metal-organic compounds
(2,3-Di-2-pyridylpyrazine-κ2N2,N3)diiodidoplatinum(II)
aSchool of Applied Chemical Engineering, The Research Institute of Catalysis, Chonnam National University, Gwangju 500-757, Republic of Korea
*Correspondence e-mail: hakwang@chonnam.ac.kr
The PtII ion in the title complex, [PtI2(C14H10N4)], exists in a distorted square-planar environment defined by the two pyridine N atoms of the chelating 2,3-di-2-pyridylpyrazine ligand and two iodide anions. The pyridine rings are inclined to the least-squares plane of the PtI2N2 unit [maximum deviation = 0.070 (3) Å] at 66.1 (2) and 65.9 (2)°; the pyrazine ring is perpendicular to this plane [dihedral angle = 89.7 (2)°]. Two intermolecular C—H⋯I hydrogen bonds, both involving the same I atom as hydrogen-bond acceptor, generate a layer structure extending parallel to (001). Molecules are stacked in columns along the a axis. Along the b axis, successive molecules stack in opposite directions.
Related literature
For [PtBr2(dpp)] and [PdI2(dpp)] (dpp = 2,3-di-2-pyridylpyrazine), see: Ha (2011a,b).
Experimental
Crystal data
|
Refinement
|
|
Data collection: SMART (Bruker, 2000); cell SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S1600536812023501/ng5273sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812023501/ng5273Isup2.hkl
The title complex was obtained as a byproduct from the reaction of K2PtCl4 (0.2089 g, 0.503 mmol) with 2,3-di-2-pyridylpyrazine (0.1198 g, 0.511 mmol) and KI (0.6785 g, 4.087 mmol) in H2O (20 ml)/MeOH (30 ml). The reaction mixture was stirred for 6 h at room temperature; the precipitate that formd was separated by filtration, washed with H2O and MeOH, and then collected to give the main product as a reddish brown powder (0.2638 g). The yellow by-product (0.0388 g) was obtained from the mixture of filtrate and washing solution. Crystals were obtained by slow evaporation from a CH3NO2 solution of the by-product.
H atoms were included in calculated positions and treated as riding atoms: C—H = 0.95 Å with Uiso(H) = 1.2Ueq(C). The highest peak (1.30 e Å-3) and the deepest hole (-1.26 e Å-3) in the difference Fourier map are located 0.26 Å and 0.63 Å, respectively, from the atoms Pt1 and I1.
Data collection: SMART (Bruker, 2000); cell
SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).[PtI2(C14H10N4)] | F(000) = 1224 |
Mr = 683.15 | Dx = 2.744 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 6167 reflections |
a = 8.7600 (7) Å | θ = 2.6–26.0° |
b = 15.4750 (12) Å | µ = 12.22 mm−1 |
c = 12.5004 (10) Å | T = 200 K |
β = 102.660 (2)° | Block, yellow |
V = 1653.4 (2) Å3 | 0.26 × 0.23 × 0.19 mm |
Z = 4 |
Bruker SMART 1000 CCD diffractometer | 3215 independent reflections |
Radiation source: fine-focus sealed tube | 2807 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.034 |
ϕ and ω scans | θmax = 26.0°, θmin = 2.1° |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | h = −10→10 |
Tmin = 0.551, Tmax = 1.000 | k = −19→13 |
10058 measured reflections | l = −15→15 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.029 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.077 | H-atom parameters constrained |
S = 1.07 | w = 1/[σ2(Fo2) + (0.0341P)2 + 4.3824P] where P = (Fo2 + 2Fc2)/3 |
3215 reflections | (Δ/σ)max = 0.001 |
190 parameters | Δρmax = 1.30 e Å−3 |
0 restraints | Δρmin = −1.26 e Å−3 |
[PtI2(C14H10N4)] | V = 1653.4 (2) Å3 |
Mr = 683.15 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 8.7600 (7) Å | µ = 12.22 mm−1 |
b = 15.4750 (12) Å | T = 200 K |
c = 12.5004 (10) Å | 0.26 × 0.23 × 0.19 mm |
β = 102.660 (2)° |
Bruker SMART 1000 CCD diffractometer | 3215 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | 2807 reflections with I > 2σ(I) |
Tmin = 0.551, Tmax = 1.000 | Rint = 0.034 |
10058 measured reflections |
R[F2 > 2σ(F2)] = 0.029 | 0 restraints |
wR(F2) = 0.077 | H-atom parameters constrained |
S = 1.07 | Δρmax = 1.30 e Å−3 |
3215 reflections | Δρmin = −1.26 e Å−3 |
190 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Pt1 | 0.47513 (3) | 0.062468 (17) | 0.68112 (2) | 0.02787 (10) | |
I1 | 0.62382 (6) | −0.08242 (3) | 0.69367 (4) | 0.04126 (14) | |
I2 | 0.73035 (6) | 0.15223 (4) | 0.73544 (4) | 0.04772 (16) | |
N1 | 0.1840 (7) | 0.0062 (4) | 0.9040 (5) | 0.0373 (14) | |
N2 | 0.2411 (8) | 0.1831 (4) | 0.9096 (5) | 0.0425 (15) | |
N3 | 0.2701 (6) | −0.0044 (3) | 0.6444 (4) | 0.0280 (12) | |
N4 | 0.3445 (7) | 0.1720 (4) | 0.6578 (5) | 0.0369 (14) | |
C1 | 0.2034 (8) | 0.0481 (4) | 0.8137 (6) | 0.0308 (15) | |
C2 | 0.2337 (8) | 0.1370 (4) | 0.8164 (6) | 0.0331 (15) | |
C3 | 0.2248 (10) | 0.1399 (5) | 0.9984 (6) | 0.047 (2) | |
H3 | 0.2330 | 0.1703 | 1.0654 | 0.056* | |
C4 | 0.1965 (10) | 0.0532 (5) | 0.9959 (6) | 0.047 (2) | |
H4 | 0.1853 | 0.0251 | 1.0613 | 0.057* | |
C5 | 0.1726 (7) | −0.0069 (4) | 0.7139 (5) | 0.0286 (14) | |
C6 | 0.0443 (8) | −0.0605 (5) | 0.6955 (6) | 0.0375 (17) | |
H6 | −0.0224 | −0.0617 | 0.7460 | 0.045* | |
C7 | 0.0125 (8) | −0.1121 (5) | 0.6041 (7) | 0.0444 (19) | |
H7 | −0.0752 | −0.1498 | 0.5913 | 0.053* | |
C8 | 0.1095 (8) | −0.1086 (5) | 0.5310 (6) | 0.0383 (17) | |
H8 | 0.0890 | −0.1434 | 0.4668 | 0.046* | |
C9 | 0.2355 (9) | −0.0544 (5) | 0.5521 (6) | 0.0343 (16) | |
H9 | 0.3012 | −0.0513 | 0.5011 | 0.041* | |
C10 | 0.2419 (8) | 0.1915 (4) | 0.7201 (6) | 0.0322 (15) | |
C11 | 0.1480 (9) | 0.2633 (5) | 0.6997 (7) | 0.0432 (19) | |
H11 | 0.0769 | 0.2761 | 0.7450 | 0.052* | |
C12 | 0.1573 (10) | 0.3169 (5) | 0.6127 (7) | 0.052 (2) | |
H12 | 0.0925 | 0.3666 | 0.5970 | 0.062* | |
C13 | 0.2640 (11) | 0.2964 (5) | 0.5491 (6) | 0.053 (2) | |
H13 | 0.2735 | 0.3322 | 0.4891 | 0.064* | |
C14 | 0.3539 (10) | 0.2253 (5) | 0.5731 (6) | 0.0449 (19) | |
H14 | 0.4265 | 0.2120 | 0.5291 | 0.054* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Pt1 | 0.03372 (16) | 0.02391 (16) | 0.02724 (15) | −0.00575 (11) | 0.00941 (11) | −0.00250 (10) |
I1 | 0.0362 (3) | 0.0397 (3) | 0.0496 (3) | 0.0012 (2) | 0.0132 (2) | 0.0003 (2) |
I2 | 0.0505 (3) | 0.0517 (3) | 0.0432 (3) | −0.0247 (3) | 0.0152 (2) | −0.0113 (2) |
N1 | 0.046 (3) | 0.029 (3) | 0.040 (3) | −0.003 (3) | 0.016 (3) | 0.000 (3) |
N2 | 0.061 (4) | 0.030 (3) | 0.037 (3) | 0.000 (3) | 0.012 (3) | −0.008 (3) |
N3 | 0.035 (3) | 0.019 (3) | 0.030 (3) | 0.000 (2) | 0.006 (2) | −0.001 (2) |
N4 | 0.055 (4) | 0.020 (3) | 0.034 (3) | −0.004 (3) | 0.005 (3) | −0.004 (2) |
C1 | 0.031 (4) | 0.026 (4) | 0.035 (4) | 0.002 (3) | 0.007 (3) | −0.005 (3) |
C2 | 0.039 (4) | 0.024 (4) | 0.034 (4) | −0.003 (3) | 0.002 (3) | −0.006 (3) |
C3 | 0.065 (5) | 0.039 (5) | 0.036 (4) | −0.005 (4) | 0.012 (4) | −0.010 (4) |
C4 | 0.066 (5) | 0.045 (5) | 0.034 (4) | −0.003 (4) | 0.019 (4) | −0.002 (4) |
C5 | 0.031 (3) | 0.021 (3) | 0.033 (3) | 0.002 (3) | 0.006 (3) | −0.001 (3) |
C6 | 0.032 (4) | 0.039 (4) | 0.042 (4) | −0.005 (3) | 0.011 (3) | −0.006 (3) |
C7 | 0.030 (4) | 0.044 (5) | 0.058 (5) | −0.008 (4) | 0.007 (3) | −0.006 (4) |
C8 | 0.042 (4) | 0.028 (4) | 0.041 (4) | −0.001 (3) | 0.002 (3) | −0.012 (3) |
C9 | 0.043 (4) | 0.032 (4) | 0.025 (3) | 0.001 (3) | 0.002 (3) | −0.006 (3) |
C10 | 0.041 (4) | 0.019 (3) | 0.034 (4) | −0.004 (3) | 0.005 (3) | −0.002 (3) |
C11 | 0.046 (4) | 0.025 (4) | 0.055 (5) | 0.005 (3) | 0.004 (4) | 0.000 (3) |
C12 | 0.060 (5) | 0.025 (4) | 0.060 (5) | 0.004 (4) | −0.007 (4) | 0.006 (4) |
C13 | 0.090 (7) | 0.029 (4) | 0.035 (4) | −0.008 (5) | 0.002 (4) | 0.002 (4) |
C14 | 0.071 (5) | 0.032 (4) | 0.032 (4) | −0.007 (4) | 0.012 (4) | 0.003 (3) |
Pt1—N4 | 2.030 (6) | C4—H4 | 0.9500 |
Pt1—N3 | 2.036 (5) | C5—C6 | 1.375 (10) |
Pt1—I1 | 2.5805 (6) | C6—C7 | 1.372 (11) |
Pt1—I2 | 2.5930 (6) | C6—H6 | 0.9500 |
N1—C4 | 1.343 (10) | C7—C8 | 1.379 (11) |
N1—C1 | 1.345 (9) | C7—H7 | 0.9500 |
N2—C3 | 1.329 (10) | C8—C9 | 1.366 (10) |
N2—C2 | 1.355 (9) | C8—H8 | 0.9500 |
N3—C5 | 1.346 (8) | C9—H9 | 0.9500 |
N3—C9 | 1.366 (8) | C10—C11 | 1.373 (10) |
N4—C10 | 1.346 (9) | C11—C12 | 1.384 (11) |
N4—C14 | 1.360 (9) | C11—H11 | 0.9500 |
C1—C2 | 1.400 (10) | C12—C13 | 1.391 (13) |
C1—C5 | 1.486 (9) | C12—H12 | 0.9500 |
C2—C10 | 1.485 (10) | C13—C14 | 1.347 (12) |
C3—C4 | 1.364 (11) | C13—H13 | 0.9500 |
C3—H3 | 0.9500 | C14—H14 | 0.9500 |
N4—Pt1—N3 | 87.2 (2) | C6—C5—C1 | 118.5 (6) |
N4—Pt1—I1 | 174.46 (16) | C7—C6—C5 | 120.0 (7) |
N3—Pt1—I1 | 88.89 (15) | C7—C6—H6 | 120.0 |
N4—Pt1—I2 | 90.97 (17) | C5—C6—H6 | 120.0 |
N3—Pt1—I2 | 176.99 (15) | C6—C7—C8 | 119.2 (7) |
I1—Pt1—I2 | 93.14 (2) | C6—C7—H7 | 120.4 |
C4—N1—C1 | 117.0 (6) | C8—C7—H7 | 120.4 |
C3—N2—C2 | 117.3 (6) | C9—C8—C7 | 119.0 (7) |
C5—N3—C9 | 118.3 (6) | C9—C8—H8 | 120.5 |
C5—N3—Pt1 | 121.5 (4) | C7—C8—H8 | 120.5 |
C9—N3—Pt1 | 120.0 (5) | N3—C9—C8 | 122.1 (7) |
C10—N4—C14 | 118.5 (6) | N3—C9—H9 | 118.9 |
C10—N4—Pt1 | 122.1 (5) | C8—C9—H9 | 118.9 |
C14—N4—Pt1 | 119.4 (5) | N4—C10—C11 | 121.5 (7) |
N1—C1—C2 | 120.8 (6) | N4—C10—C2 | 119.9 (6) |
N1—C1—C5 | 113.3 (6) | C11—C10—C2 | 118.5 (7) |
C2—C1—C5 | 125.6 (6) | C10—C11—C12 | 119.7 (8) |
N2—C2—C1 | 120.7 (7) | C10—C11—H11 | 120.2 |
N2—C2—C10 | 113.4 (6) | C12—C11—H11 | 120.2 |
C1—C2—C10 | 125.5 (6) | C11—C12—C13 | 118.3 (8) |
N2—C3—C4 | 121.9 (7) | C11—C12—H12 | 120.8 |
N2—C3—H3 | 119.1 | C13—C12—H12 | 120.8 |
C4—C3—H3 | 119.1 | C14—C13—C12 | 119.5 (8) |
N1—C4—C3 | 122.2 (7) | C14—C13—H13 | 120.2 |
N1—C4—H4 | 118.9 | C12—C13—H13 | 120.2 |
C3—C4—H4 | 118.9 | C13—C14—N4 | 122.5 (8) |
N3—C5—C6 | 121.4 (6) | C13—C14—H14 | 118.8 |
N3—C5—C1 | 120.1 (6) | N4—C14—H14 | 118.8 |
N4—Pt1—N3—C5 | −71.2 (5) | N1—C1—C5—C6 | 43.3 (9) |
I1—Pt1—N3—C5 | 112.7 (5) | C2—C1—C5—C6 | −130.3 (8) |
N4—Pt1—N3—C9 | 114.8 (5) | N3—C5—C6—C7 | −0.7 (11) |
I1—Pt1—N3—C9 | −61.4 (5) | C1—C5—C6—C7 | 180.0 (7) |
N3—Pt1—N4—C10 | 62.0 (5) | C5—C6—C7—C8 | −0.8 (12) |
I2—Pt1—N4—C10 | −115.6 (5) | C6—C7—C8—C9 | 0.6 (12) |
N3—Pt1—N4—C14 | −114.3 (6) | C5—N3—C9—C8 | −2.5 (10) |
I2—Pt1—N4—C14 | 68.1 (5) | Pt1—N3—C9—C8 | 171.7 (5) |
C4—N1—C1—C2 | −0.5 (10) | C7—C8—C9—N3 | 1.1 (11) |
C4—N1—C1—C5 | −174.5 (6) | C14—N4—C10—C11 | 0.0 (10) |
C3—N2—C2—C1 | 2.6 (11) | Pt1—N4—C10—C11 | −176.3 (5) |
C3—N2—C2—C10 | 175.9 (7) | C14—N4—C10—C2 | −177.2 (6) |
N1—C1—C2—N2 | −1.3 (11) | Pt1—N4—C10—C2 | 6.5 (8) |
C5—C1—C2—N2 | 171.8 (7) | N2—C2—C10—N4 | 129.3 (7) |
N1—C1—C2—C10 | −173.8 (7) | C1—C2—C10—N4 | −57.7 (10) |
C5—C1—C2—C10 | −0.6 (11) | N2—C2—C10—C11 | −47.9 (9) |
C2—N2—C3—C4 | −2.1 (12) | C1—C2—C10—C11 | 125.1 (8) |
C1—N1—C4—C3 | 1.1 (12) | N4—C10—C11—C12 | 0.5 (11) |
N2—C3—C4—N1 | 0.2 (14) | C2—C10—C11—C12 | 177.7 (7) |
C9—N3—C5—C6 | 2.3 (9) | C10—C11—C12—C13 | −0.6 (12) |
Pt1—N3—C5—C6 | −171.8 (5) | C11—C12—C13—C14 | 0.3 (12) |
C9—N3—C5—C1 | −178.3 (6) | C12—C13—C14—N4 | 0.1 (12) |
Pt1—N3—C5—C1 | 7.5 (8) | C10—N4—C14—C13 | −0.3 (11) |
N1—C1—C5—N3 | −136.1 (6) | Pt1—N4—C14—C13 | 176.1 (6) |
C2—C1—C5—N3 | 50.3 (10) |
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6···I1i | 0.95 | 3.04 | 3.694 (7) | 127 |
C11—H11···I1ii | 0.95 | 3.01 | 3.813 (8) | 143 |
Symmetry codes: (i) x−1, y, z; (ii) −x+1/2, y+1/2, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | [PtI2(C14H10N4)] |
Mr | 683.15 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 200 |
a, b, c (Å) | 8.7600 (7), 15.4750 (12), 12.5004 (10) |
β (°) | 102.660 (2) |
V (Å3) | 1653.4 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 12.22 |
Crystal size (mm) | 0.26 × 0.23 × 0.19 |
Data collection | |
Diffractometer | Bruker SMART 1000 CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2000) |
Tmin, Tmax | 0.551, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10058, 3215, 2807 |
Rint | 0.034 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.029, 0.077, 1.07 |
No. of reflections | 3215 |
No. of parameters | 190 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.30, −1.26 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009).
Pt1—N4 | 2.030 (6) | Pt1—I1 | 2.5805 (6) |
Pt1—N3 | 2.036 (5) | Pt1—I2 | 2.5930 (6) |
N4—Pt1—N3 | 87.2 (2) | I1—Pt1—I2 | 93.14 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6···I1i | 0.95 | 3.04 | 3.694 (7) | 127.2 |
C11—H11···I1ii | 0.95 | 3.01 | 3.813 (8) | 143.0 |
Symmetry codes: (i) x−1, y, z; (ii) −x+1/2, y+1/2, −z+3/2. |
Acknowledgements
This work was supported by the Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (grant No. 2011–0030747).
References
Bruker (2000). SADABS, SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Ha, K. (2011a). Acta Cryst. E67, m1307. Web of Science CSD CrossRef IUCr Journals Google Scholar
Ha, K. (2011b). Acta Cryst. E67, m1626. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals 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.
The title complex, [PtI2(dpp)] (dpp = 2,3-di-2-pyridylpyrazine, C14H10N4), is a structural isomer of the previously reported PtII and PdII complexes, [PtBr2(dpp)] and [PdI2(dpp)] (Ha, 2011a,b).
The PtII ion has a slightly distorted square-planar environment defined by the two pyridine N atoms of the chelating dpp ligand and two iodide anions (Fig. 1). The N3—Pt1—N4 chelate angle of 87.2 (2)° and I—I repelling contribute the distortion of square, and therefore the trans axes are slightly bent [<I1—Pt1—N4 = 174.46 (16)° and <I2—Pt1—N3 = 176.99 (15)°]. The Pt—N and Pt—I bond lengths are nearly equivalent, respectively (Table 1). In the crystal, the two pyridine rings are considerably inclined to the least-squares plane of the PtI2N2 unit [maximum deviation = 0.070 (3) Å], with dihedral angles of 66.1 (2)° and 65.9 (2)°. The nearly planar pyrazine ring [maximum deviation = 0.014 (5) Å] is perpendicular to the unit plane, with a dihedral angle of 89.7 (2)°. The dihedral angle between the two pyridine rings is 80.0 (2)°. Two independent weak intermolecular C—H···I hydrogen bonds, both involving the same I atom as a hydrogen-bond acceptor, give rise to chains running along the a and b axes, generating a layer structure extending parallel to the ab plane (Fig. 2 and Table 2). The complexes are stacked in columns along the a axis. When viewed down the b axis, the successive complexes stack in opposite directions. In the columns, numerous inter- and intramolecular π-π interactions between the six-membered rings are present, the shortest ring centroid-centroid distance being 3.935 (4) Å.