Quantitative formation of [2]catenanes using copper(I) and palladium(II) as templating and assembling centers: the entwining route and the threading approach.
Transition metal-mediated templating and self-assembly have shown powerful potentials for the synthesis of interlocked molecules. These two strategies were combined in designing and preparing a new type of coordination catenanes incorporating Cu(I) and Pd(II) metal centers. The ligand designed here contains a phenanthroline core and pyridine sidearms (compound 1). Using this phenanthroline-pyridine conjugated ligand, two approaches were examined, which were shown to be surprisingly efficient for the catenane synthesis: the entwining route (entwining of two ligands around Cu(I) followed by Pd(II) clipping) and the threading approach (Cu(I)-templated threading of a cyclic ligand on an acyclic ligand followed by the Pd(II) clipping of the second ring). In the former method, stepwise treatment of 1 with Cu(CH(3)CN)(4)PF(6) (templating center) and enPd(NO(3))(2) (assembling center) gives rise to the quantitative formation of CuPd(2) catenane 18. In the latter method, Cu(I) templates the threading of phenanthroline-containing macrocycle 2 on ligand 1, which is followed by Pd(II) clipping to give hetero catenane 20. In both approaches, the formation of catenanes is convincing thanks to the strong templating effect of Cu(I), while the ring closure steps are efficiently furnished by Pd(II)-directed self-assembly.
Laboratoire de Chimie Organo-Minérale, UMR 7513 du CNRS, Université Louis Pasteur, Faculté de Chimie, 4, Rue Blaise Pascal, 67070 Strasbourg Cedex, France. sauvage@chimie.u-strasbg.fr
Christiane
C
Dietrich-Buchecker
Benoît
B
Colasson
Makoto
M
Fujita
Akiko
A
Hori
Neri
N
Geum
Shigeru
S
Sakamoto
Kentaro
K
Yamaguchi
Jean-Pierre
JP
Sauvage