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Title: β-SiH-containing tris(silazido) rare-earth complexes as homogeneous and grafted single-site catalyst precursors for hydroamination

A series of homoleptic rare-earth silazido compounds and their silica-grafted derivatives were prepared to compare spectroscopic and catalytic features under homogeneous and interfacial conditions. Trivalent tris(silazido) compounds Ln{N(SiHMe 2) tBu} 3 (Ln = Sc (1), Y (2), Lu (3)) are prepared in high yield by salt metathesis reactions. Solution-phase and solid-state characterization of 1–3 by NMR and IR spectroscopy and X-ray diffraction reveals Ln←H–Si interactions. These features are retained in solvent-coordinated 2·Et 2O, 2·THF, and 3·THF. The change in spectroscopic features characterizing the secondary interactions (ν SiH, 1 J SiH) from the unactivated SiH in the silazane HN(SiHMe 2) tBu follows the trend 3 > 2 > 1 ≈ 2·Et 2O > 2·THF ≈ 3·THF. Ligand lability follows the same pattern, with Et 2O readily dissociating from 2·Et 2O while THF is displaced only during surface grafting reactions. 1 and 2·THF graft onto mesoporous silica nanoparticles (MSN) to give Ln{N(SiHMe 2) tBu} n@MSN (Ln = Sc (1@MSN), Y (2@MSN)) along with THF and protonated silazido as HN(SiHMe 2) tBu and H 2N tBu. The surface species are characterized by multinuclear and multidimensional solid-state (SS) NMR spectroscopic techniques, as well as diffuse reflectance FTIR, elemental analysis, and reaction stoichiometry. A keymore » 1 J SiH SSNMR measurement reveals that the grafted sites most closely resemble Ln·THF adducts, suggesting that siloxane coordination occurs in grafted compounds. These species catalyze the hydroamination/bicyclization of aminodialkenes, and both solution-phase and interfacial conditions provide the bicyclized product with equivalent cis:trans ratios. As a result, similar diastereoselectivities mediated by catalytic sites under the two conditions suggest similar effective environments.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [1]
  1. Ames Lab. and Iowa State Univ., Ames, IA (United States)
Publication Date:
Report Number(s):
IS-J-9244
Journal ID: ISSN 0276-7333
Grant/Contract Number:
AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Organometallics
Additional Journal Information:
Journal Volume: 36; Journal Issue: 6; Journal ID: ISSN 0276-7333
Publisher:
American Chemical Society
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE
OSTI Identifier:
1349902

Eedugurala, Naresh, Wang, Zhuoran, Yan, KaKing, Boteju, Kasuni C., Chaudhary, Umesh, Kobayashi, Takeshi, Ellern, Arkady, Slowing, Igor I., Pruski, Marek, and Sadow, Aaron D.. β-SiH-containing tris(silazido) rare-earth complexes as homogeneous and grafted single-site catalyst precursors for hydroamination. United States: N. p., Web. doi:10.1021/acs.organomet.6b00956.
Eedugurala, Naresh, Wang, Zhuoran, Yan, KaKing, Boteju, Kasuni C., Chaudhary, Umesh, Kobayashi, Takeshi, Ellern, Arkady, Slowing, Igor I., Pruski, Marek, & Sadow, Aaron D.. β-SiH-containing tris(silazido) rare-earth complexes as homogeneous and grafted single-site catalyst precursors for hydroamination. United States. doi:10.1021/acs.organomet.6b00956.
Eedugurala, Naresh, Wang, Zhuoran, Yan, KaKing, Boteju, Kasuni C., Chaudhary, Umesh, Kobayashi, Takeshi, Ellern, Arkady, Slowing, Igor I., Pruski, Marek, and Sadow, Aaron D.. 2017. "β-SiH-containing tris(silazido) rare-earth complexes as homogeneous and grafted single-site catalyst precursors for hydroamination". United States. doi:10.1021/acs.organomet.6b00956. https://www.osti.gov/servlets/purl/1349902.
@article{osti_1349902,
title = {β-SiH-containing tris(silazido) rare-earth complexes as homogeneous and grafted single-site catalyst precursors for hydroamination},
author = {Eedugurala, Naresh and Wang, Zhuoran and Yan, KaKing and Boteju, Kasuni C. and Chaudhary, Umesh and Kobayashi, Takeshi and Ellern, Arkady and Slowing, Igor I. and Pruski, Marek and Sadow, Aaron D.},
abstractNote = {A series of homoleptic rare-earth silazido compounds and their silica-grafted derivatives were prepared to compare spectroscopic and catalytic features under homogeneous and interfacial conditions. Trivalent tris(silazido) compounds Ln{N(SiHMe2)tBu}3 (Ln = Sc (1), Y (2), Lu (3)) are prepared in high yield by salt metathesis reactions. Solution-phase and solid-state characterization of 1–3 by NMR and IR spectroscopy and X-ray diffraction reveals Ln←H–Si interactions. These features are retained in solvent-coordinated 2·Et2O, 2·THF, and 3·THF. The change in spectroscopic features characterizing the secondary interactions (νSiH, 1JSiH) from the unactivated SiH in the silazane HN(SiHMe2)tBu follows the trend 3 > 2 > 1 ≈ 2·Et2O > 2·THF ≈ 3·THF. Ligand lability follows the same pattern, with Et2O readily dissociating from 2·Et2O while THF is displaced only during surface grafting reactions. 1 and 2·THF graft onto mesoporous silica nanoparticles (MSN) to give Ln{N(SiHMe2)tBu}n@MSN (Ln = Sc (1@MSN), Y (2@MSN)) along with THF and protonated silazido as HN(SiHMe2)tBu and H2NtBu. The surface species are characterized by multinuclear and multidimensional solid-state (SS) NMR spectroscopic techniques, as well as diffuse reflectance FTIR, elemental analysis, and reaction stoichiometry. A key 1JSiH SSNMR measurement reveals that the grafted sites most closely resemble Ln·THF adducts, suggesting that siloxane coordination occurs in grafted compounds. These species catalyze the hydroamination/bicyclization of aminodialkenes, and both solution-phase and interfacial conditions provide the bicyclized product with equivalent cis:trans ratios. As a result, similar diastereoselectivities mediated by catalytic sites under the two conditions suggest similar effective environments.},
doi = {10.1021/acs.organomet.6b00956},
journal = {Organometallics},
number = 6,
volume = 36,
place = {United States},
year = {2017},
month = {1}
}