Catalytic C-N bond formation in guanylation reaction by N-heterocyclic carbene supported magnesium(II) and zinc(II) amide complexes

The catalytic activity of N-heterocyclic carbene (NHC) supported magnesium(II) and a zinc(II) amide complex towards the addition of N-H bond of amine to carbodiimide was studied. Treatment of a free carbene i.e., 1,3-di-tert-butylimidazol-2-ylidene ((IBu)-Bu-t) with magnesium and zinc bis(amide) i.e., M [N(SiMe3)(2)](2), M = Mg or Zn in toluene led to the formation of (IBu)-Bu-t:M[N(SiMe3)(2)](2), M = Mg(1) and Zn(2) compounds, respectively. Both 1 and 2 were characterized by multinuclear (H-1, C-13 and Si-29) NMR spectroscopy and single X-ray crystal structure analysis. Solid state structures revealed that both complexes are monomeric in nature and their magnesium and zinc atoms are three coordinated and distorted trigonal planar in geometries. Furthermore, compounds 1 and 2 were tested as catalysts for the guanylation reaction of addition of amine to carbodiimide and turned to be excellent catalysts. (c) 2014 Elsevier B.V. All rights reserved.