Small steric variations in ligands with large synthetic and structural consequences

Qayyum, Sadaf, Haberland, Kristina, Forsyth, Craig M., Junk, Peter C., Deacon, Glen B., and Kempe, Rhett (2008) Small steric variations in ligands with large synthetic and structural consequences. European Journal of Inorganic Chemistry, 2008 (4). pp. 557-562.

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Abstract

The reaction of ytterbium metal with the aminopyridines2,6-(diisopropylphenyl)-[6-(2,6-dimethylphenyl)pyridin-2-yl]amine (1, Ap'H) and (2,4,6-trimethylphenyl)-[6-(2,4,6-trimethylphenyl)pyridin-2-yl]amine (2, ApMeH) at elevated temperature under vacuum in the presence of mercury gave rise to divalent [Yb(Ap')2] (3) and trivalent [Yb(ApMe)3] (4), respectively. The single-crystal X-ray structure analysis of 3 revealed a four-coordinate ytterbium atom with two chelating (N,N') Ap' ligands inclined to each other at an angle of 126.93(7)° (Cl–Yb–C26). Additionally the complex forms intermolecular CAryl–H agostic interactions [Yb1···C17 2.981(2) Å and Yb1···H17 2.56(3) Å] (all H atoms refined). Complex 4 contains a six-coordinate ytterbium atom having three chelating (N,N') ApMe ligands and has distorted octahedral stereochemistry. The reaction of the potassium salts of Ap'H (5) and ApMeH (6) with [YbI2 (thf)4] in thf gave rise to the divalent lanthanoid complexes [Yb(Ap')2(thf)] (7), and [Yb(ApMe)2(thf)2] (8), respectively, and 7 was also obtained by redox transmetallation/ligand exchange from Yb metal, HgPh2 and Ap'H. X-ray crystal structures show that 7 and 8 have five- and six-coordinate ytterbium atoms and distorted trigonal-bipyramidal and distorted octahedral stereochemistry, respectively, the difference in coordination number reflecting the difference in steric demand of the Ap' and ApMe ligands.

Item ID: 29624
Item Type: Article (Research - C1)
ISSN: 1099-0682
Keywords: agostic interactions, amidopyridine ligands, aminopyridinato ligands, N ligands, ytterbium
Funders: Deutsche Forschungsgemeinschaft, Fonds der Chemischen Industrie, Australian Research Council (ARC)
Date Deposited: 02 Oct 2013 10:34
FoR Codes: 03 CHEMICAL SCIENCES > 0302 Inorganic Chemistry > 030202 f-Block Chemistry @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970103 Expanding Knowledge in the Chemical Sciences @ 100%
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