Nucleophilic addition to di- and poly-iron arene complex cations

Abstract

Abstract:Hydride and cyanide addition to a series of di-and polycyclopentadienyliron arene complex cations with etheric bridges is described. Reaction of the di-iron complexes with sodium borohydride resulted in the formation of a number of adducts. p-Methyl-and o,o-dimethylphenoxybenzene cyclopentadienyliron complexes were used as models in this study to allow for the characterization of the analagous di-iron complexes. The use of HH COSY and CH COSY NMR techniques enabled us to identify the isomeric nature of these adducts. The hydride addition results indicated that the etheric substituent had the predominant effect over the methyl group, leading to a higher addition ratio to the meta-, followed by the ortho-, then the para-positions. It was also clear that in the di-iron system, the hydride addition to each complexed arene ring took place independently. The addition of the cyanide anion to di-and poly-iron arene systems was more selective than that of the hydride anion. Reaction of sodium cyanide with p-methyl-or o-methyl-substituted arene complexes led to the formation of one adduct, with the cyanide being added to the meta position to the etheric bridges. However, cyanide addition to the di-iron complex, with a methyl substituent attached at the meta position of each complexed arene, led to the formation of a mixture of adducts. Cyanide addition to the poly-iron system withp-substituted arenes proved to be very selective, allowing for the formation of one adduct.Oxidative demetallation with 2,3-dichloro-5,6-dicyano-1.4-benzoquinone (DDQ) produced the uncomplexed polyaromatic ethers with cyano groups in a very good yield. des Cthers polyaromatiques non complexCs portant des groupes cyano.

Design of blue fluorescence emitter star-shaped macromolecules based on pyrene and anthracene

“…[13,74] In a Pyrex test tube the star-shaped macromolecules were placed and dissolved in acetonitrile. The test tube was flushed with nitrogen for 10 minutes.…”

Sandwich Complex‐Containing Macromolecules: Property Tunability Through Versatile Synthesis

“…Like other macromolecules, sandwich complex‐containing macromolecules can be obtained through step polymerization mechanisms, which include esterification, hydrosilylation, amidation, and aromatic substitution, as well as other substitution reactions. These step polymerization reactions offer the opportunity to tune the properties of the sandwich complex‐containing macromolecule through the incorporation of various spacers . Electronics as well as the structure of the spacers tunes electronic interaction between the metal centers, solubility, and thermal properties of the resulting polymer.…”

“…In the cationic η 6 ‐aryl‐ η 5 ‐cyclopentadienyliron(II) sandwich complex, the electron‐withdrawing effect of the CpFe + moiety on the arene ring renders the latter susceptible to nucleophilic addition and substitution reactions. These reactions allow access to η 6 ‐aryl‐ η 5 ‐cyclopentadienyliron(II)‐containing polyethers, polythioethers, and polyamines under mild reaction conditions . Recently, Abd‐El‐Aziz and co‐workers reported a polyether that featured two cationic η 6 ‐aryl‐ η 5 ‐cyclopentadienyliron(II) moieties and a pendant 2‐(3‐thienyl)ethylpropanoate or 2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐ylmethyl‐propanoate per monomer unit .…”

(Arene)Cr(CO)3 Complexes: Aromatic Nucleophilic Substitution

“…Reactive nucleophiles such as cyanide, hydride [123], methyl-, and phenyl lithium [2] add to unactivated (arene)FeCp + complexes, whereas less reactive nucleophiles such as phenyl acetylide, lithium salts of acetonitrile, nitromethane and ketones [84,124] require an electron-withdrawing group to be present on the arene ring of the complex. On the other hand, cyanide or an anion derived from propionitrile added to several unactivated arene complexes [67,76,[123][124][125][126].…”