Neodymium complex

Although efficient for the intramolecular hydroamination/cyclization (abbreviated IH below) of aminoalkenes (see below), organolanthanides exhibit a much lower catalytic activity for the intermolecular hydroamination of aUcenes, as exemplified by the reaction of n-PrNH2 with 1-pentene catalyzed by a neodymium complex (Eq. 4.17) [127]. 

Catalytic Applications of SOLnC and SOAnC 491 Table 12.8 1,3-Diene polymerization by silica-supported neodymium complexes. 

Although they are not macrocyclic ligands, polyethyleneglycols behave somewhat similarly to the crown ethers regarding lanthanide complexation, as established by a number of crystal structure determinations. Thus a series of neodymium complexes shows consistent 10-coordination, namely [Nd(N03)3(tri-eg)],458 where tri-eg is triethyleneglycol, [Nd(N03)2(penta-eg)]N03,458 and [Nd(N03)2(N03)(tetra-eg)],459 where N03 is monodentate. The larger La3+ ion shows 11-coordination in [La(N03)3(tetra-eg)].460... 

Hydrosilation of 1,5- and 1,6-dienes, catalyzed by a chiral neodymium complex, leads to intramolecular bond formation and results in the formation of silylated methylcy-clopentanes (equation 147)538. This reaction is in stark contrast to the reaction catalyzed by group VHI complexes, which gives a range of silanes but no carbocyclic compounds539,540. 

Jensen, M.P., Chiarizia, R., Urban, V., Nash, K.L. 2001. Aggregation of the neodymium complexes of HDEHP, CYANEX 272, CYANEX 302, and CYANEX 301 in toluene. NUCEF 2001, Tokai-mura, Japan, October 31 to November 2. 

An unusual molecular array was obtained upon recrystallization of 30f from dimethoxyethane. In the resulting binuclear neodymium complex 31f two THF ligands are replaced by a bridging DME ligand (Fig. 11) [63]. 

The blue-green neodymium complex 58f was structurally characterized by X-ray diffraction (Fig. 18). Despite the presence of both the large, flat C8Hl ligand and the very bulky diphenyl-bis(JV-trimethylsilylimino)phosphinate anion, the coordination sphere of neodymium leaves enough room to accomodate an additional THF ligand. The central four-membered ring formed by the neodymium atom and the NPN chelate system is nearly planar. 

Scheme 10 Neodymium complex [Me2Si(3-Me3SiC5H3)2]NdCl used for copolymerization of BD and ethylene [306], reprinted with permission of Wiley-VCH Verlag GmbH Co. KGaA...

In 2004 Carpentier and co-workers were the first who isolated and characterized the active species from a Nd alcoholate/MgR2 mixture. The reaction of either a trinuclear or a monomeric Nd alcoholate precursor with Mg(CH2SiMe3)2 (Et20) yields an alkyl neodymium complex and a new het-erobimetallic Nd-Mg complex. The latter complex is considered to be the active species for the investigated catalyst system [621],... 

Scheme 44 Isolation of an alkylated neodymium complex with three different ligands from the reaction of neodymium diisopropylamide with TMA [207]...

The malonate complex of Eu(III), Eu2(malonate)3 8H2O is interesting since there are two different coordination geometries, and only five of the water molecules are coordinated [167], One of the Eu ions is eight-coordinate in the form of a distorted square antiprism and the other Eu ion is nine-coordinate, distorted tricapped trigonal prism. In the analogous neodymium complex, six water molecules are coordinated because of the difference in ionic radius. The neodymium complex is nine-coordinate with monocapped antiprismatic geometry [168]. 

The neodymium complex of the formula, Nd(N03)3(Ph3P0)2(C2H50H) has been synthesized and the crystal structure shows it to be nine-coordinate [172]. 

Spectroscopic data (A) and oscillator strengths (B) for the neodymium complex. Ref. [293]. 

The nitrate ion activities in the aqueous phase were measured with a nitrate ion selective electrode taking into account the presence of high hydrogen ion concentration by calibration of the nitrate electrode with nitric acid. The nitrate ion concentration in the organic phase owing to the extraction of neodymium complexes by HDEHP was determined by back-extraction of the organic phase with 3M sulfuric acid, dilution, and analysis with a nitrate ion electrode calibrated for different nitrate and sulfate concentrations. The amount of the nitrate species extracted into the organic phase increases as the initial neodymium nitrate concentration increases. 

Yang, L., Gong, Z., Nie, D., etal. (2006) Promoting near-infrared emission of neodymium complexes by tuning the singlet and triplet energy levels of P-diketonates. New Journal of Chemistry, 30, 791-796. 

Figure 4.5 Structure of Nd(6)CH3CN(CF3S03)2 [7]. (Redrawn fromR Wei, T. Jin and G Xu, Synthesis and crystal structure of neodymium complex of 1-methyl-1,4,7,10-tetraazacyclododecane, Acra Chimica Sinica, 50, 883, 1992.)...

Rodrigues, A.S., Kirillov, E., Roisnel, T. et al. (2007) Highly isospecific styrene polymerization catalyzed by single-component bridged bis(indenyl) allyl yttrium and neodymium complexes. Angewandte Chemie International Edition, 46, 7240. 

Faulkner, S., Carrie, M.-C., Pope, S.J.A., etal. (2004) Pyrene-sensitised near-lR luminescence from ytterbium and neodymium complexes. Dalton Transactions, 1405. 

Beeby, A., Faulkner, S., Parker, D., and Williams, J.A.G. (2000) Sensitised luminescence from phenanthridine appended lanthanide complexes analysis of triplet mediated energy transfer processes in terbium, europium and neodymium complexes. Journal of the Chemical Society, Perkin Transactions, 2, 1268. 

Complexes Ln(bipy)2(N03)3 have been studied in more detail than the other bipy complexes all appear to have 10-coordinate structures with all nitrates present as bidentate ligands. The coordination geometry has been variously described as a bicapped dodecahedron and as a sphenocorona. Unlike the La complex, the Lu complex does not possess disorder about the twofold axis. Li N distances are 2.46-2.67(1) A and Lu—O distances in the range 2.426(9)-2.556(9) A. [Y(bipy)2(N03)3] is, like [Y(phen)2(N03)3], isostructural with its lanthanide analogues. Similarly, the structure of [Nd(bipy)2(N03)3] has been shown to be isostructural with [Ln(bipy)2(N03)3] (Ln = Y, La, Lu). A number of compounds Ln(bipy)3(N03)3 (Ln = Ce, Pr, Nd, Yb) have been reported the neodymium complex was shown to be [Nd(bipy)2(N03)3]. bipy, with the third bipy molecule not associating with the neodymium-containing complex. ... 

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