Isolation of (CO)1–and (CO2)1–radical complexes of rare earths via Ln(NR2)3/K reduction and [K2(18-crown-6)2]2+oligomerization

Fang, M., Farnaby, J. H. , Ziller, J. W., Bates, J. E., Furche, F. and Evans, W. J. (2012) Isolation of (CO)1–and (CO2)1–radical complexes of rare earths via Ln(NR2)3/K reduction and [K2(18-crown-6)2]2+oligomerization. Journal of the American Chemical Society, 134(14), pp. 6064-6067. (doi: 10.1021/ja211220r) (PMID:22435647)

Abstract

Deep-blue solutions of Y2+ formed from Y(NR2)3 (R = SiMe3) and excess potassium in the presence of 18-crown-6 at −45 °C under vacuum in diethyl ether react with CO at −78 °C to form colorless crystals of the (CO)1– radical complex, {[(R2N)3Y(μ-CO)2][K2(18-crown-6)2]}n, 1. The polymeric structure contains trigonal bipyramidal [(R2N)3Y(μ-CO)2]2– units with axial (CO)1– ligands linked by [K2(18-crown-6)2]2+ dications. Byproducts such as the ynediolate, [(R2N)3Y]2(μ-OC≡CO){[K(18-crown-6)]2(18-crown-6)}, 2, in which two (CO)1– anions are coupled to form (OC≡CO)2–, and the insertion/rearrangement product, {(R2N)2Y[OC(═CH2)Si(Me2)NSiMe3]}[K(18-crown-6)], 3, are common in these reactions that give variable results depending on the specific reaction conditions. The CO reduction in the presence of THF forms a solvated variant of 2, the ynediolate [(R2N)3Y]2(μ-OC≡CO)[K(18-crown-6)(THF)2]2, 2a. CO2 reacts analogously with Y2+ to form the (CO2)1– radical complex, {[(R2N)3Y(μ-CO2)2][K2(18-crown-6)2]}n, 4, that has a structure similar to that of 1. Analogous (CO)1– and (OC≡CO)2– complexes of lutetium were isolated using Lu(NR2)3/K/18-crown-6: {[(R2N)3Lu(μ-CO)2][K2(18-crown-6)2]}n, 5, [(R2N)3Lu]2(μ-OC≡CO){[K(18-crown-6)]2(18-crown-6)}, 6, and [(R2N)3Lu]2(μ-OC≡CO)[K(18-crown-6)(Et2O)2]2, 6a.

• Item Type: Articles
• Additional Information: The authors thank the U.S. National Science Foundation for support of this research through CHE-1010002, CHE-0723168, and CHE- 0840513.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Farnaby, Dr Joy
• Authors: Fang, M., Farnaby, J. H., Ziller, J. W., Bates, J. E., Furche, F., and Evans, W. J.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Journal of the American Chemical Society
• Publisher: American Chemical Society
• ISSN: 0002-7863
• ISSN (Online): 1520-5126
• Published Online: 21 March 2012