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Synthesis of B/Ga and B/In Heteronuclear Bidentate Lewis Acids: Formation of Intramolecular π‐Arene‐Gallium( III ) and ‐Indium( III ) Complexes
Author(s) -
Schulte Marcus,
Gabbaï François P.
Publication year - 2002
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20020816)8:16<3802::aid-chem3802>3.0.co;2-5
Subject(s) - chemistry , heteronuclear molecule , medicinal chemistry , denticity , intramolecular force , transmetalation , nuclear magnetic resonance spectroscopy , lewis acids and bases , moiety , tetramethylethylenediamine , stereochemistry , crystallography , crystal structure , organic chemistry , catalysis
Reaction of 1,8‐dilithionaphthalene⋅TMEDA (TMEDA=tetramethylethylenediamine) with dimesitylboron fluoride in diethyl ether followed by treatment with THF affords the Li(THF) 4 salt of dimesityl‐1,8‐naphthalenediylborate ( 1 ). Compound 1 ‐Li(THF) 4 undergoes a ring‐opening reaction with trimethyltin chloride to afford high yields of 1‐(dimesitylboron)‐8‐(trimethyltin)naphthalenediyl ( 2 ), a compound in which a boryl and a stannyl moiety coexist at the peri positions of a naphthalene core. Compound 2 has been characterized by multinuclear NMR spectroscopy, elemental analysis, and X‐ray single‐crystal analysis which reveal the existence of a sterically crowded structure. Compound 2 is a useful starting material for the synthesis of other heteronuclear naphthalene derivatives. Thus, the transmetalation reaction of 2 with GaCl 3 or InCl 3 in THF results in high yields of 1‐(dichlorogallium)‐8‐(dimesitylboron)naphthalenediyl ( 3 ) and 1‐(dichloroindium)‐8‐(dimesitylboron)naphthalenediyl ( 4 ), respectively. These unprecedented boron/gallium and boron/indium heteronuclear bidentate Lewis acids have been characterized by multinuclear NMR spectroscopy, elemental analysis, and X‐ray single‐crystal analysis. Owing to the presence of a short contact between the ipso ‐carbon atom of a mesityl group and the heavy Group 13 element (C ipso Ga 2.279(4) Å for 3 , C ipso In 2.442(6) Å for 4 ), compounds 3 and 4 are best described as intramolecular π‐arene complexes and are the first examples of such complexes. As shown by 1 H and 13 C NMR spectroscopy, this π interaction subsists in solution.