The reactions of AlMe3 or AlEt3 with 2-pyridyl- or indolyl-substituted imines were studied, leading to the formation of different organoaluminum complexes. While the reactions of the iminopyridine Cy­[NCMe-2-(C5H4N)]2 (L 1 ) derived from 1-(pyridin-2-yl)­ethanone and trans-1,2-cyclohexanediamine with AlEt3 gave the aluminum complex Cy­[NC­(Me)­(Et)-2-(C5H4N)­AlEt2]2 (1), in which the two ketimine groups of the ligand were transformed into the amido functionality through the addition of two ethyl groups, the reaction of L 1 with AlMe3 afforded the aluminum complex Cy­[NC­(CH2)-2-(C5H4N)­AlMe2]2 (2) via a sp3 C–H activation with elimination of two methane molecules. The reactions of indolyl-2-aldimines (2-(RNCH)­C8H5NH (R = t Bu (L 2 H), C6H5 (L 3 H), 2,6-Me2C6H3 (L 4 H)) with AlMe3 or AlEt3 afforded only the deprotonated indolyl aluminum complexes [2-(RNCH)­C8H5N]­AlMe2 (R = t Bu (3), C6H5 (4), 2,6-Me2C6H3 (5)) and [2-(2,6-Me2C6H3NCH)­C8H5N]­AlEt2 (6), respectively. The structures of complexes 2–6 were characterized by spectral methods and X-ray crystallographic analyses. These aluminum complexes showed a high catalytic activity in the addition of amines to carbodiimides to form guanidines. The mechanism of the catalytic process was studied by control experiments and 1H NMR monitoring. Together with the isolation of the complex [2-(2,6-Me2C6H3NCH)­C8H5N]­[CyNC­(4-MeC6H3N)­(NHCy)]­AlMe (7), a probable mechanism for the guanylation reaction was proposed.

A series of structurally well-defined cationic rareearth metal bridged sandwich pyrrolyl rare-earth metal dialkyl complexes with the general formula of (Me 3 SiCH 2 ) 2 RE(μ- Gd (2a), Dy (3a), Er (4a), Yb (5a), Lu (6a), thf = tetrahydrofuran) were synthesized by the reactions of rare-earth metal trialkyl complexes RE(CH 2 SiMe 3 ) 3 (thf) 2 with 1 equiv of 2-(2,6-diisopropylphenylaminomethyl)pyrrole (H 2 L) in toluene at room temperature. When the reaction temperature was raised to 45 °C, the centrosymmetric half-sandwich pyrrolyl rare-earth metal alkyl complexes (Me 3 SiCH 2 RELthf) 2 (RE = Y (1b), Gd (2b), Yb (5b)) were obtained in good yields, unexpectedly. Further studies revealed that the sandwich pyrrolyl rare-earth metal dialkyl complexes can be transferred to the half-sandwich rare-earth metal isomers by heating the C 6 D 6 solution to 60 °C. Single-crystal Xray diffraction analyses revealed that the sandwich pyrrolyl rare-earth metal dialkyls were bridged by an octahedral cationic rare-earth metal coordinated by two N atoms of the pyrrolyl rings, two N atoms of the amido moieties, and two O atoms of the thf molecules; while in their isomers, the rare-earth metals were surrounded by a pyrrolyl ligand, an alkyl group, a molecule of thf, and an η 5 type of pyrrolyl ring. All complexes were characterized by spectroscopic methods, elemental analyses, and single-crystal X-ray analyses. Moreover, the catalytic behaviors of these complexes were investigated, and the results showed that, in the presence of cocatalysts, the dinuclear rare-earth metal alkyl complexes exhibited high activities and high regio-and stereoselectivities for isoprene polymerization with cis-1,4-units up to 96.6%.

Reactions of rare-earth metal amides [(Me 3 Si) 2 N] 3 RE(m-Cl)Li(THF) 3 with different equiv. of 2-(2,6-diisopropylphenylimino)-8-hydroxyquinoline (1) afforded different heterometallic rare-earth metal complexes, and catalytic activity of the resulting complexes was investigated. Reactions of rare-earth metal amides [(Me 3 Si) 2 N] 3 RE(m-Cl)Li(THF) 3 (RE = Y, Er, Dy) with 1 equiv. of compound 1 afforded the heterobimetallic rare-earth metal and lithium complexes 2-4 bridged by the oxygen atom of 2-(2,6-diisopropylphenylimino)-8-hydroxyquinoline and the nitrogen atom of N(SiMe 3 ) 2 . However, the treatment of rare-earth metal amides [(Me 3 Si) 2 N] 3 RE(m-Cl)Li(THF) 3 (RE = Sm, Er, Yb) with 2 equiv. of compound 1 gave different heterobimetallic rare-earth metal and lithium complexes 5-7 bridged by the oxygen atoms of 2-(2,6-diisopropylphenylimino)-8-hydroxyquinoline. Complex 6 can also be prepared by the treatment of 3 with 1 equiv. of 1. Complexes 2-7 were fully characterized using spectroscopic methods, elemental analyses and single crystal X-ray diffraction. Investigation of the catalytic properties of the complexes indicated that all complexes exhibited a high catalytic activity towards the addition of diphenylphosphine oxide to trans-b-nitroalkenes to afford b-nitrophosphonates under mild conditions.