Synthesis and characterization of cobalt SCS pincer complexes

Abstract

The synthesis and characterization of two Co(II) complexes stabilized by a tridentate SCS pincer ligand are described. Paramagnetic [Co(κ³-SCS^CH2-Et)₂] and [Co(κ³-SCS^CH2-tBu)(κ²-SCS^CH2-tBu)] were obtained via transmetalation protocol from CoBr₂ and S(C-Br)S^CH2-R (R = Et, tBu). Oxidation of the latter with [Cp₂Fe]PF₆ affords the diamagnetic 18 VE complex [Co(κ³-SCS^CH2-tBu)₂]PF₆. X-ray structures and DFT calculations are presented.

Supplementary information: The online version contains supplementary material available at 10.1007/s00706-022-02949-1.

Keywords: Cobalt; DFT; Pincer complex; Transmetalation.

Fig. 1

Structural view of 1 showing 50% displacement ellipsoids (H atoms omitted for clarity). Selected bond lengths [Å] and angles [°]: Co1-C1 1.9570(16), Co1-C13 1.9575(16), Co1-S1 2.3021(5), Co1-S2 2.2855(5), Co1-S3 2.4253(5), Co1-S4 2.4771(5), C1-Co1-C13 177.56(6), C1-Co1-S1 82.38(5)

Fig. 2

DFT-calculated frontier orbitals of [Co(κ³-SCS^CH2-Et)₂] (BP86/def2-SVP) and spin density plot

Fig. 3

Structural view of 2 showing 50% displacement ellipsoids (H atoms omitted for clarity). Selected bond lengths [Å] and angles [°]: Co1-C1 1.992(3), Co1-C11 1.985(3), Co1-S1 2.3185(8), Co1-S3 2.2257(8), Co1-S4 2.2553(8), C1-Co1-C11 177.67(11), S3-Co1-S4 135.11(3), S3-Co1-S1 124.72(3)