Stevan Simonovic

Publications (4)12.64 Total impact

• Article: Synthesis of Copper(I) Complexes of N‐Heterocyclic Carbene–Phenoxyimine/amine Ligands: Structures of Mononuclear Copper(II), Mixed‐Valence Copper(I)/(II), and Copper(II) Cluster Complexes

  Stevan Simonovic, Adrian C. Whitwood, William Clegg, Ross W. Harrington, Michael B. Hursthouse, Louise Male, Richard E. Douthwaite
  Berichte der deutschen chemischen Gesellschaft 03/2009; 2009(13):1786 - 1795. · 2.94 Impact Factor
• Article: Addition of N-heterocyclic carbenes to imines: phenoxide assisted deprotonation of an imidazolium moiety and generation of breslow intermediates derived from imines.

  Stevan Simonovic, Jean-Cédric Frison, Hasan Koyuncu, Adrian C Whitwood, Richard E Douthwaite
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  ABSTRACT: Reactions between imidazolium-imine salts and base result in C-C bond formation via intermediate N-heterocyclic carbenes. In the presence of a proximal OH moiety, carbene formation occurs via intramolecular deprotonation by phenoxide. For simple imines, a reactive Breslow-type intermediate gives access to new heterocycles with the formation of six- and seven-member rings.
  Organic Letters 01/2009; 11(1):245-7. · 5.86 Impact Factor
• Article: Synthesis and Structural Variation of Iron, Rhodium, Palladium, and Silver Complexes of a Chiral N-Heterocyclic Carbene−Phenoxyimine Hybrid Ligand

  Gavin Dyson, Jean-Cédric Frison, Stevan Simonovic, Adrian C. Whitwood, Richard E. Douthwaite
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  ABSTRACT: A new class of chiral N-heterocyclic carbene (NHC) precursors has been prepared incorporating a phenoxyimine moiety. Reaction between 3-((1R,2R)-2-{[1-(3,5-di-tert-butyl-2-hydroxyphenyl)meth-(E)-ylidene]amino}cyclohexyl)-1-isopropyl-4-phenyl-3H-imidazol-1-ium bromide [C(H)NO(H))][Br] (2a) and Pd(OAc)2 gives the complex [Pd(κ3-CNO)Br] (3), which exhibits tridentate ligand coordination via double deprotonation of 2a. The NHC ligand transfer agents [Ag(κ1-CNO(H))X] (X = Br (5a), Cl (5b)) are prepared from 2a, chloride analogue 2b, and Ag2O. Reaction between 5b and [Rh(COD)Cl]2 gives the NHC complex [Rh(κ1-CNO(H))Cl] (6) and, on chloride abstraction, the bidentate NHC-imine-coordinated complex [Rh(κ2-CNO(H))][B{3,5-(CF3)2C6H3}4] (7). For complexes 5 and 6 coordination of the phenoxyimine and deprotonation of the phenoxy moiety appear to be modified by intramolecular hydrogen bonding between hydroxyl and imine nitrogen groups. Reaction between 5a and Fe{N(SiMe3)2} gives an unusual bimetallic complex, [Fe(κ2-C(AgBr)NO)2] (8), that exhibits a 1-D polymeric chain motif in the solid state. Preliminary catalytic properties of an acetonitrile adduct of 3, [Pd(κ3-CNO)MeCN][BF4] (4), and 7 are reported for hydroamination and phenylation of enones, respectively, that show good activity but poor enantioselectivity.
  12/2007;
• Source

  Available from: york.ac.uk

  Article: Synthesis, structure and reactivity of palladium(II) complexes of chiral N-heterocyclic carbene-imine and -amine hybrid ligands.

  Ludovic G Bonnet, Richard E Douthwaite, Richard Hodgson, Jennifer Houghton, Benson M Kariuki, Stevan Simonovic
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  ABSTRACT: The synthesis and structures of chiral N-heterocyclic carbene (NHC)-N-donor complexes of silver(I) and palladium(II) are reported. The X-ray structure of an NHC-imine silver(I) complex [((nPr)CN(CHPh))AgBr](2) exhibits an Ag(2)Br(2) dimer motif where the imine group is not coordinated to the silver atom. Reaction between 2 and [PdCl(2)(MeCN)(2)] gives the palladium(II) complex [(kappa(2)-(nPr)CN(CHPh))PdCl(2)](3) that contains a chelating NHC-imine ligand as shown by single-crystal X-ray diffraction. Slow hydrolysis of related complexes [(kappa(2)-(nPr)CN(CHPh))PdCl(2)](3) and [(kappa(2)-((Ph)(2)CH)CN(CHPh))PdCl(2)](4) using triethylammonium chloride and water lead to the precipitation of single crystals of insoluble NHC-amino palladium(II) complexes [(kappa(2)-(nPr)CN(H(2)))PdCl(2)](6) and [(kappa(2)-((Ph)(2)CH)CN(H(2)))PdCl(2)](7), respectively. In the solid state, complexes 6 and 7 both exhibit intermolecular hydrogen bonding between chlorine and an amino-hydrogen atom resulting in an infinite chain structure. Substitution of an amino hydrogen for an ethyl group gives the soluble complex [(kappa(2)-(iPr)CN((H)Et))PdCl(2)](12). Reaction between two equivalents of 2 and [PdCl(2)(MeCN)(2)] gives the di-NHC complex [(kappa(1)-(nPr)CN(CHPh))(2)PdCl(2)](5) that does not contain a coordinated imine as shown by single crystal X-ray diffraction. Conproportionation between 5 and an equivalent of [PdCl(2)(MeCN)(2)] to does not occur at temperatures up to 100 degrees C in CD(3)CN.
  Dalton Transactions 12/2004; · 3.84 Impact Factor