Indium(III) chloride
Indium(III) chloride is the chemical compound with the formula Template:Chem2 which forms a tetrahydrate. This salt is a white, flaky solid with applications in organic synthesis as a Lewis acid. It is also the most available soluble derivative of indium.[1] This is one of three known indium chlorides.
Synthesis and structure
Being a relatively electropositive metal, indium reacts quickly with chlorine to give the trichloride. Indium trichloride is very soluble and deliquescent.[2] A synthesis has been reported using an electrochemical cell in a mixed methanol-benzene solution.[3]
Like [[Aluminium chloride|Template:Chem2]] and [[Thallium(III) chloride|Template:Chem2]], Template:Chem2 crystallizes as a layered structure consisting of a close-packed chloride arrangement containing layers of octahedrally coordinated In(III) centers,[4] a structure akin to that seen in [[Yttrium(III) chloride|Template:Chem2]].[5] In contrast, [[Gallium trichloride|Template:Chem2]] crystallizes as dimers containing Template:Chem2.[5] Molten Template:Chem2 conducts electricity,[4] whereas Template:Chem2 does not as it converts to the molecular dimer, Template:Chem2.[6]
Reactions
Template:Chem2 is a Lewis acid and forms complexes with donor ligands, L, Template:Chem2, Template:Chem2, Template:Chem2. For example, with the chloride ion it forms tetrahedral Template:Chem2, trigonal bipyramidal Template:Chem2, and octahedral Template:Chem2.[4]
In diethyl ether solution, Template:Chem2 reacts with lithium hydride, LiH, to form lithium tetrahydroindate(III) Template:Chem2. This unstable compound decomposes below 0 °C,[7] and is reacted in situ in organic synthesis as a reducing agent[8] and to prepare tertiary amine and phosphine complexes of [[indigane|Template:Chem2]].[9]
Trimethylindium, Template:Chem2, can be produced by reacting Template:Chem2 in diethyl ether solution either with the Grignard reagent methylmagnesium iodide Template:Chem2 or methyllithium Template:Chem2. Triethylindium can be prepared in a similar fashion but with the grignard reagent EtMgBr.[10]
Template:Chem2 reacts with indium metal at high temperature to form the lower valent indium chlorides Template:Chem2, Template:Chem2 and InCl.[4]
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,[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 the 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
Template:Indium compounds Template:Chlorides
- ↑ Araki, S.; Hirashita, T. "Indium trichloride" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. Script error: No such module "doi"..
- ↑ Indium Trichloride
- ↑ Habeeb, J. J.; Tuck, D. G. "Electrochemical Synthesis of Indium(III) Complexes" Inorganic Syntheses, 1979, volume XIX, Template:ISBN
- ↑ a b c d Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier Template:ISBN
- ↑ a b Wells, A.F. Structural Inorganic Chemistry, Oxford: Clarendon Press, 1984. Template:ISBN.
- ↑ Template:Greenwood&Earnshaw
- ↑ Script error: No such module "citation/CS1".
- ↑ Main Group Metals in Organic Synthesis vol 1, ed. Hisashi Yamamoto, Koichiro Oshima, Wiley VCH, 2004, Template:ISBN
- ↑ The Group 13 Metals Aluminium, Gallium, Indium and Thallium: Chemical Patterns and Peculiarities, Simon Aldridge, Anthony J. Downs, Wiley, 2011, Template:ISBN
- ↑ Main Group compounds in Inorganic Syntheses, vol 31, By Schultz, Neumayer, Marks; Ed., Alan H. Cowley, John Wiley & Sons, Inc., 1997, Template:ISBN
- ↑ 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. Beilstein Journal of Organic Chemistry 2006, 2:11 Script error: No such module "doi".