Unsymmetrically Substituted Dimethyldiaminosilanes as Ligands towards Zirconium(IV)

Abstract

Unsymmetrically substituted dimethyldiaminosilanes of the general formula SiMe2(NR2)(NR′2) have been prepared by treating LiNR2 with SiMe2Cl(NR′2) (NR2, NR′2 = NMe2, NC4H8, NHiPr, NHtBu, NHCH2CH2NMe2 or NHCH2CH2OMe). Their ligating properties towards zirconium(IV) have been investigated as a function of the nitrogen substituents and the syntheses of the binary compound Zr[SiMe2(NiPr)(NtBu)]2 and of the zirconium derivatives ZrX3(L) [X = Cl, NMe2; L = SiMe(NR)(NR′2), NR = NiPr, NtBu, NCH2CH2NMe2, NCH2CH2OMe; NR′2 = NMe2, NC4H8, NHiPr, NHtBu] are also reported. The solution structures and dynamics of the compounds have been elucidated by 1D/2D multinuclear NMR spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Lewis Base Mediated β-Elimination and Lewis Acid Mediated Insertion Reactions of Disilazido Zirconium Compounds

“…Similarly, the reaction of Cp 2 Zr{N(SiHMe 2 ) 2 }Cl and B(C 6 F 5 ) 3 gives [Cp 2 ZrN(SiHMe 2 )(SiMe 2 -μ-Cl)] + ([ 14 ][HB(C 6 F 5 ) 3 ]) via β-hydrogen abstraction. The 29 Si NMR chemical shift for the SiMe 2 Cl moiety is 29.6 ppm; for comparison, the value for Me 3 SiCl is 30.2 ppm and the value for Me 2 NSiMe 2 Cl is 13.9 ppm …”

“…Si NMR chemical shift of the SiOTf center, and the short Zr−H and Zr−Si distances argue for greater positive charge localization on Zr rather than on the Si center.Similarly, the reaction of Cp 2 Zr{N(SiHMe 2 ) 2 }Cl and B(C 6 F 5 ) 3 gives [Cp 2 ZrN(SiHMe 2 )(SiMe 2 -μ-Cl)] + ([14][HB-(C 6 F 5 ) 3 ]) via β-hydrogen abstraction. The 29 Si NMR chemical shift for the SiMe 2 Cl moiety is 29.6 ppm; for comparison, the value for Me 3 SiCl is 30.2 ppm38 and the value for Me 2 NSiMe 2 Cl is 13.9 ppm 39. Finally, reactions of 1 and paraformaldehyde or acetone provide the alkoxide (disilazido)zirconium compounds Cp 2 Zr-{N(SiHMe 2 ) 2 }OR (R = Me (15), CHMe 2 (16)).…”

Synthesis of main group, rare-earth, and d{sup 0} metal complexes containing beta-hydrogen

“…Thus, the potassium compound (3.1·TMEDA) 2 contains two types of three-centertwo-electron potassium-hydrosilyl interactions that are best described as agostic and anagostic. 33 The two potassium atoms of the dimer are separated by a distance of 4.890(2) Å, which is within the sum of van der Waals radii (5.50 Å) but longer than the sum of covalent radii (4.06 Å); a K-K bond is not chemically reasonable in (3.1·TMEDA) 2 . Three slightly broad bands were observed in the IR spectra of 3.2·TMEDA and 3.3·TMEDA in the region associated with SiH stretching modes ( Table 3.1).…”

Reaction of N-[chloro(diorganyl)silyl]anilines with isopropanol and isopropylamine

“…The first reports on synthesis of polyfunctional silanes of the general formula R 1 R 2 Si· (Cl)NR 1 R 2 (R 1 , R 2 = H, Alk, or Ar) date back to the second half of the XX century [20][21][22][23][24][25], and some data on their chemical properties have been published [26,27]. However, only a few of such silanes have been prepared, and their structure and properties have been scarcely studied.…”