Issue 27, 2015

Metallacyclic yttrium alkyl and hydrido complexes: synthesis, structures and catalytic activity in intermolecular olefin hydrophosphination and hydroamination

Abstract

Metallacyclic neutral and ionic yttrium alkyl complexes coordinated by a dianionic ene-diamido ligand ([2,6-iPr2C6H3NC(Me)[double bond, length as m-dash]C(Me)NC6H3iPr2-2,6] = L1) [L1]Y(CH2SiMe3)(THF)2 (2), {[L1]Y(CH2SiMe3)2}{Li(THF)4}+ (3), [L1]Y(OEt2)(μ-Me)2Li(TMEDA) (4) were synthesized using a salt-metathesis approach starting from the related chloro complex [L1]Y(THF)2(μ-Cl)2Li(THF)2 (1) in 70, 85 and 72% yields respectively. The reactions of 2 with H2 or PhSiH3 afford the dimeric hydride {[L1]Y(THF)(μ-H)}2(μ-THF) (5) containing two μ-bridging hydrido and one μ-bridging THF ligands (91 and 85% yields). The X-ray studies of complexes 2, 3 and 5 revealed η2-coordination of the C[double bond, length as m-dash]C fragment of an ene-diamido ligand to a Y cation. DFT calculations were carried out to give an insight into the metal–ligand bonding and especially the interaction between the metal and the ene-diamido ligand. The observed bonding of the ene-diamido fragment is found to reflect the acidity of the metal center in the complex that is partially overcome by a better donation from the double bond (better overlap with an empty d orbital at the yttrium center). The treatment of complex 4 with DME resulted in the C–O bond cleavage of DME and afforded a three nuclear methoxide oxide complex [{[L1]Y}32-OMe)33-O)]2−[Li(DME)3]+2 (6). Complexes 2, 3, 5 and 7 proved to be efficient precatalysts for the intermolecular hydrophosphination of styrene, 4-vinylpyridine, and 1-nonene with PhPH2 and Ph2PH as well as hydroamination of styrene and pyrrolidine.

Graphical abstract: Metallacyclic yttrium alkyl and hydrido complexes: synthesis, structures and catalytic activity in intermolecular olefin hydrophosphination and hydroamination

Supplementary files

Article information

Article type
Paper
Submitted
12 Jan 2015
Accepted
05 Feb 2015
First published
10 Feb 2015

Dalton Trans., 2015,44, 12137-12148

Metallacyclic yttrium alkyl and hydrido complexes: synthesis, structures and catalytic activity in intermolecular olefin hydrophosphination and hydroamination

A. A. Kissel, T. V. Mahrova, D. M. Lyubov, A. V. Cherkasov, G. K. Fukin, A. A. Trifonov, I. Del Rosal and L. Maron, Dalton Trans., 2015, 44, 12137 DOI: 10.1039/C5DT00129C

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