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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 64| Part 12| December 2008| Pages m1488-m1489

Bis(di-2-pyridylmethane­diol-κ3N,O,N′)copper(II) DL-tartrate

aCollege of Mechanical & Materials Engineering, Three Gorges University, Yichang 443002, People's Republic of China, and bDepartment of Chemistry and Chemical Engineering, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan'an University, Yan'an 716000, People's Republic of China
*Correspondence e-mail: lidongsheng1@126.com

(Received 16 September 2008; accepted 28 October 2008; online 8 November 2008)

The reaction of di-2-pyridyl ketone with copper dichloride dihydrate and tartaric acid in water afforded the title compound, [Cu(C11H10N2O2)2]C4H4O6. The CuII atom lies on an inversion center N,O,N′-chelated by two di-2-pyridylmethane­diol ligands in a tetragonally distorted octa­hedral geometry. The tartrate anion is also located on an inversion center and has disordered hydroxyl groups, each with an occupancy factor of 0.5. The hydroxyl groups of the complex cation are hydrogen bonded to the carboxyl­ate groups of the anion, thus connecting the two building units.

Related literature

For backgroung on di-2-pyridylketone complexes, see: Deveson et al. (1996[Deveson, A. C., Heath, S. L., Harding, C. J. & Powell, A. K. (1996). J. Chem. Soc. Dalton Trans. pp. 3173-3177.]); Sommerer et al. (1993[Sommerer, S. O., Baker, J. D., Jensen, W. P., Hamza, A. & Jacobson, R. A. (1993). Inorg. Chim. Acta, 210, 173-176.]); Wang et al. (1986[Wang, S. L., Richardson, J. W., Briggs, S. J. & Jacobson, R. A. (1986). Inorg. Chim. Acta, 111, 67-72.]).

[Scheme 1]

Experimental

Crystal data
  • [Cu(C11H10N2O2)2]C4H4O6

  • Mr = 616.03

  • Triclinic, [P \overline 1]

  • a = 7.7893 (8) Å

  • b = 8.1068 (8) Å

  • c = 11.3136 (12) Å

  • α = 105.973 (1)°

  • β = 90.431 (1)°

  • γ = 110.584 (1)°

  • V = 638.65 (11) Å3

  • Z = 1

  • Mo Kα radiation

  • μ = 0.92 mm−1

  • T = 293 (2) K

  • 0.45 × 0.30 × 0.18 mm

Data collection
  • Bruker SMART APEX CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996[Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.]) Tmin = 0.726, Tmax = 0.850

  • 3231 measured reflections

  • 2235 independent reflections

  • 1978 reflections with I > 2σ(I)

  • Rint = 0.015

Refinement
  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.091

  • S = 1.03

  • 2235 reflections

  • 196 parameters

  • H-atom parameters constrained

  • Δρmax = 0.37 e Å−3

  • Δρmin = −0.31 e Å−3

Table 1
Selected geometric parameters (Å, °)

Cu1—N1 2.003 (2)
Cu1—N2 2.019 (2)
Cu1—O1 2.3920 (19)
N1—Cu1—N2i 91.08 (9)
N1—Cu1—N2 88.92 (9)
N1—Cu1—O1i 104.11 (8)
N2—Cu1—O1i 106.37 (8)
N1—Cu1—O1 75.89 (8)
N2—Cu1—O1 73.63 (8)
Symmetry code: (i) -x+2, -y, -z.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1A⋯O3ii 0.85 1.73 2.582 (3) 178
O2—H2A⋯O4ii 0.82 1.84 2.648 (3) 170
O5—H5⋯O3 0.82 2.15 2.641 (5) 119
O6—H6⋯O4 0.82 2.22 2.693 (5) 118
C2—H2⋯O5iii 0.93 2.38 3.249 (6) 156
C3—H3⋯O4iv 0.93 2.50 3.217 (4) 134
C4—H4⋯O5 0.93 2.45 3.258 (5) 146
Symmetry codes: (ii) x+1, y, z; (iii) x, y-1, z; (iv) -x+1, -y+1, -z+1.

Data collection: SMART (Bruker, 2007[Bruker (2007). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2007[Bruker (2007). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Di-2-pyridylketone (dpk) functions either as a bidentate N,N'-donor or as a tridentate N,O,N'-donor towards metal ions, depending on the reaction medium used in the synthesis of the complexes (Deveson et al., 1996), and several mononuclear and polynuclear transition metal–dpk complexes have been reported (Sommerer et al., 1993; Wang et al., 1986). The structural investigations clearly demonstrate that in each case hydration occurs across the ketone double bond in the ligand and that the resulting hydroxyl group coordinates to metal.

In the title compound, two dipyridin-2-yl-methanediol ligands, each in a tridentate fashion, are bonded to the CuII atom lying on an inversion center (Fig. 1). The pyridyl N atoms are strongly coordinated to the metal in the equatorial plane, while the hydroxyl groups are relatively weakly coordinated in the axial positions (Table 1). The two Cu—O(hydroxy) bonds [2.392 (2) Å], being in a trans arrangement, significantly exceed the Cu—N bond distances, a feature which can be attributed to the Jahn-Teller effect and usually manifests in d9 metal systems. The tartrate anion is located on an inversion center with disordered hydroxyl groups, each has an occupancy factor of 0.5. The hydroxyl groups of the complex cation as donors are involved in hydrogen bonds with the tartrate anion (Table 2).

Related literature top

For backgroung on di-2-pyridylketone complexes, see: Deveson et al. (1996); Sommerer et al. (1993); Wang et al. (1986).

Experimental top

A mixture of di-2-pyridylketone (0.184 g, 1 mmol), CuCl2.2H2O (0.067 g, 0.5 mmol), tartaric acid (0.075 g, 0.5 mmol) and water (18 ml) in a 25 ml Teflon-lined stainless steel reactor was heated from 298 to 453 K in 2 h and maintained at 453 K for 72 h. After the mixture was cooled to 298 K, blue crystals of the title compound were obtained.

Refinement top

All H atoms were positioned geometrically. Aromatic H atoms were refined as riding atoms, with C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C). The other H atoms were fixed in the refinements, with Uiso(H) = 1.2Ueq(C,O).

Computing details top

Data collection: SMART (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: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level. The hydroxyl groups (O5 and O6) of the tartrate anion are half-occupied. The disordered H atoms attached to C13 have been omitted. [Symmetry codes: (i) 2 - x, -y, -z; (ii) 1 - x, 1 - y, 1 - z.]
Bis(di-2-pyridylmethanediol-κ3N,O,N')copper(II) tartrate top
Crystal data top
[Cu(C11H10N2O2)2]C4H4O6Z = 1
Mr = 616.03F(000) = 317
Triclinic, P1Dx = 1.602 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.7893 (8) ÅCell parameters from 1352 reflections
b = 8.1068 (8) Åθ = 2.8–26.5°
c = 11.3136 (12) ŵ = 0.92 mm1
α = 105.973 (1)°T = 293 K
β = 90.431 (1)°Prism, blue
γ = 110.584 (1)°0.45 × 0.30 × 0.18 mm
V = 638.65 (11) Å3
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
2235 independent reflections
Radiation source: fine-focus sealed tube1978 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.015
ϕ and ω scansθmax = 25.1°, θmin = 1.9°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 99
Tmin = 0.726, Tmax = 0.850k = 98
3231 measured reflectionsl = 1311
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)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.091H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0346P)2 + 0.5737P]
where P = (Fo2 + 2Fc2)/3
2235 reflections(Δ/σ)max < 0.001
196 parametersΔρmax = 0.37 e Å3
0 restraintsΔρmin = 0.31 e Å3
Crystal data top
[Cu(C11H10N2O2)2]C4H4O6γ = 110.584 (1)°
Mr = 616.03V = 638.65 (11) Å3
Triclinic, P1Z = 1
a = 7.7893 (8) ÅMo Kα radiation
b = 8.1068 (8) ŵ = 0.92 mm1
c = 11.3136 (12) ÅT = 293 K
α = 105.973 (1)°0.45 × 0.30 × 0.18 mm
β = 90.431 (1)°
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
2235 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1978 reflections with I > 2σ(I)
Tmin = 0.726, Tmax = 0.850Rint = 0.015
3231 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.091H-atom parameters constrained
S = 1.04Δρmax = 0.37 e Å3
2235 reflectionsΔρmin = 0.31 e Å3
196 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Cu11.00000.00000.00000.03430 (17)
N10.9447 (3)0.0410 (3)0.1761 (2)0.0337 (5)
N20.8085 (3)0.1020 (3)0.0329 (2)0.0357 (5)
O11.1369 (3)0.3273 (3)0.09003 (17)0.0394 (5)
H1A1.22670.36770.14730.047*
O21.0017 (3)0.5166 (3)0.21831 (19)0.0488 (6)
H2A1.09630.56310.26710.059*
O30.4119 (4)0.4426 (5)0.2591 (2)0.0951 (11)
O40.2982 (5)0.6254 (5)0.3782 (3)0.1005 (13)
O50.7064 (6)0.5609 (6)0.4214 (4)0.0507 (11)0.50
H50.68470.51430.34680.061*0.50
O60.5874 (7)0.7540 (6)0.5538 (4)0.0569 (12)0.50
H60.51460.79730.53660.068*0.50
C10.9098 (4)0.0858 (4)0.2372 (3)0.0411 (7)
H10.91540.20040.19770.049*
C20.8658 (5)0.0499 (5)0.3569 (3)0.0506 (8)
H20.84160.13910.39790.061*
C30.8583 (5)0.1207 (5)0.4150 (3)0.0538 (9)
H30.82740.14680.49550.065*
C40.8970 (4)0.2526 (5)0.3533 (3)0.0459 (8)
H40.89360.36850.39150.055*
C50.9407 (4)0.2086 (4)0.2340 (2)0.0339 (6)
C60.9820 (4)0.3391 (4)0.1516 (3)0.0361 (6)
C70.8205 (4)0.2618 (4)0.0498 (3)0.0365 (6)
C80.6957 (4)0.3441 (4)0.0418 (3)0.0472 (8)
H80.70370.45220.10170.057*
C90.5585 (4)0.2637 (5)0.0563 (3)0.0540 (9)
H90.47290.31740.06380.065*
C100.5493 (4)0.1036 (5)0.1432 (3)0.0483 (8)
H100.45930.04920.21110.058*
C110.6747 (4)0.0247 (4)0.1282 (3)0.0420 (7)
H110.66650.08540.18580.050*
C120.4060 (4)0.5461 (4)0.3591 (3)0.0436 (7)
C130.5422 (4)0.5732 (4)0.4673 (3)0.0406 (7)
H13A0.57130.69940.52710.049*0.50
H13B0.65680.55970.43490.049*0.50
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0397 (3)0.0388 (3)0.0277 (3)0.0214 (2)0.0000 (2)0.0060 (2)
N10.0388 (13)0.0359 (13)0.0302 (12)0.0188 (11)0.0011 (10)0.0092 (10)
N20.0385 (13)0.0404 (13)0.0289 (12)0.0186 (11)0.0017 (10)0.0063 (10)
O10.0425 (11)0.0413 (11)0.0322 (10)0.0143 (9)0.0019 (9)0.0090 (9)
O20.0607 (14)0.0365 (12)0.0458 (13)0.0235 (10)0.0110 (11)0.0002 (9)
O30.0785 (19)0.152 (3)0.0442 (15)0.076 (2)0.0195 (14)0.0292 (17)
O40.130 (3)0.121 (3)0.0594 (18)0.100 (2)0.0409 (17)0.0290 (17)
O50.041 (2)0.062 (3)0.051 (3)0.019 (2)0.001 (2)0.019 (2)
O60.068 (3)0.043 (3)0.047 (3)0.011 (2)0.012 (2)0.006 (2)
C10.0428 (17)0.0410 (17)0.0433 (17)0.0191 (14)0.0003 (14)0.0136 (14)
C20.053 (2)0.062 (2)0.0462 (19)0.0234 (17)0.0046 (15)0.0292 (17)
C30.062 (2)0.078 (2)0.0307 (16)0.0362 (19)0.0097 (15)0.0165 (17)
C40.0552 (19)0.0545 (19)0.0335 (16)0.0310 (16)0.0035 (14)0.0077 (14)
C50.0353 (15)0.0404 (16)0.0290 (14)0.0200 (13)0.0005 (12)0.0070 (12)
C60.0447 (16)0.0324 (15)0.0325 (15)0.0193 (13)0.0014 (13)0.0053 (12)
C70.0409 (16)0.0378 (16)0.0357 (16)0.0178 (13)0.0031 (13)0.0143 (13)
C80.0534 (19)0.0406 (17)0.054 (2)0.0253 (15)0.0002 (16)0.0138 (15)
C90.0451 (19)0.058 (2)0.069 (2)0.0278 (17)0.0049 (17)0.0218 (18)
C100.0428 (17)0.057 (2)0.0441 (18)0.0197 (16)0.0083 (14)0.0121 (16)
C110.0409 (17)0.0451 (17)0.0363 (16)0.0159 (14)0.0037 (13)0.0062 (13)
C120.0466 (18)0.0448 (18)0.0353 (17)0.0162 (15)0.0008 (14)0.0062 (14)
C130.0396 (16)0.0404 (17)0.0375 (16)0.0135 (13)0.0019 (13)0.0066 (13)
Geometric parameters (Å, º) top
Cu1—N1i2.003 (2)C1—C21.377 (4)
Cu1—N12.003 (2)C1—H10.9300
Cu1—N2i2.019 (2)C2—C31.380 (5)
Cu1—N22.019 (2)C2—H20.9300
Cu1—O1i2.3920 (19)C3—C41.382 (5)
Cu1—O12.3920 (19)C3—H30.9300
N1—C11.344 (4)C4—C51.375 (4)
N1—C51.348 (3)C4—H40.9300
N2—C111.339 (4)C5—C61.549 (4)
N2—C71.345 (4)C6—C71.526 (4)
O1—C61.417 (3)C7—C81.373 (4)
O1—H1A0.8554C8—C91.376 (5)
O2—C61.382 (3)C8—H80.9300
O2—H2A0.8209C9—C101.374 (5)
O3—C121.222 (4)C9—H90.9300
O4—C121.213 (4)C10—C111.374 (4)
O5—C131.409 (5)C10—H100.9300
O5—H50.8134C11—H110.9300
O5—H13B0.4145C12—C131.530 (4)
O6—C131.440 (5)C13—C13ii1.527 (6)
O6—H60.8117C13—H13A1.0044
O6—H13A0.4359C13—H13B0.9970
N1i—Cu1—N1180.0N1—C5—C4121.9 (3)
N1i—Cu1—N2i88.92 (9)N1—C5—C6113.5 (2)
N1—Cu1—N2i91.08 (9)C4—C5—C6124.6 (3)
N1i—Cu1—N291.08 (9)O2—C6—O1113.9 (2)
N1—Cu1—N288.92 (9)O2—C6—C7109.4 (2)
N2i—Cu1—N2180.0O1—C6—C7105.5 (2)
N1i—Cu1—O1i75.89 (8)O2—C6—C5111.9 (2)
N1—Cu1—O1i104.11 (8)O1—C6—C5108.2 (2)
N2i—Cu1—O1i73.63 (8)C7—C6—C5107.6 (2)
N2—Cu1—O1i106.37 (8)N2—C7—C8122.0 (3)
N1i—Cu1—O1104.11 (8)N2—C7—C6113.9 (2)
N1—Cu1—O175.89 (8)C8—C7—C6124.1 (3)
N2i—Cu1—O1106.37 (8)C7—C8—C9118.8 (3)
N2—Cu1—O173.63 (8)C7—C8—H8120.6
O1i—Cu1—O1180.00 (10)C9—C8—H8120.6
C1—N1—C5119.4 (2)C10—C9—C8119.4 (3)
C1—N1—Cu1124.79 (19)C10—C9—H9120.3
C5—N1—Cu1115.84 (18)C8—C9—H9120.3
C11—N2—C7118.8 (2)C9—C10—C11119.1 (3)
C11—N2—Cu1125.7 (2)C9—C10—H10120.5
C7—N2—Cu1115.45 (18)C11—C10—H10120.5
C6—O1—Cu193.97 (15)N2—C11—C10121.8 (3)
C6—O1—H1A105.5N2—C11—H11119.1
Cu1—O1—H1A116.8C10—C11—H11119.1
C6—O2—H2A109.5O4—C12—O3124.4 (3)
C13—O5—H5108.0O4—C12—C13118.5 (3)
C13—O5—H13B5.1O3—C12—C13117.1 (3)
H5—O5—H13B107.4O5—C13—O6107.9 (3)
C13—O6—H6108.0O5—C13—C12108.8 (3)
C13—O6—H13A2.7O6—C13—C12110.1 (3)
H6—O6—H13A105.4O5—C13—C13ii110.6 (3)
N1—C1—C2121.5 (3)O6—C13—C13ii109.6 (3)
N1—C1—H1119.3C12—C13—C13ii109.9 (3)
C2—C1—H1119.3O5—C13—H13A108.8
C1—C2—C3119.0 (3)O6—C13—H13A1.2
C1—C2—H2120.5C12—C13—H13A109.0
C3—C2—H2120.5C13ii—C13—H13A109.7
C2—C3—C4119.8 (3)O5—C13—H13B2.1
C2—C3—H3120.1O6—C13—H13B109.5
C4—C3—H3120.1C12—C13—H13B109.1
C5—C4—C3118.5 (3)C13ii—C13—H13B108.6
C5—C4—H4120.7H13A—C13—H13B110.5
C3—C4—H4120.7
Symmetry codes: (i) x+2, y, z; (ii) x+1, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···O3iii0.851.732.582 (3)178
O2—H2A···O4iii0.821.842.648 (3)170
O5—H5···O30.822.152.641 (5)119
O6—H6···O40.822.222.693 (5)118
C2—H2···O5iv0.932.383.249 (6)156
C3—H3···O4ii0.932.503.217 (4)134
C4—H4···O50.932.453.258 (5)146
Symmetry codes: (ii) x+1, y+1, z+1; (iii) x+1, y, z; (iv) x, y1, z.

Experimental details

Crystal data
Chemical formula[Cu(C11H10N2O2)2]C4H4O6
Mr616.03
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)7.7893 (8), 8.1068 (8), 11.3136 (12)
α, β, γ (°)105.973 (1), 90.431 (1), 110.584 (1)
V3)638.65 (11)
Z1
Radiation typeMo Kα
µ (mm1)0.92
Crystal size (mm)0.45 × 0.30 × 0.18
Data collection
DiffractometerBruker SMART APEX CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.726, 0.850
No. of measured, independent and
observed [I > 2σ(I)] reflections
3231, 2235, 1978
Rint0.015
(sin θ/λ)max1)0.597
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.091, 1.04
No. of reflections2235
No. of parameters196
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.37, 0.31

Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Selected geometric parameters (Å, º) top
Cu1—N12.003 (2)Cu1—O12.3920 (19)
Cu1—N22.019 (2)
N1—Cu1—N2i91.08 (9)N2—Cu1—O1i106.37 (8)
N1—Cu1—N288.92 (9)N1—Cu1—O175.89 (8)
N1—Cu1—O1i104.11 (8)N2—Cu1—O173.63 (8)
Symmetry code: (i) x+2, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···O3ii0.851.732.582 (3)178
O2—H2A···O4ii0.821.842.648 (3)170
O5—H5···O30.822.152.641 (5)119
O6—H6···O40.822.222.693 (5)118
C2—H2···O5iii0.932.383.249 (6)156
C3—H3···O4iv0.932.503.217 (4)134
C4—H4···O50.932.453.258 (5)146
Symmetry codes: (ii) x+1, y, z; (iii) x, y1, z; (iv) x+1, y+1, z+1.
 

Acknowledgements

This work was supported financially by the National Natural Science Foundation of China (grant No. 20773104), the Program for New Century Excellent Talents in Universities (NCET-06–0891), the Key Project of the Chinese Ministry of Education (grant No. 208143) and the Important Project of Hubei Provincial Education Office (09HB81).

References

First citationBruker (2007). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationDeveson, A. C., Heath, S. L., Harding, C. J. & Powell, A. K. (1996). J. Chem. Soc. Dalton Trans. pp. 3173–3177.  CSD CrossRef Web of Science Google Scholar
First citationSheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSommerer, S. O., Baker, J. D., Jensen, W. P., Hamza, A. & Jacobson, R. A. (1993). Inorg. Chim. Acta, 210, 173–176.  CSD CrossRef CAS Web of Science Google Scholar
First citationWang, S. L., Richardson, J. W., Briggs, S. J. & Jacobson, R. A. (1986). Inorg. Chim. Acta, 111, 67–72.  CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 64| Part 12| December 2008| Pages m1488-m1489
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds