Rare-earth metal ethylene and ethyne complexes

• Published in: Chemical science (Cambridge) Vol. 15; no. 1; pp. 3495 - 351
• Main Authors: Jiang, Wen, Rajeshkumar, Thayalan, Guo, Mengyue, Lin, Yuejian, Maron, Laurent, Zhang, Lixin
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 06.03.2024; The Royal Society of Chemistry
• Subjects: Ambient temperature; Chemical Sciences; Chemistry; Ethylene; Rare earth elements; Toluene; Yttrium
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d3sc06599e

Guanidinate homometallic rare-earth ethyl complexes [ L Ln( μ 2 - η 1 : η 2 -Et)(Et)] 2 (Ln = Y( 1-Y ), Lu( 1-Lu )) and heterobimetallic rare-earth ethyl complexes L Ln(Et)( μ 2 - η 1 : η 2 -Et)( μ 2 - η 1 -Et)(AlEt 2 ) (Ln = Y( 2-Y ), Lu( 2-Lu )) have been synthesized by the treatment of L Ln(CH 2 C 6 H 4 NMe 2 - o ) 2 ( L = (PhCH 2 ) 2 NC(NC 6 H 3 i Pr 2 -2,6) 2 ) with different equivalents of AlEt 3 in toluene at ambient temperature. Interestingly, the unprecedented rare-earth ethyne complex [ L Y( μ 2 - η 1 -Et) 2 (AlEt)] 2 ( μ 4 - η 1 : η 1 : η 2 : η 2 -C 2 H 2 ) ( 3-Y ) containing a [C 2 H 2 ] 4− unit was afforded from 2-Y . The formation mechanism study on 3-Y was carried out by DFT calculations. Furthermore, the nature of the bonding of 3-Y was also revealed by NBO analysis. The reactions of L Ln(CH 2 C 6 H 4 NMe 2 - o ) 2 (Ln = Y, Lu) with AlEt 3 (4 equiv.) in toluene at 50 °C produced firstly the non-Cp rare-earth ethylene complex L Y( μ 3 - η 1 : η 1 : η 2 -C 2 H 4 )[( μ 2 - η 1 -Et)(AlEt 2 )( μ 2 - η 1 -Et) 2 (AlEt)] ( 4-Y ), and the Y/Al ethyl complex L Y[( μ 2 - η 1 -Et) 2 (AlEt 2 )] 2 ( 5-Y ) as an intermediate of 4-Y was isolated from the reaction of L Y(CH 2 C 6 H 4 NMe 2 - o ) 2 with AlEt 3 (4 equiv.) in toluene at −10 °C. An unprecedented rare-earth ethyne complex is presented, and the α-H abstraction and C-C σ bond metathesis mechanism is proposed based on DFT calculations. The first example of a well-defined non-Cp rare-earth ethylene complex via the β-H abstraction reaction is also described herein.