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as
N
-(2-naphthyl)-acetamide, only weak host
−
guest interaction
−
1
was observed (
K
= 15 M
) owing to the steric reason. Harding
a
et al.
reported the encapsulation of 1,4-dimethoxybenzene and
1,2-dimethoxybenzene into the electron-deficient cavity of the
dinuclear metallacyclic Zn complex
. The X-ray structure of the
corresponding complex with the metallacycle has reasserted the
inclusion of guest within the cavity [78,79].
27
4+
4PF
6
-
N
N
4+
Guests
NH
2
OMe
H
2
N
Zn
N
N
4NO
3
-
Pd
OMe
N
N
OMe
27
O
N
O
O
N
O
F
F
F
F
OMe
Guests
OMe
OMe
F
F
F
F
OMe
O
N
O
O
N
O
OMe
OMe
OMe
N
N
Pd
OMe
H
2
N H
2
N
N
Zn
MeO
OMe
26
N
N
was
conceptualized to be a metal analogue of calix[4]arene [80]. The
metallacycle consists of four Pt atoms, four 1,2-diaminoethane, and
four uracil bases, which after deprotonation, the oxo surface formed
by the four O
Metallacyclic supramolecule
28
reported by Lippert
et al.
2
−
exocyclic atoms of the uracil nucleobases, are capable
of encapsulating additional metal ions and can include only one metal
ion in the cone. The titration of the deprotonated platinum cone with
Zn
2+
2+
3+
, Be
, and La
ions (Scheme 10.3) caused a significant chemical
shift change in the
1
H NMR spectra. Moreover, the species (such as
29
) formed with the inclusion of the metal ions in the cavity can
further act as a host for organic anions, such as
-toluenesulfonate
and 3-(trimethylsilyl)-1-propanesulfonate to form an inclusion
complex
p
30
. The association constants (
K
) were found in the range
a
−
13
−
159 M
1
. The organic anion complexation is probably due to
the cooperativity induced between the positive charge introduced
by the coordinated metal cation and the hydrophobic nature of the
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