Peter C. Kunz

Publications (52) View all

• Article: Tricarbonyl[tris(1-methyl-1H-imidazol-2-yl-κN(3))methanol]manganese(I) trifluoromethanesulfonate.

  Guido J Reiss, Peter C Kunz
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  ABSTRACT: In the title compound, [Mn(C(13)H(16)N(6)O)(CO)(3)](CF(3)O(3)S), the Mn(I) atom has a slightly distorted octa-hedral geometry. The three CO ligands have C-Mn-C angles in the range 89.44 (10)-92.31 (9)°, while the three N atoms of the tripodal ligand form significantly smaller N-Mn-N angles of 82.76 (2)-85.51 (6)°. The three N atoms of the tripodal ligand and the three carbonyl ligands coordinate facially. In the crystal, the trifluoro-methane-sulfonate counter anion is connected by a medium-strength O-H⋯O hydrogen bond to the hydroxyl group of the manganese complex.
  Acta Crystallographica Section E Structure Reports Online 09/2012; 68(Pt 9):m1202-3. · 0.35 Impact Factor
• Article: Stabilisation of water-soluble platinum nanoparticles by phosphonic acid derivatives.

  Mareike Richter, Arndt Karschin, Bernhard Spingler, Peter C Kunz, Wolfgang Meyer-Zaika, Wolfgang Kläui
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  ABSTRACT: Sodium 2-(diphenylphosphino)ethyl phosphonate (1) was investigated as a stabilising agent for platinum nanoparticles (Pt-NPs) in aqueous solution. This phosphino phosphonate is known to stabilise rhodium nanoparticles (NPs) in water. Here we report that in the case of Pt-NPs this ligand is indirectly involved in the stabilisation mechanism and the actual stabilisation agent is the platinum complex Na(2)[Pt(1)(2)] (2). The reduction of platinum(II) salts in the presence of the phosphonates 1, 2, sodium 2-(diphenylphosphoryl)ethyl phosphonate (3) and 3,3,3-triphenylpropyl phosphonate (4) leads to stable platinum NPs with a remarkably narrow particle size distribution. These platinum NPs show high catalytic activity in the hydrogenation of 1-hexene and 1-chloro-3-nitrobenzene under biphasic as well as heterogeneous (supported on charcoal) conditions. The activity of the supported NPs was 30 times higher than the commercially available catalyst Pt(0) EnCat®. Furthermore, the single-crystal X-ray structures of (1)(MeOH)(2)(H(2)O)(2), (3)(H(2)O)(4), and (4)(2)(H(2)O)(17) have been determined.
  Dalton Transactions 03/2012; 41(12):3407-13. · 3.84 Impact Factor
• Source

  Available from: PubMed Central

  Article: (Picolinato-κN,O)[tris(2-isopropyl-1H-imidazol-4-yl-κN)phosphane]cobalt(II) nitrate.

  Guido J Reiss, Markus Börgardts, Peter C Kunz
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  ABSTRACT: Single crystals of the title compound, [Co(C(6)H(4)NO(2))(C(18)H(27)N(6)P)]NO(3), were obtained from the reaction of nitrato[tris-(2-isopropyl-imidazol-4-yl)phosphane]cobalt(II) nitrate with picolinic acid in the presence of potassium tert-butoxide as base. The coordination polyhedron around the central Co(II) ion is about halfway between square-pyramidal and trigonal-bipyramidal geometry. In the structure, the nitrate counter-anion is connected by N-H⋯O hydrogen bonding to the complex cation. Additionally, the complex cations form one-dimensional chains along [010] by hydrogen bonding of the NH group of an imidazole ring to the picolinate group of a neighbouring complex cation.
  Acta Crystallographica Section E Structure Reports Online 03/2012; 68(Pt 3):m265-6. · 0.35 Impact Factor
• Article: Structural flexibility in complexes bearing a tripodal nitrogen ligand

  Peter C. Kunz, Markus Börgardts, Fabian Mohr
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  ABSTRACT: Complexes of the divalent metal ions of zinc, cobalt and nickel and a tripodal imidazol-based ligand were investigated for their solution chemistry in protic solvents of varying steric demand. Changes in the coordination number from 4 to 6 are observed depending on solvents, temperature and ions present in solution. With bio-relevant N,O ligands, e.g. amino acids as glycine and alanine, five-coordinate complexes are formed. The solid state structures of the five-coordinate complexes [LNi(H2O)Cl]Cl (3a0) and [LZn(pic)]NO3 (L = tris(2-isopropylimidazol-4(5)-yl)phosphane, pic = picolinato) were determined.
  Inorganica Chimica Acta 01/2012; 380:392-398. · 1.85 Impact Factor
• Source

  Available from: Louisa Noffke

  Article: Ruthenium piano-stool complexes bearing imidazole-based PN ligands

  Peter C. Kunz, Indre Thiel, Anna Louisa Noffke, Guido J. Reiß, Fabian Mohr, Bernhard Spingler
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  ABSTRACT: A variety of piano-stool complexes of cyclopentadienyl ruthenium(II) with imidazole-based PN ligands have been synthesized starting from the precursor complexes [CpRu(C10H8)]PF6, [CpRu(NCMe)3]PF6 and [CpRu(PPh3)2Cl]. PN ligands used are imidazol-2-yl, -4-yl and -5-yl phosphines. Depending on the ligand and precursor different types of coordination modes were observed; in the case of polyimidazolyl PN ligands these were k1P-monodentate, k2P,N-, k2N,N- and k3N,N,N- chelating and m-kP:k2N,N-brigding. The solid-state structures of [CpRu(1a)2Cl ]$H2O (5.H2O) and [{CpRu(m-k2-N,N-k’1-P-2b)}2](C6H5PO3H)2(C6H5PO3H2)2, a hydrolysis product of the as well deter- mined [{CpRu(2b)}2](PF6).22CH3CN (7b.2CH3CN) were determined (1a 1⁄4 imidazol-2-yldiphenyl phosphine, 2b 1⁄4 bis(1-methylimidazol-2-yl)phenyl phosphine, 3a 1⁄4 tris(imidazol-2-yl)phosphine). Furthermore, the complexes [CpRu(L)2]PF6 (L 1⁄4 imidazol-2-yl or imidazol-4-yl phosphine) have been screened for their catalytic activity in the hydration of 1-octyne.
  Journal of Organometallic Chemistry 01/2012; 697:33-40. · 2.38 Impact Factor