Karstedt's catalyst

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Karstedt's catalyst
KartstedtCatalyst.png
Identifiers
Properties
C24H54O3Pt2Si6
Molar mass 949.4 g/mol
Appearance colorless solid
Density 1.74 g/cm3
Melting point 12 to 13 °C (54 to 55 °F; 285 to 286 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Karstedt's catalyst is an organoplatinum compound derived from divinyl-containing disiloxane. This coordination complex is widely used in hydrosilylation catalysis. It is a colorless solid that is generally assumed to be a mixture of related Pt(0) alkene complexes.[1][2] The catalyst is named after Bruce D. Karstedt, who developed it in the early 1970s while working for General Electric.[3]

Applications[edit]

Carbon-silicon bonds are created via hydrosilylation reactions. This reaction has very important applications to industry. While it is favorable thermodynamically, hydrosilylation does not proceed in the absence of a catalyst. It is produced by treatment of chloroplatinic acid by the divinyltetramethyldisiloxane.

The catalyst can also be used in a reductive amination reaction between a carboxylic acid and an amine with phenylsilane as the reducing agent.[4]

Structure and bonding[edit]

The oxidation state of the platinum is 0. Using X-ray crystallography, the structure of the complex Pt2[(Me2SiCH=CH2)2O]3 has been confirmed. Each Pt(0) center is surrounded by three alkene ligands. The Pt center and six coordinated carbon atoms are approximately coplanar, as found for simpler complexes such as Pt(C2H4)3.[5]

References[edit]

  1. ^ Lewis, Larry N.; Stein, Judith; Gao, Yan; Colborn, Robert E.; Hutchins, Gudrun (1997). "Platinum catalysts used in the silicones industry" (PDF). Platinum Metals Review. 41 (2): 66–74. 
  2. ^ Stein, Judith; Lewis, L. N.; Gao, Y.; Scott, R. A. "In Situ Determination of the Active Catalyst in Hydrosilylation Reactions Using Highly Reactive Pt(0) Catalyst Precursors". Journal of the American Chemical Society. 121 (15): 3693–3703. doi:10.1021/ja9825377. 
  3. ^ US Patent 3775452, Bruce D. Karstedt, "Platinum complexes of unsaturated siloxanes and platinum containing organopolysiloxanes", published 1973-11-27, assigned to General Electric 
  4. ^ Sorribes, Iván; Junge, Kathrin; Beller, Matthias (29 September 2014). "Direct Catalytic N-Alkylation of Amines with Carboxylic Acids". Journal of the American Chemical Society: 140929125004007. doi:10.1021/ja5093612. 
  5. ^ Hitchcock, Peter B.; Lappert, Michael F.; Warhurst, Nicholas J. W. "Synthesis and Structure of arac-Tris(divinyldisiloxane) diplatinum(0) Complex and its Reaction with Maleic Anhydride". Angewandte Chemie International Edition in English. 30 (4): 438–440. doi:10.1002/anie.199104381.