Neodymium amide

Table 14 Polymerization of butadiene with neodymium amide catalysts utilizing borate activators...

Bochmann [184] developed a heterogeneous catalyst system of silica-supported neodymium amides (Scheme 28) that in conjunction of TIBA displayed activity for the copolymerization of ethylene and butadiene to give copolymer with relatively broad molecular weight distribution and fra i -l,4-regulatedbutadiene sequences. 

Copolymerization of styrene and conjugated dienes is another attractive subject which provides the most commonly used styrene-butadiene rubbers (SBRs). Boisson reported that by using neodymium amide Nd N(SrMe3)2 3 and TIBA and DEAC, SBRs with 10-15 mol% of styrene were produced [189], although drops in both activity and molecular weight were observed as compared with those of... 

In 2003, Livinghouse et al. also reported that chelating bis(thiophosphonic amidates) complexes of lanthanide metals, such as yttrium or neodymium, were able to catalyse intramolecular alkene hydroaminations. These complexes were prepared by attachment of the appropriate ligands to the metals by direct metalation with Ln[N(TMS)2]3- When applied to the cyclisation of 2-amino-5-hexene, these catalysts led to the formation of the corresponding pyrrolidine as a mixture of two diastereomers in almost quantitative yields and diastereos-electivities of up to 88% de (Scheme 10.81). 

The large ionic radius of neodymium as a typical representative of the early lanthanide elements allowed the formation of a homoleptic tris(alkoxysilyl amide) complex [78] ... 

Le Floch reported that treatment of [K CH(PPh2NPri)2 ] with one molar equivalent of neodymium triiodide afforded 87, but when reacted with half a molar equivalent complex 88 was instead obtained 48 Complex 87 was converted to the bis-amide derivative 89 without any evidence of ligand scrambling. 

Simultaneously to the disclosure of 112-117 by Liddle, Le Floch reported that complex 88 could be converted to complex 121, which is analogous to 112-117, by reaction with potassium bis(trimethylsilyl)amide.48 The second deprotonation of one of the methanide ligands to give a methandiide-methanide complex is noteable because amides, especially silyl-amides, are not usually basic enough to effect a second deprotonation at a carbon centre (cf. synthesis of 1-8) and it was suggested that coordination to the electropositive neodymium polarised the C-H bond sufficiently to activate it. 

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... 

NaNH2 sodium amide 7782-92-5 20.00 1.3900 1 3085 Nd2H16O20S3 neodymium sulfate octahydrate 13477-91-3 25.00 2.8500 1... 

Nb2Cl8S3Ci6H,8, Niobium(III), di-p-chloro-tetrachloro-)jL-(dimethylsulfide)-bis(dimethyl sulfide)di-, 21 16 NdCb, Neodymium chloride, 22 39 NdF,8N606Pi2C72H72, Neodymium(III), hex-akis(diphenylphosphinic amide)-, tris(hexafluorophosphate), 23 180 NdN30i3C8Hi6, Neodymium(III), trini-trato( 1,4,7,10-tetraoxacyclododecane)-, 23 151... 

Coordination Chemistry. The coordinative unsaturation of the three-coordinate derivatives suggests that these molecules should have a rich coordination chemistry. This has not been found, doubtless due to the steric congestion about the metal atom. Neodymium tris[bis(trimethylsilyl)amide] forms pale blue 1 1 coordination complexes with the sterically small Lewis bases B NC and Bu CN. Triphenylphosphine oxide yields a 1 1 complex with the silylamides of La, Eu, and Lu (16). 

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