supplementary materials


sj5306 scheme

Acta Cryst. (2013). E69, m229-m230    [ doi:10.1107/S1600536813007629 ]

Hexaaquacopper(II) bis(tetrafluoridoborate)-pyrazine 1,4-dioxide (1/3)

J. L. Wikaira, C. P. Landee and M. M. Turnbull

Abstract top

The crystal structure of the title compound, [Cu(H2O)6](BF4)2·3C4H4N2O2, comprises discrete [Cu(H2O)6]2+ cations and BF4- anions along with three equivalents of pyrazine 1,4-dioxide (pzdo). The hexaaquacopper(II) ion and all three pzdo molecules lie about crystallographic inversion centers. The lattice is supported by an extensive hydrogen-bonding network. O-H...O hydrogen bonding between the [Cu(H2O)6]2+ and pzdo units creates a pseudo-hexagonal lattice parallel to the bc plane. The BF4- anions lie in the voids of that lattice, held in place by O-H...F hydrogen bonds, and also generate BF4--pzdo-BF4--pzdo stacks via short F...N contacts [2.866 (3)-3.283 (4) Å].

Comment top

Hexaaquacopper(II) tetrafluoroborate tris-1,4-pyrazinedioxide, 1, crystallized from aqueous solution as part of our efforts in the synthesis of low-dimensional Cu(II) antiferromagnetic lattices (Schlueter, et al. 2012). The hydroscopic material crystallizes as discrete [Cu(H2O)6]2+ cations with the Cu2+ atoms located on inversion centers and BF4- anions along with three equivalents of 1,4-pyrazine dioxide (pzdo) each of which sits athwart an individual inversion center, Fig. 1. The lattice is supported by an extensive hydrogen bonding network between the coordinated water molecules and both the tetrafluoroborate anions and the pzdo molecules. The [Cu(H2O)6]2+ cations are linked, via hydrogen bonds with water molecules O1 and O2, into a pseudo-hexagonal layer parallel to the bc-plane via the pzdo molecules (see Figure 2). A similar compound with hexaaquacopper(II) chloride and 4,4'-bipyridine-N,N'-dioxide molecule (Ma et al., 2001) also shows hydrogen bonding to the amine oxide O-atoms, but does not generate the same layer pattern, likely due to the much greater length of the ligand and smaller anion which would create large cavities in the structure. The BF4- anions occupy the roughly triangular holes generated by that lattice and are held in place via hydrogen bonds to the O3 water molecules. Additional hydrogen bonds link the layers parallel to the a-axis, generating a three-dimensional structure.

Further structural support for the lattice is found via pairs of short contacts between the BF4- anions and the pyrazine nitrogen atoms which generate a chain-like motif (Figure 3). These contact distances range in length from 2.866 (3) to 3.283 (4) Å. Similar F···N interactions are seen in a number of complexes with F···N distances near 3 Å, such as the Cu(II)(hat) tetrafluoroborate complex (Shatruk et al., 2006), while distances as short as 2.837 Å have been reported in 2,5-bis(2-methoxyphenyl)-3,6-dimethylpyrazinium bis(tetrafluoroborate) (Turksoy et al., 2003) and catena-(tris(µ3-pyrazino(2,3 - f) quinoxaline)-tri-silver(I) tris(tetrafluoroborate) nitromethane) (Blake et al., 2000). Fewer structures are known with pairs of short F···N contacts to a single ring, such as seen in 1. These include 2,5-bis(2-methoxyphenyl)- 3,6-dimethylpyrazinium bis(tetrafluoroborate) (Turksoy et al., 2003), 2,3-dicyano-1-ethyl-5-(4-fluorophenyl)pyrazinium tetrafluoroborate (Verbitsky et al., 2008) and N,N'-diethylpyrazinediium bis(tetrafluoroborate) (Lu et al., 2009). We find no examples of the stacked pairwise interactions resulting in a chain-like motif such as seen in 1.

Related literature top

For related structures see: Blake et al. (2000) [catena-(tris(µ3-pyrazino(2,3-f)quinoxaline)trisilver(I) tris(tetrafluoridoborate) nitromethane)]; Muesmann et al. (2011) [hexaaquacopper(II) 2,3,5,6-tetrafluoro-1,4-benzenedisulfonate]; Jia et al. (2005) [hexakis(tricyclohexylphosphine oxide) hexaaquacopper(II) bis(tetrafluoridoborate) sesquihydrate]; Ma et al. (2001) [hexaaquacopper(II) dichloride (4,4'-bipyridine-N,N'-dioxide) dihydrate]; Lu et al. (2009) [N,N'-diethylpyrazinediium bis(tetrafluoridoborate)]; Turksoy et al. (2003) [2,5-bis(2-methoxyphenyl)-3,6-dimethylpyrazinium bis(tetrafluoridoborate)]; Schlueter et al. (2012) [catena-[(µ2-pyrazine-N,N'-dioxide)diaquadichlorocopper(II)]; Shatruk et al. (2006) [Cu(II)(hat) tetrafluoridoborate; hat = 1,4,5,8,9,12-hexaazatriphenylene]; Verbitsky et al. (2008) [2,3-dicyano-1-ethyl-5-(4-fluorophenyl)pyrazinium tetrafluoridoborate].

Experimental top

Copper(II) tetrafluoroborate hexahydrate and 1,4-pyrazine dioxide were dissolved in equimolar amounts in water. The solution was left for slow evaporation in air at room temperature. Over the course of two months, crystals of compound 1 were recovered. The crystals are hygroscopic and were transferred directly from the mother liquor into a perfluoropolyalkylether for data collection.

Refinement top

All H-atoms bound to carbon were refined using a riding model with d(C—H) = 0.93 Å, Uiso=1.2Ueq (C). Hydrogen atoms bonded to oxygen atoms were located in the difference map and their positions refined using fixed isotropic U values.

Computing details top

Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008), enCIFer (Allen et al., 2004) and publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. : Thermal ellipsoid plot of 1 (50% probability) showing the asymmetric unit and the three 1,4-pyrazinedioxide molecule that lie about inversion centers. Labeled atoms are related to unlabeled atoms by the symmetry operations: -x+1, -y+1, -z+1 for Cu(H2O)6,2+, -x, -y+1, -z for N11, C12 and C13; -1-x, -y, -z for N21, C22 and C23. Only those hydrogen atoms whose positions were refined and are involved in hydrogen-bonding are labeled.
[Figure 2] Fig. 2. : Diagram showing hydrogen-bonded [Cu(H2O)6]2+ and pzdo moieties which generate a pseudo-hexagonal lattice parallel to the bc-plane. Pzdo molecules have been represented by only the N– and O-atoms, with a solid line linking the N-atoms within a single ring, for clarity. Dashed lines represent hydrogen bonds.
[Figure 3] Fig. 3. : Diagram showing the stacking of pzdo molecules and BF4- anions. Short F···N contacts are shown as dashed lines.
Hexaaquacopper(II) bis(tetrafluoridoborate)–pyrazine 1,4-dioxide (1/3) top
Crystal data top
[Cu(H2O)6](BF4)2·3C4H4N2O2Z = 1
Mr = 681.53F(000) = 345
Triclinic, P1Dx = 1.769 Mg m3
Hall symbol: -P 1Cu Kα radiation, λ = 1.54184 Å
a = 6.4001 (4) ÅCell parameters from 3193 reflections
b = 10.2719 (7) Åθ = 4.5–73.6°
c = 10.9162 (8) ŵ = 2.40 mm1
α = 110.928 (6)°T = 120 K
β = 104.327 (6)°Block, light blue
γ = 93.937 (5)°0.5 × 0.4 × 0.35 mm
V = 639.59 (7) Å3
Data collection top
Agilent SuperNova (Dual, Cu at zero, Atlas)
diffractometer
2399 independent reflections
Radiation source: fine-focus sealed tube2356 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.015
Detector resolution: 10.6501 pixels mm-1θmax = 70.1°, θmin = 4.5°
ω scansh = 77
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
k = 812
Tmin = 0.781, Tmax = 1.000l = 1312
3851 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.045H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.111 w = 1/[σ2(Fo2) + (0.0476P)2 + 1.833P]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max = 0.001
2399 reflectionsΔρmax = 1.47 e Å3
206 parametersΔρmin = 0.85 e Å3
0 restraintsExtinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0258 (19)
Crystal data top
[Cu(H2O)6](BF4)2·3C4H4N2O2γ = 93.937 (5)°
Mr = 681.53V = 639.59 (7) Å3
Triclinic, P1Z = 1
a = 6.4001 (4) ÅCu Kα radiation
b = 10.2719 (7) ŵ = 2.40 mm1
c = 10.9162 (8) ÅT = 120 K
α = 110.928 (6)°0.5 × 0.4 × 0.35 mm
β = 104.327 (6)°
Data collection top
Agilent SuperNova (Dual, Cu at zero, Atlas)
diffractometer
2399 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
2356 reflections with I > 2σ(I)
Tmin = 0.781, Tmax = 1.000Rint = 0.015
3851 measured reflectionsθmax = 70.1°
Refinement top
R[F2 > 2σ(F2)] = 0.045H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.111Δρmax = 1.47 e Å3
S = 1.06Δρmin = 0.85 e Å3
2399 reflectionsAbsolute structure: ?
206 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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
xyzUiso*/Ueq
Cu10.50000.50000.50000.0101 (2)
O10.3542 (3)0.3009 (2)0.4022 (2)0.0147 (4)
H1A0.234 (7)0.289 (4)0.409 (4)0.018*
H1B0.340 (6)0.266 (4)0.326 (4)0.018*
O20.2162 (3)0.5606 (2)0.4493 (2)0.0226 (5)
H2A0.178 (6)0.631 (5)0.493 (4)0.027*
H2B0.131 (7)0.525 (4)0.378 (5)0.027*
O30.4517 (4)0.5081 (2)0.7053 (2)0.0184 (4)
H3A0.355 (7)0.525 (4)0.729 (4)0.022*
H3B0.475 (6)0.439 (4)0.709 (4)0.022*
N110.0418 (4)0.4676 (2)0.1034 (2)0.0140 (5)
O110.0811 (3)0.4372 (2)0.2040 (2)0.0196 (4)
C120.1425 (5)0.5635 (3)0.0635 (3)0.0189 (6)
H120.24140.60760.10690.023*
C130.1006 (5)0.4040 (3)0.0397 (3)0.0179 (6)
H130.17050.33780.06610.022*
N210.6322 (4)0.0764 (2)0.0681 (2)0.0120 (5)
O210.7602 (3)0.1492 (2)0.1319 (2)0.0173 (4)
C220.4126 (4)0.1135 (3)0.1184 (3)0.0165 (6)
H220.35080.19150.20000.020*
C230.7198 (4)0.0376 (3)0.0509 (3)0.0149 (5)
H230.87100.06430.08660.018*
N310.0263 (4)0.8928 (2)0.5452 (2)0.0136 (5)
O310.0475 (3)0.7870 (2)0.5868 (2)0.0171 (4)
C320.1066 (4)0.9842 (3)0.5873 (3)0.0159 (6)
H320.17980.97470.64810.019*
C330.1346 (4)0.9090 (3)0.4589 (3)0.0167 (6)
H330.22870.84720.43060.020*
B10.4841 (5)0.8023 (4)0.2195 (3)0.0183 (6)
F10.4718 (4)0.9441 (2)0.2745 (2)0.0390 (5)
F20.4757 (4)0.7527 (3)0.0834 (2)0.0472 (6)
F30.6823 (4)0.7802 (2)0.2911 (2)0.0506 (7)
F40.3235 (4)0.7182 (3)0.2381 (3)0.0523 (7)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0087 (3)0.0093 (3)0.0117 (3)0.00147 (19)0.0027 (2)0.0033 (2)
O10.0142 (10)0.0137 (9)0.0148 (10)0.0002 (7)0.0067 (8)0.0028 (8)
O20.0159 (10)0.0231 (11)0.0179 (11)0.0095 (9)0.0011 (8)0.0016 (9)
O30.0209 (11)0.0207 (11)0.0208 (10)0.0065 (9)0.0114 (8)0.0122 (9)
N110.0117 (10)0.0164 (11)0.0105 (11)0.0015 (8)0.0007 (8)0.0031 (9)
O110.0179 (10)0.0281 (11)0.0145 (10)0.0035 (8)0.0048 (8)0.0102 (8)
C120.0163 (13)0.0230 (14)0.0188 (14)0.0097 (11)0.0068 (11)0.0076 (12)
C130.0158 (13)0.0182 (14)0.0186 (14)0.0072 (11)0.0026 (11)0.0064 (11)
N210.0109 (10)0.0121 (10)0.0125 (11)0.0031 (8)0.0041 (8)0.0037 (9)
O210.0123 (9)0.0180 (10)0.0181 (10)0.0059 (7)0.0069 (7)0.0010 (8)
C220.0134 (13)0.0162 (13)0.0141 (13)0.0010 (10)0.0020 (10)0.0008 (10)
C230.0100 (12)0.0163 (13)0.0142 (13)0.0007 (10)0.0012 (10)0.0028 (10)
N310.0110 (10)0.0122 (10)0.0157 (11)0.0003 (8)0.0031 (9)0.0041 (9)
O310.0174 (10)0.0139 (9)0.0222 (10)0.0030 (7)0.0074 (8)0.0084 (8)
C320.0141 (13)0.0147 (13)0.0177 (13)0.0013 (10)0.0079 (10)0.0030 (11)
C330.0148 (13)0.0151 (13)0.0220 (14)0.0048 (10)0.0107 (11)0.0053 (11)
B10.0147 (15)0.0237 (16)0.0178 (15)0.0024 (12)0.0063 (12)0.0088 (13)
F10.0526 (13)0.0337 (11)0.0487 (13)0.0253 (10)0.0301 (11)0.0230 (10)
F20.0762 (17)0.0527 (14)0.0303 (11)0.0296 (13)0.0287 (11)0.0243 (10)
F30.0430 (13)0.0381 (12)0.0410 (13)0.0166 (10)0.0132 (10)0.0035 (10)
F40.0483 (14)0.0424 (13)0.0538 (15)0.0145 (11)0.0319 (12)0.0031 (11)
Geometric parameters (Å, º) top
Cu1—O11.9692 (19)N21—O211.307 (3)
Cu1—O1i1.9692 (19)N21—C221.348 (4)
Cu1—O21.974 (2)N21—C231.355 (3)
Cu1—O2i1.974 (2)C22—C23iii1.363 (4)
Cu1—O3i2.310 (2)C22—H220.9300
Cu1—O32.310 (2)C23—C22iii1.363 (4)
O1—H1A0.80 (4)C23—H230.9300
O1—H1B0.76 (4)N31—O311.322 (3)
O2—H2A0.81 (4)N31—C321.346 (4)
O2—H2B0.77 (4)N31—C331.348 (4)
O3—H3A0.74 (4)C32—C33iv1.366 (4)
O3—H3B0.74 (4)C32—H320.9300
N11—O111.318 (3)C33—C32iv1.366 (4)
N11—C131.346 (4)C33—H330.9300
N11—C121.353 (4)B1—F21.373 (4)
C12—C13ii1.363 (4)B1—F11.379 (4)
C12—H120.9300B1—F31.395 (4)
C13—C12ii1.363 (4)B1—F41.397 (4)
C13—H130.9300
O1—Cu1—O1i180.00 (14)C13ii—C12—H12119.7
O1—Cu1—O289.66 (9)N11—C13—C12ii120.1 (3)
O1i—Cu1—O290.34 (9)N11—C13—H13119.9
O1—Cu1—O2i90.34 (9)C12ii—C13—H13119.9
O1i—Cu1—O2i89.66 (9)O21—N21—C22121.0 (2)
O2—Cu1—O2i180.00 (15)O21—N21—C23120.0 (2)
O1—Cu1—O3i87.37 (8)C22—N21—C23119.0 (2)
O1i—Cu1—O3i92.63 (8)N21—C22—C23iii120.7 (3)
O2—Cu1—O3i88.50 (9)N21—C22—H22119.7
O2i—Cu1—O3i91.50 (9)C23iii—C22—H22119.7
O1—Cu1—O392.63 (8)N21—C23—C22iii120.4 (2)
O1i—Cu1—O387.37 (8)N21—C23—H23119.8
O2—Cu1—O391.50 (9)C22iii—C23—H23119.8
O2i—Cu1—O388.50 (9)O31—N31—C32120.1 (2)
O3i—Cu1—O3180.000 (1)O31—N31—C33120.5 (2)
Cu1—O1—H1A112 (3)C32—N31—C33119.3 (2)
Cu1—O1—H1B118 (3)N31—C32—C33iv120.4 (3)
H1A—O1—H1B104 (4)N31—C32—H32119.8
Cu1—O2—H2A127 (3)C33iv—C32—H32119.8
Cu1—O2—H2B123 (3)N31—C33—C32iv120.2 (3)
H2A—O2—H2B109 (4)N31—C33—H33119.9
Cu1—O3—H3A127 (3)C32iv—C33—H33119.9
Cu1—O3—H3B105 (3)F2—B1—F1113.8 (3)
H3A—O3—H3B109 (4)F2—B1—F3107.4 (3)
O11—N11—C13120.2 (2)F1—B1—F3108.8 (3)
O11—N11—C12120.6 (2)F2—B1—F4109.6 (3)
C13—N11—C12119.2 (2)F1—B1—F4111.9 (3)
N11—C12—C13ii120.7 (3)F3—B1—F4104.7 (3)
N11—C12—H12119.7
O11—N11—C12—C13ii179.4 (2)O21—N21—C23—C22iii179.5 (2)
C13—N11—C12—C13ii0.2 (5)C22—N21—C23—C22iii0.0 (4)
O11—N11—C13—C12ii179.4 (2)O31—N31—C32—C33iv177.9 (2)
C12—N11—C13—C12ii0.2 (4)C33—N31—C32—C33iv1.1 (4)
O21—N21—C22—C23iii179.5 (2)O31—N31—C33—C32iv177.9 (2)
C23—N21—C22—C23iii0.0 (4)C32—N31—C33—C32iv1.1 (4)
Symmetry codes: (i) x+1, y+1, z+1; (ii) x, y+1, z; (iii) x1, y, z; (iv) x, y+2, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···O31v0.80 (4)1.93 (4)2.711 (3)166 (4)
O1—H1B···O21vi0.76 (4)1.94 (4)2.676 (3)166 (4)
O2—H2A···O310.81 (4)1.93 (4)2.735 (3)173 (4)
O2—H2B···O110.77 (4)1.89 (5)2.669 (3)179 (4)
O3—H3A···O11v0.74 (4)2.07 (4)2.806 (3)177 (4)
O3—H3B···F4i0.74 (4)2.28 (4)2.984 (4)158 (4)
O3—H3B···F3i0.74 (4)2.41 (4)3.042 (3)145 (4)
Symmetry codes: (i) x+1, y+1, z+1; (v) x, y+1, z+1; (vi) x+1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···O31i0.80 (4)1.93 (4)2.711 (3)166 (4)
O1—H1B···O21ii0.76 (4)1.94 (4)2.676 (3)166 (4)
O2—H2A···O310.81 (4)1.93 (4)2.735 (3)173 (4)
O2—H2B···O110.77 (4)1.89 (5)2.669 (3)179 (4)
O3—H3A···O11i0.74 (4)2.07 (4)2.806 (3)177 (4)
O3—H3B···F4iii0.74 (4)2.28 (4)2.984 (4)158 (4)
O3—H3B···F3iii0.74 (4)2.41 (4)3.042 (3)145 (4)
Symmetry codes: (i) x, y+1, z+1; (ii) x+1, y, z; (iii) x+1, y+1, z+1.
Acknowledgements top

MMT is grateful to the faculty and staff of the Chemistry Department at the University of Canterbury, New Zealand, for their hospitality during his recent sabbatical visit.

references
References top

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