Ferrocenyl phenyl

The isocyanide monolayer was formed by immersing the Cr slide in a 1 mM isocyanide solution under argon for 30 min. The redox wave, which is observed in cyclic voltammograms of the modified Cr electrode, proves that the 4-ferrocenyl-phenyl isocyanide is adsorbed on the metal surface. When a Cr electrode is exposed for 2 h to a solution of ferrocene, no redox wave was observed in the CV, which demonstrates that the isocyanide group is necessary for adsorption. No spectroscopic studies were performed on the adsorbed isocyanide. 

A number of observations have been made which qualitatively suggest that carbonium ions adjacent to metallocene systems possess unusual stability. Ferro-cenecarboxaldehyde, for example, is soluble in dilute hydrochloric acid (5), ferrocenyl carbinols such as ferrocenyl phenyl carbinol form ethers with great ease (124), and ferrocenylmethylcarbinol can be dehydrated to vinylferrocene under exceedingly mild conditions (114). The concept of stabilizations of this type has also been used to explain certain anomalous ring substitution reactions. 

Thermolysis of the sodium salt of benzoylferrocene tosylhydrazone at 80 C gave ferrocenyl-phenyldiazomethane, which subsequently decomposed and gave ferrocenyl(phenyl)carbene. 

This reaction was performed with ferrocenyl phenyl ketone to explore the competition between (Fc)C-H and (Ph)C-H bonds. Surprisingly the reaction took place at room temperature and quantitative yields of the phenyl monoalkenylated products were obtained (Scheme 15b) [154]. These reactions show the regioselective orf/io-alkenylation of the phenyl C-H bond closed to the carbonyl group and that the phenyl group is alkenylated much faster than the electron-rich ferrocenyl group. 

In solutions of 3-mercapto-l, 2,4-triazoles the tautomeric equilibrium is shifted to the thione forms 181b (Scheme 65) [76AHC(S1), pp. 404, 415 96UK326]. Such an equihbrium was observed for 3-mercapto-5-ferrocenyl-4-phenyl-1,2,4-triazole 182 (94MI1121 96UK326). The thione tautomers 183 of 5-mercapto-l,2,4-triazoles are predominant [76AHC(S1), pp. 405, 414 97SA(A)699]. 

Diphenyl-propyl- 518 Diphenyl- -tetrafluoroborat 85 Dipropyl- -perchlorat 85 Dipropyl-phenyl- 518 Triphcnyl-518f, 588, 649 Triphenyl- -bromid 85 Tri propyl - 518 Tris-[ferrocenyll- 649... 

Hydrazones are also useful substrates in the preparation of pyrazoles. Reaction of N-monosubstituted hydrazones with nitroolefins led to a regioselective synthesis of substituted pyrazoles <060L3505>. lf/-3-Ferrocenyl-l-phenylpyrazole-4-carboxaldehyde was achieved by condensation of acetylferrocene with phenylhydrazine followed by intramolecular cyclization of the hydrazone obtained under Vilsmeier-Haack conditions <06SL2581>. A one-pot synthesis of oxime derivatives of l-phenyl-3-arylpyrazole-4-carboxaldehydes has been accomplished by the Vilsmeier-Haack reaction of acetophenone phenylhydrazones <06SC3479>. 

Finally, we have constructed a QM/MM model of complex 3 whereby the phenyl phosphine groups are contained in the QM region, while the ferrocenyl and phenyl substituents on the pyrazole is accounted for on a steric basis only (model E). The agreement between the X-ray structure of 3 and model E is remarkable. For example, both the Pd-P distance and the twist of the coordination plane of the Pd center, 0, are virtually identical to those of the X-ray structure. In fact, the selected parameters displayed in Table 2 are generally better than those of the full QM calculation. The good agreement between the calculated and experimental structures is important for the detailed mechanistic study of the hydrosilylation that is presented in later sections of this chapter. 

The enantioselective hydrosilylation catalyst system based on the chiral pre-catalyst dichloro l- (/ )-l- [(S)-2 (dipheaylphosphinoKP) ferrocenyl] ethyl -3- trimethyl- phenyl-5-1 H- pyrazole-tc/V) palladium, 1 (shown in Figure 2) exhibits a interesting inversion of selectivity with a series of para-... 

Ferrocenoylamino acids have been converted into 2-ferrocenyl-5(477)-oxazo-lones 348 and 350 that act as N donors in palladium, platinum, and iridium complexes. Reaction of 348 with chloro-bridged palladium(II) and platinum(II) complexes affords a series of N-coordinated oxazolone complexes 349. Reaction of the unsubstituted 2-ferrocenyl-5(477)-oxazolone 350 with the chloro-bridged iridium(III) complex [(ri -C5Me5)IrCl2]2 produces a dinuclear complex 351, analogous to that obtained from 2-phenyl-5(477)-oxazolone (Scheme 7.113)." ° ... 

The monoanionic potentially bidentate 2-[(dimethylamino)methyl]ferrocenyl ligand has coordinating properties similar to that of the 2-[(dimethylamino)methyl]phenyl ligand, and has also been used to stabilize a variety of organometallic derivatives. Bis [(2-dimethylamino)methyl]ferrocenyl magnesium (68) has been synthesized and was structurally characterized in the solid state by X-ray crystallography. 

In 1969, Elschenbroich and Cais reported the ESR spectra of several ferrocenyl anion radicals, including benzoyl, p-tolyl, p-carbomethoxy-benzoyl, p-nitrophenyl, p-cyanophenyl, and nitroferrocene, prepared by electrolytic reduction in either acetonitrile or DMF (5S). In general, the ferrocenyl group destabilizes the anion radicals compared to a phenyl substituent. When both groups are present, delocalization of the unpaired electron into the phenyl substituent is more extensive, and the ESR spectra resemble, for the most part, anion radicals of substituted aromatics. There is small spin density in the ferrocenyl moiety, which appears as small hyperfine couplings for the cyclopentadienyl protons ortho to the point of substitution (38). 

Arnett and Bushick (2) have determined the pKA values for the conjugate acids of ferrocenyl ketones in aqueous sulfuric acid. They have found, for example, that acetylferrocene is over 2000 times more basic than acetophenone and 85 times more basic than p-hydroxyacetophenone. These data support the concept that metallocenyl groups are strongly electron-releasing compared to the phenyl group and that they possess extraordinary ability to delocalize adjacent positive charges. 

Bifunctional organosilanes [l-NpRSi(X)Y R = phenyl or ferrocenyl] are good models to study the relative ability of X and Y leaving groups to be displaced. Typical reactions are shown in Table II the data lead to the following conclusions ... 

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