Synthesis, Structure, and Diverse Catalytic Activities of [Ethylenebis(indenyl)]lanthanide(III) Amides on N−H and C−H Addition to Carbodiimides and ε-Caprolactone Polymerization

Abstract

The simple silylamine elimination reaction of ethylenebis(indene) with the lanthanide amides [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 produced the [ethylenebis(η 5-indenyl)][bis(trimethylsilyl)amido]lanthanide(III) complexes (EBI)LnN(TMS)2 (Ln = Y (1), Sm (2), Yb (3)), which exhibited diverse catalytic activities on the addition of the N−H bond of amines and the C−H bond of terminal alkynes to the carbodiimides and on the ring-opening polymerization of ε-caprolactone as well. The new complexes 1 and 2 were fully characterized by spectroscopic methods, elemental analyses, and X-ray crystallographic analyses. This work offers a straightforward, highly atom efficient route for the syntheses of substituted guanidines and propiolamidines, and it represents the first application of readily accessible lanthanocene amides to these reactions.

Versatile Reactivity of Half‐Sandwich Ir and Rh Complexes toward Carboranylamidinates and Their Derivatives: Synthesis, Structure, and Catalytic Activity for Norbornene Polymerization

“…The NMR data indicate that the two isopropyl groups are located in different chemical environments, in contrast to simple amidines. [15] The 11 B NMR spectrum exhibits signals at À1.7, À5.0, and À9.8 ppm in the ratio of 1:1:8. These spectroscopic data and elemental analysis for C, H, and N indicated the formation of [Cp*IrCl-A C H T U N G T R E N N U N G (Cab N -DIC)] (1 a).…”

Synthesis, structure and reactivity of samarium complexes supported by Schiff-base ligands

“…Recently, catalytic guanylation of amines with carbodiimides provides a convenient approach to guanidines and has attracted increasing attention [39][40][41][42][43][44][45][46][47]. Therefore, in order to further reveal the catalytic activity of homoleptic Schiff-base complexes of lanthanides, we tested the catalytic activity of complexes 1-3 for guanylation of aniline with N,N-diisopropylcarbodiimide with 5 mol% catalyst loading ( Table 4).…”

A single active site metal center of neodymocene chloride for the ring‐opening polymerization of ε‐caprolactone

“…The intrinsic viscosity [g] of PCL was determined in DME at 30 C with an Ubbelohde viscometer. The viscosity-average molecular weight (M g ) was calculated by the following equation 35 :…”

“…Lanthanide alkoxides were reported by Mclain, Drysdale 14 and Shen et al [15][16][17][18] to be active catalysts to initiating e-CL polymerization with high conversion (up to 100%). The catalytic activity of rare earth halides can be increased greatly by addition of epoxide ([NdCl 3 ] ¼ 3.0 Â 10 À3 mol/L, Propylene Oxide/ NdCl 3 ¼ 20, 30 C, 4 h, conversion ¼ 100%, M w ¼ 2.21 Â 10 5 ). 19 Rare earth phenyl derivatives compound, 2,6-dialkoxylphenyl lanthanoide complexes 20 or 2-methyphenyl samarium, 21 can initiate the polymerization of e-CL with high activities.…”

“…Rare earth compounds with Ln-N bonds ({(MeC 5 27,28 have reported that (C 9 H 7 ) 2 Sm(THF) x and (C 13 H 9 ) 2 Sm(THF) 2 showed much higher activities than (C 5 Me 5 ) 2 Sm(THF) x in e-CL polymerization in THF, which may be caused by the former two complexes having more open coordination environments around the metals. Most of the rare earth compounds described above have r-bonds of the type LnAO, LnAC, LnAH, LnAN, and LnAB recently reported, [29][30][31][32] which may play the key role in initiation of e-CL polymerization. However, there is no example of germyl bridged rare earth metallocene halides in literature for the polymerization of e-CL.…”