Ferrocene, structure

Seiler P, Dunitz JD (1982) Low-temperature crystallization of orthorhombic ferrocene structure analysis at 98 K. Acta Crystallogr B 38 1741-1745... 

Most catalysts that have been developed for asymmetric catalysis contain chiral C2-symmetric bisphosphines.7 The development of chiral ferrocenylphosphines ventures away from this conventional wisdom. Chirality in this class of ligands can result from planar chirality due to 1,2-unsymmetrically ferrocene structure as well as from various chiral substituents. Two classes of ferrocenylbisphosphines exist two phosphino groups substituted at the l,l -position about the ferrocene backbone (51) and both phosphino groups contained within a single cyclopentadienyl (Cp) ring of ferrocene (4).9... 

At first it may seem odd to expect a novel structural feature with iron as the central metal. The prototypical ferrocene structure (2) with its linear Cp-Fe-Cp Dsi or Dsh symmetrical arrangement (165) has so far showed no major changes (such as strong bending) on ligand substitution and iron oxidation. 

As chiral ligands for transition metal complex-catalyzed asymmetric reactions, a variety of novel chiral ferrocenylchalcogen compounds, which possess a planar chirality due to the 1,2-unsymmetrically disubstituted ferrocene structure, have been prepared from chiral ferrocenes (Scheme 1). Thus, chiral diferrocenyl dichalcogenides bearing an optically active dimethylaminoethyl or p-tolyl-sulfoxide moiety 1-10 were prepared by lithiation of the corresponding chiral ferrocenes, highly diastereoselectively, in moderate to high chemical yields. 

R681 T. Okamura and K. Ueyama, Synthesis and Properties of New Peptide Complex Having Ferrocene Structure as Main Chain , Kobunshi Kako, 2000, 49, 261... 

Earlier results obtained with the ferrocifens [81] led Brocard et al. to apply the same concept to the chloroquine series, to produce an analog, ferroquine 45, a ferrocenic structure close to that of chloroquine 43 [132,133]. 

A surprising observation is that certain alkyl ferrocenes are surface active, although we did not anticipate this. None of our compounds formed assemblies that could be readily characterized in the neutral state and the properties of the non-oxidized systems were not investigated further. In any event, the mono-steroidal ferrocene shown above did form vesicles. In this particular studythe half wave potentials for the ferrocenyl bis(amides) fell in the range 700-1000 mV. The mono-steroid differed from the other compounds in two important respects it was the only monosubstituted system studied and it was the only compound lacking an amide carbonyl group bonded directly to the ferrocene structure. The fact that it formed vesicles may be due to its lower halfwave potential, a structural difference attributable to the ether, rather than amide, linkage, or the presence of one, rather than two, steroids. No doubt all of these variations contribute to the success of the system. 

Method 3. Reaction of Sodiobis(cyclic dienes) with Inorganic Salts Polymerization of some a,tu-bis(cyclopentadienyl)alkanes with iron salts has been reported (10, II). Reaction of the disodio derivatives of the bis(cyclo-pentadienes) with ferrous chloride in tetrahydrofuran led to polymers and oligomers possessing the ferrocene structure. The polymers were qualitatively described as viscous, brown oils. No quantitative molecular weight data on the polymeric products were obtained. 

The preparation and structure determination of ferrocene marked the beginning of metallocene chemistry Metallocenes are organometallic compounds that bear cyclo pentadiemde ligands A large number are known even some m which uranium is the metal Metallocenes are not only stucturally interesting but many of them have useful applications as catalysts for industrial processes Zirconium based metallocenes for example are the most widely used catalysts for Ziegler-Natta polymerization of alkenes We 11 have more to say about them m Section 14 15... 

Section 14 14 Transition metal complexes that contain one or more organic ligands offer a rich variety of structural types and reactivity Organic ligands can be bonded to a metal by a ct bond or through its it system Metallocenes are transition metal complexes m which one or more of the ligands is a cyclopentadienyl ring Ferrocene was the first metallocene synthesized Its electrostatic potential map opens this chapter... 

Structure of ferrocene elucidated organometallic chemistry burgeons Nobel Prize awarded jointly to E. O. Fischer and G. Wilkinson 1973,... 

The structures of the black crystalline benzene solvate C6o-4C6H6, the black charge-transfer complex with bis(ethylenedithio)tetrathiafulvene, [C6o(BEDT-TTF)2], and the black ferrocene adduct [C6o Fe(Cp)2)2] (Fig. 8.7b) ) have also been solved and all feature the packing of Cso clusters. 

Tlie importance of bis(cyclopeniadienyl)irou (Fe(jj -C5H3)2( in the developmenl of organo-metallic chemistry has already been alluded to (p. 924). Tile compound, which forms orange crystals, mpl74°, has extraordinary thermal stability (>500°) and a remarkable structure which was unique when first established. It also has an extensive aromatic-lype reaction chernisiry which is reflected in its common name ferrocene The molecular structure of ferrocene in the ciysialline slac features two parallel cyclopentadienyl rings at one lime Ihese... 

The structure of ferrocene and an MO description of its bonding have already been given (p. 937). The rings are virtually eclipsed as they are in the analogous ruthenocene (light-yellow, mp 199°C) and osmocene (white, mp 229°C). 

The synthesis, chemical properties, and structural analysis of l,T-diphospha-ferrocene have been described [78JOM(156)C33 80AX(B)1344 80JA994 ... 

Harrowfield et al. [37-39] have described the structures of several dimethyl sulfoxide adducts of homo bimetallic complexes of rare earth metal cations with p-/e rt-butyl calix[8]arene and i /i-ferrocene derivatives of bridged calix[4]arenes. Ludwing et al. [40] described the solvent extraction behavior of three calixarene-type cyclophanes toward trivalent lanthanides La (Ln = La, Nd, Eu, Er, and Yb). By using p-tert-huty ca-lix[6Jarene hexacarboxylic acid, the lanthanides were extracted from the aqueous phase at pH 2-3.5. The ex-tractability is Nb, Eu > La > Er > Yb. 

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