Polar intermetallic compounds as catalysts for hydrogenation reactions: Synthesis, structures, bonding, and catalytic properties of Ca 1-xSrxNi4Sn2 (#=0.0, 0.5, 1.0) and catalytic properties of Ni3Sn and Ni3Sn2

Viktor Hlukhyy, Fabian Raif, Peter Claus, Thomas F. Fässler

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The potential of polar intermetallic compounds to catalyze hydrogenation reactions was evaluated. The novel compounds CaNi4Sn2, SrNi4Sn2, and Ca0.5Sr0.5Ni 4Sn2 were tested as unsupported alloys in the liquid-phase hydrogenation of citral. Depending on the reaction conditions, conversions of up to 21.0% (253 K and 9.0 MPa hydrogen pressure) were reached. The binary compounds Ni3Sn and Ni3Sn2 were also tested in citral hydrogenation under the same conditions. These materials gave conversions of up to 37.5%. The product mixtures contained mainly geraniol, nerol, citronellal, and citronellol. The isotypic stannides CaNi4Sn 2, Ca0.5Sr0.5Ni4Sn2, and SrNi4Sn2 were obtained by melting mixtures of the elements in an arc-furnace under an argon atmosphere. Single crystals were synthesized in tantalum ampoules using special temperature modes. The novel structures were established by single-crystal X-ray diffraction. They crystallize in the tetragonal space group I4/mcm with parameters: a = 7.6991(7), c = 7.8150(8)Å, wR2 = 0.034, 162 F2 values, 14 variable parameters for CaNi4Sn2; a = 7.7936(2), c = 7.7816(3)Å, wR2 = 0.052, 193 F2 values, 15 variable parameters for Ca 0.5Sr0.5Ni4Sn2; and a = 7.8916(4), c = 7.7485(5) Å, wR2 = 0.071, 208 F2 values, 14 variable parameters for SrNi4Sn2. The Ca1-xSr xNi4Sn2 (x = 0.0, 0.5, 1.0) structures can be represented as a stuffed variant of the CuAl2 type by the formal insertion of one-dimensional infinite Ni-cluster chains [Ni4] into the Ca(Sr)Sn2 substructure. The Ni and Sn atoms form a three-dimensional infinite [Ni4Sn2] network in which the Ca or Sr atoms fill distorted octagonal channels. The densities of states obtained from TB-LMTO-ASA calculations show metallic character for both compounds.

Original languageEnglish
Pages (from-to)3737-3744
Number of pages8
JournalChemistry - A European Journal
Volume14
Issue number12
DOIs
StatePublished - 18 Apr 2008

Keywords

  • Calcium
  • Crystal structure
  • Hydrogenation catalysts
  • Intermetallic compounds
  • Strontium

Fingerprint

Dive into the research topics of 'Polar intermetallic compounds as catalysts for hydrogenation reactions: Synthesis, structures, bonding, and catalytic properties of Ca 1-xSrxNi4Sn2 (#=0.0, 0.5, 1.0) and catalytic properties of Ni3Sn and Ni3Sn2'. Together they form a unique fingerprint.

Cite this