Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102005620/gg1107sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102005620/gg1107Isup2.hkl |
CCDC reference: 187914
The title compound was prepared by adding I2 to a solution of [Pd(NCN)I] in CH2Cl2. Purple crystals suitable for X-ray analysis were obtained after recrystallization of the crude product from a CH2Cl2/hexanes mixture (Gossage et al., 1999).
X-ray data were collected using Zr-filtered Mo Kα radiation with a collimator broad enough to accommodate the larger than usual maximum crystal dimension of 1.45 mm (Alexander & Smith, 1962). The aromatic and methylene H atoms were placed in idealized positions and allowed to ride on their C atoms, with C—H = 0.93 or 0.97 Å, respectively, and Uiso(H) = 1.2Ueq(C). The methyl H atoms were constrained to ideal geometries and allowed to rotate freely about their C—C bonds, with C—H = 0.96 Å and Uiso(H) = 1.5Ueq(C).
Data collection: locally modified CAD-4 Software (de Boer & Duisenberg, 1984); cell refinement: SET4 (de Boer & Duisenberg, 1984); data reduction: HELENA (Spek, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2002); software used to prepare material for publication: PLATON.
[PdI(C12H19N2)]·2I2 | F(000) = 1664 |
Mr = 932.19 | Dx = 2.878 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 25 reflections |
a = 9.585 (2) Å | θ = 11.3–14.2° |
b = 15.510 (2) Å | µ = 8.03 mm−1 |
c = 15.865 (2) Å | T = 294 K |
β = 114.198 (11)° | Needle, purple |
V = 2151.3 (6) Å3 | 1.45 × 0.38 × 0.30 mm |
Z = 4 |
Enraf-Nonius CAD-4F diffractometer | 3296 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.038 |
Graphite monochromator | θmax = 25.0°, θmin = 1.9° |
ω/2θ scans | h = −11→0 |
Absorption correction: analytical (ABSTOMPA in PLATON; Spek, 2002) | k = −18→0 |
Tmin = 0.063, Tmax = 0.140 | l = −17→18 |
4036 measured reflections | 2 standard reflections every 60 min |
3796 independent reflections | intensity decay: 25% |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.040 | H-atom parameters constrained |
wR(F2) = 0.104 | w = 1/[σ2(Fo2) + (0.0422P)2 + 15.2774P] where P = (Fo2 + 2Fc2)/3 |
S = 1.16 | (Δ/σ)max < 0.001 |
3796 reflections | Δρmax = 1.45 e Å−3 |
186 parameters | Δρmin = −0.93 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.00323 (15) |
[PdI(C12H19N2)]·2I2 | V = 2151.3 (6) Å3 |
Mr = 932.19 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 9.585 (2) Å | µ = 8.03 mm−1 |
b = 15.510 (2) Å | T = 294 K |
c = 15.865 (2) Å | 1.45 × 0.38 × 0.30 mm |
β = 114.198 (11)° |
Enraf-Nonius CAD-4F diffractometer | 3296 reflections with I > 2σ(I) |
Absorption correction: analytical (ABSTOMPA in PLATON; Spek, 2002) | Rint = 0.038 |
Tmin = 0.063, Tmax = 0.140 | 2 standard reflections every 60 min |
4036 measured reflections | intensity decay: 25% |
3796 independent reflections |
R[F2 > 2σ(F2)] = 0.040 | 0 restraints |
wR(F2) = 0.104 | H-atom parameters constrained |
S = 1.16 | w = 1/[σ2(Fo2) + (0.0422P)2 + 15.2774P] where P = (Fo2 + 2Fc2)/3 |
3796 reflections | Δρmax = 1.45 e Å−3 |
186 parameters | Δρmin = −0.93 e Å−3 |
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 | ||
I1 | 0.96703 (7) | 0.06200 (5) | 0.35171 (4) | 0.0532 (2) | |
I2 | 0.64297 (7) | 0.04592 (4) | 0.37342 (4) | 0.0520 (2) | |
I3 | 0.35374 (8) | 0.04854 (5) | 0.37347 (5) | 0.0618 (2) | |
I4 | 1.09363 (8) | 0.20068 (5) | 0.52348 (5) | 0.0587 (2) | |
I5 | 1.18956 (8) | 0.30849 (5) | 0.67409 (5) | 0.0575 (2) | |
Pd1 | 0.80241 (7) | 0.08624 (4) | 0.16342 (4) | 0.03467 (19) | |
N1 | 0.7226 (8) | 0.2141 (5) | 0.1555 (5) | 0.0404 (17) | |
N2 | 0.8403 (7) | −0.0398 (4) | 0.1245 (5) | 0.0355 (15) | |
C1 | 0.7047 (9) | 0.0998 (6) | 0.0316 (6) | 0.0370 (18) | |
C2 | 0.6672 (10) | 0.1808 (6) | −0.0046 (6) | 0.042 (2) | |
C3 | 0.5996 (12) | 0.1904 (7) | −0.1002 (7) | 0.054 (2) | |
H3 | 0.5717 | 0.2447 | −0.1266 | 0.065* | |
C4 | 0.5748 (12) | 0.1189 (7) | −0.1551 (7) | 0.055 (3) | |
H4 | 0.5311 | 0.1255 | −0.2190 | 0.067* | |
C5 | 0.6134 (10) | 0.0364 (6) | −0.1176 (6) | 0.044 (2) | |
H5 | 0.5953 | −0.0114 | −0.1560 | 0.053* | |
C6 | 0.6786 (9) | 0.0266 (6) | −0.0230 (6) | 0.0384 (19) | |
C7 | 0.7107 (11) | 0.2516 (6) | 0.0657 (7) | 0.046 (2) | |
H7A | 0.6338 | 0.2967 | 0.0457 | 0.055* | |
H7B | 0.8079 | 0.2765 | 0.0732 | 0.055* | |
C8 | 0.8183 (12) | 0.2712 (7) | 0.2325 (8) | 0.061 (3) | |
H8A | 0.7798 | 0.3291 | 0.2201 | 0.091* | |
H8B | 0.9220 | 0.2701 | 0.2382 | 0.091* | |
H8C | 0.8153 | 0.2514 | 0.2891 | 0.091* | |
C9 | 0.5674 (10) | 0.2106 (6) | 0.1544 (7) | 0.046 (2) | |
H9A | 0.5711 | 0.1800 | 0.2078 | 0.068* | |
H9B | 0.4994 | 0.1814 | 0.0995 | 0.068* | |
H9C | 0.5309 | 0.2682 | 0.1550 | 0.068* | |
C10 | 0.7183 (10) | −0.0566 (5) | 0.0297 (6) | 0.041 (2) | |
H10A | 0.7548 | −0.0980 | −0.0024 | 0.049* | |
H10B | 0.6282 | −0.0804 | 0.0345 | 0.049* | |
C11 | 0.8305 (12) | −0.1102 (6) | 0.1844 (7) | 0.051 (2) | |
H11A | 0.7328 | −0.1083 | 0.1877 | 0.077* | |
H11B | 0.9102 | −0.1035 | 0.2453 | 0.077* | |
H11C | 0.8423 | −0.1646 | 0.1592 | 0.077* | |
C12 | 0.9940 (10) | −0.0410 (6) | 0.1216 (7) | 0.051 (2) | |
H12A | 1.0113 | −0.0965 | 0.1009 | 0.077* | |
H12B | 1.0714 | −0.0299 | 0.1822 | 0.077* | |
H12C | 0.9980 | 0.0026 | 0.0797 | 0.077* |
U11 | U22 | U33 | U12 | U13 | U23 | |
I1 | 0.0439 (3) | 0.0746 (5) | 0.0402 (3) | 0.0008 (3) | 0.0166 (3) | −0.0084 (3) |
I2 | 0.0510 (4) | 0.0567 (4) | 0.0457 (4) | 0.0038 (3) | 0.0171 (3) | 0.0014 (3) |
I3 | 0.0511 (4) | 0.0828 (5) | 0.0517 (4) | 0.0022 (4) | 0.0211 (3) | 0.0152 (4) |
I4 | 0.0584 (4) | 0.0566 (4) | 0.0712 (5) | 0.0034 (3) | 0.0367 (4) | 0.0055 (3) |
I5 | 0.0611 (4) | 0.0524 (4) | 0.0725 (5) | −0.0007 (3) | 0.0410 (4) | 0.0026 (3) |
Pd1 | 0.0313 (3) | 0.0360 (4) | 0.0373 (3) | −0.0007 (3) | 0.0146 (3) | −0.0064 (3) |
N1 | 0.033 (4) | 0.035 (4) | 0.056 (4) | −0.006 (3) | 0.021 (3) | −0.019 (3) |
N2 | 0.034 (4) | 0.033 (4) | 0.043 (4) | 0.006 (3) | 0.019 (3) | 0.003 (3) |
C1 | 0.033 (4) | 0.044 (5) | 0.033 (4) | 0.004 (4) | 0.013 (3) | 0.005 (4) |
C2 | 0.046 (5) | 0.037 (5) | 0.046 (5) | −0.009 (4) | 0.024 (4) | −0.005 (4) |
C3 | 0.068 (6) | 0.049 (6) | 0.053 (6) | 0.006 (5) | 0.031 (5) | 0.015 (5) |
C4 | 0.059 (6) | 0.069 (7) | 0.043 (5) | −0.006 (5) | 0.027 (5) | 0.006 (5) |
C5 | 0.049 (5) | 0.042 (5) | 0.041 (5) | 0.003 (4) | 0.019 (4) | −0.005 (4) |
C6 | 0.029 (4) | 0.046 (5) | 0.038 (4) | 0.005 (4) | 0.012 (3) | −0.006 (4) |
C7 | 0.052 (5) | 0.032 (5) | 0.065 (6) | −0.005 (4) | 0.035 (5) | −0.002 (4) |
C8 | 0.055 (6) | 0.044 (6) | 0.069 (7) | −0.008 (5) | 0.013 (5) | −0.027 (5) |
C9 | 0.039 (5) | 0.049 (5) | 0.055 (5) | −0.002 (4) | 0.025 (4) | −0.008 (4) |
C10 | 0.039 (5) | 0.036 (5) | 0.043 (5) | −0.005 (4) | 0.011 (4) | −0.011 (4) |
C11 | 0.055 (6) | 0.036 (5) | 0.062 (6) | 0.005 (4) | 0.023 (5) | 0.008 (4) |
C12 | 0.042 (5) | 0.047 (5) | 0.064 (6) | 0.005 (4) | 0.021 (5) | −0.010 (5) |
I1—Pd1 | 2.7731 (10) | C4—H4 | 0.9300 |
I1—I2 | 3.2720 (11) | C5—C6 | 1.378 (12) |
I1—I4 | 3.2886 (11) | C5—H5 | 0.9300 |
I2—I3 | 2.7729 (11) | C6—C10 | 1.499 (12) |
I4—I5 | 2.7477 (11) | C7—H7A | 0.9700 |
Pd1—C1 | 1.920 (8) | C7—H7B | 0.9700 |
Pd1—N1 | 2.111 (7) | C8—H8A | 0.9600 |
Pd1—N2 | 2.126 (7) | C8—H8B | 0.9600 |
N1—C9 | 1.481 (10) | C8—H8C | 0.9600 |
N1—C8 | 1.483 (11) | C9—H9A | 0.9600 |
N1—C7 | 1.500 (12) | C9—H9B | 0.9600 |
N2—C11 | 1.475 (11) | C9—H9C | 0.9600 |
N2—C12 | 1.493 (11) | C10—H10A | 0.9700 |
N2—C10 | 1.502 (11) | C10—H10B | 0.9700 |
C1—C2 | 1.367 (12) | C11—H11A | 0.9600 |
C1—C6 | 1.387 (12) | C11—H11B | 0.9600 |
C2—C3 | 1.393 (13) | C11—H11C | 0.9600 |
C2—C7 | 1.498 (12) | C12—H12A | 0.9600 |
C3—C4 | 1.368 (15) | C12—H12B | 0.9600 |
C3—H3 | 0.9300 | C12—H12C | 0.9600 |
C4—C5 | 1.397 (14) | ||
I1···I3i | 3.5851 (13) | I3···I5ii | 3.6495 (13) |
Pd1—I1—I2 | 88.75 (3) | C5—C6—C10 | 127.0 (8) |
Pd1—I1—I4 | 131.13 (3) | C1—C6—C10 | 114.6 (7) |
I2—I1—I4 | 90.37 (2) | C2—C7—N1 | 108.2 (7) |
I3—I2—I1 | 172.42 (3) | C2—C7—H7A | 110.1 |
I5—I4—I1 | 175.53 (3) | N1—C7—H7A | 110.1 |
C1—Pd1—N1 | 80.2 (3) | C2—C7—H7B | 110.1 |
C1—Pd1—N2 | 81.3 (3) | N1—C7—H7B | 110.1 |
N1—Pd1—N2 | 161.4 (3) | H7A—C7—H7B | 108.4 |
C1—Pd1—I1 | 174.8 (2) | N1—C8—H8A | 109.5 |
N1—Pd1—I1 | 102.9 (2) | N1—C8—H8B | 109.5 |
N2—Pd1—I1 | 95.65 (19) | H8A—C8—H8B | 109.5 |
C9—N1—C8 | 108.2 (7) | N1—C8—H8C | 109.5 |
C9—N1—C7 | 108.5 (7) | H8A—C8—H8C | 109.5 |
C8—N1—C7 | 109.4 (7) | H8B—C8—H8C | 109.5 |
C9—N1—Pd1 | 107.7 (5) | N1—C9—H9A | 109.5 |
C8—N1—Pd1 | 115.2 (6) | N1—C9—H9B | 109.5 |
C7—N1—Pd1 | 107.8 (5) | H9A—C9—H9B | 109.5 |
C11—N2—C12 | 109.6 (7) | N1—C9—H9C | 109.5 |
C11—N2—C10 | 106.7 (7) | H9A—C9—H9C | 109.5 |
C12—N2—C10 | 109.9 (7) | H9B—C9—H9C | 109.5 |
C11—N2—Pd1 | 115.5 (5) | C6—C10—N2 | 109.0 (7) |
C12—N2—Pd1 | 108.0 (5) | C6—C10—H10A | 109.9 |
C10—N2—Pd1 | 107.1 (5) | N2—C10—H10A | 109.9 |
C2—C1—C6 | 122.7 (8) | C6—C10—H10B | 109.9 |
C2—C1—Pd1 | 119.0 (6) | N2—C10—H10B | 109.9 |
C6—C1—Pd1 | 118.3 (6) | H10A—C10—H10B | 108.3 |
C1—C2—C3 | 118.7 (8) | N2—C11—H11A | 109.5 |
C1—C2—C7 | 114.6 (8) | N2—C11—H11B | 109.5 |
C3—C2—C7 | 126.6 (9) | H11A—C11—H11B | 109.5 |
C4—C3—C2 | 119.3 (9) | N2—C11—H11C | 109.5 |
C4—C3—H3 | 120.4 | H11A—C11—H11C | 109.5 |
C2—C3—H3 | 120.4 | H11B—C11—H11C | 109.5 |
C3—C4—C5 | 121.7 (9) | N2—C12—H12A | 109.5 |
C3—C4—H4 | 119.2 | N2—C12—H12B | 109.5 |
C5—C4—H4 | 119.2 | H12A—C12—H12B | 109.5 |
C6—C5—C4 | 119.2 (9) | N2—C12—H12C | 109.5 |
C6—C5—H5 | 120.4 | H12A—C12—H12C | 109.5 |
C4—C5—H5 | 120.4 | H12B—C12—H12C | 109.5 |
C5—C6—C1 | 118.4 (8) | ||
I2—I1—Pd1—N1 | 74.90 (19) | N2—Pd1—C1—C6 | 11.2 (6) |
I4—I1—Pd1—N1 | −14.49 (19) | C6—C1—C2—C3 | 0.1 (13) |
I2—I1—Pd1—N2 | −104.26 (18) | Pd1—C1—C2—C3 | 178.5 (7) |
I4—I1—Pd1—N2 | 166.35 (18) | C6—C1—C2—C7 | −177.5 (8) |
C1—Pd1—N1—C9 | 90.2 (6) | Pd1—C1—C2—C7 | 0.9 (10) |
N2—Pd1—N1—C9 | 83.3 (10) | C1—C2—C3—C4 | −0.9 (14) |
I1—Pd1—N1—C9 | −94.1 (5) | C7—C2—C3—C4 | 176.4 (9) |
C1—Pd1—N1—C8 | −149.1 (7) | C2—C3—C4—C5 | 1.0 (15) |
N2—Pd1—N1—C8 | −155.9 (8) | C3—C4—C5—C6 | −0.2 (15) |
I1—Pd1—N1—C8 | 26.7 (7) | C4—C5—C6—C1 | −0.6 (13) |
C1—Pd1—N1—C7 | −26.7 (5) | C4—C5—C6—C10 | 175.8 (9) |
N2—Pd1—N1—C7 | −33.5 (11) | C2—C1—C6—C5 | 0.7 (13) |
I1—Pd1—N1—C7 | 149.1 (5) | Pd1—C1—C6—C5 | −177.7 (6) |
C1—Pd1—N2—C11 | −143.3 (6) | C2—C1—C6—C10 | −176.2 (8) |
N1—Pd1—N2—C11 | −136.5 (8) | Pd1—C1—C6—C10 | 5.4 (10) |
I1—Pd1—N2—C11 | 41.0 (6) | C1—C2—C7—N1 | −23.8 (10) |
C1—Pd1—N2—C12 | 93.7 (6) | C3—C2—C7—N1 | 158.8 (9) |
N1—Pd1—N2—C12 | 100.5 (9) | C9—N1—C7—C2 | −83.2 (8) |
I1—Pd1—N2—C12 | −82.0 (5) | C8—N1—C7—C2 | 159.1 (7) |
C1—Pd1—N2—C10 | −24.6 (5) | Pd1—N1—C7—C2 | 33.2 (8) |
N1—Pd1—N2—C10 | −17.7 (11) | C5—C6—C10—N2 | 157.0 (8) |
I1—Pd1—N2—C10 | 159.7 (5) | C1—C6—C10—N2 | −26.5 (10) |
N1—Pd1—C1—C2 | 15.0 (7) | C11—N2—C10—C6 | 157.0 (7) |
N2—Pd1—C1—C2 | −167.2 (7) | C12—N2—C10—C6 | −84.2 (8) |
N1—Pd1—C1—C6 | −166.5 (7) | Pd1—N2—C10—C6 | 32.8 (8) |
Symmetry codes: (i) x+1, y, z; (ii) x−1, −y+1/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | [PdI(C12H19N2)]·2I2 |
Mr | 932.19 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 294 |
a, b, c (Å) | 9.585 (2), 15.510 (2), 15.865 (2) |
β (°) | 114.198 (11) |
V (Å3) | 2151.3 (6) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 8.03 |
Crystal size (mm) | 1.45 × 0.38 × 0.30 |
Data collection | |
Diffractometer | Enraf-Nonius CAD-4F diffractometer |
Absorption correction | Analytical (ABSTOMPA in PLATON; Spek, 2002) |
Tmin, Tmax | 0.063, 0.140 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4036, 3796, 3296 |
Rint | 0.038 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.104, 1.16 |
No. of reflections | 3796 |
No. of parameters | 186 |
H-atom treatment | H-atom parameters constrained |
w = 1/[σ2(Fo2) + (0.0422P)2 + 15.2774P] where P = (Fo2 + 2Fc2)/3 | |
Δρmax, Δρmin (e Å−3) | 1.45, −0.93 |
Computer programs: locally modified CAD-4 Software (de Boer & Duisenberg, 1984), SET4 (de Boer & Duisenberg, 1984), HELENA (Spek, 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2002), PLATON.
I1—Pd1 | 2.7731 (10) | I4—I5 | 2.7477 (11) |
I1—I2 | 3.2720 (11) | Pd1—C1 | 1.920 (8) |
I1—I4 | 3.2886 (11) | Pd1—N1 | 2.111 (7) |
I2—I3 | 2.7729 (11) | Pd1—N2 | 2.126 (7) |
I1···I3i | 3.5851 (13) | I3···I5ii | 3.6495 (13) |
I2—I1—I4 | 90.37 (2) | N1—Pd1—N2 | 161.4 (3) |
I3—I2—I1 | 172.42 (3) | C1—Pd1—I1 | 174.8 (2) |
I5—I4—I1 | 175.53 (3) | N1—Pd1—I1 | 102.9 (2) |
C1—Pd1—N1 | 80.2 (3) | N2—Pd1—I1 | 95.65 (19) |
C1—Pd1—N2 | 81.3 (3) |
Symmetry codes: (i) x+1, y, z; (ii) x−1, −y+1/2, z−1/2. |
In its terdentate coordination mode, the monoanionic aryldiamine ligand 2,6-bis((dimethylamino)methyl)phenyl (NCN) acts as a rigid backbone with strong electron-donating ability (Albrecht & van Koten, 2001; Rietveld et al., 1997). The unique properties of this pincer ligand allowed the preparation of the first complex containing an end-on coordinated I2 molecule, [Pt(NCN)I(η1-I2)] (van Beek et al., 1986; Gossage et al., 1999). A number of similar five-coordinate η1-I2—Pt complexes with aryldiamine pincer ligands have subsequently been reported (van Beek et al., 1990; Gossage et al., 1999). More recently, the unusual octahedral complex trans-[Pt(dmpe)2I(η1-I2)]I3 [dmpe is 1,2-bis(dimethylphosphino)ethane] has been synthesized (Makiura et al., 2001). These compounds have been proposed as models for the initial stage of the oxidative addition of dihalides to d8 transition metal complexes. An attempt to prepare an analogous palladium complex, [Pd(NCN)I(η1-I2)], by reaction of [Pd(NCN)I] with I2 led to the isolation of purple crystals with the stoichiometry [Pd(NCN)I5] (Gossage et al., 1999). In the title compound, [Pd(NCN)I]·2I2, (I), two neutral I2 molecules per [Pd(NCN)I] complex have been incorporated, but neither interacts strongly with the metal. Selected geometric parameters for (I) are presented in Table 1.
As shown in Fig. 1, the coordination environment of the palladium(II) centre in (I) is defined by the monoanionic NCN pincer ligand and one iodide anion. The terdentate NCN ligand is coordinated to the metal via the anionic C1 [Pd—C 1.920 (8) Å] and the two amine N atoms [Pd—N 2.111 (7)—2.126 (7) Å] at distances comparable to those in other NCN–Pd complexes, such as [(NCN)Pd(µ-Cl)Pd(NCN)]BF4 [Terheijden et al., 1987; Pd—C 1.929 (4) Å and Pd—N 2.100 (4)–2.105 (3) Å]. The iodide anion is coordinated trans to C1, an sp2 donor with a large trans influence, at a Pd—I distance of 2.7731 (10) Å that is somewhat longer than that observed in trans-[Pd{η1-κC-(3,5-NCN)}(PPh3)2I] {3,5-NCN is 3,5-bis[(dimethylamino)methyl]phenyl; Spee et al., 2000; Pd—I 2.6968 (4)Å}. The small 80.2 (3)–81.3 (3)° range of C—Pd—N bite angles of the NCN ligand result in a distorted square-planar geometry at the metal; although the cis angles sum to 360.0 (5)°, they deviate by up to 13° from the ideal 90° values. The two five-membered PdC3N chelate rings both adopt envelope conformations, but are puckered in opposite directions, with the N-donors mutually trans. Thus, the PdCN2I coordination plane is tilted by 13.7 (4)° with respect to the plane of the aryl ring. The meridional coordination mode of the NCN ligand observed in (I) is typical of most square planar NCN–metal complexes, including [Pt(NCN)I] (Smeets et al., 1987), and results in approximate (non-crystallographic) C2 symmetry for [Pd(NCN)I].
Two neutral I2 molecules are positioned 3.2720 (11) and 3.2886 (11) Å, respectively, from the coordinated iodide anion. These contacts are somewhat shorter than the weakly bonding 3.496 (6) Å intermolecular distance in the crystal structure of iodine. The bond lengths within the perturbed I2 molecules [I—I 2.7477 (11)–2.7729 (11) Å], on the other hand, are slightly elongated compared to the 2.715 (6) Å intramolecular distance in elemental iodine (van Bolhuis et al., 1967). These considerations suggest an alternative description of the title compound as a palladium pentaiodide complex, [Pd(NCN)I5], in which the I5- anion is an adduct of the type [I-·2I2]. The coordinated I5- anion is L-shaped, with inner and outer angles of 90.37 (2) and 172.42 (3)–175.53 (3)°, respectively, and is oriented such that one I2 component is nearly perpendicular to the NCN aryl ring plane [83.5 (4)°]. The observed values of both the I—I—I angles and I—I distances in the coordinated ion fall within the range reported for free I5- anions (Cambridge Structural Database, Version 5.22 of October 2001; Allen & Kennard, 1993).
The [Pd(NCN)I5] complexes are linked by weaker I···I interactions, listed in Table 2, that are nevertheless considerably shorter than the sum of the van der Waals radii (Bondi, 1964; 3.96 Å). The central I1 of one I5- anion interacts with the terminal I3 atom of the next [I1—I3i 3.5851 (13) Å; symmetry code: (i) 1 + x, y, z], forming infinite one-dimensional chains that run along the a direction. Head-to-tail I5-···I5- contacts [I3—I5ii 3.6495 (13) Å; symmetry code: (ii) x - 1, 1/2 - y, z - 1/2] link the chains into a two-dimensional network. In the anionic [I5-] substructure, kinked polyiodide nets composed of fused 12-membered rings, presented in Fig. 2, are stacked perpendicular to the b direction.