Indium(III) chloride

Chembox new
Name = Indium(III) chloride
ImageName = Indium(III) chloride
OtherNames = Indium Chloride
Section1 = Chembox Identifiers
CASNo = 10025-82-8
Section2 = Chembox Properties
Formula = Cl₃In
MolarMass = 221.18 g/mol
Appearance = white flakes
Density = 3.46 g/cm³, solid
Solubility = soluble, exothermic
Solvent = other solvents
SolubleOther = THF
MeltingPt = 586 °C
BoilingPt = 800 °C
(sublimes 498 °C
in a vacuum)
Section7 = Chembox Hazards
EUClass = not listed
NFPA-H = 2
NFPA-R = 0
NFPA-F = 0

Indium(III) chloride is the chemical compound with the formula InCl₃. This colorless salt finds some use in organic synthesis as a Lewis acid. It is also the most available soluble derivatives of indium. [Araki, S.; Hirashita, T. "Indium trichloride" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.]

ynthesis and structure

Being a relatively electropositive metal, indium reacts readily with chlorine to give the trichloride. A synthesis has been reported using an electrochemical cell in a mixed methanol-benzene solution. [Habeeb, J. J.; Tuck, D. G. "Electrochemical Synthesis of Indium(III) Complexes" Inorganic Syntheses, 1979, volume XIX, ISBN 0-471-04542-X]

Like AlCl₃ and TlCl₃, InCl₃ crystallizes as a layered structure consisting of close-packed chloride arrangement containing layers of In(III) centers. The motif is akin to that seen for YCl₃. [Wells, A.F. Structural Inorganic Chemistry, Oxford: Clarendon Press, 1984. ISBN 0-19-855370-6.] In contrast, GaCl₃ and InI₃ crystallize as dimers containing Ga₂Cl₆ and In₂I₆ subunits, respectively.

Catalyst in chemistry

Indium chloride is a lewis acid catalyst in organic reactions such as Friedel-Crafts acylations and Diels-Alder reactions. As an example of the latter ["An efficient synthesis of novel pyrano [2,3-d] - and furopyrano [2,3-d] pyrimidines via Indium-Catalyzed Multicomponent Domino Reaction" Prajapati, D. Mukut Gohain, M. Journal of Organic Chemistry 2006, 2:11 doi|10.1186/1860-5397-2-11] The reaction proceeds at room temperature, with 1 mole% catalyst loading in an acetonitrile-water solvent mixture. The first step is a Knoevenagel condensation between the barbituric acid and the aldehyde, the second step is a reverse electron-demand Diels-Alder reaction.

:

which is a multicomponent reaction of N.N'-dimethyl-barbituric acid, benzaldehyde and ethyl vinyl ether. With catalyst the reported chemical yield is 90% and the percentage trans isomer is 70%. Without the catalyst added the yield drops to 65% with 50% trans product.

References