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The centrosymmetric title compound, C16H32N8O4, crystallizes one half-molecule in the asymmetric unit. Single crystals were grown from water and, even though the compound contains hydrogen-bonding groups, no water molecules of crystallization were found. Two of the four pendant arms form intramolecularly hydrogen bonds to preorganize the compound into a shape similar to that required for ligation.
Supporting information
CCDC reference: 287491
Key indicators
- Single-crystal X-ray study
- T = 100 K
- Mean (C-C)= 0.002 Å
- R factor = 0.042
- wR factor = 0.111
- Data-to-parameter ratio = 17.6
checkCIF/PLATON results
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The ligand was synthesized according to the method of Maumela et al. (1995). Characterization of the ligand was consistent with their NMR data reported. Single crystals were grown from a saturated solution of the ligand in water. After four days, colourless rods were deposited using the method of slow evaporation.
All H atoms were positioned geometrically (C—H = 0.99 Å and N—H = 0.88 Å) and constrained to ride on their parent atoms; Uiso(H) values were set at 1.2 times Ueq(C,N).
Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: X-SEED (Barbour, 2001; Atwood and Barbour, 2003); software used to prepare material for publication: X-SEED.
1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane
top
Crystal data top
C16H32N8O4 | F(000) = 432 |
Mr = 400.50 | Dx = 1.377 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 2706 reflections |
a = 5.9691 (7) Å | θ = 6.4–28.1° |
b = 17.795 (2) Å | µ = 0.10 mm−1 |
c = 9.4230 (12) Å | T = 100 K |
β = 105.190 (2)° | Rod-shaped, colourless |
V = 966.0 (2) Å3 | 0.25 × 0.21 × 0.12 mm |
Z = 2 | |
Data collection top
Bruker APEX CCD area-detector diffractometer | 1903 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.030 |
Graphite monochromator | θmax = 28.2°, θmin = 2.3° |
ω scans | h = −6→7 |
5989 measured reflections | k = −23→22 |
2230 independent reflections | l = −12→7 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.042 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.111 | H-atom parameters constrained |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0652P)2 + 0.116P] where P = (Fo2 + 2Fc2)/3 |
2230 reflections | (Δ/σ)max = 0.001 |
127 parameters | Δρmax = 0.39 e Å−3 |
0 restraints | Δρmin = −0.20 e Å−3 |
Crystal data top
C16H32N8O4 | V = 966.0 (2) Å3 |
Mr = 400.50 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 5.9691 (7) Å | µ = 0.10 mm−1 |
b = 17.795 (2) Å | T = 100 K |
c = 9.4230 (12) Å | 0.25 × 0.21 × 0.12 mm |
β = 105.190 (2)° | |
Data collection top
Bruker APEX CCD area-detector diffractometer | 1903 reflections with I > 2σ(I) |
5989 measured reflections | Rint = 0.030 |
2230 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.042 | 0 restraints |
wR(F2) = 0.111 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.39 e Å−3 |
2230 reflections | Δρmin = −0.20 e Å−3 |
127 parameters | |
Special details top
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O9 | 0.06228 (17) | 0.71086 (5) | 0.66999 (10) | 0.0190 (2) | |
O13 | 0.60801 (17) | 0.63037 (5) | 0.05167 (10) | 0.0192 (2) | |
N1 | 0.38291 (18) | 0.62848 (5) | 0.53673 (11) | 0.0126 (2) | |
N4 | 0.35284 (18) | 0.51512 (6) | 0.28716 (11) | 0.0124 (2) | |
N14 | 0.62562 (19) | 0.64100 (6) | 0.29415 (12) | 0.0160 (3) | |
H14A | 0.7132 | 0.6815 | 0.3050 | 0.019* | |
H14B | 0.5836 | 0.6224 | 0.3698 | 0.019* | |
N10 | −0.0326 (2) | 0.78487 (6) | 0.46780 (12) | 0.0183 (3) | |
H10A | −0.1521 | 0.8045 | 0.4927 | 0.022* | |
H10B | 0.0003 | 0.7992 | 0.3861 | 0.022* | |
C6 | 0.5019 (2) | 0.61926 (7) | 0.69382 (13) | 0.0141 (3) | |
H6A | 0.3898 | 0.6001 | 0.7461 | 0.017* | |
H6B | 0.5577 | 0.6689 | 0.7361 | 0.017* | |
C3 | 0.1615 (2) | 0.55950 (7) | 0.31657 (14) | 0.0136 (3) | |
H3A | 0.0129 | 0.5326 | 0.2773 | 0.016* | |
H3B | 0.1514 | 0.6086 | 0.2657 | 0.016* | |
C2 | 0.1998 (2) | 0.57234 (7) | 0.48091 (13) | 0.0131 (3) | |
H2A | 0.0532 | 0.5897 | 0.5004 | 0.016* | |
H2B | 0.2440 | 0.5243 | 0.5338 | 0.016* | |
C12 | 0.5564 (2) | 0.60775 (7) | 0.16271 (14) | 0.0137 (3) | |
C7 | 0.3021 (2) | 0.70506 (6) | 0.49790 (13) | 0.0135 (3) | |
H7A | 0.2566 | 0.7090 | 0.3893 | 0.016* | |
H7B | 0.4348 | 0.7395 | 0.5348 | 0.016* | |
C8 | 0.0996 (2) | 0.73311 (7) | 0.55437 (13) | 0.0141 (3) | |
C11 | 0.4077 (2) | 0.53773 (7) | 0.15164 (14) | 0.0146 (3) | |
H11A | 0.2604 | 0.5463 | 0.0756 | 0.018* | |
H11B | 0.4890 | 0.4956 | 0.1177 | 0.018* | |
C5 | 0.2933 (2) | 0.43453 (7) | 0.28141 (14) | 0.0138 (3) | |
H5B | 0.1863 | 0.4236 | 0.1841 | 0.017* | |
H5A | 0.2084 | 0.4243 | 0.3566 | 0.017* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O9 | 0.0251 (5) | 0.0196 (5) | 0.0146 (5) | 0.0028 (4) | 0.0090 (4) | 0.0015 (4) |
O13 | 0.0234 (5) | 0.0194 (5) | 0.0172 (5) | −0.0024 (4) | 0.0096 (4) | 0.0021 (4) |
N1 | 0.0158 (5) | 0.0099 (5) | 0.0115 (5) | 0.0002 (4) | 0.0024 (4) | 0.0000 (4) |
N4 | 0.0155 (5) | 0.0111 (5) | 0.0120 (5) | 0.0002 (4) | 0.0058 (4) | 0.0003 (4) |
N14 | 0.0171 (6) | 0.0142 (5) | 0.0175 (6) | −0.0032 (4) | 0.0059 (4) | −0.0009 (4) |
N10 | 0.0220 (6) | 0.0183 (6) | 0.0173 (6) | 0.0074 (4) | 0.0100 (5) | 0.0049 (4) |
C6 | 0.0177 (7) | 0.0126 (6) | 0.0116 (6) | 0.0001 (4) | 0.0033 (5) | −0.0012 (5) |
C3 | 0.0142 (6) | 0.0127 (6) | 0.0138 (6) | 0.0012 (4) | 0.0033 (5) | −0.0002 (5) |
C2 | 0.0144 (6) | 0.0118 (6) | 0.0138 (6) | −0.0002 (4) | 0.0048 (5) | −0.0005 (5) |
C12 | 0.0128 (6) | 0.0128 (6) | 0.0162 (6) | 0.0030 (4) | 0.0048 (5) | 0.0020 (5) |
C7 | 0.0179 (6) | 0.0106 (6) | 0.0126 (6) | 0.0011 (4) | 0.0051 (5) | 0.0005 (4) |
C8 | 0.0185 (6) | 0.0109 (6) | 0.0125 (6) | −0.0013 (5) | 0.0033 (5) | −0.0027 (4) |
C11 | 0.0189 (6) | 0.0136 (6) | 0.0117 (6) | −0.0011 (5) | 0.0048 (5) | −0.0009 (5) |
C5 | 0.0157 (6) | 0.0118 (6) | 0.0134 (6) | −0.0020 (5) | 0.0027 (5) | 0.0000 (5) |
Geometric parameters (Å, º) top
O9—C8 | 1.2331 (15) | C6—H6B | 0.9900 |
O13—C12 | 1.2332 (15) | C3—C2 | 1.5222 (17) |
N1—C7 | 1.4599 (15) | C3—H3A | 0.9900 |
N1—C2 | 1.4724 (15) | C3—H3B | 0.9900 |
N1—C6 | 1.4737 (16) | C2—H2A | 0.9900 |
N4—C11 | 1.4559 (16) | C2—H2B | 0.9900 |
N4—C3 | 1.4733 (16) | C12—C11 | 1.5174 (17) |
N4—C5 | 1.4749 (15) | C7—C8 | 1.5267 (18) |
N14—C12 | 1.3366 (16) | C7—H7A | 0.9900 |
N14—H14A | 0.8800 | C7—H7B | 0.9900 |
N14—H14B | 0.8800 | C11—H11A | 0.9900 |
N10—C8 | 1.3413 (16) | C11—H11B | 0.9900 |
N10—H10A | 0.8800 | C5—C6i | 1.5214 (17) |
N10—H10B | 0.8800 | C5—H5B | 0.9900 |
C6—C5i | 1.5214 (17) | C5—H5A | 0.9900 |
C6—H6A | 0.9900 | | |
| | | |
C7—N1—C2 | 112.23 (10) | N1—C2—H2B | 109.3 |
C7—N1—C6 | 113.35 (9) | C3—C2—H2B | 109.3 |
C2—N1—C6 | 113.62 (10) | H2A—C2—H2B | 108.0 |
C11—N4—C3 | 112.36 (10) | O13—C12—N14 | 123.82 (12) |
C11—N4—C5 | 110.12 (9) | O13—C12—C11 | 118.77 (11) |
C3—N4—C5 | 109.69 (10) | N14—C12—C11 | 117.41 (11) |
C12—N14—H14A | 120.0 | N1—C7—C8 | 117.23 (10) |
C12—N14—H14B | 120.0 | N1—C7—H7A | 108.0 |
H14A—N14—H14B | 120.0 | C8—C7—H7A | 108.0 |
C8—N10—H10A | 120.0 | N1—C7—H7B | 108.0 |
C8—N10—H10B | 120.0 | C8—C7—H7B | 108.0 |
H10A—N10—H10B | 120.0 | H7A—C7—H7B | 107.2 |
N1—C6—C5i | 112.37 (10) | O9—C8—N10 | 122.98 (12) |
N1—C6—H6A | 109.1 | O9—C8—C7 | 123.08 (11) |
C5i—C6—H6A | 109.1 | N10—C8—C7 | 113.93 (11) |
N1—C6—H6B | 109.1 | N4—C11—C12 | 115.38 (10) |
C5i—C6—H6B | 109.1 | N4—C11—H11A | 108.4 |
H6A—C6—H6B | 107.9 | C12—C11—H11A | 108.4 |
N4—C3—C2 | 110.77 (10) | N4—C11—H11B | 108.4 |
N4—C3—H3A | 109.5 | C12—C11—H11B | 108.4 |
C2—C3—H3A | 109.5 | H11A—C11—H11B | 107.5 |
N4—C3—H3B | 109.5 | N4—C5—C6i | 115.47 (10) |
C2—C3—H3B | 109.5 | N4—C5—H5B | 108.4 |
H3A—C3—H3B | 108.1 | C6i—C5—H5B | 108.4 |
N1—C2—C3 | 111.40 (10) | N4—C5—H5A | 108.4 |
N1—C2—H2A | 109.3 | C6i—C5—H5A | 108.4 |
C3—C2—H2A | 109.3 | H5B—C5—H5A | 107.5 |
| | | |
C7—N1—C6—C5i | −142.57 (11) | N1—C7—C8—O9 | 29.78 (17) |
C2—N1—C6—C5i | 87.74 (12) | N1—C7—C8—N10 | −151.01 (11) |
C11—N4—C3—C2 | −144.92 (10) | C3—N4—C11—C12 | 79.79 (13) |
C5—N4—C3—C2 | 92.24 (11) | C5—N4—C11—C12 | −157.60 (10) |
C7—N1—C2—C3 | 76.28 (12) | O13—C12—C11—N4 | −179.48 (11) |
C6—N1—C2—C3 | −153.48 (10) | N14—C12—C11—N4 | 1.11 (16) |
N4—C3—C2—N1 | 74.14 (12) | C11—N4—C5—C6i | 76.65 (13) |
C2—N1—C7—C8 | 60.26 (14) | C3—N4—C5—C6i | −159.19 (10) |
C6—N1—C7—C8 | −70.12 (14) | | |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N14—H14B···N1 | 0.88 | 2.22 | 3.018 (1) | 152 |
N10—H10A···O13ii | 0.88 | 2.03 | 2.897 (1) | 168 |
N10—H10B···O9iii | 0.88 | 2.17 | 3.006 (1) | 158 |
Symmetry codes: (ii) x−1, −y+3/2, z+1/2; (iii) x, −y+3/2, z−1/2. |
Experimental details
Crystal data |
Chemical formula | C16H32N8O4 |
Mr | 400.50 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 100 |
a, b, c (Å) | 5.9691 (7), 17.795 (2), 9.4230 (12) |
β (°) | 105.190 (2) |
V (Å3) | 966.0 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.25 × 0.21 × 0.12 |
|
Data collection |
Diffractometer | Bruker APEX CCD area-detector diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5989, 2230, 1903 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.666 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.111, 1.05 |
No. of reflections | 2230 |
No. of parameters | 127 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.39, −0.20 |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N14—H14B···N1 | 0.88 | 2.22 | 3.018 (1) | 151.5 |
N10—H10A···O13i | 0.88 | 2.03 | 2.897 (1) | 168.4 |
N10—H10B···O9ii | 0.88 | 2.17 | 3.006 (1) | 158.2 |
Symmetry codes: (i) x−1, −y+3/2, z+1/2; (ii) x, −y+3/2, z−1/2. |
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It is well known that macrocyclic ligands produce enhanced thermodynamic stability with metal ions compared with their open-chain analogues. Our interest in this macrocycle is its complexing ability with the heavy post-transition elements, lead and bismuth. The chemistry of lead is of interest in relation to its toxicity and effects on intelligence in human subjects (Bryce-Smith, 1986). Bismuth has become of increasing interest in complexes such as the subsalicylate in treating gastric and duodenal ulcers (Baxter, 1992). The architecture of this ligand (see scheme), having all five-membered chelate rings and four N-donor and four O-donor atoms, should bode well for good complexing ability to lead(II) and bismuth(III). The present ligand has also been used by Amin et al. (1996) in its lanthanide(III) complex form as catalyst for the hydrolytic cleavage of RNA. One of the authors (RCL) was involved in the synthesis of the first example of a bismuth(III) complex with a nitrogen donor macrocycle (Luckay et al., 1995), and on the basis of these studies, the present macrocycle should also show good binding tendencies with bismuth(III). Furthermore, the role of the lone pair in bismuth(III) in determining coordination geometry would be examined. Also of interest is the preorganization of the ligand before ligation of a metal.
There are only three types of hydrogen bonds formed by this compound in its crystalline state (Table 1). That of most interest is the intramolecular hydrogen bond between donor and acceptor atoms N14 and N1, respectively. This preorganizes two of the four pendant arms of the ligand into positions pointing inwards to the center of the ligand (Fig. 1). Although the functional groups pointing inwards (the amines) are different from that of the ligated metal structures where the C═O functional group is pointing inwards, this is useful information as it shows that the flexibility of the pendant arms has small energy barriers as the hydrogen bond is relatively weak compared with a coordination bond. The other two hydrogen bonds, which have the hydrogen-bond donor atom N10 in common, connect the individual molecules together to form a three-dimensional hydrogen-bonded network (Fig. 2). When comparing the conformation of the free ligand in the solid state with that of the coordinated state, it does not have the same conformation as in a number of the known metal–ligand complexes (Maumela et al., 1995). Hence, this ligand is not highly preorganized for ligation of metals.