Ferrocene molecular structure

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... 

Bohn RK, Haaland A (1966) On the molecular structure of ferrocene, Fe(C5H5)2. J Organomet Chem 5 470-476... 

In support of the electrochemical evidence, the molecular structure of the biferrocenium ion in [( -CsF Fe -CsfLOf -CsfLOFe -CsHs)] [I3] shows that both pairs of cyclopentadienyl rings have an eclipsed conformation, Figure 16. Furthermore, the mean Fe-Cp(Centroid) distance is equivalent in both the ferrocenyl units and equal to 1.68 A. Speculatively, this value is intermediate between the values previously observed for ferrocene and ferrocenium ions, thus supporting charge delocalization between the two centres.27... 

We like to conclude the present section with an example which points out the role played by the electronic effects of ferrocene ligands in stabilizing uncommon oxidation states in metal complexes rather than their electrochemical properties. Figure 10 shows the molecular structure of the Ir(I) monocation [Ir(dppf)2]+ (dppf= l,l -bis(diphenylphosphi-no)ferrocene)7 and its electrochemical behaviour in thf solution.8... 

Fig. 11.18 shows experimental results concerning the frichon sensihvity of mixtures of AP parhcles and catalysts.Iil The AP parhcles are trimodal mixtures with diameters of 200 pm (33%), 35 pm (33%), and 5 pm (34%). Catocene (C27H32pe2) and ferrocene (CjoHjoFe) are both liquid organic compounds with iron atoms in their molecular structures and carborane is a liquid compound that contains boron atoms.Ii] The physicochemical properhes of -hexyl carborane are shown in Table 11.7. These catalysts are used to increase the burning rate of AP pyrolants. 

Fig. 15.34 Molecular structure of staggered decahenzy[ferrocene. (From Schumann, H. Jamah, C. Kohn. R. D. Loebel. J. Dietrich. A. J. Orgummet. Chen. UM9.365. 137-ISO...

Figure 2.3- Molecular structures of CH4, [PtCl4]2, BF3, and ferrocene [Fe(C5H5)2]-...

In the next example, a mixed SAM is discussed which aims to utilize photoinduced energy and electron transfer processes to create a photocurrent in an approach which is reminiscent of the natural photosynthetic process. Figure 5.33 illustrates the molecular structures of the components of interest, i.e. the molecular triad ferrocene-porphyrin-fullerene (Fc-P-C6o) and a boron dipyrrin thiol (BoDy) [67]. Mixed monolayers were generated by coadsorption onto vacuum-deposited gold... 

Figure 5.52 General molecular structure of the surface active porphyrin-ferrocene-thiol supra-molecular complexes reported by Uosaki and co-workers [82]. (b) Energy diagram illustrating the mechanism behind photocurrent generation in SAMs of such complexes at cathodic electrode potentials of the Fc/Fc+ couple P, porphyrin Fc, ferrocene MV2+, methyl viologen...

Figure 12.8.2(b) shows the molecular structure of NaaMg ProNjx [Fe(C5H3)2]. Each amido N atom is bound to one Na and one Mg atom to form a 16-membered macrocyclic ring, which accommodates the ferrocene-1,1 ,3,3 -tetrayl residue at its center. The deprotonated 1,3-positions of each cyclopentadienyl ring of the ferrocene moiety are each bound to a pair of Mg atoms by Mg-C covalent bonds, and the 1,2,3-positions further interact with three Na atoms via three different kinds of Na- C n bonds. 

The molecular structure of decabenzylferrocene also helped to explain the rather low solubility of this compound in toluene or benzene, in sharp contrast with the previously found excellent solubility properties of other decabenzylmetallocenes and the pentabenzyl-Cp thallium and indium complexes in these solvents. The steric crowding of the benzyl groups in the ferrocene and their limited mobility leave little space for the solvent arene molecules to interact and subsequently to dissolve the molecule. This is quite similar to the situation encountered in the pentaphenylcyclopenta-dienyl derivatives with their closely packed phenyl rings (see Fig. 3). 

The difficulties of interpretation presented by some of these complexes are well illustrated by the sequence of ferrocene derivatives (VIII to X). The spectrum of VIII shows a near-infrared absorption as expected for a mixed valence complex, but the band has a shoulder, and at low temperatures is resolved into two bands. Complex IX has a well-defined band almost certainly ascribable to intervalence transfer, but complex X with a similar molecular structure has no such... 

Figure 21 Molecular structure of Cgo(ferrocene)2. (Reprinted from Ref. 45. Reproduced by permission of The Royal Society of Chemistry)...

Figure 2.53 Molecular structure of [Nd(L )3(Fc2phen)] [33]. (Reprinted with permission from Y.F. Yuan, T. Cardinaels, K. Lunstroot et al, Rare-earth complexes of ferrocene-containing ligands visible-light excitable luminescent materials, Inorganic Chemistry, 46, 5302-5309, 2007. 2007 American Chemical Society.)...

The suggestion by Fischer et al. (210) that (l,3,r)-cyclooctatriene)tri-carbonylchromium is a ferrocene-type metal-arene complex (27), has been confirmed by X-ray diffraction (10). The molecular structure... 

Figure 7-47 shows the molecular structure of the diphenylfosphinoferrocene-nickel complex [Fe(fy -C5H4PPh2)2]NiCl2 [150]. The nickel atom assumes an essentially tetrahedral coordination. The cyclopentadienyl rings of the ferrocene group are parallel and nearly eclipsed. 

Finally, Fig. 7-62 illustrates the molecular structure of one of the two complexes shown in Scheme 7-40, namely the cyclometallated diplatinum complex [177]. Both platinum atoms have a square planar coordination. The cyclopentadienyl rings of the ferrocene fragment are eclipsed and somewhat tilted (4.9°) from the parallel arrangement. 

Liquid-crystalline phases are characterized to some degree by the shape of the molecules and by their packing arrangements and ordering in the mesomorphic state. Typically, molecules can have cither disc- or rod-like shapes and can form discotic or calamitic mesophases, respectively. Ferrocene liquid crystal systems that have so far been synthesized tend to have molecular structures that are lath- or rod-like in shape, and consequently the phases observed are calamitic. However, this does not preclude the possibility that a polysubstituted ferrocene could be prepared where the molecular shape is disc-like, thereby holding out the prospect of possibly producing discotic/columnar phases. 

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