Issue 45, 2017

Rigid NON-donor pincer ligand complexes of lutetium and lanthanum: synthesis and hydroamination catalysis

Abstract

Reaction of H2XN2 {4,5-bis(2,4,6-triisopropylanilino)-2,7-di-tert-butyl-9,9-dimethylxanthene} with [Lu(CH2SiMe3)3(THF)2], and crystallization from O(SiMe3)2, yielded [(XN2)Lu(CH2SiMe3)(THF)]·(O(SiMe3)2)1.5 (1·(O(SiMe3)2)1.5). Lanthanum complexes of the XN2 dianion were also prepared by salt metathesis; treatment of H2XN2 with excess KH in DME produced the dipotassium salt, [K2(XN2)(DME)x] (x = 2–2.5), and subsequent reaction with [LaCl3(THF)3] afforded [{(XN2)LaCl(THF)}x]·(O(SiMe3)2)0.25x (2·(O(SiMe3)2)0.25x; x = 1 or 2) after crystallization from O(SiMe3)2. Compound 2 reacted with two equivalents of LiCH2SiMe3, to form the dialkyl-‘ate’ complex, [Li(THF)x][(XN2)La(CH2SiMe3)2]·Toluene·LiCl (3·toluene·LiCl; x = 3). Both 1 and 3 (x = 4) were structurally characterized, and were evaluated as catalysts for intramolecular hydroamination; while 3 showed poor activity, 1 is highly active for both intramolecular hydroamination and more challenging intermolecular hydroamination. Reactions with unsymmetrical alkenes yielded Markovnikov products, and the activity of 1 surpassed that of the previously reported yttrium analogue in the reaction of diphenylacetylene with 4-tert-butylbenzylamine.

Graphical abstract: Rigid NON-donor pincer ligand complexes of lutetium and lanthanum: synthesis and hydroamination catalysis

Supplementary files

Article information

Article type
Paper
Submitted
19 Apr. 2017
Accepted
18 Maijs 2017
First published
26 Maijs 2017
This article is Open Access
Creative Commons BY-NC license

RSC Adv., 2017,7, 27938-27945

Rigid NON-donor pincer ligand complexes of lutetium and lanthanum: synthesis and hydroamination catalysis

K. S. A. Motolko, D. J. H. Emslie and J. F. Britten, RSC Adv., 2017, 7, 27938 DOI: 10.1039/C7RA04432A

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