9
88
I. M. Atkinson et al.
1
N, 7�8%). Mass spectrum (f.a.b.) m/z 341 (M+1). H n.m.r.
1�44, d, CCH3; 1�73, 2H, quin, CH2CH2CH2; 2�07, br s,
NH; 2�36–2�52, 4H, m, NCH2; 3�79, 2H, q, ArCH; 4�26–4�47,
to yield a 1,3-diazapentane or a 1,3-diazacyclohexane
derivative. Nevertheless, reduction of such products
�
12
13
has been demonstrated to lead to the generation of
the required linear amine backbone incorporating only
4
H, m, OCH2; 6�86–7�26.
C n.m.r. � 21�32, CCH3; 30�54
CH2CH2CH2; 58�60, NCH2; 65�93, OCH2; 110�43, 121�09,
13
1
27�96, 129�72, 132�35, 156�45, aromatics.
secondary amine groups. A cyclic 1,3-diaza derivative
may well be an intermediate in the synthesis of (7).
Macrocycle (7).H2O. Diketone (8) (0�50 g, 1�67 mmol)
was dissolved in hot methanol (200 ml). To this stirred solution
1
13
The H and C n.m.r. and mass spectra of the
cyclized products were in accord with their proposed
structures. In both cases, the n.m.r. spectra of the
respective crude products were consistent with the
formation of two isomers; these were assigned to the
meso and racemic forms, re�ecting the presence in each
structure of two asymmetric carbons (those bearing
the methyl substituents).
For (2), the n.m.r. evidence indicated that the crude
product consisted of an approximately 1�2 : 1 mixture
of each isomer. This was indicated, most notably, by
the presence of two quartets in the proton spectrum
of the mixture at 3�79 and 4�05 ppm, respectively.
These signals result from di�erent environments for
the single proton (coupled to the methyl protons) of
the ArCH(CH3) fragment in each isomer. However,
two (fractional) recrystallizations of the initial mixture
from acetonitrile resulted in the isolation of one isomer
exclusively (namely, the isomer corresponding to the
quartet at � 3�79). It was this isomer that was used
for the metal complexation studies.
was added diethylenetriamine (0�19 g, 1�84 mmol) in methanol
(
50 ml), and the resulting solution was heated at re�ux for
2
days. Sodium borohydride (1�0 g) was then added slowly
to the stirred solution at room temperature. The solution
was then evaporated to a small volume and a large excess of
water was added whereupon an oily solid formed. The pH
was adjusted to 12 with sodium hydroxide, and the mixture
was then extracted with chloroform (� 3). The combined
chloroform extracts were dried over anhydrous sodium sulfate.
The solution was �ltered and the solvent was then removed
in a rotary evaporator. The product was initially obtained
as an oil but this solidi�ed on standing. This white product
(
6
0�36 g, 58%) was recrystallized from acetonitrile (Found: C,
8�1; H, 8�5; N, 10�8. C22H33N3O3 requires C, 68�2; H, 8�6;
1
N, 10�8%). Mass spectrum (f.a.b.) m/z 370 (M+1). H n.m.r.
�
4
4
1
1�46, d, CCH3; 2�38–2�68, br, NCH2CH2N; 4�02, q, ArCH;
13
�38, s, OCH2; 6�95–7�22, m.
C n.m.r. � 20�88, CCH3;
7�01, 49�14, NCH2CH2; 54�45, ArCH; 67�61, OCH2; 111�93,
21�14, 127�80, 128�70, 133�26, 156�70, aromatics.
Metal Complex Syntheses
Ni(7)(H2O)] (ClO4)2. Nickel(II) perchlorate hexahydrate
[
(
0�40 g, 1�09 mmol) in hot methanol was added to a stirred
solution of (7) (0�40 g 1�08 mmol) in hot methanol (15 ml).
On cooling the resultant solution, �ne blue crystals formed.
These were collected and washed with methanol and air-dried
In the case of (7), the crude product consisted of an
approximately 1 : 1 mixture of the meso and racemic
forms (quartets at 4�02 and 3�92 ppm). A pure sample
of the meso form (quartet at 4�02 ppm) was obtained
from a single fractional recrystallization of the crude
product from acetonitrile; assignment of this isomer
was made possible by the determination of the X-ray
structure of its nickel(II) perchlorate derivative—see
below. It is noted that for the meso isomer the proton
signal for the OCH2CH2O group is a singlet, whereas
(
Found: C, 41�0; H, 4�8; N. 6�5. C22H33Cl2N3NiO11 requires
C, 41�0, H, 5�2, N, 6�5%). Mass spectrum (f.a.b.) m/z 526
+
� 3
(
[NiL(ClO4)] ). Ultraviolet–visible spectrum, 9�92� 10
M in
�
1
acetone: �max 363 (� 31�3), 580 (15�9), 963 nm (14�1 M
�
1
�
cm ). Magnetic moment at 19�2 C: 3�2 BM. The X-ray
crystal structure of this nickel(II) complex, recrystallized from
acetone, con�rmed that it contained the meso isomer of the
ligand.
[
Cu(7)] (ClO4)2.H2O. By a similar procedure to that
described above, Cu(ClO4)2.6H2O (0�4 g, 1�10 mmol) in warm
0
0
methanol (15 ml) was added to a stirred solution of ligand
the racemic isomer yields an AA BB coupling pattern.
(
0�4 g, 1�08 mmol) in warm methanol (15 ml). A deep blue
product formed which was washed with chloroform/ethanol
and then air-dried (Found: C, 40�7; H, 4�8; N, 6�5.
C22H33Cl2CuN3O12 requires C, 40�7, H, 5�1, N, 6�5%).
Metal Complexation
A motivation for undertaking the present study was
to investigate the in�uence of the methyl substituents
on the corresponding metal-ion chemistry of these
species relative to that of the parent unsubstituted
derivatives (1) and (3). It was of particular interest
to study the e�ect of methylation on the ‘structural
dislocation’ behaviour observed previously for the series
of nickel complexes containing the 17-membered ring
+
Mass spectrum (f.a.b.) m/z 531 ([CuL(ClO4)] ). Ultraviolet–
�
3
visible spectrum, 1�00� 10 M in acetone: �max 650vbr nm
�
1
� 1
(
� 15�5 M
cm ). Attempts to grow suitable crystals of this
complex (from acetone) for use in an X-ray di�raction study
proved unsuccessful; only twinned specimens were obtained.
Results and Discussion
Substituted Macrocycles
(
3) and the corresponding (unsubstituted) 18- and
The dimethylated macrocycles (2) and (7) were syn-
thesized through Schi�-base condensation between the
diketone (8) and propane-1,3-diamine or diethylenetri-
amine, followed by reduction in situ of the respective
products with sodium borohydride. It should be
noted that attempts to use linear polyamines in such
Schi�-base condensations have been shown in some
cases to result in a secondary amine reacting in con-
cert with one primary amine and an aldehyde group
19-membered rings (4) and (5). Dislocation behaviour
represents a little studied discrimination mechanism
9,14
�rst investigated by us;
it involves the use of a
gradual change of properties (such as macrocycle hole
size or degree of ligand substitution) along a ligand
series to trigger a sudden change in the coordination
geometry within the corresponding series of metal
complexes. If the structural dislocation occurs at
di�erent points along the ligand series for di�erent
Atkinson, Ian M.
