Neodymium compounds

Neodymium compounds have different colors (e.g., blue, olive green, rose, and black). 

The rate of BD polymerization in Nd-based Ziegler/Natta polymerization catalysis strongly depends on the amount of the neodymium compound, the Al-cocatalyst, the halide donor, and the solvent. Beside these chemical factors the temperature has a strong influence on the rate. 

The electronic structure and chemical bonding of the neodymium compound Nd[N(SiMe3>2]3 has been studied by the INDO method [24]. The net charge on the Nd atom was found to be 0.254 and from this it is concluded that the Nd-N bonds have a co-... 

The neodymium compound [( -C6H5Me)Nd N(C6F5)2 3] has a -bonded toluene molecule with a distorted piano-stool geometry. 

The amide Er NBu (SiMe2H) 3, which has an unexpectedly high vapour pressure, displays three agostic Er H Si interactions in the solid state. Other alkylamides Ln(N-i-Pr2)3 (Ln = Y, La, Nd, Yb, Lu,) are obtained with the less hindered isopropylamide ligand the neodymium compound forms... 

Aita, K., Temma, T., Kuge, Y, and Saji, H. (2007) Development of a novel neodymium compound for in vivo fluorescence imaging. Luminescence, 22, 455. 

Slight explosion hazard in the form of dust when exposed to flame. Can react violently with air, halogens, N2. Violent reaction with phosphorus above 400°C. Many of its compounds are poisons. See also RARE EARTHS and various neodymium compounds. 

Under standard conditions the tetrakis(allyl)neodymium complex, like the tris(allyl)neodymium complex, shows only moderate catalytic activity with a high trans selectivity, but in combination with appropriate Lewis acids such as alkylaluminum chlorides or methylalumoxane the activity can be increased considerably and the selectivity changes mainly to cis. Extremely active catalysts of very high cis selectivity are obtained with the chloro(allyl)neodymium compounds in combination with methylalumoxane in heptane. For more details see [39, 49, 106]. 

Medium-c/5 lithium-polybutadiene was first developed by Firestone Tire and Rubber Company in 1955 [86]. Solution polymerization using anionic catalysts is usually based on butyllithium. Alkyllithium initiation does not have the high stereospecificity of the coordination catalysts based on titanium, cobalt, nickel, or neodymium compounds. Polymerization in aliphatic hydrocarbon solvents such as hexane or cyclohexane yields a polymer of about 40 % cis, 50 % trans structure with 10 % 1,2-addition. However, there is no need for higher cis content because a completely amorphous structure is desired for mbber applications the glass transition temperature is determined by the vinyl content. The vinyl content of the polybutadiene can be increased up to 90 % by addition of small amounts of polar substances such as ethers. 

Neodymium oxide was first isolated from a mixture of oxides called didymia. The elemeut ueodymium is the secoud most abuudaut lanthanide elemeut in the igneous rocks of Earth s crust. Hydrated neodymium(III) salts are reddish and anhydrous neodymium compounds are blue. The compounds neodymium(III) chloride, bromide, iodide, nitrate, perchlorate, and acetate are very soluble neodymium sulfate is somewhat soluble the fluoride, hydroxide, oxide, carbonate, oxalate, and phosphate compoimds are insoluble. 

The phenylacetylides were obtained from the metathesis of NaC CPh with the respective chloro complex (3a)2LnCl in THE in 77% (La) and 66% (Yb) yield. ° The alkyl complexes (3a)2Nd(CH2SiMe3) and (3a)2Nd[CH(SiMe3)2] were formed almost quantitatively from (3a)2NdCl and the respective alkyllithium reagent in toluene or benzene solution the alkoxo species (3a)2Nd(OCHMe2) and (3a)2Nd(OCH-f-Bu2) have been obtained from the reaction of (3a)2Nd-(BHEts) with acetone and pivalone, respectively. Of all the neodymium compounds just described only (3a)2NdOCH-f-Bu2 has been isolated in pure form (71% yield) and subjected to the standard methods of characterization. 

The cyclohexyl isonitrile complexes of the tris(methylcyclopentadienyl) cerium, praseodymium, and neodymium compounds have been mentioned in a discussion of the NMR spectra of these and the corresponding tricyclopentadienyl rare earth complexes, which showed that the AG values of the fluxionality of the cyclohexyl ligands decreased in contrast to those of the unsubstituted cyclopentadienyl derivatives (R.D. Fischer, 1979). 

The stractural and magnetic properties of the whole series of Heusler type compoimds i Au2ln R = Y, La-Lu) has been investigated with great care by Besnus et al. (1985,1986). The indides with lanthanum, cerium, praseodymium, and neodymium show a crystallographic transition from cubic to tetragonal as is evident from X-ray powder data. The transition temperature decreases from 355 K for LaAu2ln to 70 K for the neodymium compound. This... 

The magnitude of the red shift in the spectra of praseodymium and neodymium compounds correlates with the values of the nephelauxetic effects (6) of d-transition element complexes with the same ligands. 

Shift magnitudes (Ai ) determined for the compounds of known composition, were compared. The increments, contributing to the shift in the presence of neodymium bond with nitrogen and oxygen atoms of the carboxy-, oxy- and hydroxy-groups were established. These increments may be used to investigate composition and structure of the neodymium compounds. Table I... 

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