supplementary materials


lh5649 scheme

Acta Cryst. (2013). E69, m544    [ doi:10.1107/S1600536813024914 ]

Tetrakis(acetonitrile)copper(I) hydrogen oxalate-oxalic acid-acetonitrile (1/0.5/0.5)

A. T. Royappa, J. R. Stepherson, O. D. Vu, A. D. Royappa, C. L. Stern and P. Müller

Abstract top

In the title compound, [Cu(CH3CN)4](C2HO4)·0.5C2H2O4·0.5CH3CN, the CuI ion is coordinated by the N atoms of four acetonitrile ligands in a slightly distorted tetrahedral environment. The oxalic acid molecule lies across an inversion center. The acetonitrile solvent molecule is disordered across an inversion center and was refined with half occupancy. In the crystal, the hydrogen oxalate anions and oxalic acid molecules are linked via O-H...O hydrogen bonds, forming chains along [010].

Comment top

The tetrakis(acetonitrile)copper(I) ion, an important starting material for the synthesis of copper(I) complexes, was first synthesized as the nitrate salt (Morgan, 1923). Commonly available and easily synthesized compounds containing the [Cu(CH3CN)4]+ cation generally do contain weakly coordinating anions such as BF4- (Heckel, 1966) or PF6- (Kubas et al., 1979). The structure of tetrakis(acetonitrile)copper(I) tetrafluoroborate already appears in the literature (Jones & Crespo, 1998).

In this work, we report the synthesis and crystal structure of a compound containing the [Cu(CH3CN)4]+ cation containing a potentially coordinating HC2O4- anion, which does not coordinate to the metal center. This is in keeping with the known affinity of nitrile ligands for CuI (Cotton et al., 1999), and also with the hard-soft acid-base theory (Pearson, 1968), which predicts a weak interaction between the "hard" hydrogen oxalate ligand and the "soft" Cu+ ion.

In the title compound, the [Cu(CH3CN)4]+ cation adopts a slightly distorted tetrahedral geometry. The HC2O4- anion is not coordinated to the CuI center and the distances of the nearest O atoms to the CuI ion are all greater than 4.7 Å. The anion is non-planar, whereas the oxalic acid molecules are strictly planar, and reside on inversion centers. All the OH groups (in the hydrogen oxalate anion and in oxalic acid) in this structure are involved in intermolecular hydrogen bonding interactions with the carboxylate O atoms of the hydrogen oxalate anion, forming one-dimensional chains along [010]. The acetonitrile solvent molecules present in the structure are disordered, and positioned in linear channels between the [Cu(CH3CN)4]+ cations, parallel to the b axis.

Related literature top

For background to tetrakis(acetonitrile)copper(I) complexes, see: Morgan (1923); Heckel (1966); Kubas et al. (1979). For details of the affinity of nitrile ligands for CuI ions, see: Cotton et al. (1999). For the hard–soft acid–base theory, see: Pearson (1968). For the structure of the closely related tetrakis(acetonitrile)copper(I) tetrafluoroborate, see: Jones & Crespo (1998).

Experimental top

All manipulations were carried out under nitrogen. In a 10 ml round-bottom flask, 180 mg anhydrous oxalic acid (2 mmol), 0.143 g copper(I) oxide (1 mmol) and 7 ml degassed, dry acetonitrile were stirred together. All the red Cu2O powder dissolved in 2 min., forming a white precipitate and a clear, pale blue supernatant. After 15 min. of stirring, a copious amount of white and dark purple solids settled to the bottom of the flask. The dark purple solid was likely copper metal powder. This reaction mixture was stirred for 1 hr., then heated at 313K for 15 min., during which the white solid redissolved. Cooling to room temperature produced mm-sized, colorless, air- and moisture-sensitive, platelike crystals in 2 hrs.

Refinement top

H atoms were placed in calculated positions with C—H = 0.96 Å and included in the refinement in a riding-motion approximation with Uiso(H) = 1.5Ueq(C). H atoms bonded to O atoms were refined independently with Uiso(H) = 1.5Ueq(O).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: CHEMDRAW (Cambridgesoft, 2003).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with displacement ellipsoids shown at the 50% probability level. The symmetry complete oxalic acid molecule is shown and the acetonitrile solvent molecule is half occupancy. The dotted line indicates a hydrogen bond.
Tetrakis(acetonitrile)copper(I) hydrogen oxalate–oxalic acid–acetonitrile (1/0.5/0.5) top
Crystal data top
[Cu(C2H3N)4](C2HO4)·0.5C2H2O4·0.5C2H3NF(000) = 784
Mr = 382.33Dx = 1.489 Mg m3
Monoclinic, P21/nMelting point: not measured K
Hall symbol: -P 2ynCu Kα radiation, λ = 1.54184 Å
a = 9.5637 (4) Åθ = 2.8–66.4°
b = 5.5670 (2) ŵ = 2.15 mm1
c = 32.0682 (12) ÅT = 100 K
β = 92.901 (2)°Plate, colorless
V = 1705.16 (11) Å30.17 × 0.14 × 0.03 mm
Z = 4
Data collection top
Bruker APEXII CCD
diffractometer
2928 independent reflections
Radiation source: fine-focus sealed tube2745 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.020
φ and ω scansθmax = 66.5°, θmin = 2.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
h = 1111
Tmin = 0.715, Tmax = 0.938k = 46
8349 measured reflectionsl = 3736
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.036Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.098H atoms treated by a mixture of independent and constrained refinement
S = 1.12 w = 1/[σ2(Fo2) + (0.0394P)2 + 2.6242P]
where P = (Fo2 + 2Fc2)/3
2928 reflections(Δ/σ)max < 0.001
236 parametersΔρmax = 0.89 e Å3
18 restraintsΔρmin = 0.50 e Å3
Crystal data top
[Cu(C2H3N)4](C2HO4)·0.5C2H2O4·0.5C2H3NV = 1705.16 (11) Å3
Mr = 382.33Z = 4
Monoclinic, P21/nCu Kα radiation
a = 9.5637 (4) ŵ = 2.15 mm1
b = 5.5670 (2) ÅT = 100 K
c = 32.0682 (12) Å0.17 × 0.14 × 0.03 mm
β = 92.901 (2)°
Data collection top
Bruker APEXII CCD
diffractometer
2928 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
2745 reflections with I > 2σ(I)
Tmin = 0.715, Tmax = 0.938Rint = 0.020
8349 measured reflectionsθmax = 66.5°
Refinement top
R[F2 > 2σ(F2)] = 0.036H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.098Δρmax = 0.89 e Å3
S = 1.12Δρmin = 0.50 e Å3
2928 reflectionsAbsolute structure: ?
236 parametersAbsolute structure parameter: ?
18 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*/UeqOcc. (<1)
Cu10.00357 (4)0.91194 (7)0.139464 (11)0.02214 (14)
N10.1201 (2)0.6945 (4)0.10675 (7)0.0249 (5)
C10.1869 (3)0.5512 (5)0.09207 (8)0.0223 (5)
C20.2716 (3)0.3648 (5)0.07389 (8)0.0270 (6)
H2A0.36730.37240.08630.040*
H2B0.27350.38970.04370.040*
H2C0.23120.20700.07940.040*
N20.1196 (2)1.1336 (4)0.10639 (7)0.0246 (5)
C30.1829 (3)1.2842 (5)0.09054 (7)0.0221 (5)
C40.2621 (3)1.4787 (5)0.07048 (8)0.0261 (6)
H4A0.20241.62110.06890.039*
H4B0.34331.51640.08680.039*
H4C0.29411.42970.04220.039*
N30.1258 (2)1.1393 (4)0.17405 (7)0.0233 (5)
C50.1743 (2)1.2988 (5)0.19157 (7)0.0197 (5)
C60.2332 (3)1.5037 (5)0.21462 (8)0.0228 (5)
H6A0.21871.65000.19790.034*
H6B0.33371.47830.22040.034*
H6C0.18681.52070.24100.034*
N40.0979 (2)0.6916 (4)0.17694 (7)0.0236 (5)
C70.1385 (3)0.5341 (5)0.19555 (8)0.0209 (5)
C80.1875 (3)0.3283 (5)0.21895 (8)0.0227 (5)
H8A0.18080.18260.20200.034*
H8B0.28520.35400.22570.034*
H8C0.12950.31020.24480.034*
C90.5095 (2)1.0524 (4)0.17421 (7)0.0159 (5)
C100.5127 (2)0.7966 (4)0.15534 (7)0.0163 (5)
O10.53399 (19)1.2210 (3)0.14699 (5)0.0218 (4)
H10.533 (3)1.355 (4)0.1595 (9)0.033*
O20.48651 (18)1.0852 (3)0.21057 (5)0.0203 (4)
O30.48900 (19)0.7711 (3)0.11715 (5)0.0230 (4)
O40.53722 (18)0.6316 (3)0.18140 (5)0.0203 (4)
C110.4732 (3)0.9454 (5)0.02028 (8)0.0263 (6)
O50.5469 (2)1.0158 (3)0.05293 (5)0.0268 (4)
H50.519 (3)0.957 (6)0.0747 (7)0.040*
O60.3702 (3)0.8228 (5)0.02020 (6)0.0575 (8)
N1S0.002 (6)0.4633 (17)0.0000 (16)0.0417 (18)0.50
C1S0.0067 (6)0.2602 (12)0.00027 (18)0.0306 (12)0.50
C2S0.011 (3)0.016 (4)0.0032 (11)0.042 (4)0.50
H2S10.11140.02210.00150.064*0.50
H2S20.03040.03910.03010.064*0.50
H2S30.03470.06530.01950.064*0.50
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0241 (2)0.0165 (2)0.0258 (2)0.00096 (15)0.00143 (15)0.00010 (15)
N10.0270 (11)0.0223 (11)0.0256 (11)0.0008 (10)0.0035 (9)0.0003 (9)
C10.0234 (13)0.0219 (13)0.0215 (12)0.0022 (11)0.0010 (10)0.0013 (11)
C20.0266 (14)0.0234 (14)0.0308 (14)0.0039 (11)0.0001 (11)0.0054 (11)
N20.0261 (12)0.0204 (11)0.0271 (11)0.0013 (10)0.0002 (9)0.0005 (9)
C30.0218 (12)0.0233 (13)0.0213 (12)0.0020 (11)0.0017 (10)0.0042 (11)
C40.0273 (13)0.0207 (13)0.0305 (13)0.0027 (11)0.0019 (10)0.0022 (11)
N30.0232 (11)0.0201 (11)0.0265 (11)0.0000 (9)0.0004 (9)0.0006 (10)
C50.0174 (12)0.0210 (13)0.0207 (12)0.0041 (11)0.0020 (9)0.0044 (11)
C60.0211 (12)0.0204 (13)0.0269 (13)0.0009 (10)0.0014 (10)0.0028 (11)
N40.0238 (11)0.0204 (11)0.0267 (11)0.0003 (9)0.0023 (9)0.0007 (10)
C70.0185 (12)0.0203 (13)0.0238 (12)0.0022 (11)0.0001 (9)0.0048 (11)
C80.0242 (13)0.0199 (13)0.0241 (12)0.0024 (11)0.0012 (10)0.0002 (10)
C90.0142 (11)0.0134 (11)0.0198 (12)0.0006 (9)0.0005 (9)0.0016 (9)
C100.0131 (11)0.0147 (12)0.0215 (12)0.0001 (9)0.0027 (9)0.0004 (10)
O10.0346 (10)0.0102 (8)0.0208 (8)0.0010 (8)0.0037 (7)0.0004 (7)
O20.0265 (9)0.0156 (8)0.0190 (9)0.0014 (7)0.0030 (7)0.0000 (7)
O30.0353 (10)0.0144 (8)0.0191 (9)0.0016 (8)0.0005 (7)0.0009 (7)
O40.0279 (9)0.0102 (8)0.0227 (8)0.0001 (7)0.0002 (7)0.0020 (7)
C110.0323 (15)0.0246 (14)0.0220 (13)0.0025 (12)0.0013 (11)0.0012 (11)
O50.0361 (11)0.0260 (10)0.0184 (9)0.0037 (8)0.0004 (7)0.0029 (8)
O60.0642 (16)0.0815 (19)0.0265 (11)0.0442 (15)0.0011 (10)0.0054 (12)
N1S0.048 (3)0.033 (4)0.043 (2)0.009 (14)0.002 (2)0.001 (13)
C1S0.032 (3)0.036 (3)0.024 (2)0.001 (3)0.002 (2)0.003 (3)
C2S0.073 (8)0.026 (5)0.029 (8)0.019 (6)0.017 (7)0.007 (6)
Geometric parameters (Å, º) top
Cu1—N21.977 (2)C7—C81.460 (4)
Cu1—N11.981 (2)C8—H8A0.9800
Cu1—N42.002 (2)C8—H8B0.9800
Cu1—N32.017 (2)C8—H8C0.9800
N1—C11.139 (3)C9—O21.211 (3)
C1—C21.456 (4)C9—O11.311 (3)
C2—H2A0.9800C9—C101.548 (3)
C2—H2B0.9800C10—O31.242 (3)
C2—H2C0.9800C10—O41.256 (3)
N2—C31.139 (3)O1—H10.849 (18)
C3—C41.452 (4)C11—O61.198 (4)
C4—H4A0.9800C11—O51.293 (3)
C4—H4B0.9800C11—C11i1.547 (5)
C4—H4C0.9800O5—H50.829 (18)
N3—C51.137 (3)N1S—C1S1.132 (12)
C5—C61.457 (4)C1S—C2S1.38 (3)
C6—H6A0.9800C2S—H2S10.9800
C6—H6B0.9800C2S—H2S20.9800
C6—H6C0.9800C2S—H2S30.9800
N4—C71.140 (3)
N2—Cu1—N1115.66 (9)H6A—C6—H6C109.5
N2—Cu1—N4114.26 (9)H6B—C6—H6C109.5
N1—Cu1—N4104.25 (9)C7—N4—Cu1166.9 (2)
N2—Cu1—N3102.50 (9)N4—C7—C8178.4 (3)
N1—Cu1—N3110.40 (9)C7—C8—H8A109.5
N4—Cu1—N3109.84 (9)C7—C8—H8B109.5
C1—N1—Cu1171.6 (2)H8A—C8—H8B109.5
N1—C1—C2178.9 (3)C7—C8—H8C109.5
C1—C2—H2A109.5H8A—C8—H8C109.5
C1—C2—H2B109.5H8B—C8—H8C109.5
H2A—C2—H2B109.5O2—C9—O1125.5 (2)
C1—C2—H2C109.5O2—C9—C10121.6 (2)
H2A—C2—H2C109.5O1—C9—C10112.99 (19)
H2B—C2—H2C109.5O3—C10—O4126.2 (2)
C3—N2—Cu1171.1 (2)O3—C10—C9119.0 (2)
N2—C3—C4179.2 (3)O4—C10—C9114.79 (19)
C3—C4—H4A109.5C9—O1—H1108 (2)
C3—C4—H4B109.5O6—C11—O5126.1 (2)
H4A—C4—H4B109.5O6—C11—C11i122.0 (3)
C3—C4—H4C109.5O5—C11—C11i111.8 (3)
H4A—C4—H4C109.5C11—O5—H5112 (2)
H4B—C4—H4C109.5N1S—C1S—C2S169 (3)
C5—N3—Cu1166.5 (2)C1S—C2S—H2S1109.5
N3—C5—C6178.5 (3)C1S—C2S—H2S2109.5
C5—C6—H6A109.5H2S1—C2S—H2S2109.5
C5—C6—H6B109.5C1S—C2S—H2S3109.5
H6A—C6—H6B109.5H2S1—C2S—H2S3109.5
C5—C6—H6C109.5H2S2—C2S—H2S3109.5
Symmetry code: (i) x+1, y+2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O4ii0.85 (2)1.69 (2)2.538 (2)176 (3)
O5—H5···O30.83 (2)1.74 (2)2.553 (2)165 (4)
Symmetry code: (ii) x, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O4i0.849 (18)1.690 (18)2.538 (2)176 (3)
O5—H5···O30.829 (18)1.74 (2)2.553 (2)165 (4)
Symmetry code: (i) x, y+1, z.
Acknowledgements top

ATR, JRS, ODV and ADR are grateful for support from the Office of Research and Sponsored Programs, the Office of Undergraduate Research and the Department of Chemistry at the University of West Florida.

references
References top

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