Pt/Pd–Ethynyl Bond Containing Fluorescent Molecular Architectures as Sensors for Nitroaromatics - Molecular Self-Assembly: Advances and Applications - page 265

9.2.2 Self-Assembly of Cationic Molecular Rectangles

Four new luminescent molecular rectangles 8-11 of general formulae

m

[ 1 ( -L ) ](NO ) were synthesized from the organometallic 2 n 2 3 4

molecular “clip” 1 and linear ditopic pyridyl donors 4-7 ( Scheme

9.4).

Scheme 9.4 Self-assembly of cationic molecular rectangles 8-11.

9.2.2.1 Synthesis and Characterization of the Cationic
Rectangles
The “clip” 1 was treated with the linear donors 4-7 [ 4 : 4,4

¢

-

bipyridine; 5 : trans -1,2-bis(4-pyridyl)ethylene; 6 : N -(4-pyridyl)

N ¢ -bis(4-pyridylidene) ethylenediamine] in

1:1 molar ratio in acetone to obtain the assemblies

isonicotinamide; 7 : N ,

8-11 in high

yields (Scheme 9.4).
All the self-assembled molecular rectangles were fully
characterized in the solution by

1 31

P NMR as well as
by ESI mass spectrometry. The product formations were clearly
indicated from the

H [22] and

P NMR
showed a single peak at 19.06 ppm, which was upfield shifted to
14.26, 14.33, 14.98, and 13.91 ppm for

31

P NMR spectra. In the case of 1 , the

31

, respectively,
with the appearance of concomitant platinum satellites. The upfield
shifts of the phosphorus peaks indicated the ligand to Pt electron
donation and thus the metal-ligand coordination.

8 , 9 , 10, and 11

1

H NMR spectrum

of the macrocycle 11 is shown in Fig. 9.3.