Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102013227/gg1121sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102013227/gg1121IIIsup2.hkl | |
Portable Document Format (PDF) file https://doi.org/10.1107/S0108270102013227/gg1121sup3.pdf |
CCDC reference: 195605
Hydrated copper nitrate (0.5 mmol) was added slowly over a period of 6 h to a stirred aqueous solution of (I) (1 mmol), acidified with HNO3 0.1 mol l-1. The reaction mixture was concentrated to half volume, and ethanol and acetone were added. After a period of 7 months at room temperature, small green crystals were collected from the reaction mixture, washed with acetone, and air-dried.
All H atoms were placed in geometrically calculated positions and refined using a riding model. Both nitrate groups were located in positions with the centre of gravity outside the unit cell so as to emphasis the hydrogen bonding from the amino groups. Two high residual electron densities were located close to the Cu atom as follows: 1.48 e Å-3 at 0.90 Å and 1.42 e Å-3 at 0.88 Å.
Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEX in OSCAIL (McArdle, 1994, 2000) and ORTEP-3 for Windows (Farrugia, 1999); software used to prepare material for publication: SHELXL97.
[Cu2(NO3)2(C3H7N3O2)4] | Z = 1 |
Mr = 843.58 | F(000) = 430 |
Triclinic, P1 | Dx = 1.875 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.2535 (8) Å | Cell parameters from 3425 reflections |
b = 10.3652 (12) Å | θ = 3.7–29.9° |
c = 10.5626 (12) Å | µ = 1.54 mm−1 |
α = 99.262 (2)° | T = 298 K |
β = 94.862 (2)° | Block, green |
γ = 105.844 (2)° | 0.58 × 0.22 × 0.18 mm |
V = 747.05 (15) Å3 |
Bruker SMART 1000 area-detector diffractometer | 4202 independent reflections |
Radiation source: fine-focus sealed tube | 3433 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.019 |
ϕ–ω scans | θmax = 30.0°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | h = −9→10 |
Tmin = 0.596, Tmax = 0.928 | k = −14→14 |
6444 measured reflections | l = −14→12 |
Refinement on F2 | Primary atom site location: heavy-atom method |
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) = 0.115 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0744P)2] where P = (Fo2 + 2Fc2)/3 |
4202 reflections | (Δ/σ)max < 0.001 |
226 parameters | Δρmax = 1.48 e Å−3 |
0 restraints | Δρmin = −0.82 e Å−3 |
[Cu2(NO3)2(C3H7N3O2)4] | γ = 105.844 (2)° |
Mr = 843.58 | V = 747.05 (15) Å3 |
Triclinic, P1 | Z = 1 |
a = 7.2535 (8) Å | Mo Kα radiation |
b = 10.3652 (12) Å | µ = 1.54 mm−1 |
c = 10.5626 (12) Å | T = 298 K |
α = 99.262 (2)° | 0.58 × 0.22 × 0.18 mm |
β = 94.862 (2)° |
Bruker SMART 1000 area-detector diffractometer | 4202 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | 3433 reflections with I > 2σ(I) |
Tmin = 0.596, Tmax = 0.928 | Rint = 0.019 |
6444 measured reflections |
R[F2 > 2σ(F2)] = 0.042 | 0 restraints |
wR(F2) = 0.115 | H-atom parameters constrained |
S = 1.03 | Δρmax = 1.48 e Å−3 |
4202 reflections | Δρmin = −0.82 e Å−3 |
226 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Cu1 | 0.05573 (4) | 0.39677 (3) | 0.03268 (3) | 0.02115 (10) | |
O1 | 0.2694 (3) | 0.53970 (17) | 0.14535 (18) | 0.0301 (4) | |
O2 | 0.1848 (3) | 0.71442 (17) | 0.08056 (19) | 0.0300 (4) | |
C1 | 0.2956 (3) | 0.6653 (2) | 0.1418 (2) | 0.0233 (4) | |
C2 | 0.4821 (4) | 0.7604 (2) | 0.2181 (3) | 0.0273 (5) | |
H2A | 0.4824 | 0.7539 | 0.3087 | 0.033* | |
H2B | 0.5900 | 0.7316 | 0.1880 | 0.033* | |
N1 | 0.5080 (3) | 0.9009 (2) | 0.2058 (2) | 0.0290 (5) | |
H1 | 0.4112 | 0.9332 | 0.2127 | 0.035* | |
C3 | 0.6741 (4) | 0.9828 (2) | 0.1843 (2) | 0.0257 (5) | |
N2 | 0.8383 (3) | 0.9524 (2) | 0.2049 (3) | 0.0348 (5) | |
H2C | 0.9454 | 1.0060 | 0.1890 | 0.042* | |
H2D | 0.8392 | 0.8789 | 0.2344 | 0.042* | |
N3 | 0.6731 (3) | 1.0946 (2) | 0.1395 (3) | 0.0376 (6) | |
H3A | 0.7792 | 1.1474 | 0.1238 | 0.045* | |
H3B | 0.5665 | 1.1145 | 0.1260 | 0.045* | |
O3 | 0.1931 (3) | 0.41627 (19) | −0.11745 (19) | 0.0322 (4) | |
O4 | 0.1051 (3) | 0.59314 (18) | −0.17442 (18) | 0.0294 (4) | |
C4 | 0.1972 (3) | 0.5065 (2) | −0.1854 (2) | 0.0241 (5) | |
C5 | 0.3287 (4) | 0.5058 (3) | −0.2883 (3) | 0.0323 (5) | |
H5A | 0.4525 | 0.5013 | −0.2498 | 0.039* | |
H5B | 0.2733 | 0.4243 | −0.3545 | 0.039* | |
N4 | 0.3602 (3) | 0.6244 (2) | −0.3486 (2) | 0.0294 (4) | |
H4 | 0.2650 | 0.6574 | −0.3616 | 0.035* | |
C6 | 0.5278 (4) | 0.6851 (3) | −0.3848 (2) | 0.0283 (5) | |
N5 | 0.6796 (3) | 0.6381 (3) | −0.3691 (2) | 0.0377 (5) | |
H5C | 0.6701 | 0.5663 | −0.3344 | 0.045* | |
H5D | 0.7884 | 0.6791 | −0.3934 | 0.045* | |
N6 | 0.5424 (4) | 0.7940 (3) | −0.4396 (2) | 0.0416 (6) | |
H6A | 0.4440 | 0.8240 | −0.4511 | 0.050* | |
H6B | 0.6503 | 0.8342 | −0.4636 | 0.050* | |
N7 | 1.2363 (3) | 1.1781 (2) | 0.0977 (2) | 0.0265 (4) | |
O5 | 1.0840 (3) | 1.21251 (18) | 0.0901 (2) | 0.0338 (4) | |
O6 | 1.3866 (3) | 1.2486 (2) | 0.0676 (2) | 0.0393 (5) | |
O7 | 1.2319 (3) | 1.0699 (2) | 0.1363 (3) | 0.0473 (6) | |
N8 | 1.0644 (4) | 0.8231 (3) | −0.5208 (3) | 0.0419 (6) | |
O8 | 0.9049 (3) | 0.8286 (3) | −0.5674 (3) | 0.0564 (6) | |
O9 | 1.0676 (4) | 0.7543 (3) | −0.4343 (3) | 0.0658 (8) | |
O10 | 1.2169 (4) | 0.8842 (4) | −0.5553 (4) | 0.0847 (10) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cu1 | 0.01961 (15) | 0.02001 (14) | 0.02490 (16) | 0.00489 (10) | 0.00108 (10) | 0.00995 (10) |
O1 | 0.0269 (9) | 0.0227 (8) | 0.0377 (10) | 0.0033 (7) | −0.0058 (7) | 0.0096 (7) |
O2 | 0.0250 (9) | 0.0245 (8) | 0.0380 (10) | 0.0037 (7) | −0.0061 (7) | 0.0100 (7) |
C1 | 0.0224 (11) | 0.0233 (10) | 0.0233 (11) | 0.0045 (8) | 0.0022 (8) | 0.0065 (9) |
C2 | 0.0241 (11) | 0.0236 (10) | 0.0318 (13) | 0.0034 (9) | −0.0034 (9) | 0.0084 (9) |
N1 | 0.0220 (10) | 0.0220 (9) | 0.0431 (13) | 0.0065 (8) | 0.0027 (9) | 0.0074 (9) |
C3 | 0.0243 (11) | 0.0237 (10) | 0.0270 (12) | 0.0047 (9) | −0.0001 (9) | 0.0052 (9) |
N2 | 0.0200 (10) | 0.0345 (11) | 0.0520 (14) | 0.0051 (9) | 0.0020 (9) | 0.0205 (10) |
N3 | 0.0270 (11) | 0.0303 (11) | 0.0589 (16) | 0.0074 (9) | 0.0024 (10) | 0.0215 (11) |
O3 | 0.0367 (10) | 0.0325 (9) | 0.0360 (10) | 0.0148 (8) | 0.0133 (8) | 0.0188 (8) |
O4 | 0.0326 (9) | 0.0300 (8) | 0.0315 (9) | 0.0128 (7) | 0.0107 (7) | 0.0132 (7) |
C4 | 0.0218 (11) | 0.0243 (10) | 0.0251 (11) | 0.0039 (8) | 0.0017 (9) | 0.0069 (9) |
C5 | 0.0355 (14) | 0.0304 (12) | 0.0369 (14) | 0.0122 (11) | 0.0139 (11) | 0.0138 (11) |
N4 | 0.0260 (10) | 0.0353 (11) | 0.0330 (11) | 0.0121 (9) | 0.0078 (8) | 0.0162 (9) |
C6 | 0.0292 (12) | 0.0351 (12) | 0.0186 (11) | 0.0066 (10) | 0.0017 (9) | 0.0054 (9) |
N5 | 0.0284 (11) | 0.0509 (14) | 0.0380 (13) | 0.0127 (10) | 0.0087 (10) | 0.0166 (11) |
N6 | 0.0353 (13) | 0.0506 (14) | 0.0433 (14) | 0.0080 (11) | 0.0073 (11) | 0.0281 (12) |
N7 | 0.0267 (10) | 0.0244 (9) | 0.0275 (11) | 0.0077 (8) | −0.0025 (8) | 0.0053 (8) |
O5 | 0.0246 (9) | 0.0307 (9) | 0.0522 (12) | 0.0113 (7) | 0.0043 (8) | 0.0204 (9) |
O6 | 0.0266 (10) | 0.0478 (11) | 0.0422 (12) | 0.0054 (8) | 0.0062 (8) | 0.0134 (9) |
O7 | 0.0400 (12) | 0.0387 (11) | 0.0764 (17) | 0.0214 (9) | 0.0098 (11) | 0.0308 (11) |
N8 | 0.0329 (13) | 0.0498 (14) | 0.0459 (15) | 0.0109 (11) | 0.0057 (11) | 0.0190 (12) |
O8 | 0.0389 (12) | 0.0815 (17) | 0.0598 (15) | 0.0222 (12) | 0.0027 (11) | 0.0387 (13) |
O9 | 0.0452 (14) | 0.098 (2) | 0.0730 (18) | 0.0286 (14) | 0.0094 (13) | 0.0551 (17) |
O10 | 0.0458 (15) | 0.103 (2) | 0.125 (3) | 0.0195 (16) | 0.0376 (17) | 0.067 (2) |
Cu1—O1 | 1.9696 (17) | O3—C4 | 1.263 (3) |
Cu1—O2i | 1.9766 (17) | O4—C4 | 1.254 (3) |
Cu1—O3 | 1.9520 (19) | C4—C5 | 1.506 (4) |
Cu1—O4i | 1.9814 (19) | C5—N4 | 1.447 (3) |
Cu1—O5ii | 2.1500 (18) | C5—H5A | 0.9700 |
Cu1—Cu1i | 2.6525 (6) | C5—H5B | 0.9700 |
O1—C1 | 1.271 (3) | N4—C6 | 1.326 (3) |
O2—C1 | 1.250 (3) | N4—H4 | 0.8600 |
C1—C2 | 1.511 (3) | C6—N5 | 1.328 (4) |
C2—N1 | 1.446 (3) | C6—N6 | 1.332 (3) |
C2—H2A | 0.9700 | N5—H5C | 0.8700 |
C2—H2B | 0.9700 | N5—H5D | 0.8700 |
N1—C3 | 1.332 (3) | N6—H6A | 0.8600 |
N1—H1 | 0.8600 | N6—H6B | 0.8600 |
C3—N3 | 1.322 (3) | N7—O6 | 1.234 (3) |
C3—N2 | 1.322 (3) | N7—O7 | 1.247 (3) |
N2—H2C | 0.8700 | N7—O5 | 1.251 (3) |
N2—H2D | 0.8700 | N8—O10 | 1.232 (4) |
N3—H3A | 0.8600 | N8—O8 | 1.239 (3) |
N3—H3B | 0.8600 | N8—O9 | 1.248 (3) |
O1—Cu1—O3 | 91.26 (8) | H2C—N2—H2D | 120.0 |
O1—Cu1—O2i | 167.60 (7) | C3—N3—H3A | 120.0 |
O3—Cu1—O2i | 90.80 (8) | C3—N3—H3B | 120.0 |
O1—Cu1—O4i | 88.53 (8) | H3A—N3—H3B | 120.0 |
O2i—Cu1—O4i | 86.96 (8) | C4—O3—Cu1 | 125.36 (17) |
O3—Cu1—O4i | 168.16 (7) | C4—O4—Cu1i | 119.68 (16) |
O3—Cu1—O5ii | 106.12 (8) | O4—C4—O3 | 126.6 (2) |
O1—Cu1—O5ii | 102.88 (7) | O4—C4—C5 | 119.1 (2) |
O2i—Cu1—O5ii | 88.27 (7) | O3—C4—C5 | 114.2 (2) |
O4i—Cu1—O5ii | 85.44 (8) | N4—C5—C4 | 113.5 (2) |
O1—Cu1—Cu1i | 85.12 (5) | N4—C5—H5A | 108.9 |
O2i—Cu1—Cu1i | 83.05 (5) | C4—C5—H5A | 108.9 |
O3—Cu1—Cu1i | 82.21 (5) | N4—C5—H5B | 108.9 |
O4i—Cu1—Cu1i | 85.98 (5) | C4—C5—H5B | 108.9 |
O5ii—Cu1—Cu1i | 168.10 (5) | H5A—C5—H5B | 107.7 |
C1—O1—Cu1 | 121.17 (15) | C6—N4—C5 | 123.6 (2) |
C1—O2—Cu1i | 123.92 (15) | C6—N4—H4 | 118.2 |
O2—C1—O1 | 126.3 (2) | C5—N4—H4 | 118.2 |
O2—C1—C2 | 118.9 (2) | N4—C6—N5 | 121.2 (2) |
O1—C1—C2 | 114.8 (2) | N4—C6—N6 | 119.1 (3) |
N1—C2—C1 | 112.3 (2) | N5—C6—N6 | 119.7 (3) |
N1—C2—H2A | 109.1 | C6—N5—H5C | 120.0 |
C1—C2—H2A | 109.1 | C6—N5—H5D | 120.0 |
N1—C2—H2B | 109.1 | H5C—N5—H5D | 120.0 |
C1—C2—H2B | 109.1 | C6—N6—H6A | 120.0 |
H2A—C2—H2B | 107.9 | C6—N6—H6B | 120.0 |
C3—N1—C2 | 123.3 (2) | H6A—N6—H6B | 120.0 |
C3—N1—H1 | 118.3 | O6—N7—O7 | 120.8 (2) |
C2—N1—H1 | 118.3 | O6—N7—O5 | 121.1 (2) |
N3—C3—N2 | 119.9 (2) | O7—N7—O5 | 118.0 (2) |
N3—C3—N1 | 119.2 (2) | N7—O5—Cu1iii | 125.31 (15) |
N2—C3—N1 | 120.9 (2) | O10—N8—O8 | 122.4 (3) |
C3—N2—H2C | 120.0 | O10—N8—O9 | 120.0 (3) |
C3—N2—H2D | 120.0 | O8—N8—O9 | 117.7 (3) |
O3—Cu1—O1—C1 | 75.3 (2) | O2i—Cu1—O3—C4 | 85.8 (2) |
O2i—Cu1—O1—C1 | −24.2 (5) | O4i—Cu1—O3—C4 | 6.9 (5) |
O4i—Cu1—O1—C1 | −92.9 (2) | O5ii—Cu1—O3—C4 | 174.25 (19) |
O5ii—Cu1—O1—C1 | −177.84 (19) | Cu1i—Cu1—O3—C4 | 2.95 (19) |
Cu1i—Cu1—O1—C1 | −6.76 (19) | Cu1i—O4—C4—O3 | 3.6 (3) |
Cu1i—O2—C1—O1 | −2.8 (4) | Cu1i—O4—C4—C5 | −176.16 (17) |
Cu1i—O2—C1—C2 | 175.94 (17) | Cu1—O3—C4—O4 | −4.9 (4) |
Cu1—O1—C1—O2 | 7.8 (4) | Cu1—O3—C4—C5 | 174.81 (17) |
Cu1—O1—C1—C2 | −170.95 (16) | O4—C4—C5—N4 | 10.8 (3) |
O2—C1—C2—N1 | −1.4 (3) | O3—C4—C5—N4 | −169.0 (2) |
O1—C1—C2—N1 | 177.4 (2) | C4—C5—N4—C6 | 143.2 (2) |
C1—C2—N1—C3 | −134.7 (3) | C5—N4—C6—N5 | 1.0 (4) |
C2—N1—C3—N3 | 161.5 (3) | C5—N4—C6—N6 | −180.0 (2) |
C2—N1—C3—N2 | −17.3 (4) | O6—N7—O5—Cu1iii | −2.4 (3) |
O1—Cu1—O3—C4 | −81.9 (2) | O7—N7—O5—Cu1iii | 177.83 (19) |
Symmetry codes: (i) −x, −y+1, −z; (ii) x−1, y−1, z; (iii) x+1, y+1, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O7iv | 0.86 | 2.35 | 3.114 (3) | 147 |
N2—H2D···O8v | 0.87 | 2.28 | 2.966 (3) | 136 |
N2—H2C···O7 | 0.87 | 2.15 | 2.983 (3) | 160 |
N3—H3A···O5 | 0.86 | 2.21 | 3.021 (3) | 158 |
N3—H3A···O4vi | 0.86 | 2.54 | 3.142 (3) | 128 |
N3—H3B···O6iv | 0.86 | 2.27 | 3.063 (3) | 154 |
N3—H3B···O7iv | 0.86 | 2.36 | 3.137 (3) | 151 |
N4—H4···O9iv | 0.86 | 2.12 | 2.960 (3) | 165 |
N5—H5C···O1vii | 0.87 | 2.49 | 3.278 (3) | 151 |
N5—H5D···O9 | 0.87 | 2.07 | 2.931 (4) | 170 |
N6—H6A···O10iv | 0.86 | 2.19 | 3.005 (4) | 158 |
N6—H6B···O8 | 0.86 | 2.24 | 3.017 (4) | 151 |
C2—H2A···N6v | 0.97 | 2.60 | 3.553 (4) | 166 |
C2—H2B···O3vii | 0.97 | 2.56 | 3.491 (3) | 162 |
C5—H5A···O1vii | 0.97 | 2.39 | 3.352 (3) | 172 |
C5—H5B···O8viii | 0.97 | 2.55 | 3.444 (4) | 154 |
Symmetry codes: (iv) x−1, y, z; (v) x, y, z+1; (vi) −x+1, −y+2, −z; (vii) −x+1, −y+1, −z; (viii) −x+1, −y+1, −z−1. |
Experimental details
Crystal data | |
Chemical formula | [Cu2(NO3)2(C3H7N3O2)4] |
Mr | 843.58 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 298 |
a, b, c (Å) | 7.2535 (8), 10.3652 (12), 10.5626 (12) |
α, β, γ (°) | 99.262 (2), 94.862 (2), 105.844 (2) |
V (Å3) | 747.05 (15) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 1.54 |
Crystal size (mm) | 0.58 × 0.22 × 0.18 |
Data collection | |
Diffractometer | Bruker SMART 1000 area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 1999) |
Tmin, Tmax | 0.596, 0.928 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6444, 4202, 3433 |
Rint | 0.019 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.115, 1.03 |
No. of reflections | 4202 |
No. of parameters | 226 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.48, −0.82 |
Computer programs: SMART (Bruker, 1999), SAINT (Bruker, 1999), SAINT, SHELXS86 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEX in OSCAIL (McArdle, 1994, 2000) and ORTEP-3 for Windows (Farrugia, 1999), SHELXL97.
Cu1—O1 | 1.9696 (17) | Cu1—O4i | 1.9814 (19) |
Cu1—O2i | 1.9766 (17) | Cu1—O5ii | 2.1500 (18) |
Cu1—O3 | 1.9520 (19) | Cu1—Cu1i | 2.6525 (6) |
O1—Cu1—O3 | 91.26 (8) | O2i—Cu1—O5ii | 88.27 (7) |
O1—Cu1—O2i | 167.60 (7) | O4i—Cu1—O5ii | 85.44 (8) |
O3—Cu1—O2i | 90.80 (8) | O1—Cu1—Cu1i | 85.12 (5) |
O1—Cu1—O4i | 88.53 (8) | O2i—Cu1—Cu1i | 83.05 (5) |
O2i—Cu1—O4i | 86.96 (8) | O3—Cu1—Cu1i | 82.21 (5) |
O3—Cu1—O4i | 168.16 (7) | O4i—Cu1—Cu1i | 85.98 (5) |
O3—Cu1—O5ii | 106.12 (8) | O5ii—Cu1—Cu1i | 168.10 (5) |
O1—Cu1—O5ii | 102.88 (7) |
Symmetry codes: (i) −x, −y+1, −z; (ii) x−1, y−1, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O7iii | 0.86 | 2.35 | 3.114 (3) | 147 |
N2—H2D···O8iv | 0.87 | 2.28 | 2.966 (3) | 136 |
N2—H2C···O7 | 0.87 | 2.15 | 2.983 (3) | 160 |
N3—H3A···O5 | 0.86 | 2.21 | 3.021 (3) | 158 |
N3—H3A···O4v | 0.86 | 2.54 | 3.142 (3) | 128 |
N3—H3B···O6iii | 0.86 | 2.27 | 3.063 (3) | 154 |
N3—H3B···O7iii | 0.86 | 2.36 | 3.137 (3) | 151 |
N4—H4···O9iii | 0.86 | 2.12 | 2.960 (3) | 165 |
N5—H5C···O1vi | 0.87 | 2.49 | 3.278 (3) | 151 |
N5—H5D···O9 | 0.87 | 2.07 | 2.931 (4) | 170 |
N6—H6A···O10iii | 0.86 | 2.19 | 3.005 (4) | 158 |
N6—H6B···O8 | 0.86 | 2.24 | 3.017 (4) | 151 |
C2—H2A···N6iv | 0.97 | 2.60 | 3.553 (4) | 166 |
C2—H2B···O3vi | 0.97 | 2.56 | 3.491 (3) | 162 |
C5—H5A···O1vi | 0.97 | 2.39 | 3.352 (3) | 172 |
C5—H5B···O8vii | 0.97 | 2.55 | 3.444 (4) | 154 |
Symmetry codes: (iii) x−1, y, z; (iv) x, y, z+1; (v) −x+1, −y+2, −z; (vi) −x+1, −y+1, −z; (vii) −x+1, −y+1, −z−1. |
Guanidinoacetic acid, (I), is a very significant amino acid as it is the precursor of creatine and is involved in many biological processes. It is synthesized in the kidneys (Borsook & Dubnoff, 1941; Takeda et al., 1992), and measurement of its urinary levels is considered a sensitive tool for the early diagnosis of renal failures (Tanaka et al., 1999), such as nephrotoxicity (Nakayama et al., 1989), hypertensive renal diseases (Takano et al., 1989) and rejection crizes in kidney transplantation (Ishizaki et al., 1985). In addition, (I) is important in creatine deficiency (Ilas et al., 2000), cholesterol production (Sugiyama et al., 1989), thyroid dysfunction (Verhelst et al., 1997), hepatic encephalopathy (De Deyn et al., 1995) and insulin regulation (Kuroda, 1993). Accumulation of (I) has been detected both in patients with guanidinoacetate methyltransferase deficiency (Stockler et al., 1996) and with urinary tract neoplasm on treatment with cisplatin (Yasuda et al., 2000).
Studies of the interaction of (I) with biologically active metals are limited. Previously, we reported dissociation constants of (I)–metal ion complexes by potentiometric methods in solution (Felcman & Miranda, 1997), as well as spectra of complexes in the solid state (IR) and in solution (UV and EPR) (Miranda & Felcman, 2001). Recently, the first crystal structure of a metal–guanidinoacetic acid complex, namely dichlorobis(guanidinoacetic acid)copper, (II), formed from CuCl2 and (I) in aqueous solution, was reported (Silva et al., 2000).
We have now isolated a dinuclear copper complex of (I), namely, tetrakis(µ-guanidinoacetic acid)bis[nitratocopper(II)], (III), from a dilute aqueous nitric acid solution of Cu(NO3)2 and (I). The centrosymmetric core of the green-coloured compound is made up of two Cu2+ ions bridged by four carboxylate anions, with Cu—O bond lengths ranging from 1.9520 (19) to 1.9814 (19) Å (Table 1). Each Cu2+ ion in (III) is further coordinated to a nitrate O atom, with a Cu1—O5ii distance of 2.1500 (18) Å [symmetry code: (ii) x - 1, y - 1, z]. The carboxylate O atoms are in equatorial positions about the Cu atoms, with the nitrate O atom in an apical site. Bond-valence sums (BVS) (Brown, 1981) around the copper confirm this fivefold coordination, giving a BVS of 2.02, whereas if the long Cu1—O5 bond is omitted, the BVS is 1.76, well short of the expected value of 2 for CuII. In addition, the intramolecular Cu1···Cu1i separation is 2.6525 (6) %A, with a Cu1i—Cu1—O5ii angle of 168.10 (5)° [symmetry code: (i) -x, -y + 1, -z]. Ignoring the Cu···Cu separation, the geometry about each Cu atom is square pyramidal.
The main molecule is shown in Fig. 1, together with the atom-numbering scheme and showing intramolecular hydrogen bonding to the nitrate groups. The core of (III) is similar to those generally found in dimeric copper(II) carboxylate species, [Cu2(RCO2)4L2], (IV), in which the ligands, L, are situated in apical positions [e.g. as in L = EtOH, R = 1-Ph-cyclopropyl (Agterberg et al., 1997); L = H2O, R = 4-HO-3-MeOC6H3 (Zhu et al., 2000); L = H2O, R = Me2PhSi (Steward et al., 1986); L = Me2CO, R = 2,4-Cl2-5-MeC6H2SCH2 (Smith, O'Reilly, Kennard & White, 1985); L = pyridine, R = PhCO (Harada et al., 1997); and L = CnH2n+1, n = 9, 11, 13, 15, 17 and 19, R = C12H25-pyridine (Rusjan et al., 2000)], and also in [Cu2(RCO2)4], (V), in which an intermolecular axial Cu–carboxylate coordination also occurs to each Cu centre [e.g. as in R = n-C5H11 (Doyle et al., 2000); R = PhSCHMe (Chen et al., 1987); and R = 2-ClC6H4OCH2CH2 (Smith, O'Reilly, Kennard & White, 1985).
The Cu···Cu distances in (V) are generally shorter, 2.55–2.59 Å, than those in (IV), which can be up to 2.9 Å. Of interest, the Cu···Cu distance in (III), 2.6525 (6) Å, is comparable with those generally found for (IV) (L = O-ligand), e.g. the value in [Cu2(2,4-Cl2-5-MeC6H2SCH2CO2)4(Me2CO)2] is 2.646 (1) Å (Smith, O'Reilly, Kennard, Mak & Yip, 1985). The Cu—O(equatorial) and Cu—O(apical) bond lengths in (III) are similar to distances found in related compounds.
As in the mononuclear complex, (II) (Silva et al., 2000), the guanidinoacetic acid ligand in (III) is present in the zwitterionic form, (Ib), rather than either the neutral form, (Ia), or the mono-anionic form, (Ic) (see Scheme). As with other complexes, (IV), having carboxylate ligands with additional functionality, it is only the carboxylate group of (I) which coordinates to Cu in (III). The nitrogen centres in the guanidinoacetic acid ligand, while not involved in the complexation to the metal, are however extensively involved in hydrogen bonding.
A number of strong intermolecular hydrogen bonds form (PLATON; Spek, 2002), in addition to the intramolecular N—H···Onitrate bonds shown in Fig. 1. These are supported by three C—H···O H-bonds (Table 2). The first set of strong hydrogen bonds form between the molecule at (x, y, z) and those at (x - 1, y, z) (symmetry code iii) and (1 - x, 1 - y, -z) (symmetry code iv). This involves N1—H1···O7iii, N3—H3B···O6iii, N4—H4···O9iii, N6—H6A···O10iii and N5—H5C···O1iv (Fig. 2), which combine to form a chain along (100). Fig. 3 shows the chain resulting from the N2—H2D···O8v hydrogen bond [symmetry code: (v) x, y, z + 1] propagating along (001) and formed from R22(32) dimers. Finally N3—H3A···O4vi [symmetry code: (vi) 1 - x, 2 - y, -z] gives an R22(18) dimer centred on (1/2, 1, 0) (Fig. 4). These hydrogen bonds combine to form a three-dimensional framework.
The antiferromagnetic properties of many of the dicopper compounds, (IV) and (V), have been studied [e.g. (IV) (Rusjan et al., 2000; Agterberg et al., 1997; Harada et al., 1997) and (V) (Doyle et al., 2000)]. While the biological aspects of (III), and related complexes, are our dominant interest, the magnetic properties of (III) have not been neglected and will be reported in due course.