Pt/Pd–Ethynyl Bond Containing Fluorescent Molecular Architectures as Sensors for Nitroaromatics - Molecular Self-Assembly: Advances and Applications - page 280

9.3.4 Complementary Approach: Molecular Prisms

Using Trigonal Donors

A complementary approach was adopted to obtain an analogous
cage 23 by treating a tritopic planar donor 22 in combination with

the organometallic acceptor 1 by 2:3 self-assembly (Scheme 9.11).

Scheme 9.11 Complementary approach of synthesizing nanoscopic

prisms.

Initially a transparent yellow solution was formed upon mixing
the components. However, the prism 23 was precipitated as a yellow

°

product upon heating at 50 C for 12 h. A sharp singlet appeared at

31 1

14 ppm in P{ H} NMR spectrum, which was 5 ppm upfield shifted

31 1

from the (Fig. 9.16). In the

proton NMR spectra the downfield shift of the pyridine H

P{ H} NMR of the starting linker 1

proton α

by 0.3 ppm and 0.1 ppm upfield shift of the H of the “clip” were in 10

strong support of the coordination of ligand to the acceptor and

formation of a symmetrical supramolecular prism (Fig. 9.16).

14

9.3.5 Absorption and Fluorescence Properties of the

Molecular Prisms

Absorption spectra of the complexes 18 , 21 , and 23 were recorded in

DMF, whereas for 17 it was recorded in CH Cl -DMF (4:1) solution.

2 2