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Rare earth metal bis(trimethylsilyl)amido complexes bearing pyrrolyl-methylamide ligand. Synthesis, structure, and catalytic activity towards guanylation of amines

2010; Royal Society of Chemistry; Volume: 39; Issue: 38 Linguagem: Inglês

10.1039/c0dt00246a

1477-9234

Chao Liu, Shuangliu Zhou, Shaowu Wang, Lijun Zhang, Gaosheng Yang,

Asymmetric Hydrogenation and Catalysis

The N-arylaminomethyl substituted pyrrolyl ligand 2-[(2,4,6-Me3C6H2)NHCH2](C4H3NH) (1) was synthesized by reduction of 2-[(2,4,6-Me3C6H2)NCH](C4H3NH) using NaBH4. Treatment of [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 with 1 equiv. of 1 in reflux toluene for 24 h, afforded the corresponding trivalent rare earth metal amides with formula {(μ-η5:η1):η1-2-[(2,4,6-Me3C6H2)NCH2]C4H3N]LnN(SiMe3)2}2 (Ln = Y(2), Nd(3), Sm(4), Dy(5), Er(6)). All compounds were fully characterised by spectroscopic methods and elemental analyses. The structures of complexes 2, 4 and 6 were determined by single-crystal X-ray analyses. X-Ray analyses discovered that two rare-earth metal ions were bridged by dianion ligand with the pyrrolyl ring which coordinated to one rare earth metal in an η5 mode, the tethered nitrogen anion and nitrogen atom of the pyrrolyl ring coordinated to another rare earth metal in η1 modes forming the centrosymmetric dinuclear structures. The rare earth metal complexes as catalysts for the guanylation of aromatic amines were studied. Results showed all rare earth metal complexes exhibited a high catalytic activity on the guanylation of aromatic amines.