Bis-o-semiquinonato cadmium(II) complexes with o-quinonato and N-heterocyclic carbene neutral ligands

The reaction of cadmium amalgam with excess of 3,6-di- tert -butyl- o -quinone (3,6-Q) in THF afforded the new bis- o -semiquinonato cadmium(II) complex coordinated with one molecule of neutral o -quinone (3,6-SQ) 2 Cd(3,6-Q) ( 1 ) acting as a starting reagent to other bis- o -semiquinonato cadmium(II) complex with N-heterocyclic carbene (NHC)–(3,6-SQ) 2 Cd{C[N(Ar)(CH)] 2 } (Ar = 2,6-dimethylphenyl) ( 2 ). Both complexes possess a singlet ground state with thermally accessible triplet state (the singlet-triplet gap is 8 cm − 1 for 1 and 132 cm − 1 for 2 ) as confirmed by magnetic data. The antiferromagnetic exchange SQ–SQ is observed for both complexes. The new bis- o -semiquinonato cadmium(II) complexes with o -quinonato and N-heterocyclic carbene neutral ligands were obtained. Both complexes possess a singlet ground state with thermally accessible triplet state as confirmed by the magnetic data. The antiferromagnetic exchange SQ–SQ is observed for both complexes. • New bis- o -semiquinonato cadmium(II) complexes with o -quinonato and N-heterocyclic carbene neutral ligands were synthesized. • Magnetic properties of obtained complexes were determined. • Molecular structure of (3,6-SQ)2Cd(3,6-Q) was confirmed by X-ray analysis.