Poly magnetic properties

Figure 2.30 Representation of the asymmetric unit of [Nd(L )4(H20)][(TTF—CH=CH—Py+)] 2-The radical cation donors are drawn as balls and sticks the paramagnetic anionic coordination complexes of Nd(III) are drawn as capped sticks [23d], (Reprinted with permission from F. Pointillart, O. Maury, Y. Fe Gal, S. Golhen, O. Cador and F. Ouahab, 4-(2-Tetrathiafulvalenyl-ethenyl)pyridine (TTF—CH=CH—py) radical cation salts containing poly(P-diketonate) rare earth complexes synthesis, crystal structure, photoluminescent and magnetic properties, Inorganic Chemistry, 48, 7421-7429, 2009. 2009 American Chemical Society.)...

TCNE is one among several compounds belonging to the class of poly- or percyanated olefinic acceptors. Indeed, CT complexes of [FeCpf] with, e.g., penta-cyanopropenide ([C3(CN)5] ) [28], hexacyanobutadienide ([C4(CN)g] ) [29], hexa-cyanotrimethylenecyclopropanide ([C3(C(CN)2 3] ) [30], as well as with the simplest representative tricyanomethanide ([C(CN)3] ) [36] have been reported. The respective 1 1 CT complexes with [FeCp ] have been structurally characterized and their magnetic properties studied. 

Barta P. S., Nniziol M.. Pron A, and Pacyna A, ( 1993) Low temperature magnetic properties for poly (3-alky Ithiophenes) and po ly (4,4 -dialky 1-2,2 -bithiophenes). Synthetic Metals, 55-57,5003-5007. 

For a recent theoretical investigation on the energy, spectra and magnetic properties of polymers derived from the poly radical ions of inhnite radialenes, see N. Tyutyulkov, F. Dietz, K. MuUen, M. Baumgarten and S. KarabunarUev, Chem. Phys., 189, 83 (1994). 

Xulu, P.M. Filipcsei, G. Zrinyi, M. Preparation and responsive properties of magnetically soft poly(A-isopropylacrylamide) gels. Macromolecules 2000, 33, 1716-1719. 

Electron behavior, optical properties, catalytic properties, conductivity, and magnetic properties of nanocomposites were discussed in an extensive review pa-per. Complementary use of electron paramagnetic resonance and nuclear magnetic resonance helped to understand chain mobility in nanocomposites obtained from poly(ethylene oxide) encapped with triethoxy silicon. This nanocomposite is composed of PEO chains attached to silica clusters. It was found that chain fragments close to the silica clusters have hindered mobility due to the reduction of local free volume. The length of this hindered segment is estimated as three ethylene oxide units. 

Iron nanoparticles prepared by pyrolysis of poly(ferrocenylsilanes) inside periodic mesoporous sihca displayed the absence of room-temperature hysteresis in the magnetization curves which shows their superparamagnetic behavior [55]. However, magnetic properties cannot always be easily interpreted. For example, for this material data analysis of magnetization curves resulted in the ambiguous conclusion that either particle size distribution is bimodal, or iron particles have an oxide layer which behaves as small superparamagnetic nanoparticles. So magnetic measurements should be combined with other techniques (probably, in this case, EXAFS may be useful) to allow more accurate evaluation of particle structure. 

Thomas reported a very similar study (decomposition of Co2(CO)8 in a hydrocarbon in the presence of a terpolymer), which resulted in the formation of nanoparticies of 2-30 nm according to the reaction conditions. The author was particularly interested in the modification of the magnetic properties due to dipolar couplings as a function of the separation of the particles.Similar procedures are still used for the production of cobalt particles in organic matrices. For example, a recent paper reports thermolysis reactions of Co2(CO)8 in a block co-polymer, PS2S3oo- -MMA2S9oo, hence producing cobalt nanoparticies embedded in the poly(methylmethacrylate) (PMMA) blocks. ... 

T. Quid Ely, C. Amiens, B. Chaudret, E. Snoeck, M. Verelst, M. Respaud, and J, M. Broto. Synthesis of nickel nanoparticles. Influence of aggregation induced by modification of poly(vinylpyrrolidone) chain length on their magnetic properties. Chem. Mater, 11 526—h, 1999... 

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