supplementary materials


hy2494 scheme

Acta Cryst. (2012). E68, m57    [ doi:10.1107/S1600536811053402 ]

Bis(tetra-n-butylammonium) bis(5,6-dicyanopyrazine-2,3-dithiolato-[kappa]2S,S')palladium(II)

M. Tomura and Y. Yamashita

Abstract top

In the title complex, (C16H36N)2[Pd(C6N4S2)2], the centrosymmetric dianion is planar, with an r.m.s. deviation of 0.034 (8) Å. The PdII atom, lying on an inversion center, has a square-planar coordination geometry, with Pd-S bond lengths of 2.276 (3) and 2.294 (3) Å.

Comment top

Metal dithiolene complexes have been widely investigated as molecular conductors and superconductors. Several superconductors (Brossard et al., 1986; Cassoux et al., 1991; Kobayashi et al., 1987; Tajima et al., 1993) and single-component molecular metals (Tanaka et al., 2001) involving dithiolene complexes have been discovered to date. We have synthesized the title palladium dithiolene complex, (I), derived from 2,3-dicyano-5,6-dimercaptopyrazine ligand (Tomura et al., 1994). The ligand is expected to extend the π-conjugation of the complex resulting in decreased Coulombic repulsion (Belo et al., 1999, 2004; Nomura et al., 2009; Rabaça & Almeida, 2010). Intermolecular interactions caused by S···S and S···N heteroatom contacts may increase the dimensionality in the solid state (Yamashita & Tomura, 1998). We report here the molecular and crystal structures of (I).

In the complex (I) the dianion molecule is located on an inversion center. The molecular structure of the dianion is shown in Fig. 1. The dianion is a flat molecule with an r.m.s. deviation of 0.034 (8) Å of fitted atoms from the least-squares plane. The central Pd atom has a square-planar coordination geometry and the Pd1—S1 and Pd1—S2 distances and the S1—Pd1—S2 angle are 2.276 (3), 2.294 (3) Å and 89.39 (10)°, respectively. These values are comparable to those found in bis(tetra-n-butylammonium) bis(4,5-dicyanobenzene-1,2-dithiolato-S,S')palladium(II) complex (Alves et al., 2004). Fig. 2 shows the packing diagram of (I) viewed along the a axis. The dianion molecules form a layered structure with an interlayer distance of 6.5 Å. The tetra-n-butylammonium cations are inserted between the layers.

Related literature top

For the synthesis of the title complex, see: Tomura et al. (1994). For molecular conductors and superconductors based on metal dithiolene complexes, see: Brossard et al. (1986); Cassoux et al. (1991); Kobayashi et al. (1987); Tajima et al. (1993); Tanaka et al. (2001). For related structures, including the 2,3-dicyano-5,6-dimercaptopyrazine system, see: Belo et al. (1999, 2004); Nomura et al. (2009); Rabaça & Almeida (2010). For related structures, including the 1,2-dicyano-4,5-dimercaptobenzene system, see: Alves et al. (2004). For intermolecular interactions caused by heteroatoms, see: Yamashita & Tomura (1998).

Experimental top

The title compound (I) was synthesized according to the literature method (Tomura et al., 1994). Orange crystals of (I) suitable for X-ray analysis were grown from an acetone solution.

Refinement top

All H atoms were placed in geometrically calculated positions and refined using a riding model, with C—H = 0.97 (methylene) and 0.96 (methyl) Å and Uiso(H) = 1.2(1.5 for methyl)Ueq(C).

Computing details top

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1988); cell refinement: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1988); data reduction: TEXSAN (Molecular Structure Corporation & Rigaku, 2000); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the dianion in (I). Displacement ellipsoids are drawn at the 50% probability level. Unlabeled atoms are related to the labeled atoms by -x+2, -y-1, -z.
[Figure 2] Fig. 2. The perspective view of the crystal packing of (I), viewed along the a axis. H atoms have been omitted for clarity.
Bis(tetra-n-butylammonium) bis(5,6-dicyanopyrazine-2,3-dithiolato-κ2S,S')palladium(II) top
Crystal data top
(C16H36N)2[Pd(C6N4S2)2]Z = 1
Mr = 975.80F(000) = 516
Triclinic, P1Dx = 1.260 Mg m3
Hall symbol: -P 1Melting point: 520.5 K
a = 9.912 (3) ÅMo Kα radiation, λ = 0.7107 Å
b = 10.635 (4) ÅCell parameters from 24 reflections
c = 13.286 (4) Åθ = 20.1–22.7°
α = 68.82 (2)°µ = 0.56 mm1
β = 87.74 (3)°T = 296 K
γ = 80.16 (3)°Needle, orange
V = 1286.3 (8) Å30.25 × 0.10 × 0.05 mm
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.087
Radiation source: rotating anodeθmax = 27.5°, θmin = 1.6°
graphite monochromatorh = 1211
ω–2θ scansk = 120
5102 measured reflectionsl = 1514
4835 independent reflections3 standard reflections every 150 reflections
1751 reflections with I > 2σ(I) intensity decay: 1.0%
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)] = 0.093Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.222H-atom parameters constrained
S = 0.98 w = 1/[σ2(Fo2) + (0.0782P)2]
where P = (Fo2 + 2Fc2)/3
4835 reflections(Δ/σ)max < 0.001
272 parametersΔρmax = 0.39 e Å3
0 restraintsΔρmin = 0.41 e Å3
Crystal data top
(C16H36N)2[Pd(C6N4S2)2]γ = 80.16 (3)°
Mr = 975.80V = 1286.3 (8) Å3
Triclinic, P1Z = 1
a = 9.912 (3) ÅMo Kα radiation
b = 10.635 (4) ŵ = 0.56 mm1
c = 13.286 (4) ÅT = 296 K
α = 68.82 (2)°0.25 × 0.10 × 0.05 mm
β = 87.74 (3)°
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.087
5102 measured reflectionsθmax = 27.5°
4835 independent reflections3 standard reflections every 150 reflections
1751 reflections with I > 2σ(I) intensity decay: 1.0%
Refinement top
R[F2 > 2σ(F2)] = 0.093H-atom parameters constrained
wR(F2) = 0.222Δρmax = 0.39 e Å3
S = 0.98Δρmin = 0.41 e Å3
4835 reflectionsAbsolute structure: ?
272 parametersFlack parameter: ?
0 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*/Ueq
Pd11.00000.50001.00000.0590 (5)
S11.0651 (3)0.7047 (3)0.9048 (2)0.0750 (9)
S20.7779 (3)0.5945 (3)0.9425 (2)0.0677 (9)
N10.9253 (10)0.9342 (10)0.7768 (7)0.063 (2)
N20.6744 (9)0.8402 (11)0.8066 (8)0.073 (3)
N30.8122 (11)1.2596 (11)0.5958 (9)0.095 (3)
N40.4777 (11)1.1342 (12)0.6318 (11)0.127 (5)
N50.4587 (7)0.5033 (8)0.7369 (6)0.052 (2)
C10.9162 (9)0.8100 (12)0.8408 (7)0.045 (3)
C20.7894 (11)0.7582 (11)0.8586 (8)0.060 (3)
C30.8115 (12)1.0150 (12)0.7253 (9)0.064 (3)
C40.6864 (11)0.9648 (13)0.7422 (10)0.071 (3)
C50.8184 (11)1.1533 (14)0.6519 (10)0.069 (3)
C60.5674 (13)1.0600 (13)0.6803 (10)0.083 (4)
C70.5687 (9)0.5275 (10)0.6517 (7)0.063 (3)
H7A0.60800.44050.64580.075*
H7B0.52560.58590.58250.075*
C80.6833 (10)0.5921 (11)0.6738 (8)0.073 (3)
H8A0.72600.53510.74350.087*
H8B0.64520.68070.67740.087*
C90.7918 (11)0.6105 (11)0.5879 (8)0.075 (3)
H9A0.75030.67040.51850.090*
H9B0.82840.52260.58260.090*
C100.9092 (11)0.6720 (12)0.6152 (9)0.095 (4)
H10A0.87250.75760.62290.142*
H10B0.97390.68680.55810.142*
H10C0.95410.61000.68150.142*
C110.3911 (9)0.6377 (9)0.7481 (7)0.054 (3)
H11A0.32120.61810.80210.065*
H11B0.45970.67340.77510.065*
C120.3266 (12)0.7474 (11)0.6475 (9)0.084 (3)
H12A0.25210.71670.62250.100*
H12B0.39380.76600.59120.100*
C130.2724 (13)0.8766 (12)0.6698 (10)0.100 (4)
H13A0.20810.85580.72810.120*
H13B0.34800.90690.69360.120*
C140.2024 (14)0.9909 (12)0.5733 (11)0.129 (5)
H14A0.26861.02150.51910.193*
H14B0.16041.06550.59460.193*
H14C0.13350.95890.54470.193*
C150.3575 (9)0.4356 (10)0.7003 (7)0.063 (3)
H15A0.40770.35560.68860.076*
H15B0.31730.49850.63140.076*
C160.2417 (10)0.3915 (11)0.7775 (8)0.071 (3)
H16A0.18650.47120.78630.085*
H16B0.28010.33070.84770.085*
C170.1509 (10)0.3179 (11)0.7340 (8)0.075 (3)
H17A0.10970.38000.66520.090*
H17B0.20700.24050.72230.090*
C180.0388 (11)0.2682 (13)0.8123 (10)0.109 (5)
H18A0.07930.21120.88180.163*
H18B0.01170.21670.78590.163*
H18C0.02180.34550.81880.163*
C190.5197 (10)0.4106 (11)0.8485 (8)0.063 (3)
H19A0.58450.45670.86870.076*
H19B0.44640.40190.89980.076*
C200.5915 (11)0.2686 (11)0.8611 (8)0.075 (3)
H20A0.67220.27350.81710.090*
H20B0.53090.22090.83820.090*
C210.6318 (13)0.1934 (12)0.9792 (9)0.099 (4)
H21A0.68890.24471.00140.119*
H21B0.54980.18931.02170.119*
C220.7070 (16)0.0519 (14)1.0024 (11)0.144 (6)
H22A0.64910.00120.98460.216*
H22B0.73240.01071.07770.216*
H22C0.78780.05490.96000.216*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pd10.0540 (9)0.0755 (11)0.0521 (8)0.0223 (7)0.0036 (6)0.0235 (7)
S10.0555 (19)0.082 (2)0.081 (2)0.0214 (17)0.0010 (16)0.0172 (18)
S20.0515 (18)0.084 (2)0.0647 (19)0.0243 (16)0.0047 (14)0.0173 (17)
N10.073 (7)0.072 (7)0.059 (6)0.019 (6)0.009 (5)0.037 (6)
N20.055 (6)0.071 (7)0.098 (7)0.017 (6)0.014 (5)0.035 (6)
N30.108 (9)0.065 (8)0.111 (9)0.014 (7)0.009 (7)0.031 (7)
N40.071 (8)0.124 (11)0.190 (13)0.012 (7)0.055 (8)0.069 (9)
N50.048 (5)0.061 (6)0.051 (5)0.009 (4)0.002 (4)0.027 (5)
C10.041 (6)0.078 (8)0.038 (6)0.028 (6)0.015 (5)0.040 (6)
C20.050 (7)0.072 (8)0.071 (7)0.008 (6)0.009 (6)0.042 (7)
C30.069 (8)0.059 (9)0.074 (8)0.011 (7)0.024 (7)0.036 (7)
C40.043 (7)0.063 (9)0.102 (10)0.003 (7)0.007 (6)0.029 (8)
C50.062 (8)0.068 (10)0.081 (9)0.022 (7)0.006 (6)0.028 (8)
C60.070 (9)0.083 (10)0.103 (10)0.022 (8)0.006 (8)0.038 (8)
C70.055 (7)0.068 (8)0.055 (6)0.003 (6)0.002 (5)0.014 (6)
C80.057 (7)0.084 (9)0.071 (7)0.017 (6)0.008 (6)0.019 (6)
C90.081 (8)0.062 (8)0.075 (8)0.007 (7)0.017 (6)0.019 (6)
C100.071 (8)0.102 (10)0.097 (9)0.031 (8)0.013 (7)0.014 (8)
C110.054 (6)0.048 (7)0.056 (6)0.010 (5)0.007 (5)0.023 (6)
C120.078 (8)0.065 (8)0.101 (10)0.003 (7)0.004 (7)0.029 (8)
C130.101 (10)0.072 (10)0.119 (11)0.018 (8)0.029 (9)0.026 (9)
C140.143 (13)0.075 (10)0.134 (12)0.028 (9)0.015 (10)0.016 (10)
C150.063 (7)0.062 (7)0.064 (7)0.015 (6)0.012 (6)0.019 (6)
C160.059 (7)0.089 (9)0.068 (7)0.011 (7)0.006 (6)0.035 (7)
C170.064 (7)0.087 (9)0.082 (8)0.014 (7)0.010 (6)0.039 (7)
C180.088 (9)0.138 (12)0.129 (11)0.062 (9)0.021 (8)0.066 (10)
C190.056 (7)0.076 (9)0.072 (8)0.026 (6)0.007 (6)0.038 (7)
C200.079 (8)0.080 (9)0.072 (8)0.013 (7)0.005 (6)0.033 (7)
C210.102 (10)0.084 (10)0.094 (10)0.000 (8)0.038 (8)0.014 (8)
C220.174 (16)0.094 (12)0.128 (12)0.010 (11)0.030 (11)0.008 (10)
Geometric parameters (Å, °) top
Pd1—S1i2.276 (3)C11—H11B0.9700
Pd1—S12.276 (3)C12—C131.514 (14)
Pd1—S22.294 (3)C12—H12A0.9700
Pd1—S2i2.294 (3)C12—H12B0.9700
S1—C11.732 (10)C13—C141.503 (15)
S2—C21.716 (11)C13—H13A0.9700
N1—C11.304 (11)C13—H13B0.9700
N1—C31.336 (12)C14—H14A0.9600
N2—C41.315 (12)C14—H14B0.9600
N2—C21.351 (12)C14—H14C0.9600
N3—C51.100 (12)C15—C161.527 (12)
N4—C61.126 (13)C15—H15A0.9700
N5—C151.516 (10)C15—H15B0.9700
N5—C71.525 (10)C16—C171.537 (12)
N5—C111.527 (10)C16—H16A0.9700
N5—C191.532 (11)C16—H16B0.9700
C1—C21.434 (12)C17—C181.519 (13)
C3—C41.412 (14)C17—H17A0.9700
C3—C51.452 (15)C17—H17B0.9700
C4—C61.469 (16)C18—H18A0.9600
C7—C81.513 (12)C18—H18B0.9600
C7—H7A0.9700C18—H18C0.9600
C7—H7B0.9700C19—C201.508 (13)
C8—C91.520 (12)C19—H19A0.9700
C8—H8A0.9700C19—H19B0.9700
C8—H8B0.9700C20—C211.514 (13)
C9—C101.542 (13)C20—H20A0.9700
C9—H9A0.9700C20—H20B0.9700
C9—H9B0.9700C21—C221.488 (15)
C10—H10A0.9600C21—H21A0.9700
C10—H10B0.9600C21—H21B0.9700
C10—H10C0.9600C22—H22A0.9600
C11—C121.497 (12)C22—H22B0.9600
C11—H11A0.9700C22—H22C0.9600
S1i—Pd1—S1180.00 (15)C11—C12—H12B109.7
S1i—Pd1—S290.61 (10)C13—C12—H12B109.7
S1—Pd1—S289.39 (10)H12A—C12—H12B108.2
S1i—Pd1—S2i89.39 (10)C14—C13—C12113.4 (11)
S1—Pd1—S2i90.61 (10)C14—C13—H13A108.9
S2—Pd1—S2i180.0C12—C13—H13A108.9
C1—S1—Pd1104.8 (4)C14—C13—H13B108.9
C2—S2—Pd1103.6 (4)C12—C13—H13B108.9
C1—N1—C3118.1 (9)H13A—C13—H13B107.7
C4—N2—C2117.0 (9)C13—C14—H14A109.5
C15—N5—C7105.9 (7)C13—C14—H14B109.5
C15—N5—C11112.2 (7)H14A—C14—H14B109.5
C7—N5—C11110.8 (7)C13—C14—H14C109.5
C15—N5—C19110.3 (7)H14A—C14—H14C109.5
C7—N5—C19111.4 (7)H14B—C14—H14C109.5
C11—N5—C19106.3 (7)N5—C15—C16115.8 (7)
N1—C1—C2122.7 (11)N5—C15—H15A108.3
N1—C1—S1117.7 (7)C16—C15—H15A108.3
C2—C1—S1119.6 (9)N5—C15—H15B108.3
N2—C2—C1119.2 (11)C16—C15—H15B108.3
N2—C2—S2118.3 (8)H15A—C15—H15B107.4
C1—C2—S2122.5 (9)C15—C16—C17110.7 (8)
N1—C3—C4119.6 (11)C15—C16—H16A109.5
N1—C3—C5119.5 (10)C17—C16—H16A109.5
C4—C3—C5120.8 (12)C15—C16—H16B109.5
N2—C4—C3123.5 (11)C17—C16—H16B109.5
N2—C4—C6120.8 (10)H16A—C16—H16B108.1
C3—C4—C6115.7 (12)C18—C17—C16111.2 (8)
N3—C5—C3174.2 (13)C18—C17—H17A109.4
N4—C6—C4178.9 (15)C16—C17—H17A109.4
C8—C7—N5114.8 (8)C18—C17—H17B109.4
C8—C7—H7A108.6C16—C17—H17B109.4
N5—C7—H7A108.6H17A—C17—H17B108.0
C8—C7—H7B108.6C17—C18—H18A109.5
N5—C7—H7B108.6C17—C18—H18B109.5
H7A—C7—H7B107.5H18A—C18—H18B109.5
C7—C8—C9112.6 (9)C17—C18—H18C109.5
C7—C8—H8A109.1H18A—C18—H18C109.5
C9—C8—H8A109.1H18B—C18—H18C109.5
C7—C8—H8B109.1C20—C19—N5117.6 (8)
C9—C8—H8B109.1C20—C19—H19A107.9
H8A—C8—H8B107.8N5—C19—H19A107.9
C8—C9—C10111.1 (9)C20—C19—H19B107.9
C8—C9—H9A109.4N5—C19—H19B107.9
C10—C9—H9A109.4H19A—C19—H19B107.2
C8—C9—H9B109.4C19—C20—C21107.8 (9)
C10—C9—H9B109.4C19—C20—H20A110.1
H9A—C9—H9B108.0C21—C20—H20A110.1
C9—C10—H10A109.5C19—C20—H20B110.1
C9—C10—H10B109.5C21—C20—H20B110.1
H10A—C10—H10B109.5H20A—C20—H20B108.5
C9—C10—H10C109.5C22—C21—C20113.3 (11)
H10A—C10—H10C109.5C22—C21—H21A108.9
H10B—C10—H10C109.5C20—C21—H21A108.9
C12—C11—N5116.3 (8)C22—C21—H21B108.9
C12—C11—H11A108.2C20—C21—H21B108.9
N5—C11—H11A108.2H21A—C21—H21B107.7
C12—C11—H11B108.2C21—C22—H22A109.5
N5—C11—H11B108.2C21—C22—H22B109.5
H11A—C11—H11B107.4H22A—C22—H22B109.5
C11—C12—C13110.0 (9)C21—C22—H22C109.5
C11—C12—H12A109.7H22A—C22—H22C109.5
C13—C12—H12A109.7H22B—C22—H22C109.5
S2—Pd1—S1—C12.2 (3)N1—C3—C4—C6178.7 (9)
S2i—Pd1—S1—C1177.8 (3)C5—C3—C4—C60.8 (15)
S1i—Pd1—S2—C2177.6 (3)C15—N5—C7—C8178.6 (9)
S1—Pd1—S2—C22.4 (3)C11—N5—C7—C859.4 (10)
C3—N1—C1—C20.7 (13)C19—N5—C7—C858.7 (11)
C3—N1—C1—S1178.5 (7)N5—C7—C8—C9178.5 (8)
Pd1—S1—C1—N1177.7 (6)C7—C8—C9—C10178.1 (9)
Pd1—S1—C1—C21.6 (7)C15—N5—C11—C1260.9 (10)
C4—N2—C2—C10.4 (14)C7—N5—C11—C1257.3 (10)
C4—N2—C2—S2179.5 (8)C19—N5—C11—C12178.5 (8)
N1—C1—C2—N20.6 (14)N5—C11—C12—C13176.3 (8)
S1—C1—C2—N2178.6 (7)C11—C12—C13—C14178.4 (10)
N1—C1—C2—S2179.7 (7)C7—N5—C15—C16175.8 (8)
S1—C1—C2—S20.5 (11)C11—N5—C15—C1663.1 (11)
Pd1—S2—C2—N2176.8 (7)C19—N5—C15—C1655.2 (11)
Pd1—S2—C2—C12.3 (8)N5—C15—C16—C17177.1 (8)
C1—N1—C3—C40.6 (14)C15—C16—C17—C18177.6 (10)
C1—N1—C3—C5178.9 (8)C15—N5—C19—C2057.1 (10)
C2—N2—C4—C30.3 (16)C7—N5—C19—C2060.2 (11)
C2—N2—C4—C6178.5 (9)C11—N5—C19—C20179.0 (8)
N1—C3—C4—N20.4 (16)N5—C19—C20—C21175.2 (8)
C5—C3—C4—N2179.2 (10)C19—C20—C21—C22178.6 (11)
Symmetry codes: (i) −x+2, −y+1, −z+2.
Acknowledgements top

The authors thank the Instrument Center of the Institute for Molecular Science for the X-ray crystallographic analysis.

references
References top

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.

Alves, H., Simão, D., Santos, I. C., Gama, V., Henriques, R. T., Novais, H. & Almeida, M. (2004). Eur. J. Inorg. Chem. pp. 1318–1329.

Belo, D., Morgado, J., Lopes, E. B., Santos, I. C., Rabaça, S., Duarte, M. T., Gama, V., Henriques, R. T. & Almeida, M. (1999). Synth. Met. 102, 1751–1752.

Belo, D., Santos, I. C. & Almeida, M. (2004). Polyhedron, 23, 1351–1359.

Brossard, L., Ribault, M., Valade, L. & Cassoux, P. (1986). Physica B & C, 143, 378–380.

Cassoux, P., Valade, L., Kobayashi, H., Kobayashi, A., Clarck, R. A. & Underhill, A. E. (1991). Coord. Chem. Rev. 110, 115–160.

Kobayashi, A., Kim, H., Sasaki, Y., Kato, R., Kobayashi, H., Moriyama, S., Nishio, Y., Kajita, K. & Sasaki, W. (1987). Chem. Lett. pp. 1819–1822.

Molecular Structure Corporation (1988). MSC/AFC Diffractometer Control Software. MSC, The Woodlands, Texas, USA.

Molecular Structure Corporation & Rigaku (2000). TEXSAN. MSC, The Woodlands, Texas, USA, and Rigaku Corporation, Tokyo, Japan.

Nomura, M., Tsukano, E., Fujita-Takayama, C., Sugiyama, T. & Kajitani, M. (2009). J. Organomet. Chem. 694, 3116–3124.

Rabaça, S. & Almeida, M. (2010). Coord. Chem. Rev. 254, 1493–1508.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2009). Acta Cryst. D65, 148–155.

Tajima, H., Inokuchi, M., Kobayashi, A., Ohta, T., Kato, R., Kobayashi, H. & Kuroda, H. (1993). Chem. Lett. pp. 1235–1238.

Tanaka, H., Okano, Y., Kobayashi, H., Suzuki, W. & Kobayashi, A. (2001). Science, 291, 285–287.

Tomura, M., Tanaka, S. & Yamashita, Y. (1994). Synth. Met. 64, 197–202.

Yamashita, Y. & Tomura, M. (1998). J. Mater. Chem. 8, 1933–1944.