Jump to main content
Jump to site search

Issue 8, 2017
Previous Article Next Article

Palladacycles of sulfated and selenated Schiff bases of ferrocene-carboxaldehyde as catalysts for O-arylation and Suzuki–Miyaura coupling

Author affiliations

Abstract

Schiff base ligands (L1: sulfated and L2: selenated) having a ferrocene core synthesized by reacting ferrocene-carboxaldehyde with 2-(phenylthio/seleno)ethylamine on treatment with Na2PdCl4 in the presence of NaOAc give cyclopalladated complexes [Pd(L1/L2-H)Cl] (1/2). Complex 1 of a sulfated Schiff base L1, on reacting with one equivalent of triphenylphosphine gives complex [Pd(L1-H)PPh3Cl] (3), formed due to cleavage of a Pd–S bond. With 2 such a reaction does not occur, as a Pd–Se bond being stronger than that of its sulfur analogue does not get cleaved. L1, L2 and their complexes 1–3 were authenticated with HR-MS, 1H, 13C{1H} and 77Se{1H} NMR spectroscopy. The single crystal structures of 1–3 were determined with X-ray diffraction. Palladium in all three complexes has nearly a square planar geometry. The Pd–S, Pd–Se and Pd–P bond distances are 2.4249(12), 2.5058(14) and 2.2445(17) Å respectively. The catalytic activity of complexes 1–3 was explored for O-arylation of phenol and Suzuki–Miyaura coupling (SMC) of phenylboronic acid with aryl bromides and chlorides. The optimum reaction time for SMC of ArBr is 3 h whereas for ArCl it is 6 h. The TON values of O-arylation catalyzed with complexes 1–3 are up to ∼170 (TOF, 28 h−1) and SMC ∼9300 (TOF, 3100 h−1) for the reaction time of the order of 3 and 6 h respectively. The catalytic process is somewhat more efficient with 2 (Pd bonded with a selenoether group), than 3, followed by 1.

Graphical abstract: Palladacycles of sulfated and selenated Schiff bases of ferrocene-carboxaldehyde as catalysts for O-arylation and Suzuki–Miyaura coupling

Back to tab navigation

Supplementary files

Publication details

The article was received on 10 Jan 2017, accepted on 17 Jan 2017 and first published on 17 Jan 2017


Article type: Paper
DOI: 10.1039/C7DT00083A
Citation: Dalton Trans., 2017,46, 2485-2496
  •   Request permissions

    Palladacycles of sulfated and selenated Schiff bases of ferrocene-carboxaldehyde as catalysts for O-arylation and Suzuki–Miyaura coupling

    A. K. Sharma, H. Joshi, R. Bhaskar, S. Kumar and A. K. Singh, Dalton Trans., 2017, 46, 2485
    DOI: 10.1039/C7DT00083A

Search articles by author

Spotlight

Advertisements