Ruthenocene complexes

The last approach depends upon particular aspects of ruthenium in the II and Til oxidation states as well as certain differences between tumor and normal tissue metabolism. It Is, In concept, applicable to each of the major categories of anticancer pharmaceuticals mentioned above and provides 

ACS Symposium Series American Chemical Society Washington, DC, 1980. 

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The effect of metal replacement has not been established with certainty. Direct comparison of ferrocene complexes with analogous ruthenocene complexes is only possible for the parent compounds, with ruthenocene having a slightly larger cubic nonlinearity.1819 This result needs to be treated cautiously, as the technique employed (OPL) is susceptible to thermal contributions (see earlier) and the low nonlinearities of the complexes induce substantial errors. The differing fundamental frequencies employed... 

Table 7 Observed and calculated excitation energies (eV) for the MC transitions of ferrocene and ruthenocene complexes...

Ruthenocene complexes have been studied mainly as a way of tagging biomolecules with mthenium isotopes which have favorable radioactive properties. 

The substituted ruthenocene complex [Cp Ru(t -CsH4C9Hio)], shown as 2, is obtained on reaction of [Cp 2Ru2Cl2] with an excess of 1,5-norbornadiene in ethanol. In this reaction the substituted cyclopentadienyl ligand is obtained from the coupling of two norbornadiene units, followed by C-C bond cleavage and hydrogen migration and finally HGl loss. ... 

The silanol complex 57 exhibits a Si H M agostic interaction characterized by a /(Si-H) of 41 Hz and a Si-H distance of 1.70(7) It would be incautious to interpret such a low value of the Si-H coupling in terms of a significant Si-H bond activation, because the Si-H bond forms rather acute angles with the Si-C and Si-Si bonds (about 82 and 101°, respectively) and thus must have a considerable p character on silicon, which should contribute to the decrease of /(Si-H). The silanol ligand is -coordinate to ruthenium and the Ru-Si bond of 2.441(3) A is not exceptional, but the Si(SiMe3)3 deviates from the silanol plane by 19.0°, probably as a result of the Si-H interaction. Deprotonation of 57 by strong bases affords a neutral ruthenocene-like product. 

Ruthenium reacts with cyclopentadiene in ether to form a sandwich complex, a yellow crystalline compound, bis(cyclopentadiene) ruthenium(0), also known as ruthenocene. 

The traditional names ferrocene, manganocene, ruthenocene, nickelocene, etc. are given to the respective bis(ri5-cyclopentadienyl)metal complexes. Ocene names should not be coined for isoelectronic species such as chromocene for bis(ri6-benzene)chromium, for structurally analogous... 

Alkyl-substituted ruthenocenes, preparation, 6, 635-636 Alkyl sulfonates, cross coupling, and Grignard reactions, 9, 44 Alkyltantalum imido complexes, as catalysts, 5, 193 Alkyl tellurides... 

Aza complexes, with mono-Cp Ti(IV), 4, 417 Aza-crown-substituted ruthenocenes, preparation, 6, 635-636 Aza-Diels-Alder reactions, via silver catalysts, 9, 567... 

Cyclopentadienyl rings, in chromocenes with heteroatom substitutions, 5, 330 with pentalene rings, 5, 331 with substitutions, 5, 329 Cyclopentadienyl ruthenocenes, synthesis, 6, 639 Cyclopentadienyl—silylamido complexes, with Zr(IV) and Hf(IV) and monodentate ligands, 4, 852 Cyclopentadienyl—silylamido dienes, with Zr(IV) and Hf(IV),... 

This procedure was first used to prepare ruthenocene and other ruthenium complexes of cyclic olefin (136). The acyclic ruthenocenes are pale yellow, air-stable materials, soluble in organic solvents and readily sublimed. One representative compound of the lanthanides, NdPl 3 (137), and one of the actinides, UP1 3 (138), have also been described. 

Unlike the compounds obtained with the heavier halogens, polyfluori-nated metallocene derivatives cannot be prepared from the permercurated metallocenes. Thermally stable pentafluorinated ruthenocenes have been made from the (oxocyclohexadienyl)(cyclopentadienyl)metal complexes by flash vacuum pyrolysis (Scheme 6).53 54 Decafluorometallocenes, [M(C5F5)2], are still unknown potential routes to these compounds starting from fluorinated cyclopentadiene (C5F5H)55 or from the decachlorometal-locenes48 have been unsuccessful. However, there seems to be no fundamental steric or electronic barrier to their eventual preparation. 

Reasonably similar observations can be made for the complexes bis(2,3,4-trimethyl-pentadienyl)ruthenium and bis(2,4-dimethylpentadienyl)chromium, both of which contain metals larger than iron. Thus, in ruthenocene and chromocene the average M-C bond distances have been found to be 2.196(3) and 2.169(4) A, respectively, whereas for their open analogs, the distances are quite comparable, if not actually shorter, at 2.188(3) and 2.165(4) A, respectively. Thus it does seem that the Fe-C bond distances in Fe(2,4-... 

Most decaphenylmetailocenes also exhibit an unsurpassed thermal stability for sandwich complexes. The decaphenyl Ge, Sn, and Pb derivatives do not decompose until above 350°C (under nitrogen) (39), in contrast with around 100°C for the decabenzyl analogs (106). For sym-penta- and decaphenylferrocene and -ruthenocene an extraordinary degree of thermal and oxidative stability is noted (40) they are unchanged in air ( ) at 315°C and volatilize only at 250-300° C in the mass spectrometer. 

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