The isomorphous title compounds, [Ni{(NH
2)
2CO}
4(H
2O)
2](NO
3)
2 and [Co{(NH
2)
2CO}
4(H
2O)
2](NO
3)
2, feature discrete centrosymmetric cations in octahedral coordinations, formed by four urea molecules linked
via their O atoms to the central ion in equatorial positions and two water molecules in
trans positions. The complexes are packed in a pseudo-hexagonal manner separated by the nitrate counter-ions. All H atoms are involved in moderate hydrogen bonds of four types: N-H
O=C, N-H
O-N, O-H
O-N and N-H
O-H. Graph-set analysis was applied to distinguish the hydrogen-bond patterns at unitary and higher level graph sets.
Supporting information
CCDC references: 665486; 665487
Nickel(II) nitrate hexahydrate was dissolved in hot propan-2-ol under reflux, to which crystalline urea was added. The molar ratio of nickel salt to urea was 1:4. The solution was filtered and then left to evaporate slowly at room temperature. Green crystals of (I) were obtained after a few weeks.
Diaquatetrakis(urea)cobalt(II) nitrate, (II), was obtained by spontaneous recrystallization of tetrakis(urea)cobalt(II) nitrate (Gentile et al., 1974) in the presence of a trace amount of water.
The H atoms of the water molecules and urea amino groups were found in difference Fourier maps and refined in a riding model, with O—H = ? and N—H = ? [Please complete], and with Uiso(H) = 1.2Ueq of the parent atom.
For both compounds, data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003), ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Version 1.4; Macrae et al., 2006); software used to prepare material for publication: SHELXL97.
(I) Diaquatetrakis(urea-
κO)nickel(II) dinitrate
top
Crystal data top
[Ni(CH4N2O)4(H2O)2](NO3)2 | F(000) = 476 |
Mr = 459.01 | Dx = 1.745 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 1746 reflections |
a = 6.4580 (2) Å | θ = 1.0–27.5° |
b = 18.0522 (5) Å | µ = 1.19 mm−1 |
c = 7.5331 (3) Å | T = 293 K |
β = 95.758 (2)° | Block, green |
V = 873.79 (5) Å3 | 0.50 × 0.48 × 0.35 mm |
Z = 2 | |
Data collection top
Nonius KappaCCD area-detector diffractometer | 1950 independent reflections |
Radiation source: fine-focus sealed tube | 1663 reflections with I > 2σ(I) |
Horizontally mounted graphite crystal monochromator | Rint = 0.029 |
Detector resolution: 9 pixels mm-1 | θmax = 27.5°, θmin = 2.9° |
ϕ and ω scans to fill Ewald sphere | h = −8→8 |
Absorption correction: multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997) | k = −23→20 |
Tmin = 0.569, Tmax = 0.660 | l = −9→9 |
5566 measured reflections | |
Refinement top
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.029 | w = 1/[σ2(Fo2) + (0.0337P)2 + 0.3336P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.077 | (Δ/σ)max < 0.001 |
S = 1.04 | Δρmax = 0.20 e Å−3 |
1950 reflections | Δρmin = −0.43 e Å−3 |
124 parameters | |
Crystal data top
[Ni(CH4N2O)4(H2O)2](NO3)2 | V = 873.79 (5) Å3 |
Mr = 459.01 | Z = 2 |
Monoclinic, P21/n | Mo Kα radiation |
a = 6.4580 (2) Å | µ = 1.19 mm−1 |
b = 18.0522 (5) Å | T = 293 K |
c = 7.5331 (3) Å | 0.50 × 0.48 × 0.35 mm |
β = 95.758 (2)° | |
Data collection top
Nonius KappaCCD area-detector diffractometer | 1950 independent reflections |
Absorption correction: multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997) | 1663 reflections with I > 2σ(I) |
Tmin = 0.569, Tmax = 0.660 | Rint = 0.029 |
5566 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.029 | 0 restraints |
wR(F2) = 0.077 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.20 e Å−3 |
1950 reflections | Δρmin = −0.43 e Å−3 |
124 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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Ni1 | 0.0000 | 0.0000 | 0.0000 | 0.02691 (11) | |
O1 | 0.2551 (2) | 0.06238 (7) | 0.09298 (18) | 0.0376 (3) | |
C1 | 0.3259 (3) | 0.12642 (9) | 0.0760 (2) | 0.0318 (4) | |
N1 | 0.5128 (3) | 0.14395 (10) | 0.1590 (3) | 0.0498 (4) | |
H1A | 0.5976 | 0.1075 | 0.1908 | 0.060* | |
H1B | 0.5691 | 0.1866 | 0.1364 | 0.060* | |
N2 | 0.2204 (3) | 0.17820 (9) | −0.0177 (3) | 0.0526 (5) | |
H2A | 0.2726 | 0.2225 | −0.0313 | 0.063* | |
H2B | 0.0984 | 0.1672 | −0.0742 | 0.063* | |
O2 | −0.1384 (2) | 0.09345 (7) | −0.11655 (18) | 0.0369 (3) | |
C2 | −0.2888 (3) | 0.10667 (9) | −0.2303 (2) | 0.0319 (4) | |
N3 | −0.3903 (3) | 0.05388 (10) | −0.3254 (3) | 0.0554 (5) | |
H3A | −0.3679 | 0.0077 | −0.2924 | 0.066* | |
H3B | −0.5071 | 0.0630 | −0.3926 | 0.066* | |
N4 | −0.3443 (3) | 0.17702 (9) | −0.2661 (2) | 0.0477 (4) | |
H4A | −0.2958 | 0.2097 | −0.1867 | 0.057* | |
H4B | −0.4649 | 0.1839 | −0.3279 | 0.057* | |
O3W | −0.1327 (2) | 0.02209 (7) | 0.23516 (17) | 0.0360 (3) | |
H1W | −0.1394 | −0.0170 | 0.2917 | 0.043* | |
H2W | −0.0699 | 0.0534 | 0.3018 | 0.043* | |
N5 | 0.1171 (3) | 0.15980 (8) | 0.4816 (2) | 0.0379 (4) | |
O4 | 0.1725 (3) | 0.09362 (7) | 0.5065 (2) | 0.0519 (4) | |
O5 | 0.2291 (3) | 0.21104 (8) | 0.5462 (2) | 0.0598 (5) | |
O6 | −0.0461 (3) | 0.17342 (10) | 0.3884 (3) | 0.0618 (5) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Ni1 | 0.02700 (17) | 0.02084 (15) | 0.03216 (17) | −0.00152 (11) | −0.00065 (11) | 0.00122 (11) |
O1 | 0.0351 (7) | 0.0276 (6) | 0.0483 (8) | −0.0081 (5) | −0.0042 (6) | 0.0056 (5) |
C1 | 0.0313 (8) | 0.0280 (8) | 0.0367 (9) | −0.0046 (7) | 0.0070 (7) | −0.0038 (7) |
N1 | 0.0377 (9) | 0.0422 (9) | 0.0676 (12) | −0.0143 (7) | −0.0045 (8) | 0.0039 (9) |
N2 | 0.0429 (10) | 0.0292 (8) | 0.0828 (14) | −0.0080 (7) | −0.0082 (9) | 0.0103 (9) |
O2 | 0.0353 (7) | 0.0264 (6) | 0.0469 (8) | −0.0005 (5) | −0.0064 (6) | 0.0034 (5) |
C2 | 0.0308 (9) | 0.0301 (8) | 0.0346 (9) | 0.0029 (6) | 0.0025 (7) | 0.0045 (7) |
N3 | 0.0580 (11) | 0.0341 (8) | 0.0673 (12) | −0.0042 (8) | −0.0273 (10) | 0.0048 (8) |
N4 | 0.0557 (11) | 0.0309 (8) | 0.0531 (10) | 0.0109 (7) | −0.0108 (8) | 0.0012 (7) |
O3W | 0.0409 (7) | 0.0322 (6) | 0.0348 (6) | −0.0052 (5) | 0.0036 (5) | −0.0012 (5) |
N5 | 0.0485 (9) | 0.0299 (7) | 0.0348 (8) | 0.0017 (7) | 0.0015 (7) | −0.0007 (6) |
O4 | 0.0722 (10) | 0.0270 (6) | 0.0574 (9) | 0.0074 (7) | 0.0106 (8) | 0.0043 (6) |
O5 | 0.0652 (10) | 0.0340 (7) | 0.0733 (11) | 0.0022 (7) | −0.0267 (9) | −0.0089 (7) |
O6 | 0.0508 (9) | 0.0526 (9) | 0.0768 (12) | 0.0023 (7) | −0.0185 (8) | −0.0029 (8) |
Geometric parameters (Å, º) top
Ni1—O1i | 2.060 (1) | O2—C2 | 1.252 (2) |
Ni1—O1 | 2.060 (1) | C2—N3 | 1.326 (3) |
Ni1—O2 | 2.064 (1) | C2—N4 | 1.340 (2) |
Ni1—O2i | 2.064 (1) | N3—H3A | 0.8777 |
Ni1—O3Wi | 2.082 (1) | N3—H3B | 0.8803 |
Ni1—O3W | 2.082 (1) | N4—H4A | 0.8753 |
O1—C1 | 1.254 (2) | N4—H4B | 0.8750 |
C1—N2 | 1.319 (3) | O3W—H1W | 0.8278 |
C1—N1 | 1.340 (2) | O3W—H2W | 0.8336 |
N1—H1A | 0.8746 | N5—O6 | 1.231 (2) |
N1—H1B | 0.8757 | N5—O5 | 1.243 (2) |
N2—H2A | 0.8779 | N5—O4 | 1.256 (2) |
N2—H2B | 0.8797 | | |
| | | |
O1i—Ni1—O1 | 180.0 (1) | H1A—N1—H1B | 117.1 |
O1i—Ni1—O2 | 90.28 (5) | C1—N2—H2A | 121.6 |
O1—Ni1—O2 | 89.72 (5) | C1—N2—H2B | 119.3 |
O1i—Ni1—O2i | 89.72 (5) | H2A—N2—H2B | 119.0 |
O1—Ni1—O2i | 90.28 (5) | C2—O2—Ni1 | 136.1 (1) |
O2—Ni1—O2i | 180.00 (8) | O2—C2—N3 | 122.7 (2) |
O1i—Ni1—O3Wi | 89.39 (5) | O2—C2—N4 | 119.5 (2) |
O1—Ni1—O3Wi | 90.61 (5) | N3—C2—N4 | 117.7 (2) |
O2—Ni1—O3Wi | 89.55 (5) | C2—N3—H3A | 118.1 |
O2i—Ni1—O3Wi | 90.45 (5) | C2—N3—H3B | 121.7 |
O1i—Ni1—O3W | 90.61 (5) | H3A—N3—H3B | 116.6 |
O1—Ni1—O3W | 89.39 (5) | C2—N4—H4A | 115.5 |
O2—Ni1—O3W | 90.45 (5) | C2—N4—H4B | 116.5 |
O2i—Ni1—O3W | 89.55 (5) | H4A—N4—H4B | 120.4 |
O3Wi—Ni1—O3W | 180.00 (10) | Ni1—O3W—H1W | 108.8 |
C1—O1—Ni1 | 139.16 (13) | Ni1—O3W—H2W | 115.2 |
O1—C1—N2 | 122.3 (2) | H1W—O3W—H2W | 108.4 |
O1—C1—N1 | 119.4 (2) | O6—N5—O5 | 120.4 (2) |
N2—C1—N1 | 118.4 (2) | O6—N5—O4 | 119.3 (2) |
C1—N1—H1A | 117.4 | O5—N5—O4 | 120.3 (2) |
C1—N1—H1B | 119.3 | | |
Symmetry code: (i) −x, −y, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O3Wii | 0.87 | 2.32 | 3.185 (2) | 168 |
N1—H1B···O5iii | 0.88 | 2.25 | 3.125 (2) | 172 |
N2—H2A···O6iii | 0.88 | 2.33 | 3.188 (2) | 167 |
N2—H2B···O2 | 0.88 | 2.03 | 2.814 (2) | 148 |
N3—H3A···O1i | 0.88 | 2.04 | 2.815 (2) | 146 |
N3—H3B···O4iv | 0.88 | 2.20 | 3.062 (3) | 165 |
N4—H4A···O5v | 0.88 | 2.26 | 3.101 (3) | 162 |
N4—H4B···O5iv | 0.88 | 2.16 | 3.031 (2) | 173 |
O3W—H1W···O4vi | 0.83 | 2.08 | 2.884 (2) | 163 |
O3W—H2W···O4 | 0.83 | 2.21 | 2.987 (2) | 156 |
O3W—H2W···O6 | 0.83 | 2.26 | 2.996 (2) | 147 |
Symmetry codes: (i) −x, −y, −z; (ii) x+1, y, z; (iii) x+1/2, −y+1/2, z−1/2; (iv) x−1, y, z−1; (v) x−1/2, −y+1/2, z−1/2; (vi) −x, −y, −z+1. |
(II) Diaquatetrakis(urea-
κO)cobalt(II) nitrate
top
Crystal data top
[Co(CH4N2O)4(H2O)2](NO3)2 | F(000) = 474 |
Mr = 459.23 | Dx = 1.731 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 2469 reflections |
a = 6.4655 (2) Å | θ = 1.0–30.5° |
b = 17.9321 (5) Å | µ = 1.06 mm−1 |
c = 7.6201 (2) Å | T = 293 K |
β = 94.428 (1)° | Block, pink |
V = 880.84 (4) Å3 | 0.32 × 0.32 × 0.20 mm |
Z = 2 | |
Data collection top
Nonius KappaCCD diffractometer | 2661 independent reflections |
Radiation source: fine-focus sealed tube | 2133 reflections with I > 2σ(I) |
Horizontally mounted graphite crystal monochromator | Rint = 0.017 |
Detector resolution: 9 pixels mm-1 | θmax = 30.5°, θmin = 2.9° |
ϕ and ω scans to fill Ewald sphere | h = −9→9 |
Absorption correction: multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997) | k = −25→16 |
Tmin = 0.729, Tmax = 0.816 | l = −10→10 |
8072 measured reflections | |
Refinement top
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.032 | w = 1/[σ2(Fo2) + (0.0306P)2 + 0.3065P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.082 | (Δ/σ)max < 0.001 |
S = 1.04 | Δρmax = 0.22 e Å−3 |
2661 reflections | Δρmin = −0.31 e Å−3 |
124 parameters | |
Crystal data top
[Co(CH4N2O)4(H2O)2](NO3)2 | V = 880.84 (4) Å3 |
Mr = 459.23 | Z = 2 |
Monoclinic, P21/n | Mo Kα radiation |
a = 6.4655 (2) Å | µ = 1.06 mm−1 |
b = 17.9321 (5) Å | T = 293 K |
c = 7.6201 (2) Å | 0.32 × 0.32 × 0.20 mm |
β = 94.428 (1)° | |
Data collection top
Nonius KappaCCD diffractometer | 2661 independent reflections |
Absorption correction: multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997) | 2133 reflections with I > 2σ(I) |
Tmin = 0.729, Tmax = 0.816 | Rint = 0.017 |
8072 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.032 | 0 restraints |
wR(F2) = 0.082 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.22 e Å−3 |
2661 reflections | Δρmin = −0.31 e Å−3 |
124 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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Co1 | 0.0000 | 0.0000 | 0.0000 | 0.03007 (9) | |
O1 | 0.25432 (17) | 0.06469 (6) | 0.09121 (16) | 0.0399 (3) | |
C1 | 0.3279 (2) | 0.12845 (8) | 0.0699 (2) | 0.0336 (3) | |
N1 | 0.5123 (2) | 0.14661 (9) | 0.1514 (2) | 0.0506 (4) | |
H1A | 0.5891 | 0.1087 | 0.1901 | 0.061* | |
H1B | 0.5751 | 0.1878 | 0.1260 | 0.061* | |
N2 | 0.2265 (2) | 0.17982 (8) | −0.0271 (2) | 0.0505 (4) | |
H2A | 0.2842 | 0.2227 | −0.0470 | 0.061* | |
H2B | 0.1046 | 0.1686 | −0.0791 | 0.061* | |
O2 | −0.13365 (18) | 0.09466 (6) | −0.12187 (16) | 0.0405 (3) | |
C2 | −0.2825 (2) | 0.10766 (8) | −0.2332 (2) | 0.0336 (3) | |
N3 | −0.3842 (3) | 0.05372 (9) | −0.3228 (2) | 0.0575 (5) | |
H3A | −0.3558 | 0.0078 | −0.2906 | 0.069* | |
H3B | −0.4997 | 0.0638 | −0.3872 | 0.069* | |
N4 | −0.3378 (3) | 0.17796 (8) | −0.2710 (2) | 0.0474 (4) | |
H4A | −0.2852 | 0.2115 | −0.1979 | 0.057* | |
H4B | −0.4529 | 0.1868 | −0.3347 | 0.057* | |
O3W | −0.13752 (18) | 0.02501 (6) | 0.23823 (15) | 0.0387 (2) | |
H1W | −0.1400 | −0.0139 | 0.2980 | 0.046* | |
H2W | −0.0730 | 0.0575 | 0.2988 | 0.046* | |
N5 | 0.1322 (2) | 0.15805 (7) | 0.48042 (18) | 0.0400 (3) | |
O4 | 0.1887 (2) | 0.09217 (7) | 0.50999 (19) | 0.0557 (4) | |
O5 | 0.2408 (2) | 0.21074 (7) | 0.5405 (2) | 0.0594 (4) | |
O6 | −0.0294 (2) | 0.17065 (8) | 0.3883 (2) | 0.0598 (4) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Co1 | 0.03102 (15) | 0.02249 (13) | 0.03619 (16) | −0.00132 (10) | −0.00070 (11) | 0.00200 (10) |
O1 | 0.0393 (6) | 0.0289 (5) | 0.0504 (7) | −0.0090 (4) | −0.0045 (5) | 0.0054 (5) |
C1 | 0.0353 (7) | 0.0294 (7) | 0.0367 (8) | −0.0044 (6) | 0.0069 (6) | −0.0036 (6) |
N1 | 0.0399 (8) | 0.0429 (8) | 0.0677 (11) | −0.0138 (6) | −0.0043 (7) | 0.0064 (7) |
N2 | 0.0473 (9) | 0.0290 (7) | 0.0733 (11) | −0.0076 (6) | −0.0075 (8) | 0.0085 (7) |
O2 | 0.0394 (6) | 0.0274 (5) | 0.0528 (7) | 0.0002 (4) | −0.0076 (5) | 0.0049 (5) |
C2 | 0.0339 (7) | 0.0296 (7) | 0.0376 (8) | 0.0031 (6) | 0.0040 (6) | 0.0042 (6) |
N3 | 0.0615 (10) | 0.0336 (7) | 0.0725 (11) | −0.0018 (7) | −0.0275 (9) | 0.0048 (7) |
N4 | 0.0573 (9) | 0.0298 (6) | 0.0530 (9) | 0.0096 (6) | −0.0096 (7) | 0.0018 (6) |
O3W | 0.0424 (6) | 0.0349 (5) | 0.0384 (6) | −0.0060 (5) | 0.0017 (5) | 0.0005 (5) |
N5 | 0.0520 (8) | 0.0305 (6) | 0.0376 (7) | 0.0030 (6) | 0.0040 (6) | 0.0000 (5) |
O4 | 0.0792 (10) | 0.0292 (6) | 0.0593 (8) | 0.0086 (6) | 0.0089 (7) | 0.0064 (5) |
O5 | 0.0677 (9) | 0.0350 (6) | 0.0709 (9) | 0.0016 (6) | −0.0235 (7) | −0.0079 (6) |
O6 | 0.0524 (8) | 0.0509 (8) | 0.0728 (10) | 0.0026 (6) | −0.0159 (7) | −0.0052 (7) |
Geometric parameters (Å, º) top
Co1—O1i | 2.087 (1) | O2—C2 | 1.254 (2) |
Co1—O1 | 2.087 (1) | C2—N3 | 1.328 (2) |
Co1—O2i | 2.090 (1) | C2—N4 | 1.336 (2) |
Co1—O2 | 2.090 (1) | N3—H3A | 0.8743 |
Co1—O3Wi | 2.130 (1) | N3—H3B | 0.8801 |
Co1—O3W | 2.130 (1) | N4—H4A | 0.8711 |
O1—C1 | 1.254 (2) | N4—H4B | 0.8713 |
C1—N2 | 1.323 (2) | O3W—H1W | 0.8334 |
C1—N1 | 1.341 (2) | O3W—H2W | 0.8352 |
N1—H1A | 0.8784 | N5—O6 | 1.234 (2) |
N1—H1B | 0.8712 | N5—O5 | 1.244 (2) |
N2—H2A | 0.8732 | N5—O4 | 1.252 (2) |
N2—H2B | 0.8779 | | |
| | | |
O1i—Co1—O1 | 180.00 (9) | H1A—N1—H1B | 117.9 |
O1i—Co1—O2i | 89.12 (4) | C1—N2—H2A | 120.7 |
O1—Co1—O2i | 90.88 (4) | C1—N2—H2B | 118.8 |
O1i—Co1—O2 | 90.88 (4) | H2A—N2—H2B | 120.3 |
O1—Co1—O2 | 89.12 (4) | C2—O2—Co1 | 136.1 (1) |
O2i—Co1—O2 | 180.00 (7) | O2—C2—N3 | 122.4 (1) |
O1i—Co1—O3Wi | 88.23 (5) | O2—C2—N4 | 120.0 (2) |
O1—Co1—O3Wi | 91.77 (5) | N3—C2—N4 | 117.5 (2) |
O2i—Co1—O3Wi | 91.27 (5) | C2—N3—H3A | 117.1 |
O2—Co1—O3Wi | 88.73 (5) | C2—N3—H3B | 120.2 |
O1i—Co1—O3W | 91.77 (5) | H3A—N3—H3B | 120.0 |
O1—Co1—O3W | 88.23 (5) | C2—N4—H4A | 115.4 |
O2i—Co1—O3W | 88.73 (5) | C2—N4—H4B | 119.7 |
O2—Co1—O3W | 91.27 (5) | H4A—N4—H4B | 120.3 |
O3Wi—Co1—O3W | 180.00 (8) | Co1—O3W—H1W | 108.4 |
C1—O1—Co1 | 139.5 (1) | Co1—O3W—H2W | 113.2 |
O1—C1—N2 | 122.1 (2) | H1W—O3W—H2W | 108.2 |
O1—C1—N1 | 119.6 (2) | O6—N5—O5 | 120.0 (1) |
N2—C1—N1 | 118.3 (1) | O6—N5—O4 | 119.9 (2) |
C1—N1—H1A | 115.3 | O5—N5—O4 | 120.1 (2) |
C1—N1—H1B | 121.0 | | |
Symmetry code: (i) −x, −y, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O3Wii | 0.88 | 2.33 | 3.176 (2) | 163 |
N1—H1B···O5iii | 0.87 | 2.23 | 3.104 (2) | 176 |
N2—H2A···O6iii | 0.87 | 2.33 | 3.202 (2) | 173 |
N2—H2B···O2 | 0.88 | 2.04 | 2.831 (2) | 150 |
N3—H3A···O1i | 0.87 | 2.07 | 2.846 (2) | 148 |
N3—H3B···O4iv | 0.88 | 2.16 | 3.030 (2) | 167 |
N4—H4A···O5v | 0.87 | 2.29 | 3.113 (2) | 159 |
N4—H4B···O5iv | 0.87 | 2.17 | 3.037 (2) | 172 |
O3W—H1W···O4vi | 0.83 | 2.07 | 2.882 (2) | 165 |
O3W—H2W···O4 | 0.84 | 2.33 | 3.084 (2) | 151 |
O3W—H2W···O6 | 0.84 | 2.15 | 2.914 (2) | 152 |
Symmetry codes: (i) −x, −y, −z; (ii) x+1, y, z; (iii) x+1/2, −y+1/2, z−1/2; (iv) x−1, y, z−1; (v) x−1/2, −y+1/2, z−1/2; (vi) −x, −y, −z+1. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | [Ni(CH4N2O)4(H2O)2](NO3)2 | [Co(CH4N2O)4(H2O)2](NO3)2 |
Mr | 459.01 | 459.23 |
Crystal system, space group | Monoclinic, P21/n | Monoclinic, P21/n |
Temperature (K) | 293 | 293 |
a, b, c (Å) | 6.4580 (2), 18.0522 (5), 7.5331 (3) | 6.4655 (2), 17.9321 (5), 7.6201 (2) |
β (°) | 95.758 (2) | 94.428 (1) |
V (Å3) | 873.79 (5) | 880.84 (4) |
Z | 2 | 2 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 1.19 | 1.06 |
Crystal size (mm) | 0.50 × 0.48 × 0.35 | 0.32 × 0.32 × 0.20 |
|
Data collection |
Diffractometer | Nonius KappaCCD area-detector diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997) | Multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997) |
Tmin, Tmax | 0.569, 0.660 | 0.729, 0.816 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5566, 1950, 1663 | 8072, 2661, 2133 |
Rint | 0.029 | 0.017 |
(sin θ/λ)max (Å−1) | 0.649 | 0.714 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.029, 0.077, 1.04 | 0.032, 0.082, 1.04 |
No. of reflections | 1950 | 2661 |
No. of parameters | 124 | 124 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.20, −0.43 | 0.22, −0.31 |
Selected bond lengths (Å) for (I) topNi1—O1 | 2.060 (1) | O2—C2 | 1.252 (2) |
Ni1—O2 | 2.064 (1) | C2—N3 | 1.326 (3) |
Ni1—O3W | 2.082 (1) | C2—N4 | 1.340 (2) |
O1—C1 | 1.254 (2) | N5—O6 | 1.231 (2) |
C1—N2 | 1.319 (3) | N5—O5 | 1.243 (2) |
C1—N1 | 1.340 (2) | N5—O4 | 1.256 (2) |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O3Wi | 0.87 | 2.32 | 3.185 (2) | 168 |
N1—H1B···O5ii | 0.88 | 2.25 | 3.125 (2) | 172 |
N2—H2A···O6ii | 0.88 | 2.33 | 3.188 (2) | 167 |
N2—H2B···O2 | 0.88 | 2.03 | 2.814 (2) | 148 |
N3—H3A···O1iii | 0.88 | 2.04 | 2.815 (2) | 146 |
N3—H3B···O4iv | 0.88 | 2.20 | 3.062 (3) | 165 |
N4—H4A···O5v | 0.88 | 2.26 | 3.101 (3) | 162 |
N4—H4B···O5iv | 0.88 | 2.16 | 3.031 (2) | 173 |
O3W—H1W···O4vi | 0.83 | 2.08 | 2.884 (2) | 163 |
O3W—H2W···O4 | 0.83 | 2.21 | 2.987 (2) | 156 |
O3W—H2W···O6 | 0.83 | 2.26 | 2.996 (2) | 147 |
Symmetry codes: (i) x+1, y, z; (ii) x+1/2, −y+1/2, z−1/2; (iii) −x, −y, −z; (iv) x−1, y, z−1; (v) x−1/2, −y+1/2, z−1/2; (vi) −x, −y, −z+1. |
Quantitative graph-set descriptors of the first and second levels for structures (I) and (II) topH-bond type | (a) | (b) | (c) | (d) |
(a) | R44(16) | | | |
(b) | D44(16) | DD, R22(8) | | |
(c) | | | R22(8), R12(4), D21(8)[R22(8)] | |
(d) | | | | R22(12) |
(a) N—H···O═C; (b) N—H···O—N; (c) O—H···O—N; (d) N—H···O—H. |
Urea plays an important role in crystal engineering. Possessing donor and acceptor functional groups (one carbonyl and two amino groups), it can form rich hydrogen-bond networks. Due to lone electron pairs on the N and O atoms, urea can also coordinate to metal ions through either N or O. Several nickel(II) and cobalt(II) complexes containing more than two urea molecules in the coordination environment are found in the Cambridge Structural Database (CSD, Version 5.28, 2006; Allen, 2002) with refcodes ADUFEK (Rybak-Akimova et al., 2002), FOWQIR (Kuzmina et al., 2000), NIIURC (Suleyman & Porai-Koshits, 1971), COLLAQ (Suleymanov et al., 1984), FADGEX (Kuzmina et al., 2001) and FOWQOX (Kuzmina et al., 2000). They consist mainly of discrete M(urea)6 cations, one additional free urea molecule per cation, and counterions such as Cl−, Br−, I−, I3− and NO3−.
Here, we report the crystal structures of the isostructural complexes diaquatetrakis(urea)nickel(II) nitrate, (I), and diaquatetrakis(urea)cobalt(II) nitrate, (II). The crystal structure of (II), previously reported by Rau & Kurkutova (1971), was redetermined because of the high R-factor (0.192) and lack of H atoms in the earlier work. The presence of many hydrogen bonds in (I) and (II) results in characteristic arrays which may be described by graph-set analysis according to Etter et al. (1990) and Bernstein et al. (1995).
The centrosymmetric complex cation of (I) consists of four urea molecules coordinated via O atoms to the NiII central atom in equatorial positions and two water molecules in trans positions. The coordination polyhedron is a near-perfect octahedron, with angular deviations of less than 0.5°. The positive charge of the Ni cation is balanced by two nitrate anions, NO3−, as shown in Fig. 1. The urea C═O bond lengths (Table 1) are shortened and the C—N bonds (C1—N1 and C2—N4) are elongated in both symmetry-independent molecules. The shortening of the C═O bond lengths is caused by two functions of the O atom: it acts as an acceptor in intramolecular N—H···O hydrogen bonds and, at the same time, as the ligand to the central cation. The elongation of the urea C—N bond lengths is induced by the strong acceptor properties of the O atoms of the nitrate groups in intermolecular hydrogen bonds of N—H···O—N type. The packing in (I) viewed along [100] is shown in Fig. 2. The discrete coordination polyhedra are packed in a pseudo-hexagonal pattern and are separated by nitrate anions.
For both structures, the geometric parameters of the urea molecules are equal within the limits of error, whereas the M—O bond lengths of (I) are relatively short compared with those of (II), which is caused by the difference in the Ni2+ and Co2+ ionic radii (Shannon, 1976). The differences in M—O bond lengths are typical for all structures quoted from the CSD.
All H atoms participate in hydrogen bonds, which can be classified into four types by functional group: (a) N—H···O═C, (b) N—H···O—N, (c) O—H···O—N and (d) N—H···O—H. For the network of observed hydrogen bonds, graph-set analysis (Etter et al., 1990; Bernstein et al., 1995) was applied, taking into account unitary, binary and ternary graph sets.
The unitary graph sets (N1) are shown in Fig. 3. Patterns for (a), (b) and (c) type hydrogen bonds are in the same layer, perpendicular to [101]. Inside the complex cation, there is an R44(16) motif built of N—H···O═C hydrogen bonds [i.e. type(a)]. The patterns consisting of type (b) hydrogen bonds can be described as ring arrays. However, the hydrogen bonds are not crystallographically equivalent, so the pattern should have a DD descriptor assigned, which on the binary graph level converts to an R22(8) descriptor. A similar situation is observed in the case of type (c) bond patterns. The motifs composed of bifurcated hydrogen bonds between water molecules and nitrate anions have DD descriptors on the first-level graph set and R12(4) on the second-level graph set. For type (c) hydrogen bonds, one can also distinguish an R22(8) ring at the unitary level and an R42(12) ring, which can be obtained by assembling three rings, two R12(4) and one R22(8).
Additionally, there is a motif composed of type (c) hydrogen bonds which occurs as a `chain of rings', having descriptor D21(8)[R22(8)], which describes the chain along the [001] direction with only one branch of the R22(8) ring included. The motif built of type (d) hydrogen bonds, in the form of an R22(12) ring, is shown in Fig. 4; it joins neighbouring layers perpendicular to [101] into a three-dimensional structure. Higher level graph sets, not marked in the figures, can also be defined. Among them there are, for example, a D44(16) binary graph set (N2) built with (a) and (b) type hydrogen bonds, and a D46(20) third-level graph set (N3) formed by (a), (b) and (c) type hydrogen bonds. The quantitative descriptors of hydrogen-bond patterns at the unitary and binary graph set levels, identical for the isostructural crystalline phases of (I) and (II), are given in Table 3.
In conclusion, the most important description seems to be that of the first-level graph sets (motifs), as, in general, assembling the unitary graph sets provides the patterns consisting of a few hydrogen-bond types which are then described by higher level graph sets.