metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890
Volume 67| Part 8| August 2011| Pages m1125-m1126

Bis(aceto­nitrile-κN)di­aqua­bis­­(perchlorato-κO)copper(II)

aChemistry Department, Moscow State University, 119991 Moscow, Russian Federation
*Correspondence e-mail: Aslanov@struct.chem.msu.ru

(Received 27 May 2011; accepted 7 July 2011; online 23 July 2011)

In the title compound, [Cu(ClO4)2(CH3CN)2(H2O)2], the Cu2+ ion, located on a special position (site symmetry [\overline{1}]), is coordinated by six monodentate ligands, viz. an N-coordin­ated acetonitrile, a perchlorate anion and a water mol­ecule, and their symmetry-related counterparts. The perchlorate anion is disordered over two sets of sites with occupancies of 0.53 (2) and 0.47 (2). The crystal structure is stabilized by O—H⋯O hydrogen bonds involving the perchlorate ion and aqua H atoms.

Related literature

For details of the changing Cu(II/I) redox potential with increasing acetonitrile contents in water–acetonitrile solution, see: Cox et al. (1988[Cox, B. G., Jedral, W. & Palou, J. (1988). J. Chem. Soc. Dalton Trans. pp. 733-740.]); Verma & Sood (1979[Verma, B. C. & Sood, R. K. (1979). Talanta, 26, 906-907.]); Sumalekshmy & Gopidas (2005[Sumalekshmy, S. & Gopidas, K. R. (2005). Chem. Phys. Lett. 413, 294-299.]); Ajayakumar et al. (2009[Ajayakumar, G., Sreenath, K. & Gopidas, K. R. (2009). Dalton Trans. pp. 1180-1186.]); Drew et al. (1985[Drew, M. G. B., Yates, P. C., Trocha-Grimshaw, J., McKillop, K. P. & Nelson, S. M. (1985). J. Chem. Soc. Chem. Commun. pp. 262-263.]). For the dependence of the luminescent properties (emission energy) of the 3-cyano-4-dicyano­methyl­ene-5-oxo-4,5-dihydro-1H-pyrrol-2-olate (A)-based salts depend on the mol­ecular environment around (A), see: Tafeenko et al. (2009[Tafeenko, V. A., Gurskiy, S. I., Baranov, A. N., Kaisarova, T. V. & Aslanov, L. A. (2009). Acta Cryst. C65, m52-m55.], 2010[Tafeenko, V. A., Gurskiy, S. I., Fazylbekov, M. F., Baranov, A. N. & Aslanov, L. A. (2010). Acta Cryst. C66, m32-m34.]). For transition metals as fluorescence quenchers, see: Xu et al. (2005[Xu, Z., Xiao, V., Qian, X., Cui, J. & Cui, D. (2005). Org. Lett. 7, 889-892.], 2010[Xu, Z., Han, S. J., Lee, C., Yoon, J. & Spring, D. R. (2010). Chem. Commun. 46, 1679-1681.]). For a previous study on the formation of related compounds, see: Inamo et al. (2001[Inamo, M., Kamiya, N., Inada, Y., Nomura, M. & Funahashi, S. (2001). Inorg. Chem. 40, 5636-5641.]).

[Scheme 1]

Experimental

Crystal data
  • [Cu(ClO4)2(C2H3N)2(H2O)2]

  • Mr = 380.59

  • Triclinic, [P \overline 1]

  • a = 5.581 (1) Å

  • b = 7.244 (2) Å

  • c = 8.733 (2) Å

  • α = 82.82 (2)°

  • β = 76.86 (1)°

  • γ = 77.12 (1)°

  • V = 334.1 (1) Å3

  • Z = 1

  • Ag Kα radiation

  • λ = 0.56085 Å

  • μ = 1.09 mm−1

  • T = 296 K

  • 0.15 × 0.1 × 0.08 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • 2518 measured reflections

  • 1259 independent reflections

  • 1020 reflections with I > 2s(I)

  • Rint = 0.049

  • 2 standard reflections every 120 min intensity decay: none

Refinement
  • R[F2 > 2σ(F2)] = 0.066

  • wR(F2) = 0.192

  • S = 1.08

  • 1259 reflections

  • 138 parameters

  • 11 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.70 e Å−3

  • Δρmin = −1.09 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H11⋯O3i 0.83 (7) 2.03 (7) 2.758 (17) 146 (6)
O1—H12⋯O3ii 0.79 (9) 2.22 (10) 3.00 (3) 165 (8)
Symmetry codes: (i) x, y-1, z; (ii) -x+1, -y+1, -z+1.

Data collection: CAD-4 Software (Enraf–Nonius, 1989[Enraf-Nonius (1989). CAD-4 Software. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: DIAMOND (Brandenburg, 2000[Brandenburg, K. (2000). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

It was found (Tafeenko et al., 2009; Tafeenko et al., 2010) that the luminescent properties (emission energy) of the 3-cyano-4-dicyanomethylene-5-oxo-4,5-dihydro-1H-pyrrol-2-olate (A)-based salts depend on the molecular environment around (A). To investigate the effect of transition metals, which act usually as fluorescence quenchers (Xu et al., 2005, 2010), we made an attempt to synthesize (A)-based salts with Cu2+. Acetonitrile treatment of crude crystalline mass, obtained after evaporation of CuSO4 + BaA2 (equivalent amounts) mixture in water-ethanol (v/v=1/1) solution, and posterior evaporation of an acetonitrile solution in an air atmosphere at room temperature resulted in formation of (A)-based salts with Cu+. We saw several reasons for the reduction of Cu2+ to Cu+:

- iodide anion I- reduces Cu2+ in water-ethanol solution, as it was detected that BaA2 salt used for synthesis contained I-;

- anion (A) exhibits of reducing properties;

- acetonitrile-water mixture causes reduction of copper(II) to copper(I), as it was documented that i) copper(II) salt solution in acetonitrile-water mixture is a powerful oxidizer of organic molecules (Verma et al., 1979; Cox et al.,1988; Sumalekshmy et al., 2005; Ajayakumar et al., 2009); ii) acetonitrile can reduce Cu2+ to Cu+ (Drew et al., 1985).

To find out whether acetonitrile-water mixture can cause a reduction of Cu2+ to Cu+, we prepared a Cu(ClO4)2 solution in a mixture of 99.5% CH3CN and 0.5% H2O (volume percentage) and evaporated this solution, which yielded crystals of the title compound, [Cu(CH3CN)2(H2O)2(ClO4)2]. No other phases could be detected using powder-XRD. The crystal and molecular structure of the title compound (Fig.1) is presented in this paper.

The structure is composed of monomeric units built up around a Cu2+ on a special position (site symmetry –1). The Cu2+ cation is surrounded by six monodentate ligands, viz. an N–coordinated acetonitrile, a perchlorate anion and a water molecule, and their symmetry related counterparts. The perchlorate anion is disordered over two positions, with occupancies (0.53 (2) and 0.47 (2)), but it's O atoms displacement ellipsoids are still quite large, indicating possible rotational disorder, with the rotation axis passing through oxygen O1 of the perchlorate coordinated with Cu1 and Cl1. The complex adopts an elongated octahedral coordination geometry.

The axial Cu–O1 (perchlorate) bond length is 2.401 (15) and in plane Cu–N1(acetonitrile) 1.960 (5), Cu1–O2(aqua) 1.950 (5) Å respectively.

Besides ionic forces, the crystal structure is stabilized by hydrogen bonding interaction via the perchlorate and aqua H atoms (Fig. 2).

In conclusion, we have to note that the structure of the title compound differs from reported by Inamo with co-workers (Inamo et al., 2001) compounds. They reporteded the formation of [Cu(H2O)n(CH3CN)(6-n)]2+ (n = 0–3) in (water/acetonitrile) solutions with [Cu(H2O)m(CH3CN)6-m]2+ (m < 3) as the dominant species for H2O concentration lower than 0.5 M (99% acetonitrile).

Related literature top

For details of the changing Cu(II/I) redox potential with increasing acetonitrile contents in water–acetonitrile solution, see: Cox et al. (1988); Verma & Sood (1979); Cox et al. (1988); Sumalekshmy & Gopidas (2005); Ajayakumar et al. (2009); Drew et al. (1985). For the dependence of the luminescent properties (emission energy) of the 3-cyano-4-dicyanomethylene-5-oxo-4,5-dihydro-1H-pyrrol-2-olate (A)-based salts depend on the molecular environment around (A), see: Tafeenko et al. (2009, 2010). For transition metals as fluorescence quenchers, see: Xu et al. (2005, 2010). For a previous study, see: Inamo et al. (2001).

Experimental top

Blue crystals of the title salt were obtained by slow evaporation of 0.045 M Cu(H2O)6(ClO4)2 solution in acetonitrile at room temperature in an air atmosphere. The crystals are not stable in the open air, so suitable for X-ray investigation crystal was placed in a sealed capillary. Copper(II) perchlorate hexahydrate of 98% (Aldrich) grade was used for synthesis. Acetonitrile was boiled with phosphorus pentaoxide and then distilled at 353 K.

Refinement top

During the refinement a difference maps showed peaks consistent with the perchlorate atoms Cl1,O2—O5 being unequally disorder over two interpenetrating sites. This was allowed for by use of the appropriate SHELXL SAME, EADP restraints. At convergence the perchlorate disorder was modelled with occupancies (0.53 (2) and 0.47 (2)).

The positions of the H atoms of the water molecule were determined from Fourier difference maps and refined freely; the positions of the H atoms of the methyl group were placed in calculated positions and allowed to ride on their parent atoms [C—H = 0.96 Å]. Uiso(H) = xUeq(parent atom), where x = 1.5 for attached C atoms.

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2000); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with displacement ellipsoids drawn at the 50% probability level. Only one of the two disordered positions of the perchlorate ion is shown. Symmetry code: (i) – x,1 – y, – z.
[Figure 2] Fig. 2. The hydrogen bonding pattern in the title compound. H bonds are drawn as dashed lines. Symmetry codes (ii) x, 1–y, z; (iii): 1–x, 1–y, 1–z; (iv) 1–x, –y, 1–z.
Bis(acetonitrile-κN)diaquabis(perchlorato-κO)copper(II) top
Crystal data top
[Cu(ClO4)2(C2H3N)2(H2O)2]Z = 1
Mr = 380.59F(000) = 191
Triclinic, P1Dx = 1.891 Mg m3
Hall symbol: -P 1Melting point: 422 K
a = 5.581 (1) ÅAg Kα radiation, λ = 0.56085 Å
b = 7.244 (2) ÅCell parameters from 25 reflections
c = 8.733 (2) Åθ = 11–13°
α = 82.82 (2)°µ = 1.09 mm1
β = 76.86 (1)°T = 296 K
γ = 77.12 (1)°Prism, light-blue
V = 334.1 (1) Å30.15 × 0.1 × 0.08 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
Rint = 0.049
Radiation source: fine-focus sealed tubeθmax = 20.0°, θmin = 1.9°
Graphite monochromatorh = 66
non–profiled ω scansk = 88
2518 measured reflectionsl = 1010
1259 independent reflections2 standard reflections every 120 min
1020 reflections with I > 2s(I) intensity decay: none
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)] = 0.066Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.192H atoms treated by a mixture of independent and constrained refinement
S = 1.08 w = 1/[σ2(Fo2) + (0.1161P)2 + 0.4339P]
where P = (Fo2 + 2Fc2)/3
1259 reflections(Δ/σ)max = 0.042
138 parametersΔρmax = 0.70 e Å3
11 restraintsΔρmin = 1.09 e Å3
Crystal data top
[Cu(ClO4)2(C2H3N)2(H2O)2]γ = 77.12 (1)°
Mr = 380.59V = 334.1 (1) Å3
Triclinic, P1Z = 1
a = 5.581 (1) ÅAg Kα radiation, λ = 0.56085 Å
b = 7.244 (2) ŵ = 1.09 mm1
c = 8.733 (2) ÅT = 296 K
α = 82.82 (2)°0.15 × 0.1 × 0.08 mm
β = 76.86 (1)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
Rint = 0.049
2518 measured reflections2 standard reflections every 120 min
1259 independent reflections intensity decay: none
1020 reflections with I > 2s(I)
Refinement top
R[F2 > 2σ(F2)] = 0.06611 restraints
wR(F2) = 0.192H atoms treated by a mixture of independent and constrained refinement
S = 1.08Δρmax = 0.70 e Å3
1259 reflectionsΔρmin = 1.09 e Å3
138 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.

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)
Cu10.00000.50000.50000.0477 (4)
O10.2556 (10)0.2741 (6)0.5295 (6)0.0574 (12)
N10.2362 (12)0.5987 (8)0.3237 (7)0.0631 (16)
C10.3717 (13)0.6605 (9)0.2302 (8)0.0555 (15)
C20.5546 (16)0.7387 (12)0.1089 (9)0.072 (2)
H2A0.71970.68990.12970.109*
H2B0.51740.87470.10880.109*
H2C0.54780.70340.00790.109*
Cl10.120 (3)0.803 (2)0.7550 (16)0.0538 (10)0.53 (2)
O20.195 (3)0.656 (3)0.651 (2)0.082 (6)0.53 (2)
O30.295 (5)0.921 (3)0.694 (3)0.142 (9)0.53 (2)
O40.143 (3)0.729 (3)0.9072 (14)0.105 (6)0.53 (2)
O50.124 (3)0.902 (2)0.755 (2)0.096 (5)0.53 (2)
Cl110.132 (3)0.820 (2)0.7453 (18)0.0538 (10)0.47 (2)
O210.112 (5)0.637 (2)0.717 (2)0.079 (6)0.47 (2)
O310.383 (2)0.837 (3)0.729 (2)0.080 (5)0.47 (2)
O410.008 (6)0.853 (6)0.899 (3)0.22 (2)0.47 (2)
O510.017 (6)0.955 (2)0.644 (4)0.156 (12)0.47 (2)
H110.212 (12)0.172 (10)0.565 (7)0.041 (16)*
H120.357 (17)0.228 (12)0.458 (10)0.07 (3)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0492 (7)0.0344 (6)0.0530 (7)0.0110 (4)0.0021 (4)0.0024 (4)
O10.063 (3)0.034 (2)0.064 (3)0.004 (2)0.001 (2)0.002 (2)
N10.060 (3)0.045 (3)0.068 (3)0.013 (3)0.014 (3)0.008 (2)
C10.057 (4)0.042 (3)0.060 (4)0.006 (3)0.005 (3)0.002 (3)
C20.073 (5)0.075 (5)0.060 (4)0.028 (4)0.005 (4)0.016 (3)
Cl10.0544 (13)0.040 (2)0.0630 (16)0.0150 (12)0.0034 (11)0.0097 (13)
O20.062 (9)0.085 (11)0.107 (13)0.011 (7)0.033 (9)0.051 (10)
O30.115 (16)0.087 (11)0.23 (2)0.061 (11)0.042 (14)0.062 (13)
O40.093 (11)0.152 (15)0.046 (6)0.002 (9)0.000 (6)0.013 (7)
O50.072 (8)0.088 (11)0.110 (11)0.018 (7)0.007 (7)0.028 (8)
Cl110.0544 (13)0.040 (2)0.0630 (16)0.0150 (12)0.0034 (11)0.0097 (13)
O210.111 (17)0.047 (7)0.090 (12)0.027 (9)0.039 (10)0.003 (7)
O310.044 (7)0.117 (14)0.085 (9)0.034 (8)0.006 (6)0.028 (9)
O410.18 (3)0.31 (4)0.17 (3)0.16 (3)0.12 (2)0.15 (3)
O510.19 (3)0.041 (8)0.26 (3)0.028 (10)0.11 (2)0.040 (11)
Geometric parameters (Å, º) top
Cu1—O11.950 (5)C2—H2C0.9600
Cu1—N11.960 (5)Cl1—O51.390 (14)
Cu1—O22.401 (15)Cl1—O41.391 (14)
O1—H110.83 (7)Cl1—O31.414 (14)
O1—H120.79 (9)Cl1—O21.418 (12)
N1—C11.103 (9)Cl11—O511.386 (15)
C1—C21.450 (9)Cl11—O411.387 (15)
C2—H2A0.9600Cl11—O311.409 (14)
C2—H2B0.9600Cl11—O211.413 (13)
O1—Cu1—O1i180.000 (1)C1—C2—H2C109.5
O1—Cu1—N190.4 (2)H2A—C2—H2C109.5
O1i—Cu1—N189.6 (2)H2B—C2—H2C109.5
N1—Cu1—N1i180.0 (3)O5—Cl1—O4110.2 (13)
O1—Cu1—O2i93.3 (4)O5—Cl1—O3110.9 (15)
N1—Cu1—O2i97.7 (6)O4—Cl1—O3110.2 (14)
N1i—Cu1—O2i82.3 (6)O5—Cl1—O2112.1 (11)
O1—Cu1—O286.7 (4)O4—Cl1—O2110.3 (13)
O2i—Cu1—O2180.0 (7)O3—Cl1—O2102.9 (14)
Cu1—O1—H11120 (4)Cl1—O2—Cu1137.3 (11)
Cu1—O1—H12123 (6)O51—Cl11—O41109 (2)
H11—O1—H1293 (7)O51—Cl11—O31109.9 (15)
C1—N1—Cu1176.0 (7)O41—Cl11—O31108.2 (15)
N1—C1—C2178.6 (8)O51—Cl11—O21109.8 (13)
C1—C2—H2A109.5O41—Cl11—O21107.7 (16)
C1—C2—H2B109.5O31—Cl11—O21112.3 (14)
H2A—C2—H2B109.5
Symmetry code: (i) x, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H11···O3ii0.83 (7)2.03 (7)2.758 (17)146 (6)
O1—H12···O3iii0.79 (9)2.22 (10)3.00 (3)165 (8)
Symmetry codes: (ii) x, y1, z; (iii) x+1, y+1, z+1.

Experimental details

Crystal data
Chemical formula[Cu(ClO4)2(C2H3N)2(H2O)2]
Mr380.59
Crystal system, space groupTriclinic, P1
Temperature (K)296
a, b, c (Å)5.581 (1), 7.244 (2), 8.733 (2)
α, β, γ (°)82.82 (2), 76.86 (1), 77.12 (1)
V3)334.1 (1)
Z1
Radiation typeAg Kα, λ = 0.56085 Å
µ (mm1)1.09
Crystal size (mm)0.15 × 0.1 × 0.08
Data collection
DiffractometerEnraf–Nonius CAD-4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2s(I)] reflections
2518, 1259, 1020
Rint0.049
(sin θ/λ)max1)0.609
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.066, 0.192, 1.08
No. of reflections1259
No. of parameters138
No. of restraints11
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.70, 1.09

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2000), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H11···O3i0.83 (7)2.03 (7)2.758 (17)146 (6)
O1—H12···O3ii0.79 (9)2.22 (10)3.00 (3)165 (8)
Symmetry codes: (i) x, y1, z; (ii) x+1, y+1, z+1.
 

References

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Volume 67| Part 8| August 2011| Pages m1125-m1126
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