing ferrocenyl derivatives as aryl ligands have also been prepared in recent years (see Table X). Most of them contain the ligand 2-(dimethylaminomethyl)ferrocenyl (FcN)104 106 and, with the sole exception of [(FcN)Au P(4-C1C6H4)3 ],106 have been... 

Due to the high degree of conjugation, oh go(thiophene)s advanced as attractive candidates for molecular bridges. For instance, Sato et al. [34] constructed hexyl-sexithiophene and methoxy-terthiophene derivatives bearing two terminal ferrocenyl groups. These served as model compounds for molecular wires. In the hexyl-sexithiophene derivative, the resultant oxidized states spread over both the ferrocene and the sexithiophene moieties. Similarly, in the methoxy-terthiophene derivative, the oxidized species spreads over the entire molecule containing the terthiophene and the other ferrocene moiety. In both cases, CT between the terminal units is inferred as it is mediated via the oh go(thiophene)s. 

A number of ferrocene-containing 1,3,4-oxadiazoIes have been prepared. The reaction of ferrocenecarboxhydrazide with triethyl orthoformate gave three products, the principal one being 2-ferro-cenyl-l,3,4-oxadiazole (126 R = H). 76 2-Phenyl-5-ferrocenyl-l,3,4-oxadiazole (126 R = CgH5) and 2,5-diferrocenyl-l,3,4-oxadiazole (126 R = ferrocenyl) were prepared from the appropriate 1,2-diacyl-hydrazines.117 A number of other ferrocenyloxadiazoles, including the bis compound 127, were prepared in a similar manner.117 The oxadi-... 

Palladium-carbon-catalyzed hydrogenation of (16) gave (24), and NaBH4 reduction of (22) gave (25), both receptors now containing a saturated linkage between the aza crown system and the ferrocenyl redox center. This methylene-ferrocene linkage was found to serve as an insulator both compounds (24) and (25) are totally electrochemically insensitive to the presence of any alkali metal cation. 

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