Mercury(II) Complexes of Anionic N -Heterocyclic Carbene Ligands: Steric Effects of the Backbone Substituent

• Published in: Molecules (Basel, Switzerland) Switzerland), 2020-08, Vol.25 (16), p.3741
• Main Authors: Dash, Chandrakanta, Das, Animesh, Dias, H V Rasika
• Format: Article
• Language: English
• Subjects: Acids; Backbone; Carbenes; Carbon; Chromatography; Crystal structure; Crystallography, X-Ray; Heterocyclic Compounds - chemistry; Infrared analysis; Infrared spectroscopy; Ligands; Mercuric chloride; Mercury; Mercury - chemistry; Mercury compounds; mercury(II) complex; Methane - analogs & derivatives; Methane - chemistry; Models, Molecular; Molecular Structure; N-heterocyclic carbene; NMR; Nuclear magnetic resonance; Potassium; Potassium salts; Salts; Stereoisomerism; Steric effects; T shape; T-shaped; X-ray
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules25163741

Mercury(II) complexes (Me-maloNHC )HgCl ( ), ( -Bu-maloNHC )HgCl ( ) and ( -Bu-maloNHC )HgMe ( ) supported by anionic -heterocyclic carbenes have been obtained in good yields from the reaction of the potassium salt of -heterocyclic carbene ligand precursors and mercury(II) salts, HgCl and MeHgI. These molecules have been characterized by H-NMR, C-NMR and IR spectroscopy and elemental analysis. X-ray crystal structures of and are also presented. Interestingly, complex is polymeric {(Me-maloNHC )HgCl} in the solid state, as a result of inter-molecular Hg-O contacts, and features rare three coordinate mercury sites with a T-shaped arrangement, whereas the ( -Bu-maloNHC )HgCl ( ) is monomeric and has a linear, two-coordinate mercury center. The formation of T-shaped structure and the aggregation of complex is attributable to the reduced steric demand of the -heterocyclic carbene ligand backbone substituent.