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The crystal structures are reported of trans-dioxocyclam dihydrate, C10H20N4O2·2H2O, a structural isomer of the well known cis-dioxocyclam, and of its novel Ni complex, (1,4,8,11-tetraazacyclotetradecane-2,9-dionato-κ4N)nickel(II) dihydrate, [Ni(C10H18N4O2)]·2H2O, the first example of a transition metal complex of this ligand. Both molecules lie on crystallographic centres of inversion. The free ligand has two of its N atoms turned outwards from the ring and hydrogen bonded to water molecules. A major conformational change takes place in the complex in which the ligand binds in a trans tetradentate fashion, as suggested by the electronic spectrum. The nickel(II) ion is low spin, although the electronic spectrum of the complex in water indicates an equilibrium mixture of low-spin and high-spin species. The irreversible electrochemical oxidation of [NiL1] (L1 is deprotonated trans-dioxocyclam, C10H18N4O2) in water occurs at a potential of 0.964 V [versus SHE (standard hydrogen electrode)], which is very similar to that for the Ni–cis-dioxocyclam complex.
Supporting information
CCDC references: 163881; 163882
For both compounds, data collection: SMART (Siemens, 1994); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.
(I) 1,4,8,11-tetraazacyclotetradecane-2,9-dione dihydrate
top
Crystal data top
C10H20N4O2·2H2O | Z = 1 |
Mr = 264.33 | F(000) = 144 |
Triclinic, P1 | Dx = 1.339 Mg m−3 |
a = 4.869 (3) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 7.530 (5) Å | Cell parameters from 1077 reflections |
c = 9.150 (5) Å | θ = 3–20° |
α = 83.037 (10)° | µ = 0.10 mm−1 |
β = 88.727 (15)° | T = 200 K |
γ = 79.806 (10)° | Prism AUTHOR: please specify what kind, colourless |
V = 327.7 (3) Å3 | 0.48 × 0.10 × 0.10 mm |
Data collection top
Siemens SMART CCD area-detector diffractometer | 1118 independent reflections |
Radiation source: normal-focus sealed tube | 825 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.018 |
Detector resolution: 8.192 pixels mm-1 | θmax = 25.0°, θmin = 2.2° |
ω scans | h = −5→5 |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | k = −8→8 |
Tmin = 0.58, Tmax = 0.96 | l = −10→6 |
1627 measured reflections | |
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)] = 0.046 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.118 | H atoms treated by a mixture of independent and constrained refinement |
S = 0.97 | w = 1/[σ2(Fo2) + (0.073P)2] where P = (Fo2 + 2Fc2)/3 |
1118 reflections | (Δ/σ)max = 0.025 |
102 parameters | Δρmax = 0.18 e Å−3 |
0 restraints | Δρmin = −0.24 e Å−3 |
Special details top
Experimental. The data collection nominally covered over a hemisphere of reciprocal space, by
a combination of three sets of exposures with different φ angles for the
crystal; each 10 s exposure covered 0.3° in ω. The crystal-to-detector
distance was 5.0 cm. Coverage of the unique set is over 97% complete to at
least 26° in θ. Crystal decay was found to be negligible by by repeating the
initial frames at the end of data collection and analyzing the duplicate
reflections. The program SADABS (Sheldrick, 1996) can correct for factors other than
absorption, including for any time-dependent changes: among other possible
factors might be crystal incompletely bathed in the X-ray beam; formation of
ice; severe absorption caused by oblique inclination of the beam and the
fibre. Although no particular factor has been identified as being responsible
for the discrepant range of transmission coefficients in the present case, it
is clear that some factors or factors other than absorption were affecting the
data, and refinement using the corrected data was more valid than that using
the uncorrected set. Our estimate of the transmission coefficient range
actually due to absorption would be of the order of 0.85–0.96. |
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. Weighted R-factors
wR and all goodnesses of fit S are based on F2,
conventional R-factors R are based on F, with F
set to zero for negative F2. The observed criterion of F2 >
σ(F2) is used only for calculating _R_factor_obs 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 | Occ. (<1) |
O1 | 0.5423 (3) | 0.2685 (2) | 0.44403 (15) | 0.0340 (4) | |
C1 | 0.3047 (4) | 0.2498 (3) | 0.4106 (2) | 0.0238 (5) | |
N2 | 0.1230 (4) | 0.1947 (2) | 0.51042 (19) | 0.0254 (4) | |
H2 | −0.054 (5) | 0.202 (3) | 0.479 (3) | 0.036 (6)* | |
C3 | 0.1882 (4) | 0.1570 (3) | 0.6668 (2) | 0.0271 (5) | |
H3A | 0.3912 | 0.1129 | 0.6793 | 0.033* | |
H3B | 0.0898 | 0.0596 | 0.7118 | 0.033* | |
C4 | 0.1038 (4) | 0.3241 (3) | 0.7458 (2) | 0.0269 (5) | |
H4A | 0.1868 | 0.3005 | 0.8456 | 0.032* | |
H4B | 0.1782 | 0.4273 | 0.6915 | 0.032* | |
N5 | −0.2007 (4) | 0.3733 (2) | 0.7581 (2) | 0.0251 (4) | |
H5A | −0.274 (4) | 0.384 (3) | 0.672 (2) | 0.028 (6)* | |
C6 | −0.2931 (4) | 0.5413 (3) | 0.8254 (2) | 0.0261 (5) | |
H6A | −0.2202 | 0.5223 | 0.9273 | 0.031* | |
H6B | −0.4993 | 0.5618 | 0.8319 | 0.031* | |
C7 | −0.2066 (4) | 0.7140 (3) | 0.7471 (2) | 0.0268 (5) | |
H7A | −0.2868 | 0.8185 | 0.7998 | 0.032* | |
H7B | −0.0009 | 0.7013 | 0.7495 | 0.032* | |
O2 | −0.2756 (5) | 0.0943 (3) | 0.9866 (2) | 0.0480 (5) | |
H2A | −0.291 (6) | 0.173 (4) | 0.909 (3) | 0.064 (9)* | |
H2B | −0.43 (2) | 0.059 (13) | 0.988 (12) | 0.15 (5)* | 0.50 |
H2C | −0.120 (9) | 0.033 (6) | 1.002 (5) | 0.030 (14)* | 0.50 |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0201 (8) | 0.0440 (9) | 0.0370 (9) | −0.0073 (6) | −0.0037 (6) | 0.0017 (7) |
C1 | 0.0202 (11) | 0.0197 (10) | 0.0297 (12) | 0.0012 (8) | 0.0000 (8) | −0.0024 (9) |
N2 | 0.0221 (9) | 0.0266 (10) | 0.0276 (10) | −0.0052 (7) | −0.0010 (7) | −0.0023 (7) |
C3 | 0.0274 (11) | 0.0236 (11) | 0.0287 (12) | −0.0028 (9) | −0.0005 (9) | 0.0012 (9) |
C4 | 0.0244 (11) | 0.0281 (11) | 0.0279 (12) | −0.0055 (8) | −0.0023 (8) | −0.0005 (9) |
N5 | 0.0241 (9) | 0.0261 (10) | 0.0253 (10) | −0.0056 (7) | −0.0012 (7) | −0.0014 (8) |
C6 | 0.0238 (11) | 0.0299 (11) | 0.0241 (11) | −0.0036 (9) | 0.0023 (8) | −0.0033 (9) |
C7 | 0.0268 (11) | 0.0239 (11) | 0.0301 (12) | −0.0033 (8) | 0.0015 (9) | −0.0066 (9) |
O2 | 0.0498 (14) | 0.0418 (11) | 0.0459 (12) | −0.0043 (10) | 0.0047 (10) | 0.0144 (9) |
Geometric parameters (Å, º) top
O1—C1 | 1.239 (2) | C6—C7 | 1.528 (3) |
C1—N2 | 1.339 (3) | C7—C1i | 1.507 (3) |
C1—C7i | 1.507 (3) | N2—H2A | 0.905 (10) |
N2—C3 | 1.456 (3) | N5—H5A | 0.864 (10) |
C3—C4 | 1.516 (3) | O2—H2A | 0.86 (1) |
C4—N5 | 1.469 (3) | O2—H2B | 0.85 (2) |
N5—C6 | 1.469 (3) | O2—H2C | 0.82 (2) |
| | | |
O1—C1—N2 | 122.49 (19) | N5—C4—C3 | 111.71 (16) |
O1—C1—C7i | 121.17 (18) | C4—N5—C6 | 113.66 (15) |
N2—C1—C7i | 116.33 (17) | N5—C6—C7 | 116.61 (16) |
C1—N2—C3 | 122.27 (18) | C1i—C7—C6 | 111.41 (16) |
N2—C3—C4 | 111.94 (16) | | |
Symmetry code: (i) −x, −y+1, −z+1. |
(II) (1,4,8,11-tetraazacyclotetradecane-2,9-dione-
κ4N)nickel(II) dihydrate
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Crystal data top
[Ni(C10H18N4O2)]·2H2O | F(000) = 680 |
Mr = 321.03 | Dx = 1.565 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 20.861 (3) Å | Cell parameters from 1275 reflections |
b = 7.3385 (10) Å | θ = 3–20° |
c = 9.6130 (13) Å | µ = 1.44 mm−1 |
β = 112.205 (2)° | T = 180 K |
V = 1362.5 (3) Å3 | Plate, red |
Z = 4 | 0.40 × 0.15 × 0.04 mm |
Data collection top
Siemens SMART CCD area-detector diffractometer | 1193 independent reflections |
Radiation source: normal-focus sealed tube | 799 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.073 |
Detector resolution: 8.192 pixels mm-1 | θmax = 25.0°, θmin = 3.0° |
ω scans | h = −24→24 |
Absorption correction: ψ-scan (SADABS; Sheldrick, 1996) | k = −6→8 |
Tmin = 0.67, Tmax = 0.96 | l = −11→11 |
3255 measured reflections | |
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)] = 0.060 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.153 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | w = 1/[σ2(Fo2) + (0.079P)2] where P = (Fo2 + 2Fc2)/3 |
1193 reflections | (Δ/σ)max = 0.025 |
91 parameters | Δρmax = 0.90 e Å−3 |
0 restraints | Δρmin = −0.53 e Å−3 |
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 | |
Ni1 | 1/4 | 1/4 | 0 | 0.0239 (4) | |
O1 | 0.1331 (2) | 0.6724 (6) | 0.0596 (5) | 0.0422 (12) | |
C1 | 0.2651 (3) | 0.5716 (9) | 0.1724 (7) | 0.0339 (16) | |
H1A | 0.2564 | 0.7034 | 0.1518 | 0.041* | |
H1B | 0.2633 | 0.5444 | 0.2717 | 0.041* | |
N2 | 0.2128 (2) | 0.4618 (7) | 0.0531 (5) | 0.0296 (12) | |
C3 | 0.1502 (3) | 0.5278 (10) | 0.0070 (7) | 0.0350 (16) | |
C4 | 0.0935 (3) | 0.4286 (10) | −0.1181 (8) | 0.0477 (19) | |
H4A | 0.0490 | 0.4529 | −0.1069 | 0.057* | |
H4B | 0.0903 | 0.4824 | −0.2150 | 0.057* | |
C5 | 0.1009 (3) | 0.2303 (10) | −0.1273 (8) | 0.0399 (17) | |
H5A | 0.1000 | 0.1740 | −0.0344 | 0.048* | |
H5B | 0.0606 | 0.1830 | −0.2127 | 0.048* | |
N6 | 0.1635 (3) | 0.1744 (8) | −0.1461 (6) | 0.0318 (13) | |
H6A | 0.169 (3) | 0.230 (9) | −0.220 (7) | 0.038* | |
C7 | 0.1670 (3) | −0.0209 (9) | −0.1706 (7) | 0.0397 (17) | |
H7A | 0.1302 | −0.0552 | −0.2674 | 0.048* | |
H7B | 0.1589 | −0.0886 | −0.0896 | 0.048* | |
O2 | 0.0083 (2) | 0.8499 (6) | −0.0915 (5) | 0.0465 (13) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Ni1 | 0.0207 (6) | 0.0223 (6) | 0.0244 (6) | 0.0015 (6) | 0.0037 (4) | −0.0033 (6) |
O1 | 0.038 (3) | 0.031 (3) | 0.047 (3) | 0.014 (2) | 0.005 (2) | −0.009 (2) |
C1 | 0.024 (3) | 0.026 (4) | 0.044 (4) | 0.005 (3) | 0.004 (3) | −0.005 (3) |
N2 | 0.025 (3) | 0.028 (3) | 0.031 (3) | 0.000 (2) | 0.005 (2) | −0.002 (2) |
C3 | 0.030 (4) | 0.040 (4) | 0.033 (3) | 0.001 (3) | 0.010 (3) | 0.001 (3) |
C4 | 0.033 (4) | 0.051 (5) | 0.050 (4) | 0.012 (4) | 0.005 (3) | −0.011 (4) |
C5 | 0.023 (3) | 0.036 (5) | 0.058 (4) | −0.003 (3) | 0.011 (3) | −0.011 (4) |
N6 | 0.026 (3) | 0.032 (3) | 0.033 (3) | 0.002 (2) | 0.006 (2) | −0.005 (3) |
C7 | 0.032 (4) | 0.029 (4) | 0.050 (4) | −0.007 (3) | 0.006 (3) | −0.010 (3) |
O2 | 0.044 (3) | 0.034 (3) | 0.053 (3) | 0.012 (2) | 0.009 (2) | 0.000 (2) |
Geometric parameters (Å, º) top
Ni1—N2i | 1.892 (5) | N2—C3 | 1.303 (7) |
Ni1—N2 | 1.892 (5) | C3—C4 | 1.517 (9) |
Ni1—N6i | 1.902 (5) | C4—C5 | 1.470 (9) |
Ni1—N6 | 1.902 (5) | C5—N6 | 1.444 (8) |
O1—C3 | 1.282 (7) | N6—C7 | 1.458 (8) |
C1—C7i | 1.470 (8) | C7—C1i | 1.470 (8) |
C1—N2 | 1.487 (7) | N6—H6A | 0.864 (10) |
| | | |
N2i—Ni1—N2 | 180 | O1—C3—N2 | 124.4 (6) |
N2i—Ni1—N6i | 93.9 (2) | O1—C3—C4 | 117.4 (5) |
N2—Ni1—N6i | 86.1 (2) | N2—C3—C4 | 118.2 (6) |
N2i—Ni1—N6 | 86.1 (2) | C5—C4—C3 | 117.0 (6) |
N2—Ni1—N6 | 93.9 (2) | N6—C5—C4 | 114.2 (6) |
N6i—Ni1—N6 | 180 | C5—N6—C7 | 113.7 (5) |
C7i—C1—N2 | 106.4 (5) | C5—N6—Ni1 | 118.3 (4) |
C3—N2—C1 | 114.2 (5) | C7—N6—Ni1 | 108.3 (4) |
C3—N2—Ni1 | 132.4 (4) | N6—C7—C1i | 110.9 (5) |
C1—N2—Ni1 | 113.4 (3) | | |
Symmetry code: (i) −x+1/2, −y+1/2, −z. |
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