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Solvent‐Free Lanthanoid Complexes Derived From Chelation‐Supported Organoamide Ligands
Author(s) -
Deacon Glen B.,
Forsyth Craig M.,
Scott Natalie M.
Publication year - 2002
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200206)2002:6<1425::aid-ejic1425>3.0.co;2-t
Subject(s) - homoleptic , chemistry , lanthanide , amide , trimethylsilyl , molar ratio , lithium (medication) , medicinal chemistry , chelation , solvent , stereochemistry , crystallography , inorganic chemistry , catalysis , organic chemistry , ion , metal , medicine , endocrinology
Treatment of LnCl 3 with three molar equivalents of LiL [(L = N ‐(2‐methoxyphenyl)‐ N ‐(trimethylsilyl)amide (L 1 ) or N ‐(2‐phenoxyphenyl)‐ N ‐(trimethylsilyl)amide (L 2 )], generated in situ from LH and n BuLi, or with the isolated lithium complex [Li(L 1 )(OEt 2 )] 2 (for Ln = Yb) in THF afforded the solvent‐free homoleptic complexes [Ln(L) 3 ] [Ln = Yb ( 1a ), Er ( 1b ), Sm ( 1c ), Pr ( 1d ), Nd ( 1e ), L = L 1 ; Ln = Yb ( 2a ), Y ( 2b ), Sm ( 2c ), Nd ( 2d ), La ( 2e ), L = L 2 ). With a 2:1 LiL (generated in situ) to LnCl 3 molar ratio, the solvent‐free heteroleptic complexes [Ln(L) 2 (μ‐Cl)] 2 were obtained for L = N , N ‐dimethyl‐ N′ ‐trimethylsilylethane‐1,2‐diaminate (en′) [Ln = Yb ( 3a ), Er ( 3b ), Sm ( 3c ), Nd ( 3d ), La ( 3e )], but not for L 1 or L 2 , which gave [Ln(L) 3 ] [Ln = Yb ( 1a ), Nd ( 1e ), L = L 1 ; Ln = Yb ( 2a ), Nd ( 2d ), La ( 2e ), L = L 2 ]. However, treatment of LnCl 3 with two molar equivalents of the isolated crystalline lithium salt [Li(L 1 )(OEt 2 )] 2 in THF gave, for the heavier lanthanoids, the solvent‐free heteroleptic complexes [Ln(L 1 ) 2 (μ‐Cl)] 2 [Ln = Yb ( 4a ), Er ( 4b ), Tb ( 4c )], although the homoleptic complex [Nd(L 1 ) 3 ] ( 1e ) was obtained for Nd. In contrast, similar reactions of isolated [Li(L 2 )(DME)] with LnCl 3 yielded the heteroleptic species [Ln(L 2 ) 2 (μ‐Cl)] 2 only for Ln = Nd [ 5a· (PhMe) 2 ]. At either end of the Ln series, the homoleptic [Ln(L 2 ) 3 ] complexes [Ln = Yb( 2a ), La ( 2e )] were obtained. Single crystal X‐ray analyses of 1e or 2a − 2e (as their PhMe or C 5 H 9 Me solvates) showed these complexes to be monomeric and six‐coordinate ( mer isomer), whereas the heteroleptic complexes 4a − 4c , 5a were found to be dimeric with bridging chloride atoms. Two chelating [L 1 ] − or [L 2 ] − units [ trans O(Me/Ph) and cis amido groups] are bound to each lanthanoid centre completing a six‐coordinate very distorted octahedral environment. The X‐ray structure of [Li(L 1 )(OEt 2 )] 2 revealed a dimeric structure with each lithium four‐coordinate and surrounded by one diethyl ether, two bridging amide nitrogens and a methoxy oxygen in a distorted tetrahedral array. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)