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Tris(ethyl­enedi­amine)nickel(II) tetra­iodo­cadmate(II)

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aDepartment of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan, and bDepartment of Chemistry, University of Bath, Bath BA2 7AY, England
*Correspondence e-mail: mazhar42pk@yahoo.com

(Received 29 November 2005; accepted 20 January 2006; online 31 January 2006)

The title compound, [Ni(C6H24N6)][CdI4], contains two discrete ions, an [Ni(en)3]2+ (en = ethyl­enediamine) cation and a [CdI4]2− anion. The Ni2+ ion is coordinated by three chelating ethyl­enediamine ligands in a distorted octa­hedral geometry while the Cd2+ ion binds four iodide ions in a slightly distorted tetra­hedron. Both the Ni and Cd atoms lie on threefold axes of rotation. The structure is disordered at cadmium, with two alternative sites for the metal in a 97:3 ratio; the minor component of the disorder inverts the CdI4 tetra­hedron and reverses the direction of propagation of the aligned [CdI4]n2− units.

Comment

There has been considerable inter­est in the development of chemical routes for the deposition of nickel oxide (NiO) and complex oxides containing nickel, which have a number of important industrial applications. For instance, nickel oxide is a component of electrochromic devices such as automotive mirrors and smart windows, optical or electrical gas sensors. (Ozer & Lampert, 1998[Ozer, N. & Lampert, C. M. (1998). Sol. Energy Mater. Sol. Cells, 54, 147-152.]). Complex (I)[link] (Fig. 1[link] and Table 1[link]) has been synthesized in a continuation of attempts to obtain suitable precursors for the deposition of complex oxides containing nickel through aerosol-assisted chemical vapour deposition (AACVD) (Sohail et al., 2005[Sohail, M., Molloy, K. C. Mazhar, M., Kociok-Köhn, G. & Khosa, M. K. (2005). Acta Cryst. E61, m2001-m2002.]).

[Scheme 1]

The structure is disordered at cadmium, with two alternative sites for the metal in a 97:3 ratio; the minor component of the disorder inverts the CdI4 tetra­hedron and reverses the direction of propagation of the aligned [CdI4]n2− units. Only the major component of the structure is shown in Fig. 1[link] and discussed here. Complex (I)[link] contains discrete [Ni(en)3]2+ and [CdI4]2− ions, with each of the Ni and Cd atoms lying on threefold axes of rotation. The NiII ion is coordinated by three chelating ethyl­enediamine ligands, resulting in distorted octa­hedral geometry. All axial/equatorial N—Ni—N bond angles lie in the range 82.01 (10)–93.47 (12)°, showing a significant distortion, while symmetry dicta­tes that all trans N—Ni—N angles are identical [173.05 (11)°], as are all Ni—N bonds [2.130 (3) Å], the latter being slightly longer than analogous bonds in related compounds (Colacio et al., 2003[Colacio, E., Lloret, F., Kivekas, R., Suarez-Varela, J., Sundberg, R. M. & Uggla, R. (2003). Inorg. Chem. 42, 560-565.]). The CdII ion in the [CdI4]2− anion is coordinated by four I atoms with a distorted tetra­hedral geometry.

The range of relevant I—Cd1—I bond angles, 105.377 (14)–113.237 (12)°, indicates that the geometry shows some significant deviation from regular tetra­hedral, as is the case in other complexes containing [CdI4]2− (Bailey & Pennington, 1995[Bailey, D. R. & Pennington, T. M. (1995). Acta Cryst. C51, 226-229.]). The Cd1—I bond lengths are comparable to those of similar compounds (Bengtsson-Kloo et al., 1996[Bengtsson-Kloo, L., Berglund, J., Stegemann, H., Svensson, C. & Svensson, H. P. (1996). Acta Cryst. C52, 3045-3047.]). The anions align to allow the cadmium centres to become linked to each other through bridging iodine ligands [I2⋯Cd1e = 4.223 (1) Å] [symmetry code: (e) −x + y, y, z[{1\over 2}]]. This inter­action is weak, and consistent with a lengthening of the Cd—I2 bond [2.7889 (11)] at the limit of detection in comparison with analogous bonds involving non-bridging halogens [2.7815 (15) Å]. However, a flattening of the tetra­hedron, evident from the I1—Cd—I1 angle [113.237 (12)°] is evidence of a meaningful anion–anion inter­action. The distortions from octa­hedral and tetra­hedral in both of the ions of the complex (I)[link] may result from packing effects and are observed in other such complexes (Kallel & Bats, 1981[Kallel, A. & Bats, W. J. (1981). Acta Cryst. B37, 676-677.]).

[Figure 1]
Figure 1
The structure of (I)[link], showing the atom-numbering scheme and displacement ellipsoids drawn at the 30% probability level. Only the major disorder component is shown. H atoms have been omitted.[Symmetry codes: (a) −y + 1, xy, z; (b) −x + y + 1, −x + 1, z; (c) −x + y, −x + 1, z; (d) −y + 1, xy + 1, z; (e) −x + y, y, z[{1\over 2}].]

Experimental

Tris(ethyl­enediammine)nickel(II) bromide, [Ni(en)3]Br2 (3.199 g, 6.8 mmol), and potassium tetra­iodo­cadmate(II), K2[CdI4] (3.62 g, 6.8 mmol), were dissolved in water (30 ml), resulting in the formation of a precipitate of complex (I)[link]. This was washed several times with distilled water and recrystallized from ethyl­ene glycol over a two-month period at room temperature.

Crystal data
  • [Ni(C6H24N6)][CdI4]

  • Mr = 859.02

  • Trigonal, P 3c 1

  • a = 9.023 (5) Å

  • c = 14.203 (5) Å

  • V = 1001.4 (9) Å3

  • Z = 2

  • Dx = 2.849 Mg m−3

  • Mo Kα radiation

  • Cell parameters from 15955 reflections

  • θ = 2.9–30.0°

  • μ = 8.16 mm−1

  • T = 150 (2) K

  • Block, colourless

  • 0.25 × 0.20 × 0.20 mm

Data collection
  • Nonius KappaCCD diffractometer

  • ω scans

  • Absorption correction: multi-scan(SORTAV; Blessing, 1995[Blessing, R. H. (1995). Acta Cryst. A51, 33-38.])Tmin = 0.120, Tmax = 0.195

  • 21288 measured reflections

  • 1944 independent reflections

  • 1937 reflections with I > 2σ(I)

  • Rint = 0.056

  • θmax = 30.0°

  • h = −11 → 12

  • k = −12 → 12

  • l = −19 → 19

Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.018

  • wR(F2) = 0.039

  • S = 1.17

  • 1944 reflections

  • 72 parameters

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

  • w = 1/[σ2(Fo2) + (0.0075P)2 + 1.6741P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max = 0.001

  • Δρmax = 0.99 e Å−3

  • Δρmin = −0.61 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 968 Friedel pairs

  • Flack parameter: 0.00 (3)

Table 1
Selected geometric parameters (Å, °)

Cd1—I1i 2.7815 (15)
Cd1—I2 2.7889 (11)
Cd1A—I1i 2.771 (4)
Cd1A—I2ii 2.879 (15)
Ni—N2iii 2.130 (3)
I1i—Cd1—I1iv 113.237 (12)
I1i—Cd1—I2 105.377 (14)
I1i—Cd1A—I1iv 113.90 (2)
I1i—Cd1A—I2ii 104.60 (3)
N2iii—Ni—N2v 92.83 (12)
N2iii—Ni—N1iii 82.01 (10)
N2—Ni—N1iii 173.05 (11)
N1iii—Ni—N1 93.47 (12)
Symmetry codes: (i) -x+y, -x+1, z; (ii) [-x+y, y, z-{\script{1\over 2}}]; (iii) -x+y+1, -x+1, z; (iv) -y+1, x-y+1, z; (v) -y+1, x-y, z.

The coordinates of H atoms attached to N atoms were found in difference maps and allowed to refine freely with fixed isotropic displacement parameters. H atoms bound to C atoms were refined using a riding model, with C—H = 0.99 Å and Uiso(H) = 1.2Ueq(C). PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]) reveals metrical relationships among atoms consistent with a higher symmetry space group. The highly symmetric ions also suggest the higher symmetry space group [P\overline{6}c]2. However, checking the Rint values, the structure is unequivocally trigonal ([\overline{3}]m1 or [\overline{3}] symmetry; Rint < 0.057). Rint for any hexa­gonal 6/m or 6/mmm symmetry (or trigonal [\overline{3}]1m) symmetry is > 0.187. Disorder in the occupation of the anions has been resolved and refined, the principal disorder component having an occupancy of 0.972 (8). Analysis of the model considering long-range hydrogen bonds between the cation and the anion favours the 97% position of the anion.

Data collection: COLLECT (Nonius, 2000[Nonius (2000). KappaCCD Server Software. Windows 3.11 Version. Nonius BV, Delft, The Netherlands.]); cell refinement: SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: DENZO (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) and SCALEPACK; program(s) used to solve structure: SIR (Altomare et al., 1999[Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115-119.]); program(s) used to refine structure: SHELX97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. Release 97-2. University of Göttingen, Germany.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Computing details top

Data collection: COLLECT (Nonius, 2000); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR (Altomare et al., 1999); program(s) used to refine structure: SHELX97 (Sheldrick, 1997); molecular graphics: ORTEP 3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Tris(ethylenediamine)nickel(II) tetraiodocadmate(II) top
Crystal data top
[Ni(C6H24N6)][CdI4]Dx = 2.849 Mg m3
Mr = 859.02Mo Kα radiation, λ = 0.71073 Å
Trigonal, P3c1Cell parameters from 15955 reflections
Hall symbol: P 3 -2 " cθ = 2.9–30.0°
a = 9.023 (5) ŵ = 8.16 mm1
c = 14.203 (5) ÅT = 150 K
V = 1001.4 (9) Å3Block, colourless
Z = 20.25 × 0.20 × 0.20 mm
F(000) = 780
Data collection top
Nonius KappaCCD
diffractometer
1944 independent reflections
Radiation source: fine-focus sealed tube1937 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.056
188 2.0° images with ω scansθmax = 30.0°, θmin = 3.9°
Absorption correction: multi-scan
(SORTAV; Blessing, 1995)
h = 1112
Tmin = 0.120, Tmax = 0.195k = 1212
21288 measured reflectionsl = 1919
Refinement top
Refinement on F2H atoms treated by a mixture of independent and constrained refinement
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.0075P)2 + 1.6741P]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.018(Δ/σ)max = 0.001
wR(F2) = 0.039Δρmax = 0.99 e Å3
S = 1.17Δρmin = 0.61 e Å3
1944 reflectionsAbsolute structure: Flack (1983), 968 Friedel pairs
72 parametersAbsolute structure parameter: 0.00 (3)
1 restraint
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)
Cd10.33330.66670.29989 (3)0.01805 (12)0.972 (2)
Cd1A0.33330.66670.1989 (10)0.013 (4)0.028 (2)
I10.27173 (3)0.34346 (3)0.24797 (2)0.02170 (7)
I20.33330.66670.49626 (2)0.01908 (9)
Ni0.66670.33330.50028 (5)0.01247 (13)
N10.8571 (4)0.5390 (4)0.5815 (2)0.0175 (6)
H10A0.815 (6)0.555 (6)0.633 (3)0.021*
H10B0.935 (7)0.520 (6)0.598 (4)0.021*
N20.6844 (4)0.5391 (3)0.4181 (2)0.0170 (6)
H20A0.731 (7)0.546 (6)0.367 (3)0.02*
H20B0.589 (7)0.523 (6)0.407 (3)0.02*
C10.9232 (4)0.6989 (4)0.5266 (2)0.0179 (6)
H1A1.01090.70790.48150.021*
H1B0.97730.79860.56950.021*
C20.7773 (4)0.6991 (4)0.4738 (2)0.0180 (6)
H2A0.69790.7070.5190.022*
H2B0.82280.79940.43130.022*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cd10.01746 (15)0.01746 (15)0.0192 (2)0.00873 (8)00
Cd1A0.011 (5)0.011 (5)0.019 (7)0.005 (2)00
I10.02936 (12)0.02101 (11)0.01761 (10)0.01474 (9)0.00047 (8)0.00215 (8)
I20.01780 (12)0.01780 (12)0.02164 (18)0.00890 (6)00
Ni0.01157 (18)0.01157 (18)0.0143 (3)0.00578 (9)00
N10.0161 (13)0.0168 (13)0.0189 (14)0.0078 (11)0.0035 (10)0.0007 (10)
N20.0179 (13)0.0171 (13)0.0176 (14)0.0100 (11)0.0020 (10)0.0006 (9)
C10.0142 (14)0.0146 (13)0.0213 (15)0.0045 (12)0.0008 (11)0.0007 (11)
C20.0187 (14)0.0135 (13)0.0228 (15)0.0089 (12)0.0003 (12)0.0002 (12)
Geometric parameters (Å, º) top
Cd1—Cd1A1.434 (15)Ni—N12.130 (3)
Cd1—I1i2.7815 (15)Ni—N1vi2.130 (3)
Cd1—I1ii2.7815 (15)N1—C11.477 (4)
Cd1—I12.7815 (15)N1—H10A0.86 (5)
Cd1—I22.7889 (11)N1—H10B0.84 (5)
Cd1A—I1i2.771 (4)N2—C21.484 (4)
Cd1A—I1ii2.771 (4)N2—H20A0.82 (5)
Cd1A—I12.771 (4)N2—H20B0.81 (5)
Cd1A—I2iii2.879 (15)C1—C21.516 (5)
I2—Cd1Aiv2.879 (15)C1—H1A0.99
Ni—N2v2.130 (3)C1—H1B0.99
Ni—N2vi2.130 (3)C2—H2A0.99
Ni—N22.130 (3)C2—H2B0.99
Ni—N1v2.130 (3)
Cd1A—Cd1—I1i74.623 (14)N1v—Ni—N193.47 (12)
Cd1A—Cd1—I1ii74.623 (14)N2v—Ni—N1vi173.05 (11)
I1i—Cd1—I1ii113.237 (12)N2vi—Ni—N1vi82.01 (11)
Cd1A—Cd1—I174.623 (14)N2—Ni—N1vi92.08 (12)
I1i—Cd1—I1113.237 (12)N1v—Ni—N1vi93.47 (12)
I1ii—Cd1—I1113.237 (12)N1—Ni—N1vi93.47 (12)
Cd1A—Cd1—I2180.00 (2)C1—N1—Ni108.7 (2)
I1i—Cd1—I2105.377 (14)C1—N1—H10A106 (3)
I1ii—Cd1—I2105.377 (14)Ni—N1—H10A112 (3)
I1—Cd1—I2105.377 (14)C1—N1—H10B112 (3)
Cd1—Cd1A—I1i75.40 (3)Ni—N1—H10B112 (3)
Cd1—Cd1A—I1ii75.40 (3)H10A—N1—H10B107 (5)
I1i—Cd1A—I1ii113.90 (2)C2—N2—Ni108.4 (2)
Cd1—Cd1A—I175.4 (3)C2—N2—H20A112 (4)
I1i—Cd1A—I1113.9 (2)Ni—N2—H20A111 (3)
I1ii—Cd1A—I1113.9 (2)C2—N2—H20B108 (3)
Cd1—Cd1A—I2iii180Ni—N2—H20B110 (3)
I1i—Cd1A—I2iii104.60 (3)H20A—N2—H20B107 (5)
I1ii—Cd1A—I2iii104.60 (3)N1—C1—C2109.6 (3)
I1—Cd1A—I2iii104.60 (3)N1—C1—H1A109.8
Cd1A—I1—Cd129.9 (3)C2—C1—H1A109.8
Cd1—I2—Cd1Aiv180.00 (3)N1—C1—H1B109.8
N2v—Ni—N2vi92.83 (12)C2—C1—H1B109.8
N2v—Ni—N292.83 (12)H1A—C1—H1B108.2
N2vi—Ni—N292.83 (12)N2—C2—C1109.3 (3)
N2v—Ni—N1v82.01 (10)N2—C2—H2A109.8
N2vi—Ni—N1v92.08 (12)C1—C2—H2A109.8
N2—Ni—N1v173.05 (11)N2—C2—H2B109.8
N2v—Ni—N192.08 (12)C1—C2—H2B109.8
N2vi—Ni—N1173.05 (11)H2A—C2—H2B108.3
N2—Ni—N182.01 (11)
I1ii—Cd1—Cd1A—I1i120.000N2v—Ni—N1—C179.3 (2)
I1—Cd1—Cd1A—I1i120.000N2vi—Ni—N1—C155.6 (13)
I1i—Cd1—Cd1A—I1ii120.000N2—Ni—N1—C113.2 (2)
I1—Cd1—Cd1A—I1ii120.000N1v—Ni—N1—C1161.5 (2)
I1i—Cd1—Cd1A—I1120.00N1vi—Ni—N1—C1104.8 (3)
I1ii—Cd1—Cd1A—I1120.00N2v—Ni—N2—C2106.3 (3)
II1i—Cd1A—I1—Cd166.50 (4)N2vi—Ni—N2—C2160.7 (2)
I1ii—Cd1A—I1—Cd166.50 (4)N1v—Ni—N2—C264.3 (12)
I2iii—Cd1A—I1—Cd1180N1—Ni—N2—C214.6 (2)
I1i—Cd1—I1—Cd1A65.33 (2)N1vi—Ni—N2—C278.6 (2)
I1ii—Cd1—I1—Cd1A65.33 (2)Ni—N1—C1—C238.6 (3)
I2—Cd1—I1—Cd1A180.000 (2)Ni—N2—C2—C139.6 (3)
Cd1A—Cd1—I2—Cd1Aiv0 (16)N1—C1—C2—N252.9 (3)
Symmetry codes: (i) x+y, x+1, z; (ii) y+1, xy+1, z; (iii) x+y, y, z1/2; (iv) x+y, y, z+1/2; (v) x+y+1, x+1, z; (vi) y+1, xy, z.
 

Acknowledgements

The authors thank the Pakistan Science Foundation Islam­abad 45320, Pakistan, for funding [contract/grant No. PSF/R&D/C-QU/Chem(218)].

References

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