Ferrocenyl-containing Complexes

4 Ferrocenyl-containing Complexes. - A collection of compounds derived from ferrocenyl-substituted acetylide Ti-based tweezer molecules have been prepared and characterised. The crystal structure of the cyclohexadienyl-containing complex 168 has been reported. A series of multimetallic complexes have been prepared by addition of enolates of bis-(ferrocenyl)-1,3-diketones to a range of p -ethene-, riCcydohexatriene-, p -cycloheptatrienyl- and pCcyclo-heptatrienyl-containing complexes. The crystal structure of 169 has been described. Compounds 170 and 171 were obtained from the reaction between 

The result of refluxing [Os3(CO)io( i3-Fc-C = C-C = C-Fc)] with H2O in THF was three new cluster compounds in which the bridging butadiene ligand had been partially hydrogenated. The crystal structures and electrochemistry of these new compounds was presented. A series of compounds of which 172 is representative have been prepared and electrochemical studies showed inter-metal communication. Compound 173 has been synthesised and fully characterised. Its utility in hydrogenation reactions was also presented. Compound 174 has been shown to deliver ees of up to 86% in enantioselective isomerisation of allyl alcohols.49  

Compound 175 has been prepared where dimerisation has occurred through the y-carbon atom. Incorporation of the bulky ferrocenyl group prevents this dimerisation and afforded the monomeric Rh-based compound Hetero- 

Flower, in Organometallic Chemistry, ed. M. Green, Specialist Periodieal Reports, Royal Society of Chemistry, Cambridge, Vol. 29,2001, pp. 384-441. 

Venne-Dunker, W. Ahlers, G. Erker and R. Frohlich, Eur. J. Inorg. Chem., 2000, 1671. 

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Ferrocenyl-containing zinc complexes 64 and 65 were analyzed by El mass spectrome-try57"58 For 64, the intact M+ has been recorded at 70 eV gj mass spectra for the other heterometallic compounds, such as Zn F. containing mixed-valence Mn Fjy[n( 7... 

These contain redox-active centers able to switch on/off cation or anion complexation when treated with redox reagents or electrochemical stimulation. Examples include some ferrocenyl-containing macrocycles, such as (159), or donors with an anthraquinone fragment, as in (160).252 The functionalization of electroactive polymers by monocyclic polyethers has been used for the building of cation-responsive electrodes. 

Scheme 5. Synthesis of heterometallic ferrocenyl alkynyl complexes of platinum, mthenium and osmium containing fluorenone spacers.

As detailed in earlier sections. Beer and co-workers (1469,1470) prepared a range of complexes in which two zinc bis(dithiocarbamate) centers are incorporated into macrocycles (Fig. 255). The terphenyl-based macrocycles 477 bind bidentate Lewis bases in their cavities (as discussed in Section IV.H.l.a), while 478 containing the well-known [Ru(bpy)3] " subunit has been utilized in anion-binding studies. The same group have also prepared a number of ferrocenyl-containing macrocycles 479-481, containing up to six iron(II) centers, probing their electrochemical properties (see later) (1468). 

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 bis-benzo-15-crown-5 ferrocene compound [7] containing two vinylic linkages was formed in a mixture of three isomeric components, the cis-cis, cis-trans and trans-trans isomers, which proved inseparable. However, the precedent of insignificant differences found between the magnitudes of the metal cation-induced anodic shifts in the ferrocenyl redox potentials of the respective separated cis and trans isomers [2a] and [2b] led us to use the same isomeric mixture of [7] throughout the subsequent FABMS and electrochemical group 1 and 2 metal cation complexation experiments,... 

The first iron-containing silsesquioxanes which appeared in the literature were compounds containing ferrocenyl units as side-groups.However, these are not within the scope of this review as iron is not part of the metallasilsesquioxane skeleton. Meanwhile, several ferrasilsesquioxane complexes have been synthesized. The first iron(III) compound of this type was prepared in our laboratory according to Scheme 56. ° In 161, the coordination sphere of iron is completed by TMEDA (N,N,N, N -tetramethylethylenediamine) as a chelating amine ligand. Pale yellow, crystalline 161 was isolated in 80% yield and structurally characterized by X-ray diffraction. This compound was later used by Maxim et to prepare iron... 

The PFg" salts of [Ru(bpy)2(110)] and [Ru(110)3] and analogous complexes containing 4,4 -bis(substituted) ferrocenyl ligands (110 ), have been synthesized and characterized the tris(chelate) complexes are either poorly soluble or insoluble. Electropolymerization of [Ru(110 )3][PF6]2 produces an electrochromic film. The complex [Ru(bpy)2(lll)] undergoes electropolymerization on Pt and glassy carbon electrodes, although the related complex [Ru(bpy)2(112)] does not. Electrochemical and spectroscopic properties of the films indicate that they form by both head-to-tail and tail-to-tail monomer coupling. ... 

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