PdII and PtII Metal-Directed Self-Assembly of Supramolecular Structures Based on N-Monoalkyl-4,4¢-Bipyridinium Derivatives - Molecular Self-Assembly: Advances and Applications - page 367

this type of self-assembly process should lead to the formation of
catenanes in a thermodynamically controlled fashion.

11.5.1 [2]Catenanes

II II

In this way, Pd and Pt hybrid [2]catenanes were assembled

from ligand (Scheme 11.2) [30]. The diffusion

coefficients obtained from DOSY experiments of catenane
BPP34C10 ⊂ M3a

L3 and BPP34C10

showed that the
catenane are significantly larger than their components. The signals
from the ligand, macrocycle

·5NO and ligand L3 ·3NO

3 3

II

complex showed
the same diffusion coefficients, indicating that the three components
diffuse as a whole. In the [2]catenane, exchange between the “inside”
and “alongside” hydroquinol rings is slow at room temperature,
resulting in all of the OCH

BPP34C10 , and the Pd

1

groups being anisochronous on the H

2

1 13

C NMR spectra showed the upfield shift
of the signals for the “inside” hydroquinol ring protons and carbons
as a result of the π-π

NMR time scale. The H and

stacking and [C-H



π] interactions with the

pyridine and -phenylene rings on the short side of the rectangle. The

protons and carbons of these rings are shifted downfield from those
of the macrocycle

p

. Moreover, the signals for the protons
and carbons at the central positions of the bipyridine moieties have
shifted upfield as a result of the shielding effect of the macrocycle
BPP34C10

M3a ·5NO

3

.

Scheme 11.2 Synthesis of catenanes BPP34C10 ⊂ M3a,b ·5NO .

3

Employing the same strategy that we used for the preparation of
catenane BPP34C10 ⊂ M3a

, the analogous platinum catenane
could be isolated as its hexafluorophosphate salt in high yield (85%).

·5NO

3