Synthesis, crystal structure, and chirality of divalent lanthanide reagents containing tri- and tetraglyme

• Six new divalent lanthanide complexes using triglyme (trigly) and tetraglyme (tetgly) as achiral ligands have been prepared, using a facile synthetic method, in search for enantioselective solid-state reagents. The crystal structures of cis-[SmI2(trigly)thfl] (1), trans[YbI2(trigly)thf] (2), trans-[SMI2(trigly)dme] (3), trans-[YbI2(tetgly)] (4), trans-[EuI2(tetgly)thfl] (5), and [SM(tetgly)2][SMI3(tetgly)]I (6) have been determined. All complexes, except 5, are chiral. The 10-coordinate cation in 6 displays a helical chirality since the two tetraglyme ligands are wrapped around the samarium ion. Since trans-[YbI2(tetgly)] (4), which has a chiral arrangement of terminal methyl groups, crystallizes as a conglomerate, preferential crystallization and consequent enantioselective reduction of acetophenone was attempted, but resulted in racemic products, possibly on account of racemic twinning in 4. (C) 2004 Elsevier B.V. All rights reserved.

Subject headings

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Keyword

lanthanide

triglyme

tetraglyme

crystal structure

ABSOLUTE ASYMMETRIC-SYNTHESIS

ORGANIC-CHEMISTRY

SAMARIUM DIIODIDE

GRIGNARD-REAGENTS

COMPLEXES

SMI2

REDUCTION

KETONES

IODIDE

Publication and Content Type

ref (subject category)

art (subject category)