metal-organic compounds
1,4-Diazoniabicyclo[2.2.2]octane aquabis(oxalato-κ2O,O′)copper(II) dihydrate
aSchool of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, England
*Correspondence e-mail: daniel.price@soton.ac.uk
The title compound, (C6H14N2)[Cu(C2O4)2(H2O)]·2H2O, crystallizes in the P. In the solid state, the [Cu(ox)2(H2O)]2− units (ox is oxalate, C2O4) dimerize to give a tetragonally distorted CuO6 coordination environment. Extensive hydrogen bonding between the oxalate, the coordinated water, the 1,4-diazoniabicyclo[2.2.2]octane dications ([dabcoH2]2+) and the water of crystallization determines the crystal packing.
Comment
Blue crystals of the title compound, (I), were obtained by a slow diffusion technique in an aqueous gel. This ionic compound crystallizes in the triclinic P, with two formula units per The structure of (I) contains [Cu(ox)2(H2O)]2− (ox is oxalate, C2O4) units, in which the CuII ion is coordinated by two chelating oxalate ions in a planar geometry, and the coordinated water molecule forms a long axial contact [Cu1—O1W 2.344 (7) Å]. These units dimerize through one of the coordinating O atoms of the oxalate (Fig. 1 and Table 1), resulting in a Cu1⋯Cu1i separation of 3.818 (8) Å [symmetry code: (i) −x, 1 − y, 1 − z]. The long Cu1—O3i contact of 2.906 (10) Å gives an idea of the weakness of the dimerization interaction.
The number of hydrogen-bond acceptor sites in (I) is greater than the number of potential hydrogen-bond donating groups. We note that all D—H groups are involved in hydrogen bonding, and that there are seven different (near) linear and one bifurcated hydrogen-bond interactions (Table 2). Neighbouring [Cu(ox)2(H2O)]24− units are directly hydrogen-bonded into chains. These chains are hydrogen-bonded through the water of crystallization, resulting in an extensive three-dimensional network (Fig. 2). The unsymmetric bifurcated hydrogen bond between the oxalate and 1,4-diazoniabicyclo[2.2.2]octane ([dabcoH2]2+) is a motif seen in almost all other compounds containing [dabcoH2]2+ and ox2− (Vaidhyanathan et al., 2001; Lee & Wang, 1999; Malfant et al., 1990), although we note that this hydrogen-bonding pattern is not uncommon in oxalate compounds.
As described previously (Keene et al., 2003, 2004), discrete mono- and dinuclear metal oxalate species may be formed when the bridging potential of the oxalate is reduced. This can be achieved either through the use of capping ligands or by a high concentration of the oxalate dianion, in both cases resulting in coordinatively saturated complexes. The large Jahn–Teller effect in CuII makes the structural chemistry of copper oxalate compounds different from that of other 3d transition metals. In particular, a displacement of the labile axial water molecules during crystallization is commonly observed, and a polycatenation process results in chains of [Cu(ox)2]22n− in the solid state. Very few examples of isolated [Cu(ox)2(H2O)2]2− (Insausti et al., 1994; Keene et al., 2004) or dimerized species (Savel'eva et al., 1992) have been observed in the solid state. In the case of (I), the extensive hydrogen-bonded network stabilizes the discrete dimerization of the copper bisoxalate dianions, to give isolated [Cu(ox)2(H2O)]24− units.
Experimental
Single crystals of (I) were synthesized by a gel-crystallization technique. CuSO4·5H2O (100 mg, 0.40 mmol) was dissolved in distilled water (18 ml). Tetramethoxysilane (2 ml) was added and the mixture stirred until monophasic, then allowed to set in a test tube. A solution of 1,4-diazoniabicyclo[2.2.2]octane bis(hydrogenoxalate) (200 mg, 0.68 mmol) was added to the top of the gel. After two weeks, light-blue crystals of (I) had formed in the gel. IR (KBr, diffuse reflectance, cm−1): 3450 s (O—H stretch), 2823 s (C—H stretch), 2650 s (N—H stretch), 1681 s and 1658 s (oxalate), 1412 s (oxalate), 1291 s, 1059 s, 850 s, 801 s, 607 m, 540 m, 495 m; UV/VIS/NIR (diffuse reflectance, cm−1): 14 400 (d-d), 35 700 (oxalate).
Crystal data
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Refinement
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H atoms bound to C and N atoms were positioned geometrically and refined as riding, with C—H = 0.97 and N—H = 0.91 Å, and with Uiso(H) = 1.2Ueq(parent atom). H atoms bound to O atoms were located in difference maps, but their distances and angles were restrained to literature values.
Data collection: DENZO (Otwinowski & Minor, 1997); cell DENZO and COLLECT (Nonius, 1998); data reduction: DENZO and COLLECT; program(s) used to solve structure: SIR92 (Altomare et al., 1993) in WinGX (Farrugia, 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997) in WinGX; molecular graphics: DIAMOND (Brandenburg, 1999).
Supporting information
https://doi.org/10.1107/S1600536804005033/hb6023sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536804005033/hb6023Isup2.hkl
Data collection: DENZO (Otwinowski & Minor, 1997); cell
DENZO and COLLECT (Nonius, 1998); data reduction: DENZO and COLLECT; program(s) used to solve structure: SIR92 (Altomare et al., 1993) in WinGX (Farrugia, 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997) in WinGX; molecular graphics: DIAMOND (Brandenburg, 1999).(C6H14N2)[Cu(C2O4)2(H2O)]·2H2O | Z = 2 |
Mr = 407.82 | F(000) = 422 |
Triclinic, P1 | Dx = 1.793 Mg m−3 |
Hall symbol: -P 1 | Melting point: N/A K |
a = 9.3847 (7) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 9.4884 (6) Å | Cell parameters from 9717 reflections |
c = 9.6936 (5) Å | θ = 2.9–27.5° |
α = 62.150 (4)° | µ = 1.51 mm−1 |
β = 81.987 (4)° | T = 167 K |
γ = 87.868 (3)° | Block, blue |
V = 755.36 (9) Å3 | 0.42 × 0.12 × 0.08 mm |
Nonius KappaCCD areadetector diffractometer | 3018 reflections with I > 2σ(I) |
φ and ω scans to fill Ewald sphere | Rint = 0.060 |
Absorption correction: multi-scan (SORTAV; Blessing, 1997) | θmax = 27.6°, θmin = 3.0° |
Tmin = 0.696, Tmax = 0.886 | h = −10→12 |
7866 measured reflections | k = −12→12 |
3465 independent reflections | l = −11→12 |
Refinement on F2 | 9 restraints |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.04 | w = 1/[σ2(Fo2) + (0.0396P)2 + 0.8532P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.103 | (Δ/σ)max < 0.001 |
S = 1.05 | Δρmax = 0.53 e Å−3 |
3465 reflections | Δρmin = −0.71 e Å−3 |
241 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. |
x | y | z | Uiso*/Ueq | ||
Cu1 | 0.15412 (3) | 0.65517 (4) | 0.42178 (3) | 0.01844 (11) | |
O1W | 0.3493 (2) | 0.7610 (2) | 0.2200 (2) | 0.0272 (4) | |
O8 | 0.2783 (2) | 0.4889 (2) | 0.5517 (2) | 0.0194 (4) | |
O2W | 0.6147 (2) | 0.8080 (3) | 0.4064 (2) | 0.0287 (5) | |
O5 | 0.3221 (2) | 0.7258 (2) | 0.7332 (2) | 0.0255 (4) | |
O3 | 0.0787 (2) | 0.5310 (2) | 0.3337 (2) | 0.0214 (4) | |
O6 | 0.1949 (2) | 0.7605 (2) | 0.5422 (2) | 0.0200 (4) | |
O7 | 0.4125 (2) | 0.4410 (2) | 0.7398 (2) | 0.0229 (4) | |
O4 | −0.0491 (2) | 0.5699 (2) | 0.1426 (2) | 0.0228 (4) | |
O1 | 0.0246 (2) | 0.8192 (2) | 0.3001 (2) | 0.0218 (4) | |
O3W | 0.2755 (3) | 0.8810 (4) | 0.9159 (3) | 0.0501 (7) | |
N1 | 0.6965 (2) | 0.8110 (3) | 0.6610 (2) | 0.0200 (5) | |
H1 | 0.66 | 0.8363 | 0.5704 | 0.024* | |
O2 | −0.1199 (2) | 0.8612 (2) | 0.1207 (2) | 0.0282 (4) | |
N2 | 0.7966 (2) | 0.7424 (3) | 0.9072 (3) | 0.0211 (5) | |
H2 | 0.8332 | 0.7169 | 0.9979 | 0.025* | |
C4 | 0.9168 (3) | 0.8005 (4) | 0.7740 (3) | 0.0284 (6) | |
H4A | 0.986 | 0.7174 | 0.7911 | 0.034* | |
H4B | 0.9656 | 0.8923 | 0.7672 | 0.034* | |
C2 | 0.6907 (4) | 0.8692 (4) | 0.8822 (3) | 0.0331 (7) | |
H2A | 0.7377 | 0.9635 | 0.8722 | 0.04* | |
H2B | 0.6151 | 0.8328 | 0.9717 | 0.04* | |
C5 | 0.6648 (3) | 0.6382 (3) | 0.7716 (3) | 0.0232 (6) | |
H5A | 0.7069 | 0.574 | 0.7235 | 0.028* | |
H5B | 0.5616 | 0.617 | 0.7957 | 0.028* | |
C1 | 0.6263 (3) | 0.9093 (3) | 0.7327 (3) | 0.0221 (5) | |
H1A | 0.5233 | 0.8865 | 0.7577 | 0.027* | |
H1B | 0.6425 | 1.0218 | 0.6591 | 0.027* | |
C6 | 0.7282 (3) | 0.5964 (3) | 0.9210 (3) | 0.0258 (6) | |
H6A | 0.653 | 0.5542 | 1.0108 | 0.031* | |
H6B | 0.7995 | 0.5154 | 0.9369 | 0.031* | |
C3 | 0.8556 (3) | 0.8458 (3) | 0.6226 (3) | 0.0258 (6) | |
H3A | 0.8749 | 0.9583 | 0.551 | 0.031* | |
H3B | 0.9005 | 0.7851 | 0.5718 | 0.031* | |
C8 | −0.0006 (3) | 0.6126 (3) | 0.2280 (3) | 0.0185 (5) | |
C9 | 0.2796 (3) | 0.6833 (3) | 0.6437 (3) | 0.0182 (5) | |
C10 | 0.3301 (3) | 0.5234 (3) | 0.6479 (3) | 0.0166 (5) | |
C7 | −0.0364 (3) | 0.7803 (3) | 0.2126 (3) | 0.0194 (5) | |
H21 | 0.646 (3) | 0.7160 (17) | 0.419 (3) | 0.028 (9)* | |
H22 | 0.646 (4) | 0.878 (3) | 0.310 (2) | 0.046 (11)* | |
H31 | 0.262 (4) | 0.826 (4) | 0.867 (4) | 0.047 (11)* | |
H11 | 0.427 (2) | 0.706 (4) | 0.238 (3) | 0.032 (9)* | |
H12 | 0.337 (3) | 0.788 (4) | 0.1230 (19) | 0.045 (11)* | |
H32 | 0.210 (3) | 0.953 (3) | 0.893 (4) | 0.053 (12)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cu1 | 0.02148 (18) | 0.01728 (18) | 0.02011 (18) | 0.00559 (12) | −0.00930 (12) | −0.01031 (13) |
O1W | 0.0246 (10) | 0.0295 (11) | 0.0250 (10) | 0.0103 (8) | −0.0053 (8) | −0.0109 (9) |
O8 | 0.0223 (9) | 0.0186 (9) | 0.0208 (9) | 0.0055 (7) | −0.0095 (7) | −0.0107 (7) |
O2W | 0.0382 (12) | 0.0284 (11) | 0.0253 (11) | 0.0103 (9) | −0.0119 (9) | −0.0160 (9) |
O5 | 0.0277 (10) | 0.0270 (10) | 0.0310 (10) | 0.0070 (8) | −0.0129 (8) | −0.0194 (9) |
O3 | 0.0256 (10) | 0.0193 (9) | 0.0239 (9) | 0.0066 (7) | −0.0123 (8) | −0.0120 (8) |
O6 | 0.0226 (9) | 0.0177 (9) | 0.0226 (9) | 0.0053 (7) | −0.0109 (7) | −0.0100 (7) |
O7 | 0.0224 (9) | 0.0251 (10) | 0.0241 (9) | 0.0087 (8) | −0.0112 (7) | −0.0123 (8) |
O4 | 0.0267 (10) | 0.0228 (10) | 0.0246 (10) | 0.0050 (8) | −0.0125 (8) | −0.0139 (8) |
O1 | 0.0265 (10) | 0.0185 (9) | 0.0230 (9) | 0.0054 (7) | −0.0099 (8) | −0.0104 (8) |
O3W | 0.0565 (16) | 0.0730 (19) | 0.0554 (15) | 0.0433 (14) | −0.0380 (13) | −0.0535 (15) |
N1 | 0.0218 (11) | 0.0226 (11) | 0.0178 (10) | 0.0046 (9) | −0.0082 (8) | −0.0101 (9) |
O2 | 0.0349 (11) | 0.0229 (10) | 0.0307 (10) | 0.0104 (8) | −0.0189 (9) | −0.0125 (9) |
N2 | 0.0238 (11) | 0.0230 (12) | 0.0185 (10) | 0.0026 (9) | −0.0079 (9) | −0.0102 (9) |
C4 | 0.0186 (13) | 0.0318 (16) | 0.0323 (15) | −0.0037 (11) | −0.0058 (11) | −0.0120 (13) |
C2 | 0.0452 (18) | 0.0332 (16) | 0.0283 (15) | 0.0185 (14) | −0.0124 (13) | −0.0198 (13) |
C5 | 0.0223 (13) | 0.0196 (13) | 0.0314 (14) | 0.0029 (10) | −0.0088 (11) | −0.0138 (11) |
C1 | 0.0209 (13) | 0.0211 (13) | 0.0255 (13) | 0.0040 (10) | −0.0066 (10) | −0.0112 (11) |
C6 | 0.0308 (15) | 0.0192 (13) | 0.0239 (13) | −0.0034 (11) | −0.0055 (11) | −0.0064 (11) |
C3 | 0.0214 (13) | 0.0281 (15) | 0.0239 (13) | 0.0010 (11) | 0.0011 (10) | −0.0099 (11) |
C8 | 0.0173 (12) | 0.0187 (12) | 0.0188 (12) | 0.0017 (9) | −0.0036 (9) | −0.0080 (10) |
C9 | 0.0199 (12) | 0.0172 (12) | 0.0199 (12) | 0.0013 (9) | −0.0036 (9) | −0.0103 (10) |
C10 | 0.0152 (11) | 0.0183 (12) | 0.0164 (11) | 0.0019 (9) | −0.0026 (9) | −0.0082 (10) |
C7 | 0.0189 (12) | 0.0188 (13) | 0.0202 (12) | 0.0026 (9) | −0.0037 (10) | −0.0088 (10) |
Cu1—O6 | 1.9366 (18) | O2—C7 | 1.228 (3) |
Cu1—O3 | 1.9458 (19) | N2—C2 | 1.484 (4) |
Cu1—O3i | 2.9058 (18) | N2—C4 | 1.489 (4) |
Cu1—O1 | 1.9584 (18) | N2—C6 | 1.490 (3) |
Cu1—O8 | 1.9617 (17) | N2—H2 | 0.91 |
Cu1—O1W | 2.343 (2) | C4—C3 | 1.515 (4) |
O1W—H11 | 0.87 (3) | C4—H4A | 0.97 |
O1W—H12 | 0.875 (10) | C4—H4B | 0.97 |
O8—C10 | 1.278 (3) | C2—C1 | 1.524 (4) |
O2W—H21 | 0.871 (10) | C2—H2A | 0.97 |
O2W—H22 | 0.872 (10) | C2—H2B | 0.97 |
O5—C9 | 1.228 (3) | C5—C6 | 1.515 (4) |
O3—C8 | 1.278 (3) | C5—H5A | 0.97 |
O6—C9 | 1.280 (3) | C5—H5B | 0.97 |
O7—C10 | 1.225 (3) | C1—H1A | 0.97 |
O4—C8 | 1.221 (3) | C1—H1B | 0.97 |
O1—C7 | 1.275 (3) | C6—H6A | 0.97 |
O3W—H31 | 0.88 (4) | C6—H6B | 0.97 |
O3W—H32 | 0.87 (3) | C3—H3A | 0.97 |
N1—C1 | 1.489 (3) | C3—H3B | 0.97 |
N1—C5 | 1.493 (3) | C8—C7 | 1.555 (4) |
N1—C3 | 1.498 (3) | C9—C10 | 1.557 (4) |
N1—H1 | 0.91 | ||
O6—Cu1—O3 | 168.20 (8) | N2—C2—H2B | 109.9 |
O6—Cu1—O1 | 94.13 (7) | C1—C2—H2B | 109.9 |
O3—Cu1—O1 | 84.94 (8) | H2A—C2—H2B | 108.3 |
O6—Cu1—O8 | 84.77 (7) | N1—C5—C6 | 108.4 (2) |
O3—Cu1—O8 | 95.69 (7) | N1—C5—H5A | 110 |
O1—Cu1—O8 | 177.59 (7) | C6—C5—H5A | 110 |
O6—Cu1—O1W | 98.46 (8) | N1—C5—H5B | 110 |
O3—Cu1—O1W | 93.33 (8) | C6—C5—H5B | 110 |
O1—Cu1—O1W | 93.02 (7) | H5A—C5—H5B | 108.4 |
O8—Cu1—O1W | 89.27 (7) | N1—C1—C2 | 108.4 (2) |
Cu1—O1W—H11 | 115 (2) | N1—C1—H1A | 110 |
Cu1—O1W—H12 | 120 (2) | C2—C1—H1A | 110 |
H11—O1W—H12 | 106.5 (15) | N1—C1—H1B | 110 |
C10—O8—Cu1 | 112.33 (16) | C2—C1—H1B | 110 |
H21—O2W—H22 | 107.0 (15) | H1A—C1—H1B | 108.4 |
C8—O3—Cu1 | 112.38 (16) | N2—C6—C5 | 109.2 (2) |
C9—O6—Cu1 | 113.35 (16) | N2—C6—H6A | 109.8 |
C7—O1—Cu1 | 111.87 (17) | C5—C6—H6A | 109.8 |
H31—O3W—H32 | 106.9 (15) | N2—C6—H6B | 109.8 |
C1—N1—C5 | 109.7 (2) | C5—C6—H6B | 109.8 |
C1—N1—C3 | 110.1 (2) | H6A—C6—H6B | 108.3 |
C5—N1—C3 | 110.7 (2) | N1—C3—C4 | 108.7 (2) |
C1—N1—H1 | 108.7 | N1—C3—H3A | 110 |
C5—N1—H1 | 108.7 | C4—C3—H3A | 110 |
C3—N1—H1 | 108.7 | N1—C3—H3B | 110 |
C2—N2—C4 | 110.2 (2) | C4—C3—H3B | 110 |
C2—N2—C6 | 111.3 (2) | H3A—C3—H3B | 108.3 |
C4—N2—C6 | 109.0 (2) | O4—C8—O3 | 126.0 (2) |
C2—N2—H2 | 108.7 | O4—C8—C7 | 119.3 (2) |
C4—N2—H2 | 108.7 | O3—C8—C7 | 114.7 (2) |
C6—N2—H2 | 108.7 | O5—C9—O6 | 125.6 (2) |
N2—C4—C3 | 108.8 (2) | O5—C9—C10 | 119.8 (2) |
N2—C4—H4A | 109.9 | O6—C9—C10 | 114.5 (2) |
C3—C4—H4A | 109.9 | O7—C10—O8 | 125.2 (2) |
N2—C4—H4B | 109.9 | O7—C10—C9 | 119.8 (2) |
C3—C4—H4B | 109.9 | O8—C10—C9 | 115.0 (2) |
H4A—C4—H4B | 108.3 | O2—C7—O1 | 126.4 (3) |
N2—C2—C1 | 108.9 (2) | O2—C7—C8 | 118.2 (2) |
N2—C2—H2A | 109.9 | O1—C7—C8 | 115.4 (2) |
C1—C2—H2A | 109.9 |
Symmetry code: (i) −x, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O2W | 0.91 | 1.84 | 2.698 (4) | 157 |
N2—H2···O4ii | 0.91 | 1.90 | 2.690 (3) | 144 |
N2—H2···O2ii | 0.91 | 2.28 | 2.978 (5) | 133 |
O2W—H21···O8iii | 0.87 (2) | 1.95 (2) | 2.819 (5) | 178 (2) |
O2W—H22···O3Wiv | 0.87 (2) | 2.36 (2) | 3.201 (4) | 163 (2) |
O3W—H31···O5 | 0.88 (4) | 1.95 (4) | 2.770 (6) | 155 (4) |
O1W—H11···O7iii | 0.87 (3) | 1.98 (3) | 2.837 (5) | 169 (3) |
O1W—H12···O3Wv | 0.88 (2) | 1.94 (2) | 2.800 (6) | 166 (2) |
O3W—H32···O2vi | 0.87 (3) | 1.88 (3) | 2.703 (6) | 157 (3) |
Symmetry codes: (ii) x+1, y, z+1; (iii) −x+1, −y+1, −z+1; (iv) −x+1, −y+2, −z+1; (v) x, y, z−1; (vi) −x, −y+2, −z+1. |
Acknowledgements
The authors thank the EPSRC for funding of crystallographic facilities and for an Advanced Research Fellowship to DJP.
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