Jump to main content
Jump to site search


Synthesis of quinolinyl-based pincer copper(II) complexes: an efficient catalyst system for Kumada coupling of alkyl chlorides and bromides with alkyl Grignard reagents

Author affiliations

Abstract

Quinolinamide-based pincer copper(II) complexes, κNNN-{C9H6N-(μ-N)-C(O)CH2NEt2}CuX [(QNNNEt2)CuX (X = Cl, 2; X = Br, 3; X = OAc, 4)], were synthesized by the reaction of ligand (QNNNEt2)-H (1) with CuX2 (X = Cl, Br or OAc) in the presence of Et3N. The reaction of (QNNNEt2)-H with CuX (X = Cl, Br or OAc) also afforded the Cu(II) complexes 2, 3 and 4, respectively, instead of the expected Cu(I) pincer complexes. The formation of Cu(II) complexes from Cu(I) precursors most likely occurred via the disproportionation reaction of Cu(I) into Cu(0) and Cu(II). A cationic complex [(QNNNEt2)Cu(CH3CN)]OTf (5) was synthesized by the treatment of neutral complex 2 with AgOTf. On the other hand, the reaction of (QNNNEt2)-H (1) with [Cu(MeCN)4]ClO4 produced cationic Cu(I) complex, [(QNN(H)NEt2)Cu(CH3CN)]ClO4 (6), in good yield. All complexes 2–5 were characterized by elemental analysis and HRMS measurements. Furthermore, the molecular structures of 2, 3 and 4 were elucidated by X-ray crystallography. Complex 4 crystallizes in a dimeric and catemeric pattern. The cationic complex 5 was found to be an efficient catalyst for the Kumada coupling reaction of diverse nonactivated alkyl chlorides and bromides with alkyl magnesium chloride under mild reaction conditions.

Graphical abstract: Synthesis of quinolinyl-based pincer copper(ii) complexes: an efficient catalyst system for Kumada coupling of alkyl chlorides and bromides with alkyl Grignard reagents

Back to tab navigation

Supplementary files

Publication details

The article was received on 06 Aug 2018, accepted on 19 Oct 2018 and first published on 19 Oct 2018


Article type: Paper
DOI: 10.1039/C8DT03210F
Citation: Dalton Trans., 2018, Advance Article
  •   Request permissions

    Synthesis of quinolinyl-based pincer copper(II) complexes: an efficient catalyst system for Kumada coupling of alkyl chlorides and bromides with alkyl Grignard reagents

    H. Pandiri, R. G. Gonnade and B. Punji, Dalton Trans., 2018, Advance Article , DOI: 10.1039/C8DT03210F

Search articles by author

Spotlight

Advertisements