Properties of Substituted Metallocenes

Spin crossover temperatures for manganocenes as a function of alkyl groups. Data for [MnCp,], [Mn(C5MeH4)2]. and IMniCyi-PrljH,) .], from Refs. 203, 169, and 179, respectively. 

For gaseous l,l -dimethylmanganocene, He(I) PES data conclusively established the existence of a mixture of both low and high spin states in almost equal proportions.ESR measurements on the compound are also consistent with the presence of a low-spin/high-spin equilibrium. 

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In 1983 the Exxon Chemical Company reported the discovery that the properties of the metallocene catalyst (e.g., molecular weight, comonomer selectivity, and activity) could be controlled by the choice of metal (Ti, Zr, or Hf) and by substituting and/or bridging the two cyclopentadienyl rings on the catalyst precursor [21]. 

Figure 3a-b illustrate the LCB effect on the melt rheological properties. The response of the rheological behaviour to the copolymerisation ability and vinyl end group selectivity of the siloxy-substituted metallocenes has been investigated from their dynamic modulus curves. The frequency dependency of the dynamic modulus of the polyethenes produced with catalysts 2 is demonstrated in Fig. 3a. For comparison dynamic modulus for a linear polyethene, prepared by the catalyst -BuCp2ZrCl2, is shown in Fig. 3b. 

Analytical Properties (i-Cyclodextrin (cycloheptamylose) normal phase separation of positional isomers of substituted benzoic acids reverse phase separation of dansyl and napthyl amino acids, several aromatic drugs, steroids, alkaloids, metallocenes, binapthyl crown ethers, aromatics acids, aromatic amines, and aromatic sulfoxides this substrate has seven glucose units and has a relative molecular mass of 1135 the inside cavity has a diameter of 0.78 nm, and the substrate has a water solubility of 1.85 g/ml, although this can be increased by derivatization Reference 13-28... 

A notable substitution product of ruthenocene is ethynyl-ruthenocene, which can be bound to estradiol, a form of estrogen studied for breast cancer treatment. With the rigid alkyne spacer, the steroid s affinity to the estrogen receptor was surprisingly unchanged upon addition of the metallocene. The addition of organometallic complexes to biomolecules may allow for the selective tuning of properties of the molecule. ... 

The substitution of the iron atom by ruthenium has been performed to evaluate the importance of the redox properties of iron, while maintaining the presence of metallocene in the side chain of the molecule [60]. The molecule was named ruthenoquine (RQ). Methyl ruthenoquine (MeRQ) features both modifications (i.e., replacement of the iron atom by a ruthenium atom and alkyl substitution of nitrogen atom 11) [60]. This molecule is not able to establish the intramolecular hydrogen bond and is also not able to produce the reactive oxygen species (ROS) in oxidizing conditions of the digestive vacuole. 

In connection with the elucidation of the structures of the products obtained upon reaction of the tropone (496) with perchloric acid, the 6-methoxy-substituted derivatives have been prepared by reaction of (496) with methyl iodide and silver fluoroborate. -Comparison of u.v. spectra indicated that the salts between the tropones (496) and perchloric acid were 6-hydroxy-derivatives of the perchlorate of (497). U.v. and n.m.r. spectra of the systems (496)—(499) are discussed and their properties and reactivities compared with the corresponding JV-phenyl-pyrrole analogue. A preliminary report of the polarographic, i.r., and u.v. spectroscopic properties, as well as the dipole moments, of both the C-annelated systems (496) and (497) without methyl groups in the thiophen ring and also the ion (500) with alkyl, hydroxy, and methoxy-groups in the seven-membered ring has been published. Values of piirR+ between 6 and 7 have been obtained for this system. The spectroscopic properties of metallocene derivatives such as (501)—(503) have also... 

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