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Metallocene Derivatives of Early Transition elements. Part 1. Niobium(IV) Chlorides, Chloroalkyls, and Dialkyls , and the Crystal and Molecular Structure of

DOI: 10.1039/DT9810000180

Source and publish data:

Journal of the Chemical Society, Dalton Transactions p. 180 - 186 (1981)

Update date:2022-08-02

Topics: Crystal structure   Molecular structure   Derivatives   Metallocene  

Authors:

Hitchcock, Peter B.Hitchcock, Peter B.

Lappert, Michael F.Lappert, Michael F.

Milne, Charles R. C.Milne, Charles R. C.

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Article abstract of DOI:10.1039/DT9810000180

Reaction of with Li (X=h, Me, or SiMe3) in tetrahydrofuran (thf) gives a high yield of the volatile , (1).Treatment of (1) with 2Li provides , (2a)-(2c), whereas 2Mg(R)Cl (R=CH2SiMe3 or CH2CMe3) affords the chloroalkys , (3a)-(3e); using the less bulky Grignard reagent Mg(Me)I or Mg(CH2Ph)Cl yields the dialkys , (2e)-(2h).The solution ESR spectra of compounds (1)-(3) have been recorded and show a ten-line spectrum due to hyperfine coupling to (93)Nb but not α hydrogens.The gav. values are in the range 1.97-200 <(1) < (3) < (2)> and a((93)Nb) (8.6-11.7 mT) decrease in the reverse sequence and in the order X=H > Me > SiMe3.An X-ray crystal-structure determination (to R=0.045, R'=0.064) of shows it to possess roughly tetrahedral geometry, taking each C5H5 ring as unidentate, Nb-C(benzyl)av. 2.304(3) Angstroem, Nb-C(C5H5)av. 2.410(28) Angstroem, Nb-C-Phav. 120.0(5) deg., and C-Nb-Cav. (C=benzyl C) 79.0(4) deg.There is a relationship between a((93)Nb) and (a) electronic configuration of M, d0 > d1, (b) electronegativity of ligand L, (1-)Cl > (1-)R, and (c) steric effects, X=H > Me > SiMe3; X-ray data establish that L -M-L (e.g.C-Nb-C) also correlates with (a) and (b).

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Product name:di(neopentyl)bis(η-trimethylsilylcyclopentadienyl)niobium(IV)

Cas No:77674-54-5

77674-54-5

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