Ferrocene-zinc complexes

The 1,4,7-trithiacyclononane ligand, [9]aneS3, zinc complex was synthesized to compare with the electrochemistry of related complexes and showed an irreversible oxidation and an irreversible reduction at +1.30 V and —1.77 V vs. ferrocene/ferrocenium, and the X-ray crystal structure of the bis macrocycle zinc complex was reported.5 0,720... 

Ferrocene Complexes of Homometallic Metal Fragments 417 7.2.9 Group 12 Metal Complexes 7.2.9.1 Zinc Complexes... 

Poddutoori P, Co DT, Samuel APS, Kim CH, Vagnini MT, Wasielewski MR (2011) Photoinitiated multistep charge separation in ferrocene-zinc porph5oin-diiron hydrogenase model complex triads. Energ Environ Sci 4(7) 2441-2450... 

In 2005, Riant et al. reported the synthesis of a new air-stable S/N-chelating zinc catalyst, depicted in Scheme 10.50, which was fully characterised by all spectroscopic methods. This complex, prepared from the corresponding ferrocene oxazoline, was applied to the enantioselective hydrosilylation of ketones in the presence of polymethylhydrosiloxane, PMHS, providing modest enan-tioselectivities (<55% ee). ... 

Ferrocene-containing sulfur ligands have been used in complex formation with zinc. 3-Ferro-cenyl-3-mercaptopropenale and l,l -bis(3-mercaptopropenale)ferrocene (112) form stable complexes as do their Schiff base derivatives with aniline or 1,2-ethylenediamine. The Fen/Fein redox couple shows only minor metal dependence, this is attributed to tetrahedral distortion.884... 

Representative results are shown in Fig. 2.1.2.1. Both reactions with mixtures of diphenylzinc and diethylzinc and those with pure diphenylzinc are catalyzed by ferrocene 9 as indicated by the comparisons between curves A and C as well as B and D, respectively. Apparently the reaction becomes slower when the mixture of the zinc reagents is applied (curve A versus curve B). We presume that this effect is - as hoped - due to a less pronounced background reaction as well as to a modification of the aryl source (potentially PhZnEt or complexes thereof). Consequently, a better control of the enantioselectivity at the expense of the reaction rate is observed. 

Recently, a ternary complex for a signal transmission system has been constructed by Aida and his co-workers [36], It involved three movable components a biaryl derivative bearing four zinc porphyrins (2), a pyridine-appended dithienylethene derivative (1), and a chiral tetrasubstituted ferrocene (3 ), as illustrated by its structure (Scheme 8). The three components were interconnected with bidentate coordination bonds. Component 2 was the bridge between 1 and 3. The well-designed triad was built up by multi-step reactions through routine methods. 

On the basis of recent " Fe Mossbauer spectroscopic data, the l,l -bis(diphenyl-phosphino)ferrocene derivative [Fe( / -C5H4PPh2)2]CdCl2 likely possesses square planar geometry [204], As for the corresponding zinc(ii) complex, it also undergoes an irreversible one-electron oxidation in 1,2-dichloroethane [151],... 

The colorless zinc compound, Zn(CisH6)2, which sublimes at 160° under partial decomposition, is obtained in small yield from zinc chloride and cyclopentadienyl sodium in diethyl ether however, the less stable cadmium compound decomposes, with separation of cadmium, under these conditions (55). The mercury compound, Hg(CsH5)2, is produced in 20% yield by the action of the sodium derivative on mercuric chloride in tetrahydrofuran (215). The action of cyclopentadiene on the complex K2(HgI ) in aqueous alkaline solution results in the precipitation of a mixture of CsHsHgl and Hg(CsH6)2, from which the latter compound may be obtained in good yield by extraction with a mixture of tetrahydrofuran and petroleum ether (62). It forms pale yellow crystals which begin to decompose at about 60° and which melt at 83-85°. The compound is readily soluble in most solvents it decomposes slowly even when kept in the dark at room temperature it is insoluble in water and reacts with neither water nor bases. On the other hand, decomposition occurs in dilute hydrochloric acid. It converts ferric chloride to ferrocene quantitatively, and it yields an adduct with maleic anhydride (215). 

As with chromophores, the steric encapsulation of a dendrimer core can be utilized to prevent intermolecular interactions between redox active sites. A number of different redox active core moieties have been investigated, including, iron—sulfide clusters,9394 bis(terpyridine)iron(II) complexes,92 tris-(bipyridine)ruthenium(II) complexes,330 zinc porphyrins,252 oligothienylenevinylenes,331 fullerenes,236,332 ferrocenes,333-336 oligothiophenes,322 oligonaphtha-lenes,337 and 4,4 -bipyridinium.338... 

This method has been extended to the reaction of PhCsCZnBr with aldehydes in the presence of stoichiometric amounts of the lithium alcoholate of 1.14 (R = Me). Divinylzincs (RCH=CH)2Zn react under similar conditions, or also in the presence of other lithium alcoholates [650]. Under precise experimental conditions, PhMgBr adds to aliphatic or aromatic aldehydes in the presence of zinc salts and 1.14 (R = n-Bu). The enantiomeric excesses in these additions are higher than 75%. Diaiylzincs react with aldehydes in the presence of aminoalcohols bearing a ferrocene skeleton 2.47 with a very high enantioselectivity [651, 652], Schiff bases have also been used as catalysts in such reactions [367], as have some titanium complexes (see below) [559,653,654,655],... 

Organometallic and Coordination Compounds. - Crystallization of ferrocene and ruthenocene substituted in the 1- and T-positions by two nitronyl nitroxide radicals gave the new crystal phases p-1 (besides the known phase a-1, a-2, and a-2 whose structures were determined by X-ray analysis and were investigated by C and H NMR spectroscopy with MAS NMR. The solid state Sn CP MAS NMR spectra of a series of triaryltin chlorides of the form ArsSnCl have been acquired. The indirect spin-spin coupling constants (J( Sn- C1)), quadrupolar-dipolar shifts (6( Sn- Cl)), and the Sn chemical shift tensors were extracted. " Powders of the zinc and copper(II) dimethyl-(MDtc), diethyl-(EDtc), and morpholinedithiocarbamate (MfDtc) complexes quantitatively absorb hexamethyleneimine (Hmi) to produce the adducts... 

A new class of ferrocene (also cobaltocenium) receptors which sense anions both spectrally and electrochemically, is based upon attachment of metallocene moieties to a porphyrin skeleton. The porphyrin fragment can be simultaneously complexed by zinc [120]. 

Organoruthenium compounds tend to form complexes coordinated by the 10 electrons of cyclic unsaturated compounds similar to ferrocene in organoiron compounds, for example, ruthenocene (r/ -C5H5)2Ru and tf( / -C6Hx)Ru. As shown in Scheme 16.1, ruthenium chloride 3H20 reacts with unsaturated cyclic compounds in the presence of zinc metal to afford cyclic compounds coordinated by 10 electrons by dehydrogenation [15-18]. In the case of cyclopentadiene, ruthenocene is formed by the coordination of two five-electron rings. In the case of 1,3-cyclohexadiene, the complex is obtained to be coordinated with 4-electron 1,3-cyclohexadiene and with 6-electron benzene. In the case of 1,3-cycloheptadiene... 

---