Macrocycles with pendant arms
0.35 × 0.40 × 0.30 mm and 0.30 × 0.38 × 0.35 mm for
Compound 3. The hexaazamacrocycle tetraamine was pre-
pared in the same way as described above using barium()
chloride dihydrate (3.22 g, 13.2 mmol), 2,6-diformylpyridine
(3.56 g, 26.4 mmol) in methanol (150 cm3) and 1,2-
diaminoethane (1.6 g, 25.7 mmol) in methanol (10 cm3).
The orange–red oil (1) was refluxed in methanol (40 cm3) for 30
min before 2,4-dimethylphenol (9.8 g, 80.3 mmol) was added
neat and the mixture refluxed for 1 h. A solution of aqueous
methanal (3.2 g, 106.7 mmol, 37% solution in water) in meth-
anol (20 cm3) was added dropwise over a period of 1–2 h.
The white solid 3 (4.46 g, 39%) precipitated during reflux and
was filtered under suction, washed with methanol (3 × 20 cm3)
and dried under vacuum (10Ϫ2 mmHg) over calcium chloride.
Yield 39%, mp 189–191 ЊC (C54H66N6O4 requires C, 75.1; H,
7.6; N, 9.7. Found: C, 75.1; H, 7.5; N, 9.4%), νmax/cmϪ1 3062,
3009, 2966, 2915, 2849, 1614, 1590, 1574, 1485, 1457, 1343,
1376, 1241.
Compound 4. The same procedure was used as in preparing
3. The quantities used were as follows: barium() chloride
dihydrate (1.87 g, 7.7 mmol), 2,6-diacetylpyridine (2.51 g,
15.4 mmol) in methanol (150 cm3), 1,2-diaminoethane
(1.0 g, 16.7 mmol) in methanol (10 cm3), sodium borohydride
(2.28 g, 60 mmol followed by 1.14 g, 30 mmol), 2,4-
dimethylphenol (7.3 g, 59.8 mmol) and aqueous methanal
(1.4 g, 46.7 mmol) in methanol (10 cm3). Yield 35%, mp
202–205 ЊC (C58H74N6O4 requires C, 75.7; H, 8.2; N, 9.2.
Found: C, 75.7; H, 8.2; N, 9.1%), νmax/cmϪ1 3060, 3006,
2972, 2937, 2914, 2855, 1614, 1588, 1574, 1485, 1456, 1377,
1244.
Compound 7. The same procedure was used as in preparing
3. The quantities used were as follows: barium() chloride
dihydrate (2.44 g, 10.0 mmol), 2,6-diformylpyridine (3.04 g,
22.5 mmol) in methanol (200 cm3), diethylenetriamine (2.1 g,
21.0 mmol) in methanol (20 cm3), sodium borohydride
(4.05 g, 106.6 mmol followed by 2.05 g, 54.0 mmol), 2,4-
dimethylphenol (11.1 g, 91.0 mmol) and aqueous methanal
(3.2 g, 106.7 mmol) in methanol (15 cm3). Yield 47%, mp
211–212 ЊC (C76H96N8O6 requires C, 75.0; H, 7.9; N, 9.2.
Found: C, 75.1; H, 8.0; N, 9.3%), νmax/cmϪ1 3054, 3009,
2954, 2916, 2850, 1612, 1590, 1573, 1485, 1456, 1442, 1378,
1244.
Compound 8. The same procedure was used as in preparing 3.
The quantities used were as follows: barium() chloride dihy-
drate (1.12 g, 4.6 mmol), 2,6-diacetylpyridine (1.52 g, 9.2 mmol)
in methanol (100 cm3), diethylenetriamine (0.95 g, 9.5 mmol) in
methanol (10 cm3), sodium borohydride (2.28 g, 60.0 mmol fol-
lowed by 1.14 g, 30 mmol), 2,4-dimethylphenol (4.9 g, 40.2
mmol) and aqueous methanal (1.5 g, 50.0 mmol) in methanol
(10 cm3). Yield 32%, mp 232–236 ЊC (C80H104N8O6 requires C,
75.5; H, 8.2; N, 8.8. Found: C, 75.5; H, 8.2; N, 9.1%), νmax/cmϪ1
3057, 2970, 2938, 2906, 2850, 1613, 1587, 1575, 1485, 1454,
1376, 1243.
[H42]Br4ؒ2H2O and 4 respectively. In each case, three reference
reflections were measured every 5 h which showed no significant
variation in intensities throughout data collection. Lorentz and
polarization corrections were applied to the data and equivalent
reflections were merged to give 1581 and 2098 unique reflections
with I/σ(I) у 3 for [H42]Br4ؒ2H2O and
4
respectively
(Rint = 0.021 for [H42]Br4ؒ2H2O and 0.027 for 4).
Structure solution31 and refinement.32 Direct methods were
used to solve both structures and gave the positions of most
non-hydrogen atoms. The remaining non-hydrogen atoms, in
each case, were located from subsequent difference-Fourier
syntheses. For [H42]Br4ؒ2H2O, the asymmetric unit contains
only half of the macrocyclic ligand, the second half being gen-
erated by an inversion centre in the middle of the molecule.
After all the atoms had been refined with isotropic displace-
ment parameters, absorption corrections33 were applied to the
data (maximum = 1.15 and minimum = 0.86). For 4, the solu-
tion was complicated by the existence of two independent cen-
trosymmetric molecules A and B. In molecule A the methyl
group, attached to the chiral carbon atom C(4b), is disordered
with the hydrogen atom; refinement of the partial atoms [C(6b)
and C(60b)] at two sites with fixed thermal displacement par-
ameter indicated occupancy of ca. 0.6 and 0.4 respectively.
Similarly, in molecule B, disorder was established for the
equivalent methyl carbon atom C(6c) for which two sites [C(6c)
and C(60c)] of 0.5 occupancy were established. For both mol-
ecules, the sites of two hydrogen atoms [H(4b) and H(40b) for
A and H(4c) and H(40c) for B] partial occupancy were calcu-
lated and included in structure factor calculation with the
appropriate occupancy but were not refined. Due to shortage
of data, the phenylene rings were constrained to refine as ideal-
ised hexagons with C᎐C and C᎐H bond lengths fixed at 1.395
and 1.08 Å respectively. A succession of difference-Fourier syn-
theses calculated using data with sin θ < 0.35 revealed the posi-
tions of all hydrogen atoms bonded to nitrogen and oxygen for
[H42]Br4ؒ2H2O, and these were included at the observed posi-
tions but were not refined; for 4, only some of the carbon
bonded hydrogen atoms were found. In each case, for consist-
ency all carbon bonded hydrogen atoms were placed at ideal-
ised geometry (C᎐H 1.08 Å) and their displacement parameters
fixed at 0.08 Å2 for [H42]Br4ؒ2H2O and 0.1 Å2 for 4. Aniso-
tropic displacement parameters were assigned to all non-
hydrogen atoms in [H42]Br4ؒ2H2O, and in 4 the nitrogen, oxy-
gen and seven of the methyl carbon atoms of the phenyl groups
[except for C(8b) which became non-positive definite during
refinement so that an isotropic parameter was used]. The final
cycles of full-matrix least-squares refinement converged at
R = 0.0642 and Rω = 0.0681 for 154 parameters with weights 1/
[σ2(F) ϩ 0.000 881 (F2)] assigned to the individual reflections
for [H42]Br4ؒ2H2O, and at R = 0.0997 and Rω = 0.1059 for 313
parameters with weights of 1/[σ2(F) ϩ 0.000 093 (F2)] for 4. In
the final difference-Fourier map a number of residual peaks of
ca. 0.8 e ÅϪ3 were found in the vicinity of the bromine atom
Br(2), in [H42]Br4ؒ2H2O, and there were no residual peaks
greater than 0.8 e ÅϪ3 in 4.
X-Ray structural analyses of [H42]Br4ؒ2H2O and 4
Crystal data. [H42]Br4ؒ2H2O. C22H42Br4N6O2, M = 742.23,
¯
triclinic, space group, P1 (No. 2), a = 9.655(2), b = 10.391(3),
Atomic coordinates, thermal parameters and bond lengths
and angles have been deposited at the Cambridge Crystallo-
graphic Data Centre (CCDC). See Instructions for Authors,
J. Chem. Soc., Perkin Trans. 1, 1997, Issue 1. Any request to the
CCDC for this material should quote the full literature citation
and the reference number 207/150.
c = 8.059(2) Å, α = 103.71(2), β = 98.85(2), γ = 74.76(2)Њ,
U = 754.24 Å3, Z = 2, F(000) = 372, DC = 1.634 g cmϪ3, µ(Mo-
Kα) = 53.1 cmϪ1, λ = 0.710 69 Å.
Compound 4. C58H74N6O4, M = 919.26, triclinic, space group,
¯
P1 (No. 2), a = 12.320(3), b = 22.594(3), c = 10.591(3) Å,
α = 98.82(2), β = 104.81(2), γ = 102.57(2)Њ, U = 2712.77 Å3,
Z = 2, F(000) = 992, DC = 1.125 g cmϪ3, µ(Mo-Kα) = 0.7 cmϪ1
λ = 0.710 69 Å.
,
Acknowledgements
Data collection. Intensity data were collected on a Philips
PW1100 four-circle diffractometer using Mo-Kα radiation
from a graphite monochromator, in the θ-range of 3–25Њ with a
scan width of 0.90Њ, using the method described previously.30
The crystals used were colourless with dimensions
We thank the EPSRC and Amersham International plc for a
CASE studentship (to E. G. E.), and Polytechnic Central Fund-
ing Council (to N. C.) for studentships, Amersham Inter-
national plc for financial support, and the EPSRC for access to
the Chemical Database Service at Daresbury.
J. Chem. Soc., Perkin Trans. 1, 1997
3155