Ytterbium (III) chloride

Crystal structure
__ Yb 3+      __ Cl -
General
Surname	Ytterbium (III) chloride
Ratio formula	YbCl 3
Brief description	colorless solid
External identifiers / databases
CAS number 10361-91-8 10035-01-5 (hexahydrate) PubChem 61510 Wikidata Q415548
properties
Molar mass	279.40 g mol −1 (anhydrous) 387.49 g mol −1 (hexahydrate)
Physical state	firmly
density	2.57 g cm −3
Melting point	703 ° C
boiling point	1900 ° C
solubility	soluble in water
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Ytterbium (III) chloride is an inorganic chemical compound of ytterbium and is one of the chlorides . In addition to this, another ytterbium chloride is known with ytterbium (II) chloride .

Extraction and presentation

Ytterbium chloride is made by reacting ytterbium (III) oxide with either carbon tetrachloride or hot hydrochloric acid.

${\displaystyle \mathrm {2\ Yb_{2}O_{3}+3\ CCl_{4}\longrightarrow 4\ YbCl_{3}+3CO_{2}} }$

${\displaystyle \mathrm {Yb_{2}O_{3}+6\ HCl\longrightarrow 2\ YbCl_{3}+3\ H_{2}O} }$

The anhydrous compound is produced by heating the water-containing compound in a stream of HCl at a slowly increasing temperature. At 350 ° C the substance is anhydrous.

properties

Ytterbium (III) chloride

Ytterbium (III) chloride crystallizes in a cubic aluminum chloride layer structure. Smaller units such as [YbCl ₆ ] ³⁻ or Yb ₂ Cl ₆ are formed in the gas phase .

use

Catalyst in organic chemistry

Ytterbium (III) chloride acts as a Lewis acid due to the single unpaired f-electron . This enables the compound to form complexes in transition states and thus to catalyze alkylation reactions such as aldol reactions and the Pictet-Spengler reaction .

Aldol reaction

In the aldol reaction , ytterbium (III) chloride serves as an auxiliary catalyst in the palladium- catalyzed decarboxylating aldol reaction of an enolate with an aldehyde . The transition states A and B show the coordination of the ytterbium salt. For the decarboxylating aldol reaction described above with R = tert -butyl and R '= - (CH ₂ ) ₂ Ph, the comparison of the yields of different Lewis acids shows a particularly high yield for ytterbium (III) chloride.

salt	% Yield of 2
Iron (III) chloride	40
Zinc chloride	68
Copper (II) chloride	40
Lanthanum (III) chloride	60
Ytterbium (III) chloride	93

Pictet-Spengler reaction

As a Lewis acid, ytterbium (III) chloride catalyzes the Pictet-Spengler reaction to obtain tetrahydro- beta-carbolines , from which synthetic indole alkaloids are produced. It enables high yields and reduces the reaction time from days to 24 hours.

Ester formation

The small size of the Yb ³⁺ ion enables rapid catalysis, but the selectivity is low. For example, the mono- acetylation of meso - 1,2-diols is fastest with ytterbium (III) chloride in two hours, whereas the chemoselectivity for the monoacetylated product is 50% low compared to cerium (III) chloride (23 h response time, 85%).

Acetal formation

Ytterbium (III) chloride is a powerful catalyst for acetal formation with trimethyl orthoformate . Compared with cerium (III) chloride and erbium (III) chloride , the ytterbium salt is the most effective. It achieves high yields in a rapid reaction at room temperature with a wide variety of aldehydes.

NMR shift reagent

Ytterbium can be used as an NMR shift reagent , for example in membrane biology for tracking the movements of ³⁹ K ⁺ and ²³ Na ⁺ , which play an important role in nerve signals .

Individual evidence

1. ↑ ^{a b c} data sheet ytterbium (III) chloride from AlfaAesar, accessed on February 28, 2012 ( PDF )(JavaScript required) .
2. ↑ Data sheet Ytterbium (III) chloride hexahydrate, 99.9999% trace metals basis from Sigma-Aldrich , accessed on March 25, 2012 ( PDF ).
3. ↑ ^{a b} David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Properties of the Elements and Inorganic Compounds, pp. 4-99.
4. ^ ^{A b} John Harris, Walter Benenson, Horst Stöcker: Handbook of physics. Springer, 2002, ISBN 0-387-95269-1 , p. 781 ( limited preview in the Google book search).
5. ↑ VF Goryushkin, SA Zalymova, AI Poshevneva. In: Russ. J. Inorg. Chem. 1990, 35, 12, pp. 1749-1752.
6. ↑ Joerg Sebastian, Hans-Joachim Seifert: Ternary chlorides in the systems ACl / YbCl ₃ (A = Cs, Rb, K). In: Thermochimica Acta. 318, 1998, pp. 29-37, doi : 10.1016 / S0040-6031 (98) 00326-8 .
7. ↑ G. Jantsch, N. Skalla, H. Jawurek: “To the knowledge of the halides of the rare earths. V. - About the halides of ytterbium ”, in: Journal for inorganic and general chemistry , 1931 , 201 , pp. 207–220; doi : 10.1002 / zaac.19312010119 .
8. ↑ Wei-Jyh Gau: Electrochemical and Spectroscopic Studies of ytterbium in the Aluminum Chloride-1-methyl-3-ethylimidazolium chlorides Room Temperature Molten Salt. In: Journal of The Electrochemical Society. 143, 1996, pp. 170-174, doi : 10.1149 / 1.1836403 .
9. ↑ AD Chervonnyi, NA Chervonnaya: Thermodynamic Properties of ytterbium chloride. In: Russian Journal of Inorganic Chemistry. 2004, 49, 12, pp. 1889–1897 ( Abstract ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove it Note. ). 
10. ↑ ^{a b c} Sha Lou, John A. Westbrook, Scott E. Schaus: Decarboxylative Aldol Reactions of Allyl β-Keto Esters via Heterobimetallic Catalysis. In: Journal of the American Chemical Society. 126, 2004, pp. 11440-11441, doi : 10.1021 / ja045981k .
11. ↑ ^{a b} Natarajan Srinivasan, A. Ganesan: Highly efficient Lewis acid-catalysed Pictet-Spengler reactions discovered by parallel screening. In: Chemical Communications. , Pp. 916-917, doi : 10.1039 / B212063A .
12. ^ Paul A. Clarke: Selective mono-acylation of meso- and C ₂ -symmetric 1,3- and 1,4-diols. In: Tetrahedron Letters. 43, 2002, pp. 4761-4763, doi : 10.1016 / S0040-4039 (02) 00935-8 .
13. ^ Jean-Louis Luche, André Luis Gemal: Efficient synthesis of acetals catalysed by rare earth chlorides. In: Journal of the Chemical Society, Chemical Communications. 1978, p. 976, doi : 10.1039 / c39780000976 .
14. ↑ Manajit K. Hayer, Frank G. Riddell: Shift reagents for ³⁹ K Nmr. In: Inorganica Chimica Acta . 92, 1984, pp. L37-L39, doi : 10.1016 / S0020-1693 (00) 80044-4 .