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Studies of Aryl Substituent and Solvent Donor Imposed Structural Diversity in N , N′ ‐Diarylformamidinate Complexes of Lithium
Author(s) -
Baldamus Jens,
Berghof Christiane,
Cole Marcus L.,
HeyHawkins Evamarie,
Junk Peter C.,
Louis Lance 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(200211)2002:11<2878::aid-ejic2878>3.0.co;2-q
Subject(s) - chemistry , steric effects , deprotonation , medicinal chemistry , aryl , substituent , stereochemistry , lithium (medication) , lithium diisopropylamide , nuclear magnetic resonance spectroscopy , amidine , lewis acids and bases , organic chemistry , catalysis , ion , alkyl , medicine , endocrinology
Treatment of N , N′ ‐bis(2,4,6‐trimethylphenyl)formamidine, (2,4,6‐Me 3 C 6 H 2 )NC(H)NH(2,4,6‐Me 3 C 6 H 2 ) (HFMes) with n ‐butyllithium in DME leads to deprotonation of the amidine affording the dimeric compound [{Li(FMes)(dme)} 2 ] ( 1 ). Similar treatment of the less sterically encumbered formamidine N , N′ ‐bis( o ‐tolyl)formamidine, (2‐MeC 6 H 4 )NC(H)NH(2‐MeC 6 H 4 ) (HFTolO) in DME (1,2‐dimethoxyethane) or HFMes in hexane/TMEDA ( N , N , N′ , N′ ‐tetramethylethylenediamine) yields the compounds [Li(dme) 3 ][Li(FTolO) 2 ] ( 2 ) and [Li(FMes)(tmeda)] ( 3 ), respectively. Both the anion of 2 and 3 are the first monomeric group 1 formamidinates to exhibit η 2 ‐chelation in the solid state, and 3 is the first Lewis base stabilised mononuclear group 1 formamidinate complex. Complexes 1 − 3 have been characterised by spectroscopy ( 1 H and 13 C NMR, FTIR) and X‐ray crystallography, and are discussed herein vis‐à‐vis formamidinate binding modes exhibited by N , N′ ‐diarylformamidinates of smaller steric size, e.g. N , N′ ‐bis( p ‐tolyl)formamidine, (4‐MeC 6 H 4 )NC(H)NH(4‐MeC 6 H 4 ) (HFTolP).