Intramolecular rearrangement for regioselective complexation by intramolecular CH/pi interaction in a hydrophobic cavity of a ruthenium coordination sphere.
A Ru(II) complex with a hydrophobic cavity formed from two 1-naphthoylamide groups was prepared. Its reactions with beta-diketones gave beta-diketonato complexes in which hydrophobic pi-pi or CH/pi interactions were confirmed by NMR spectroscopy and X-ray crystallography. In the case of the asymmetric beta-diketone benzoylacetone, an isomer with a CH/pi interaction was afforded as the sole product owing to thermodynamic control. The reaction was found to involve a novel intramolecular rearrangement from the phenyl-included isomer to the methyl-included one without rupture of Ru-beta-diketonato coordination bonds (activation energy 52 kJ mol(-1)). This indicates that CH/pi interactions can be more favored thermodynamically than pi-pi interactions in a suitable hydrophobic environment.
Kojima
Takahiko
T
Department of Chemistry, Faculty of Sciences, Kyushu University, Hakozaki, Higashi-Ku, Fukuoka 812-8581, Japan.
Miyazaki
Soushi
S
Hayashi
Ken-ichi
K
Shimazaki
Yuichi
Y
Tani
Fumito
F
Naruta
Yoshinori
Y
Matsuda
Yoshihisa
Y
D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009930:Organic Chemicals / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
D009930:Organic Chemicals; D012428:Ruthenium