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

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Bis(μ-nitrito-κ2O:O)bis­­[bis­­(1-methyl-1H-imidazole-κN3)(nitrito-κO)copper(II)]

aOrdered Matter Science Research Center, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, People's Republic of China
*Correspondence e-mail: zhurunqiang@163.com

(Received 25 February 2012; accepted 6 March 2012; online 10 March 2012)

In the binuclear title compound, [Cu2(NO2)4(C4H6N2)4], centro­symmetric­ally related complex mol­ecules are linked via weak Cu—O inter­actions, forming dimeric units. The CuII atom displays an elongated square-pyramidal CuN2O3 coordination geometry with a slight tetra­hedral distortion of the basal plane [maximum deviation = 0.249 (2) Å]. The dihedral angle formed by the imidazole rings is 26.20 (10)°.

Related literature

The structure of the title compound was determined as part of our ongoing study of potential ferroelectric phase change materials. For general background to ferroelectric compounds with metal-organic framework structures, see: Fu et al. (2009[Fu, D.-W., Ge, J.-Z., Dai, J., Ye, H.-Y. & Qu, Z.-R. (2009). Inorg. Chem. Commun. 12, 994-997.]); Ye et al. (2006[Ye, Q., Song, Y.-M., Wang, G.-X., Chen, K. & Fu, D.-W. (2006). J. Am. Chem. Soc. 128, 6554-6555.]); Zhang et al. (2008[Zhang, W., Xiong, R.-G. & Huang, S.-P. D. (2008). J. Am. Chem. Soc. 130, 10468-10469.], 2010[Zhang, W., Ye, H.-Y., Cai, H.-L., Ge, J.-Z. & Xiong, R.-G. (2010). J. Am. Chem. Soc. 132, 7300-7302.]). For a related structure, see: Costes et al. (1995[Costes, J. P., Dahan, F., Ruiz, J. & Laurent, J. P. (1995). Inorg. Chim. Acta, 239, 53-59.]).

[Scheme 1]

Experimental

Crystal data
  • [Cu2(NO2)4(C4H6N2)4]

  • Mr = 639.55

  • Triclinic, [P \overline 1]

  • a = 7.8281 (16) Å

  • b = 8.4873 (17) Å

  • c = 10.054 (2) Å

  • α = 80.35 (3)°

  • β = 77.72 (3)°

  • γ = 79.46 (3)°

  • V = 635.9 (2) Å3

  • Z = 1

  • Mo Kα radiation

  • μ = 1.74 mm−1

  • T = 293 K

  • 0.29 × 0.23 × 0.20 mm

Data collection
  • Rigaku SCXmini diffractometer

  • Absorption correction: multi-scan (CrystalClear; Rigaku, 2005[Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.625, Tmax = 0.706

  • 6578 measured reflections

  • 2900 independent reflections

  • 2465 reflections with I > 2σ(I)

  • Rint = 0.035

Refinement
  • R[F2 > 2σ(F2)] = 0.037

  • wR(F2) = 0.091

  • S = 1.05

  • 2900 reflections

  • 174 parameters

  • H-atom parameters constrained

  • Δρmax = 0.40 e Å−3

  • Δρmin = −0.29 e Å−3

Data collection: CrystalClear (Rigaku, 2005[Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]); cell refinement: CrystalClear; data reduction: CrystalClear; 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 & Putz, 2005[Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

As part of our ongoing study of potential ferroelectric phase change materials we have determined the structures of several copper complexes and examined the changes in their dielectric constants with temperature, which is the usual method for detecting such behaviour (Fu et al., 2009; Ye et al., 2006; Zhang et al., 2008; Zhang et al., 2010). Unfortunately, the dielectric constant of the title compound indicates the onset of a ferroelectric phase change over the range 80–298 K.

As show in Fig. 1, the copper ion adopts an elongated square pyramidal geometry with a slight tetrahedral distortion in the basal plane (maximum deviation 0.249 (2) Å for atom N4) which is primarily associated with the coordination of the nitrite ions (O2—Cu1—O3 = 167.15 (8)°). As observed in a related compound (Costes et al., 1995), this geometry displaces atom O2 from the ideal coordination plane towards the centrosymmetrically related Cu1i copper atom [symmetry code: (i) 1-x, 1-y, -z] resulting in an O2—Cu1 distance of 2.578 (5) Å. While this distance is considerably longer than those in basal plane (Cu1—O2 and Cu1—O3 are 2.0221 (19) and 2.0085 (19) Å, respectively), the direction of the displacement of atom O2 and the orientations of the two nitrite ligands which place both atoms O1 and O3 on the opposite side of the coordination plane, suggest that there is a weak association of one complex molecule with its centrosymmetrically related. The dihedral angle formed by the trans-arranged imidazole rings is 26.20 (10)°. The crystal packing (Fig. 2) is governed only by van der Waals interactions.

Related literature top

The structure of the title compound was determined part of our ongoing study of potential ferroelectric phase change materials. For general background to ferroelectric metal-organic frameworks, see: Fu et al. (2009); Ye et al. (2006); Zhang et al. (2008, 2010). For a related structure, see: Costes et al. (1995).

Experimental top

An aqueous solution of 1-methylimidazole (2.0 g, 25 mmol) and H2SO4 (12.5 mmol) was treated with CuSO4 (250 g, 12.5 mmol). After the mixture was stirred for a few minutes, Ba(NO2)2 (6.18 g, 25 mmol) was added to give a blue solution. Slow evaporation of the solution following removal of the precipitated BaSO4 yielded blue crystals after a few days. M. p. 319–329 K.

Refinement top

All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C—H = 0.93–0.96 Å, and with Uiso(H) = 1.2 Uiso(C) or 1.5 Uiso(C) for methy H atoms.

Structure description top

As part of our ongoing study of potential ferroelectric phase change materials we have determined the structures of several copper complexes and examined the changes in their dielectric constants with temperature, which is the usual method for detecting such behaviour (Fu et al., 2009; Ye et al., 2006; Zhang et al., 2008; Zhang et al., 2010). Unfortunately, the dielectric constant of the title compound indicates the onset of a ferroelectric phase change over the range 80–298 K.

As show in Fig. 1, the copper ion adopts an elongated square pyramidal geometry with a slight tetrahedral distortion in the basal plane (maximum deviation 0.249 (2) Å for atom N4) which is primarily associated with the coordination of the nitrite ions (O2—Cu1—O3 = 167.15 (8)°). As observed in a related compound (Costes et al., 1995), this geometry displaces atom O2 from the ideal coordination plane towards the centrosymmetrically related Cu1i copper atom [symmetry code: (i) 1-x, 1-y, -z] resulting in an O2—Cu1 distance of 2.578 (5) Å. While this distance is considerably longer than those in basal plane (Cu1—O2 and Cu1—O3 are 2.0221 (19) and 2.0085 (19) Å, respectively), the direction of the displacement of atom O2 and the orientations of the two nitrite ligands which place both atoms O1 and O3 on the opposite side of the coordination plane, suggest that there is a weak association of one complex molecule with its centrosymmetrically related. The dihedral angle formed by the trans-arranged imidazole rings is 26.20 (10)°. The crystal packing (Fig. 2) is governed only by van der Waals interactions.

The structure of the title compound was determined part of our ongoing study of potential ferroelectric phase change materials. For general background to ferroelectric metal-organic frameworks, see: Fu et al. (2009); Ye et al. (2006); Zhang et al. (2008, 2010). For a related structure, see: Costes et al. (1995).

Computing details top

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Partial packing diagram of the title compound, with displacement ellipsoids drawn at the 30% probability level. The weak Cu—O interactions are shown as dashed lines. Primed atoms are generated by the symmetry operator: (') 1-x, 1-y, -z.
[Figure 2] Fig. 2. Packing diagram of the title compound. The weak Cu—O interactions are shown as dashed lines.
Bis(µ-nitrito-κ2O:O)bis[bis(1-methyl-1H-imidazole- κN3)(nitrito-κO)copper(II)] top
Crystal data top
[Cu2(NO2)4(C4H6N2)4]Z = 1
Mr = 639.55F(000) = 326
Triclinic, P1Dx = 1.670 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.8281 (16) ÅCell parameters from 2900 reflections
b = 8.4873 (17) Åθ = 2.3–27.5°
c = 10.054 (2) ŵ = 1.74 mm1
α = 80.35 (3)°T = 293 K
β = 77.72 (3)°Prism, blue
γ = 79.46 (3)°0.29 × 0.23 × 0.20 mm
V = 635.9 (2) Å3
Data collection top
Rigaku SCXmini
diffractometer
2465 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.035
Graphite monochromatorθmax = 27.5°, θmin = 3.0°
ω scansh = 1010
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
k = 1111
Tmin = 0.625, Tmax = 0.706l = 1313
6578 measured reflections2 standard reflections every 150 reflections
2900 independent reflections 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)] = 0.037Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.091H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.0423P)2 + 0.1143P]
where P = (Fo2 + 2Fc2)/3
2900 reflections(Δ/σ)max = 0.001
174 parametersΔρmax = 0.40 e Å3
0 restraintsΔρmin = 0.29 e Å3
Crystal data top
[Cu2(NO2)4(C4H6N2)4]γ = 79.46 (3)°
Mr = 639.55V = 635.9 (2) Å3
Triclinic, P1Z = 1
a = 7.8281 (16) ÅMo Kα radiation
b = 8.4873 (17) ŵ = 1.74 mm1
c = 10.054 (2) ÅT = 293 K
α = 80.35 (3)°0.29 × 0.23 × 0.20 mm
β = 77.72 (3)°
Data collection top
Rigaku SCXmini
diffractometer
2465 reflections with I > 2σ(I)
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
Rint = 0.035
Tmin = 0.625, Tmax = 0.7062 standard reflections every 150 reflections
6578 measured reflections intensity decay: none
2900 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0370 restraints
wR(F2) = 0.091H-atom parameters constrained
S = 1.05Δρmax = 0.40 e Å3
2900 reflectionsΔρmin = 0.29 e Å3
174 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*/Ueq
C10.7413 (4)0.2449 (4)0.4825 (3)0.0549 (8)
H1A0.77350.13130.47610.082*
H1B0.72200.26190.57690.082*
H1C0.83490.30120.43020.082*
C20.5675 (3)0.4011 (3)0.3090 (3)0.0365 (6)
H20.66290.43890.24800.044*
C30.3061 (4)0.3554 (4)0.4028 (3)0.0496 (8)
H30.18470.35530.41780.059*
C40.4134 (4)0.2788 (4)0.4889 (3)0.0520 (8)
H40.38030.21850.57380.062*
C50.1244 (4)0.9207 (4)0.2032 (3)0.0490 (8)
H5A0.21480.85970.15230.074*
H5B0.09520.89780.29640.074*
H5C0.16671.03410.20200.074*
C60.0619 (3)0.7480 (3)0.0451 (3)0.0341 (6)
H60.01650.67460.00900.041*
C70.2892 (4)0.8716 (3)0.0865 (3)0.0384 (6)
H70.39840.89800.08370.046*
C80.1763 (4)0.9545 (3)0.1664 (3)0.0411 (6)
H80.19251.04800.22770.049*
N10.6145 (3)0.7315 (3)0.0924 (3)0.0485 (6)
N30.5793 (3)0.3061 (3)0.4283 (2)0.0376 (5)
N20.0346 (3)0.5775 (3)0.2749 (3)0.0495 (7)
N40.4024 (3)0.4338 (3)0.2893 (2)0.0334 (5)
N50.2167 (3)0.7405 (2)0.0090 (2)0.0314 (5)
N60.0336 (3)0.8755 (3)0.1406 (2)0.0355 (5)
O10.5052 (3)0.7955 (3)0.1808 (2)0.0541 (5)
O20.5618 (2)0.6202 (2)0.04605 (19)0.0402 (4)
O30.0807 (3)0.4952 (2)0.1912 (2)0.0422 (5)
O40.0182 (3)0.6897 (3)0.3082 (2)0.0542 (6)
Cu10.31394 (4)0.57713 (4)0.13253 (3)0.02903 (12)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0475 (18)0.067 (2)0.0476 (18)0.0037 (15)0.0230 (15)0.0039 (16)
C20.0324 (13)0.0429 (16)0.0316 (14)0.0020 (11)0.0056 (11)0.0021 (11)
C30.0389 (15)0.063 (2)0.0424 (17)0.0159 (14)0.0080 (13)0.0158 (14)
C40.0492 (18)0.066 (2)0.0363 (16)0.0152 (15)0.0087 (14)0.0143 (14)
C50.0434 (16)0.0549 (19)0.0458 (17)0.0069 (14)0.0183 (14)0.0016 (14)
C60.0320 (13)0.0338 (14)0.0361 (14)0.0022 (10)0.0103 (11)0.0019 (11)
C70.0386 (14)0.0354 (15)0.0410 (15)0.0103 (11)0.0087 (12)0.0016 (12)
C80.0473 (16)0.0341 (15)0.0391 (15)0.0068 (12)0.0096 (13)0.0051 (12)
N10.0425 (14)0.0497 (16)0.0550 (16)0.0166 (12)0.0174 (12)0.0094 (13)
N30.0383 (12)0.0435 (13)0.0294 (11)0.0013 (10)0.0103 (10)0.0004 (9)
N20.0326 (13)0.0622 (18)0.0475 (15)0.0074 (12)0.0065 (11)0.0092 (13)
N40.0328 (11)0.0378 (12)0.0275 (11)0.0043 (9)0.0053 (9)0.0007 (9)
N50.0299 (11)0.0318 (11)0.0313 (11)0.0036 (9)0.0056 (9)0.0023 (9)
N60.0368 (12)0.0352 (12)0.0324 (11)0.0020 (9)0.0093 (9)0.0032 (9)
O10.0652 (14)0.0489 (13)0.0529 (13)0.0133 (11)0.0137 (11)0.0116 (10)
O20.0361 (10)0.0439 (11)0.0383 (10)0.0065 (8)0.0062 (8)0.0008 (8)
O30.0395 (10)0.0432 (11)0.0450 (11)0.0135 (9)0.0125 (9)0.0041 (9)
O40.0547 (13)0.0539 (14)0.0501 (13)0.0016 (11)0.0062 (10)0.0076 (11)
Cu10.02605 (17)0.03196 (19)0.02820 (18)0.00537 (12)0.00609 (12)0.00075 (12)
Geometric parameters (Å, º) top
C1—N31.460 (4)C6—N51.325 (3)
C1—H1A0.9600C6—N61.341 (3)
C1—H1B0.9600C6—H60.9300
C1—H1C0.9600C7—C81.344 (4)
C2—N41.321 (3)C7—N51.385 (3)
C2—N31.339 (3)C7—H70.9300
C2—H20.9300C8—N61.363 (3)
C3—C41.341 (4)C8—H80.9300
C3—N41.370 (3)N1—O11.219 (3)
C3—H30.9300N1—O21.286 (3)
C4—N31.356 (4)N2—O41.225 (3)
C4—H40.9300N2—O31.286 (3)
C5—N61.466 (3)N4—Cu11.989 (2)
C5—H5A0.9600N5—Cu11.985 (2)
C5—H5B0.9600O2—Cu12.0221 (19)
C5—H5C0.9600O3—Cu12.0085 (19)
N3—C1—H1A109.5N5—C7—H7125.5
N3—C1—H1B109.5C7—C8—N6107.0 (2)
H1A—C1—H1B109.5C7—C8—H8126.5
N3—C1—H1C109.5N6—C8—H8126.5
H1A—C1—H1C109.5O1—N1—O2114.3 (2)
H1B—C1—H1C109.5C2—N3—C4107.2 (2)
N4—C2—N3111.1 (2)C2—N3—C1126.1 (2)
N4—C2—H2124.4C4—N3—C1126.8 (2)
N3—C2—H2124.4O4—N2—O3114.5 (2)
C4—C3—N4109.7 (3)C2—N4—C3105.2 (2)
C4—C3—H3125.2C2—N4—Cu1126.73 (18)
N4—C3—H3125.2C3—N4—Cu1127.94 (19)
C3—C4—N3106.8 (2)C6—N5—C7105.6 (2)
C3—C4—H4126.6C6—N5—Cu1125.75 (18)
N3—C4—H4126.6C7—N5—Cu1128.63 (18)
N6—C5—H5A109.5C6—N6—C8107.5 (2)
N6—C5—H5B109.5C6—N6—C5125.5 (2)
H5A—C5—H5B109.5C8—N6—C5127.0 (2)
N6—C5—H5C109.5N1—O2—Cu1115.28 (17)
H5A—C5—H5C109.5N2—O3—Cu1114.51 (17)
H5B—C5—H5C109.5N5—Cu1—N4173.10 (8)
N5—C6—N6110.9 (2)N5—Cu1—O390.30 (8)
N5—C6—H6124.6N4—Cu1—O389.99 (9)
N6—C6—H6124.6N5—Cu1—O290.40 (8)
C8—C7—N5109.1 (2)N4—Cu1—O290.85 (8)
C8—C7—H7125.5O3—Cu1—O2167.15 (8)
N4—C3—C4—N31.2 (4)C7—C8—N6—C5179.9 (3)
N5—C7—C8—N60.5 (3)O1—N1—O2—Cu10.8 (3)
N4—C2—N3—C40.9 (3)O4—N2—O3—Cu11.9 (3)
N4—C2—N3—C1179.4 (3)C6—N5—Cu1—O39.1 (2)
C3—C4—N3—C21.3 (3)C7—N5—Cu1—O3168.4 (2)
C3—C4—N3—C1179.0 (3)C6—N5—Cu1—O2158.1 (2)
N3—C2—N4—C30.2 (3)C7—N5—Cu1—O224.4 (2)
N3—C2—N4—Cu1177.04 (17)C2—N4—Cu1—O3168.7 (2)
C4—C3—N4—C20.7 (4)C3—N4—Cu1—O315.1 (3)
C4—C3—N4—Cu1176.2 (2)C2—N4—Cu1—O21.6 (2)
N6—C6—N5—C70.1 (3)C3—N4—Cu1—O2177.7 (2)
N6—C6—N5—Cu1178.14 (16)N2—O3—Cu1—N582.48 (18)
C8—C7—N5—C60.3 (3)N2—O3—Cu1—N490.62 (18)
C8—C7—N5—Cu1177.67 (19)N2—O3—Cu1—O2175.6 (3)
N5—C6—N6—C80.5 (3)N1—O2—Cu1—N590.08 (18)
N5—C6—N6—C5179.8 (2)N1—O2—Cu1—N483.13 (18)
C7—C8—N6—C60.6 (3)N1—O2—Cu1—O3176.8 (3)

Experimental details

Crystal data
Chemical formula[Cu2(NO2)4(C4H6N2)4]
Mr639.55
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)7.8281 (16), 8.4873 (17), 10.054 (2)
α, β, γ (°)80.35 (3), 77.72 (3), 79.46 (3)
V3)635.9 (2)
Z1
Radiation typeMo Kα
µ (mm1)1.74
Crystal size (mm)0.29 × 0.23 × 0.20
Data collection
DiffractometerRigaku SCXmini
Absorption correctionMulti-scan
(CrystalClear; Rigaku, 2005)
Tmin, Tmax0.625, 0.706
No. of measured, independent and
observed [I > 2σ(I)] reflections
6578, 2900, 2465
Rint0.035
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.091, 1.05
No. of reflections2900
No. of parameters174
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.40, 0.29

Computer programs: CrystalClear (Rigaku, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Putz, 2005).

 

Acknowledgements

This work was supported by Southeast University.

References

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