Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100016401/gg1030sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270100016401/gg1030Isup2.hkl |
CCDC reference: 162539
For related literature, see: Allen & Kennard (1993); Asselt & Elsevier (1992); Asselt et al. (1994, 1997); Britton & Gleason (1982); Ittel & Ibers (1976); Kranenburg et al. (1997); Schleis et al. (1998); Tatsumi et al. (1981).
The synthesis of [Pd(C26H26N4)] has been described (van Asselt et al., 1997). The complex was recrystallized from a hexane/dichloromethane solution. The crystal selected for data collection was cut to size in inert oil and mounted under the liquid nitrogen jet.
In the penultimate stages of refinement a large positive residual electron peak was located towards the centre of the camphor ring indicating some minor disorder of the backbone. Subsequent analysis revealed a second orientation equivalent to 12.3 (4)% disorder of the camphor backbone. All distances and angles were restrained (using the SAME instruction), and additionally, the distances to the disordered methyl atom C10B were constrained with a DFIX command. The displacement parameters for the disordered camphor atoms (C1B to C10B) were refined isotropically and tied to a free variable which converged to 0.028 (3). A large negative residual electron density of -1.44 e·A-3 (0.03 Å from Pd1) remained in the final difference maps.
All hydrogen atoms, except for H24 and H25 on the fumaronitrile ligand, were constrained and allowed to ride on their carbon atoms with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C) for CH3 groups. A sensible geometry was not obtained when hydrogen atoms H24 and H25 were constrained using the normal instructions, thus both were located in the Fourier map, their distances constrained and their displacement parameters allowed to ride on their parent atom with Uiso(H) = 1.2Ueq(C). 360° psi-scans showed no significant variations, thus no correction for absorption was performed.
Group ten complexes of chiral bicyclic nitrogen ligands have been used in the study of homogeneous hydrogenation, polymerization and other catalytic reactions (Schleis et al., 1998; van Asselt et al., 1997; van Asselt & Elsevier, 1992). The reactivity and selectivity in these zerovalent complexes can be controlled by varying the groups on the nitrogen or by changing the electron-poor alkene (van Asselt et al., 1994).
The Y-shaped trigonal-planar geometry of the title complex, (I), is shown in Figure 1 with selected geometric parameters presented in Table 1. The palladium centre is coordinated to two imine nitrogen atoms attached to a camphor backbone, and to the alkenic carbon atoms of fumaronitrile. The metal distances [Pd—N 2.157 (2) and 2.157 (2) Å, Pd—C 2.037 (3), 2.047 (3) Å] are comparable to those found in dimethyl-{2-(phenylimino)-3- (2,6-dimethylphenylimino)-1,7,7-trimethylbicyclo(2.2.1)heptane-2,3-diylidene}- palladium(II), (II) (Schleis et al., 1998). The metal distances in (I) are more symmetrical than in (II) due to the more crowded coordination sphere of the 2,6-dimethylphenyl group in the latter. The phenyl rings in (I) are tilted, relative to the PdN2C2 plane, to a greater extent than in (II) [dihedral angle between aryl rings and PdN2C2 plane are 74.54 (16) and 35.54 (14)° in (I), compared to 69.6 and 87.6° in (II)]. Presumably there are unfavourable interactions between the methyl groups on either the camphor backbone or phenyl ring in (II) [the latter being absent in (I)]. \sch
The disposition of the nitrogen atoms ensures a cis orientation at the metal; constrained σ-donating ligands are known to induce small bite angles in similar systems (Tatsumi et al., 1981). The N1—Pd1—N2 bite angle of 77.31 (9)° is comparable to that found in (II) [77.2 (1)°] and is of a similar magnitude to related complexes in the Cambridge Structural Database (Allen & Kennard, 1993). The imine C═N bonds of 1.281 (5) and 1.271 (4) Å are marginally different, one of them is slightly longer than those found in (II) [1.272 (5) and 1.273 (5) Å].
The C═C bond distance in the fumaronitrile ligand [1.441 (4) Å] is longer than in the free ligand [1.249 (10) Å, Britton & Gleason, 1982], due to coordination to palladium; the π-back bond donation from the filled metal orbital to the empty π* orbital in the alkene causes an elongation of this bond. There is a concomitant shortening of the C—C(N) single bonds from 1.480 (8) Å in the free ligand to 1.435 (4)/1.433 (4) Å in (I). The secondary effect (of ligand coordination) is a bending of the substituents away from the metal plane, which has been quantified by Ittel & Ibers (1976). Two angles, designated α and β/β', describe deviations of the alkene ligands from the metal plane. Their values, 66.3 (3) and 57.7 (3)/55.8 (3)°, correlate well with those in other bidentate systems, for example 59.3 (8), 60.8 (6)/59.9 (5)° for the tetracyanoethane ligand in [Pd(C23H16N6)] (Kranenburg et al., 1997). The olefinic carbon atoms are notionally sp2 hydridized, as shown by the C—C—C angles of 119.7 (3) and 118.6 (3)°. The cyano groups are linear [C—C≡N 179.0 (3) and 179.3 (4)°] and form very weak C—H···N hydrogen bond contacts, H3A···N3i of 2.58 Å, H4B···N4ii of 2.60 Å [symmetry operators (i) x, 1/2 - y, -1/2 + z; (ii) -x, -y, -z].
For related literature, see: Allen & Kennard (1993); Asselt & Elsevier (1992); Asselt et al. (1994, 1997); Britton & Gleason (1982); Ittel & Ibers (1976); Kranenburg et al. (1997); Schleis et al. (1998); Tatsumi et al. (1981).
Data collection: Locally modified CAD4-Version 5 Software (Enraf-Nonius, 1989); cell refinement: SET4 (de Boer & Duisenberg, 1984); data reduction: HELENA (Spek, 1997); program(s) used to solve structure: DIRDIF99 (Beurskens et al. 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2000); software used to prepare material for publication: PLATON.
Fig. 1. Displacement ellipsoid plot of the major disordered component in (I) drawn at 50% probability level. Hydrogen atoms omitted for clarity. |
[Pd(C22H24N2)(C4H2N2)] | F(000) = 1024 |
Mr = 500.91 | Dx = 1.451 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 11.8073 (13) Å | Cell parameters from 25 reflections |
b = 10.0751 (12) Å | θ = 11.4–13.8° |
c = 21.453 (3) Å | µ = 0.83 mm−1 |
β = 116.024 (8)° | T = 150 K |
V = 2293.3 (5) Å3 | Block, orange |
Z = 4 | 0.55 × 0.25 × 0.25 mm |
Enraf-Nonius CAD4 diffractometer | Rint = 0.076 |
Radiation source: rotating anode | θmax = 27.5°, θmin = 1.9° |
Graphite monochromator | h = −10→15 |
ω–2θ scans | k = −13→0 |
7053 measured reflections | l = −27→25 |
5235 independent reflections | 3 standard reflections every 60 min |
4462 reflections with I > 2σ(I) | intensity decay: <1% |
Refinement on F2 | Primary atom site location: heavy-atom method |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.042 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.086 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0311P)2 + 2.2454P] where P = (Fo2 + 2Fc2)/3 |
5235 reflections | (Δ/σ)max < 0.002 |
317 parameters | Δρmax = 0.83 e Å−3 |
33 restraints | Δρmin = −1.46 e Å−3 |
[Pd(C22H24N2)(C4H2N2)] | V = 2293.3 (5) Å3 |
Mr = 500.91 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 11.8073 (13) Å | µ = 0.83 mm−1 |
b = 10.0751 (12) Å | T = 150 K |
c = 21.453 (3) Å | 0.55 × 0.25 × 0.25 mm |
β = 116.024 (8)° |
Enraf-Nonius CAD4 diffractometer | Rint = 0.076 |
7053 measured reflections | 3 standard reflections every 60 min |
5235 independent reflections | intensity decay: <1% |
4462 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.042 | 33 restraints |
wR(F2) = 0.086 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | Δρmax = 0.83 e Å−3 |
5235 reflections | Δρmin = −1.46 e Å−3 |
317 parameters |
Experimental. In the penultimate stages of refinement a large positive residual electron peak was located towards the centre of the camphor ring indicating some minor disorder of the backbone. Subsequent analysis revealed a second orientation equivalent to 12.3 (4)% disorder of the camphor backbone. All distances and angles were restrained (using the SAME instruction), and additionally, the distances to the disordered methyl atom C10B were constrained with a DFIX command. The displacement parameters for the disordered camphor atoms (C1B to C10B) were refined isotropically and tied to a free variable which converged to 0.028 (3). A large negative residual electron density of -1.44 e·A-3 (0.03 Å from Pd1) remained in the final difference maps. All hydrogen atoms, except for H24 and H25 on the fumaronitrile ligand were constrained and allowed to ride on their carbon atoms with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C) for CH3 groups. A sensible geometry was not obtained when hydrogen atoms H24 and H25 were constrained using the normal instructions, thus both were located in the Fourier map, their distances constrained and their displacement parameters allowed to ride on their parent atom with Uiso(H) = 1.2Ueq(C). This resulted in the shorter than normal C25—H25 distance of 0.84 Å. Due to the instability in the refinement of hydrogen atoms on C10B, a riding model was used for H10D, H10E and H10F with displacement parameters fixed to Uiso(H) = 1.5Ueq(C). 360° psi-scans showed no significant variations, thus no correction for absorption was performed. |
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 | Occ. (<1) | |
Pd1 | 0.224795 (18) | 0.08720 (2) | 0.189247 (9) | 0.02215 (8) | |
N1 | 0.3558 (2) | 0.1375 (3) | 0.14774 (12) | 0.0276 (5) | |
N2 | 0.1028 (2) | 0.1608 (2) | 0.08716 (11) | 0.0263 (5) | |
N3 | 0.4469 (3) | 0.1934 (3) | 0.37370 (14) | 0.0420 (7) | |
N4 | 0.0082 (3) | −0.1524 (4) | 0.23466 (16) | 0.0575 (10) | |
C1 | 0.3036 (4) | 0.1966 (4) | 0.08894 (19) | 0.0288 (9) | 0.872 (4) |
C2 | 0.3455 (4) | 0.2694 (4) | 0.04120 (19) | 0.0364 (8) | 0.872 (4) |
C3 | 0.3040 (5) | 0.1768 (4) | −0.0232 (2) | 0.0451 (11) | 0.872 (4) |
H3A | 0.3393 | 0.2079 | −0.0549 | 0.054* | 0.872 (4) |
H3B | 0.3323 | 0.0845 | −0.0089 | 0.054* | 0.872 (4) |
C4 | 0.1599 (5) | 0.1851 (4) | −0.0584 (2) | 0.0449 (11) | 0.872 (4) |
H4A | 0.1216 | 0.0969 | −0.0603 | 0.054* | 0.872 (4) |
H4B | 0.1286 | 0.2206 | −0.1061 | 0.054* | 0.872 (4) |
C5 | 0.1303 (4) | 0.2817 (4) | −0.01120 (17) | 0.0369 (9) | 0.872 (4) |
H5 | 0.0444 | 0.3225 | −0.0327 | 0.044* | 0.872 (4) |
C6 | 0.1631 (4) | 0.2064 (3) | 0.05521 (16) | 0.0279 (8) | 0.872 (4) |
C7 | 0.2395 (4) | 0.3787 (4) | 0.0129 (2) | 0.0404 (9) | 0.872 (4) |
C8 | 0.2408 (12) | 0.4581 (10) | −0.0483 (5) | 0.0616 (17) | 0.872 (4) |
H8A | 0.2516 | 0.3970 | −0.0808 | 0.092* | 0.872 (4) |
H8B | 0.3107 | 0.5217 | −0.0307 | 0.092* | 0.872 (4) |
H8C | 0.1610 | 0.5061 | −0.0721 | 0.092* | 0.872 (4) |
C9 | 0.2453 (6) | 0.4725 (4) | 0.0708 (2) | 0.0499 (11) | 0.872 (4) |
H9A | 0.1724 | 0.5322 | 0.0525 | 0.075* | 0.872 (4) |
H9B | 0.3231 | 0.5248 | 0.0878 | 0.075* | 0.872 (4) |
H9C | 0.2442 | 0.4201 | 0.1090 | 0.075* | 0.872 (4) |
C10 | 0.4758 (3) | 0.3160 (4) | 0.0671 (2) | 0.0371 (8) | 0.872 (4) |
H10A | 0.4955 | 0.3750 | 0.1069 | 0.056* | 0.872 (4) |
H10B | 0.4861 | 0.3643 | 0.0303 | 0.056* | 0.872 (4) |
H10C | 0.5331 | 0.2397 | 0.0816 | 0.056* | 0.872 (4) |
C1B | 0.160 (2) | 0.238 (2) | 0.0699 (12) | 0.028 (2)* | 0.128 (4) |
C2B | 0.1287 (15) | 0.3485 (17) | 0.0188 (8) | 0.028 (2)* | 0.128 (4) |
C3B | 0.1769 (19) | 0.4753 (19) | 0.0619 (11) | 0.028 (2)* | 0.128 (4) |
H3B1 | 0.1458 | 0.4817 | 0.0978 | 0.034* | 0.128 (4) |
H3B2 | 0.1495 | 0.5551 | 0.0320 | 0.034* | 0.128 (4) |
C4B | 0.3246 (19) | 0.4610 (19) | 0.0961 (10) | 0.028 (2)* | 0.128 (4) |
H4B1 | 0.3650 | 0.5374 | 0.0847 | 0.034* | 0.128 (4) |
H4B2 | 0.3600 | 0.4514 | 0.1471 | 0.034* | 0.128 (4) |
C5B | 0.3390 (16) | 0.3324 (19) | 0.0614 (9) | 0.028 (2)* | 0.128 (4) |
H5B | 0.4240 | 0.3199 | 0.0627 | 0.034* | 0.128 (4) |
C6B | 0.302 (2) | 0.225 (3) | 0.0987 (15) | 0.028 (2)* | 0.128 (4) |
C7B | 0.2326 (16) | 0.3250 (18) | −0.0087 (8) | 0.028 (2)* | 0.128 (4) |
C8B | 0.232 (5) | 0.454 (4) | −0.0492 (19) | 0.028 (2)* | 0.128 (4) |
H8B1 | 0.2246 | 0.4310 | −0.0951 | 0.042* | 0.128 (4) |
H8B2 | 0.3100 | 0.5037 | −0.0233 | 0.042* | 0.128 (4) |
H8B3 | 0.1596 | 0.5097 | −0.0545 | 0.042* | 0.128 (4) |
C9B | 0.215 (3) | 0.197 (2) | −0.0481 (13) | 0.028 (2)* | 0.128 (4) |
H9B1 | 0.2871 | 0.1824 | −0.0581 | 0.042* | 0.128 (4) |
H9B2 | 0.1376 | 0.2028 | −0.0918 | 0.042* | 0.128 (4) |
H9B3 | 0.2075 | 0.1237 | −0.0202 | 0.042* | 0.128 (4) |
C10B | 0.0267 (16) | 0.3510 (17) | −0.0479 (8) | 0.028 (2)* | 0.128 (4) |
H10D | 0.0210 | 0.4285 | −0.0768 | 0.042* | 0.128 (4) |
H10E | −0.0354 | 0.3592 | −0.0294 | 0.042* | 0.128 (4) |
H10F | 0.0096 | 0.2703 | −0.0761 | 0.042* | 0.128 (4) |
C11 | 0.4901 (3) | 0.1218 (3) | 0.18427 (15) | 0.0304 (6) | |
C12 | 0.5497 (3) | 0.0231 (4) | 0.1663 (2) | 0.0440 (8) | |
H12 | 0.5021 | −0.0348 | 0.1289 | 0.053* | |
C13 | 0.6788 (4) | 0.0071 (4) | 0.2021 (2) | 0.0516 (9) | |
H13 | 0.7199 | −0.0614 | 0.1894 | 0.062* | |
C14 | 0.7474 (3) | 0.0906 (4) | 0.25625 (19) | 0.0473 (9) | |
H14 | 0.8363 | 0.0805 | 0.2807 | 0.057* | |
C15 | 0.6877 (4) | 0.1886 (4) | 0.27494 (17) | 0.0473 (9) | |
H15 | 0.7356 | 0.2466 | 0.3122 | 0.057* | |
C16 | 0.5574 (3) | 0.2039 (4) | 0.23984 (15) | 0.0385 (7) | |
H16 | 0.5156 | 0.2696 | 0.2539 | 0.046* | |
C17 | −0.0322 (3) | 0.1677 (3) | 0.05820 (14) | 0.0277 (6) | |
C18 | −0.0848 (3) | 0.1911 (3) | 0.10305 (15) | 0.0330 (6) | |
H18 | −0.0320 | 0.2022 | 0.1512 | 0.040* | |
C19 | −0.2150 (3) | 0.1984 (3) | 0.07812 (17) | 0.0386 (7) | |
H19 | −0.2516 | 0.2151 | 0.1089 | 0.046* | |
C20 | −0.2905 (3) | 0.1809 (3) | 0.00783 (17) | 0.0383 (7) | |
H20 | −0.3795 | 0.1870 | −0.0098 | 0.046* | |
C21 | −0.2380 (3) | 0.1549 (3) | −0.03645 (16) | 0.0378 (8) | |
H21 | −0.2911 | 0.1424 | −0.0844 | 0.045* | |
C22 | −0.1080 (3) | 0.1467 (3) | −0.01225 (15) | 0.0330 (7) | |
H22 | −0.0718 | 0.1271 | −0.0430 | 0.040* | |
C23 | 0.3771 (3) | 0.1190 (3) | 0.33632 (14) | 0.0297 (6) | |
C24 | 0.2913 (3) | 0.0241 (3) | 0.28937 (13) | 0.0275 (6) | |
H24 | 0.3162 | −0.0663 | 0.2956 | 0.033* | |
C25 | 0.1575 (3) | 0.0477 (3) | 0.26053 (13) | 0.0280 (6) | |
H25 | 0.1238 | 0.1236 | 0.2719 | 0.034* | |
C26 | 0.0750 (3) | −0.0644 (4) | 0.24611 (15) | 0.0365 (7) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Pd1 | 0.02105 (10) | 0.02605 (11) | 0.01807 (10) | −0.00027 (8) | 0.00739 (8) | 0.00115 (8) |
N1 | 0.0258 (11) | 0.0327 (12) | 0.0266 (11) | −0.0045 (10) | 0.0136 (9) | −0.0025 (10) |
N2 | 0.0258 (11) | 0.0261 (12) | 0.0217 (10) | −0.0006 (10) | 0.0055 (9) | 0.0022 (9) |
N3 | 0.0375 (14) | 0.0483 (17) | 0.0341 (14) | −0.0054 (13) | 0.0100 (12) | −0.0060 (12) |
N4 | 0.0497 (18) | 0.070 (2) | 0.0420 (17) | −0.0257 (19) | 0.0106 (14) | 0.0098 (16) |
C1 | 0.0341 (17) | 0.028 (2) | 0.0268 (18) | −0.0054 (15) | 0.0157 (14) | −0.0047 (15) |
C2 | 0.047 (2) | 0.0293 (18) | 0.044 (2) | −0.0091 (16) | 0.0293 (17) | −0.0048 (16) |
C3 | 0.081 (3) | 0.0292 (19) | 0.046 (2) | −0.006 (2) | 0.047 (2) | −0.0041 (16) |
C4 | 0.073 (3) | 0.036 (2) | 0.0299 (19) | −0.012 (2) | 0.027 (2) | −0.0034 (15) |
C5 | 0.050 (2) | 0.0315 (19) | 0.0282 (17) | −0.0006 (16) | 0.0163 (16) | 0.0074 (14) |
C6 | 0.0352 (17) | 0.0241 (17) | 0.0217 (16) | −0.0021 (14) | 0.0101 (14) | −0.0002 (12) |
C7 | 0.055 (2) | 0.0271 (18) | 0.049 (2) | −0.0018 (17) | 0.032 (2) | −0.0011 (16) |
C8 | 0.072 (4) | 0.047 (3) | 0.081 (3) | 0.003 (3) | 0.046 (3) | 0.028 (3) |
C9 | 0.068 (3) | 0.030 (2) | 0.063 (3) | −0.007 (2) | 0.039 (3) | −0.0131 (19) |
C10 | 0.0309 (17) | 0.039 (2) | 0.049 (2) | −0.0042 (15) | 0.0250 (16) | 0.0034 (16) |
C11 | 0.0247 (13) | 0.0365 (16) | 0.0297 (14) | −0.0060 (12) | 0.0115 (11) | 0.0022 (12) |
C12 | 0.0344 (16) | 0.0413 (19) | 0.057 (2) | −0.0046 (15) | 0.0206 (16) | −0.0098 (16) |
C13 | 0.0370 (18) | 0.047 (2) | 0.070 (2) | 0.0057 (16) | 0.0229 (18) | −0.0012 (19) |
C14 | 0.0287 (15) | 0.060 (2) | 0.0498 (19) | 0.0007 (16) | 0.0141 (15) | 0.0126 (18) |
C15 | 0.0380 (17) | 0.066 (2) | 0.0302 (16) | −0.0093 (18) | 0.0079 (14) | −0.0014 (16) |
C16 | 0.0347 (16) | 0.0497 (19) | 0.0292 (14) | −0.0038 (14) | 0.0123 (13) | −0.0069 (13) |
C17 | 0.0278 (13) | 0.0221 (13) | 0.0258 (13) | 0.0006 (11) | 0.0051 (11) | 0.0057 (10) |
C18 | 0.0305 (15) | 0.0334 (15) | 0.0296 (14) | 0.0062 (13) | 0.0079 (12) | 0.0029 (12) |
C19 | 0.0329 (16) | 0.0368 (17) | 0.0422 (17) | 0.0060 (13) | 0.0127 (14) | 0.0027 (14) |
C20 | 0.0245 (14) | 0.0331 (16) | 0.0436 (17) | 0.0015 (12) | 0.0022 (13) | 0.0074 (14) |
C21 | 0.0330 (15) | 0.0337 (17) | 0.0306 (15) | −0.0095 (13) | −0.0007 (13) | 0.0075 (13) |
C22 | 0.0376 (16) | 0.0309 (15) | 0.0249 (13) | −0.0093 (13) | 0.0086 (12) | 0.0028 (12) |
C23 | 0.0267 (13) | 0.0387 (17) | 0.0208 (12) | 0.0016 (12) | 0.0079 (11) | 0.0033 (11) |
C24 | 0.0287 (14) | 0.0299 (14) | 0.0198 (12) | 0.0011 (12) | 0.0068 (11) | 0.0025 (11) |
C25 | 0.0286 (13) | 0.0346 (15) | 0.0201 (12) | 0.0016 (12) | 0.0102 (11) | 0.0041 (11) |
C26 | 0.0324 (15) | 0.050 (2) | 0.0234 (13) | −0.0066 (14) | 0.0090 (12) | 0.0094 (13) |
Pd1—C24 | 2.037 (3) | C3B—H3B2 | 0.9900 |
Pd1—C25 | 2.047 (3) | C4B—C5B | 1.540 (18) |
Pd1—N1 | 2.157 (2) | C4B—H4B1 | 0.9900 |
Pd1—N2 | 2.157 (2) | C4B—H4B2 | 0.9900 |
N1—C1 | 1.281 (5) | C5B—C7B | 1.480 (16) |
N1—C6B | 1.31 (2) | C5B—C6B | 1.520 (18) |
N1—C11 | 1.436 (4) | C5B—H5B | 1.0000 |
N2—C1B | 1.19 (2) | C7B—C9B | 1.502 (17) |
N2—C6 | 1.271 (5) | C7B—C8B | 1.563 (18) |
N2—C17 | 1.436 (4) | C8B—H8B1 | 0.9800 |
N3—C23 | 1.142 (4) | C8B—H8B2 | 0.9800 |
N4—C26 | 1.139 (5) | C8B—H8B3 | 0.9800 |
C1—C6 | 1.495 (5) | C9B—H9B1 | 0.9800 |
C1—C2 | 1.509 (5) | C9B—H9B2 | 0.9800 |
C2—C10 | 1.465 (5) | C9B—H9B3 | 0.9800 |
C2—C3 | 1.558 (5) | C10B—H10D | 0.9800 |
C2—C7 | 1.575 (6) | C10B—H10E | 0.9800 |
C3—C4 | 1.531 (7) | C10B—H10F | 0.9800 |
C3—H3A | 0.9900 | C11—C12 | 1.368 (5) |
C3—H3B | 0.9900 | C11—C16 | 1.381 (4) |
C4—C5 | 1.552 (6) | C12—C13 | 1.383 (5) |
C4—H4A | 0.9900 | C12—H12 | 0.9500 |
C4—H4B | 0.9900 | C13—C14 | 1.374 (6) |
C5—C6 | 1.507 (5) | C13—H13 | 0.9500 |
C5—C7 | 1.517 (6) | C14—C15 | 1.372 (6) |
C5—H5 | 1.0000 | C14—H14 | 0.9500 |
C5—H10F | 1.4967 | C15—C16 | 1.393 (5) |
C7—C9 | 1.538 (6) | C15—H15 | 0.9500 |
C7—C8 | 1.542 (7) | C16—H16 | 0.9500 |
C8—H8A | 0.9800 | C17—C18 | 1.375 (5) |
C8—H8B | 0.9800 | C17—C22 | 1.394 (4) |
C8—H8C | 0.9800 | C18—C19 | 1.390 (5) |
C9—H9A | 0.9800 | C18—H18 | 0.9500 |
C9—H9B | 0.9800 | C19—C20 | 1.386 (4) |
C9—H9C | 0.9800 | C19—H19 | 0.9500 |
C10—H10A | 0.9800 | C20—C21 | 1.368 (5) |
C10—H10B | 0.9800 | C20—H20 | 0.9500 |
C10—H10C | 0.9800 | C21—C22 | 1.390 (5) |
C1B—C2B | 1.490 (17) | C21—H21 | 0.9500 |
C1B—C6B | 1.511 (18) | C22—H22 | 0.9500 |
C2B—C10B | 1.410 (16) | C23—C24 | 1.435 (4) |
C2B—C3B | 1.533 (17) | C24—C25 | 1.441 (4) |
C2B—C7B | 1.595 (17) | C24—H24 | 0.9490 |
C3B—C4B | 1.574 (18) | C25—C26 | 1.433 (4) |
C3B—H3B1 | 0.9900 | C25—H25 | 0.9426 |
C24—Pd1—C25 | 41.31 (11) | C6B—C5B—C4B | 103.0 (16) |
C24—Pd1—N1 | 119.61 (11) | C7B—C5B—H5B | 114.6 |
C25—Pd1—N1 | 159.63 (10) | C6B—C5B—H5B | 114.6 |
C24—Pd1—N2 | 162.56 (11) | C4B—C5B—H5B | 114.6 |
C25—Pd1—N2 | 121.33 (11) | N1—C6B—C1B | 116.7 (18) |
N1—Pd1—N2 | 77.31 (9) | N1—C6B—C5B | 139 (2) |
C1—N1—C6B | 16.1 (15) | C1B—C6B—C5B | 104.4 (15) |
C1—N1—C11 | 121.8 (3) | C5B—C7B—C9B | 117.6 (16) |
C6B—N1—C11 | 123.2 (11) | C5B—C7B—C8B | 109 (2) |
C1—N1—Pd1 | 113.2 (2) | C9B—C7B—C8B | 116 (2) |
C6B—N1—Pd1 | 107.8 (12) | C5B—C7B—C2B | 93.7 (11) |
C11—N1—Pd1 | 124.65 (19) | C9B—C7B—C2B | 113.2 (16) |
C1B—N2—C6 | 21.2 (13) | C8B—C7B—C2B | 105 (2) |
C1B—N2—C17 | 120.5 (11) | C7B—C8B—H8B1 | 109.5 |
C6—N2—C17 | 121.8 (3) | C7B—C8B—H8B2 | 109.5 |
C1B—N2—Pd1 | 108.8 (11) | H8B1—C8B—H8B2 | 109.5 |
C6—N2—Pd1 | 112.9 (2) | C7B—C8B—H8B3 | 109.5 |
C17—N2—Pd1 | 125.17 (19) | H8B1—C8B—H8B3 | 109.5 |
N1—C1—C6 | 117.4 (3) | H8B2—C8B—H8B3 | 109.5 |
N1—C1—C2 | 137.3 (4) | C7B—C9B—H9B1 | 109.5 |
C6—C1—C2 | 105.3 (3) | C7B—C9B—H9B2 | 109.5 |
C10—C2—C1 | 120.0 (3) | H9B1—C9B—H9B2 | 109.5 |
C10—C2—C3 | 113.4 (4) | C7B—C9B—H9B3 | 109.5 |
C1—C2—C3 | 104.0 (3) | H9B1—C9B—H9B3 | 109.5 |
C10—C2—C7 | 116.6 (3) | H9B2—C9B—H9B3 | 109.5 |
C1—C2—C7 | 99.2 (3) | C2B—C10B—H10D | 116.5 |
C3—C2—C7 | 100.9 (3) | C2B—C10B—H10E | 92.7 |
C4—C3—C2 | 104.7 (3) | H10D—C10B—H10E | 109.5 |
C4—C3—H3A | 110.8 | C2B—C10B—H10F | 117.7 |
C2—C3—H3A | 110.8 | H10D—C10B—H10F | 109.5 |
C4—C3—H3B | 110.8 | H10E—C10B—H10F | 109.5 |
C2—C3—H3B | 110.8 | C12—C11—C16 | 120.5 (3) |
H3A—C3—H3B | 108.9 | C12—C11—N1 | 120.5 (3) |
C3—C4—C5 | 103.5 (3) | C16—C11—N1 | 119.0 (3) |
C3—C4—H4A | 111.1 | C11—C12—C13 | 120.4 (3) |
C5—C4—H4A | 111.1 | C11—C12—H12 | 119.8 |
C3—C4—H4B | 111.1 | C13—C12—H12 | 119.8 |
C5—C4—H4B | 111.1 | C14—C13—C12 | 119.8 (4) |
H4A—C4—H4B | 109.0 | C14—C13—H13 | 120.1 |
C6—C5—C7 | 100.1 (3) | C12—C13—H13 | 120.1 |
C6—C5—C4 | 105.3 (3) | C15—C14—C13 | 120.0 (3) |
C7—C5—C4 | 103.0 (4) | C15—C14—H14 | 120.0 |
C6—C5—H5 | 115.5 | C13—C14—H14 | 120.0 |
C7—C5—H5 | 115.5 | C14—C15—C16 | 120.6 (3) |
C4—C5—H5 | 115.5 | C14—C15—H15 | 119.7 |
C6—C5—H10F | 125.9 | C16—C15—H15 | 119.7 |
C7—C5—H10F | 133.3 | C11—C16—C15 | 118.8 (3) |
C4—C5—H10F | 74.9 | C11—C16—H16 | 120.6 |
H5—C5—H10F | 40.9 | C15—C16—H16 | 120.6 |
N2—C6—C1 | 118.7 (3) | C18—C17—C22 | 120.8 (3) |
N2—C6—C5 | 136.0 (4) | C18—C17—N2 | 117.5 (2) |
C1—C6—C5 | 105.2 (3) | C22—C17—N2 | 121.7 (3) |
C5—C7—C9 | 113.6 (4) | C17—C18—C19 | 120.2 (3) |
C5—C7—C8 | 111.6 (5) | C17—C18—H18 | 119.9 |
C9—C7—C8 | 110.8 (6) | C19—C18—H18 | 119.9 |
C5—C7—C2 | 95.4 (3) | C20—C19—C18 | 119.2 (3) |
C9—C7—C2 | 111.8 (4) | C20—C19—H19 | 120.4 |
C8—C7—C2 | 112.8 (6) | C18—C19—H19 | 120.4 |
N2—C1B—C2B | 136.3 (19) | C21—C20—C19 | 120.6 (3) |
N2—C1B—C6B | 119.6 (17) | C21—C20—H20 | 119.7 |
C2B—C1B—C6B | 103.8 (15) | C19—C20—H20 | 119.7 |
C10B—C2B—C1B | 125.9 (16) | C20—C21—C22 | 121.0 (3) |
C10B—C2B—C3B | 121.5 (15) | C20—C21—H21 | 119.5 |
C1B—C2B—C3B | 105.8 (15) | C22—C21—H21 | 119.5 |
C10B—C2B—C7B | 94.6 (12) | C21—C22—C17 | 118.3 (3) |
C1B—C2B—C7B | 100.2 (13) | C21—C22—H22 | 120.8 |
C3B—C2B—C7B | 101.8 (13) | C17—C22—H22 | 120.8 |
C2B—C3B—C4B | 104.3 (13) | N3—C23—C24 | 179.0 (3) |
C2B—C3B—H3B1 | 110.9 | C23—C24—C25 | 119.7 (3) |
C4B—C3B—H3B1 | 110.9 | C23—C24—Pd1 | 111.0 (2) |
C2B—C3B—H3B2 | 110.9 | C25—C24—Pd1 | 69.71 (15) |
C4B—C3B—H3B2 | 110.9 | C23—C24—H24 | 117.4 |
H3B1—C3B—H3B2 | 108.9 | C25—C24—H24 | 115.6 |
C5B—C4B—C3B | 100.7 (13) | Pd1—C24—H24 | 113.6 |
C5B—C4B—H4B1 | 111.6 | C26—C25—C24 | 118.4 (3) |
C3B—C4B—H4B1 | 111.6 | C26—C25—Pd1 | 116.2 (2) |
C5B—C4B—H4B2 | 111.6 | C24—C25—Pd1 | 68.99 (17) |
C3B—C4B—H4B2 | 111.6 | C26—C25—H25 | 111.7 |
H4B1—C4B—H4B2 | 109.4 | C24—C25—H25 | 122.1 |
C7B—C5B—C6B | 100.7 (14) | Pd1—C25—H25 | 112.5 |
C7B—C5B—C4B | 108.0 (13) | N4—C26—C25 | 179.1 (4) |
C24—Pd1—N1—C1 | −168.8 (2) | C10B—C2B—C3B—C4B | −139.0 (18) |
C25—Pd1—N1—C1 | −151.0 (3) | C1B—C2B—C3B—C4B | 68.2 (19) |
N2—Pd1—N1—C1 | 6.7 (2) | C7B—C2B—C3B—C4B | −36.1 (18) |
C24—Pd1—N1—C6B | −152.6 (15) | C2B—C3B—C4B—C5B | 5 (2) |
C25—Pd1—N1—C6B | −134.8 (15) | C3B—C4B—C5B—C7B | 31 (2) |
N2—Pd1—N1—C6B | 22.9 (15) | C3B—C4B—C5B—C6B | −74.9 (18) |
C24—Pd1—N1—C11 | 4.4 (3) | C1—N1—C6B—C1B | 95 (5) |
C25—Pd1—N1—C11 | 22.2 (5) | C11—N1—C6B—C1B | −174.5 (17) |
N2—Pd1—N1—C11 | 179.9 (3) | Pd1—N1—C6B—C1B | −17 (3) |
C24—Pd1—N2—C1B | 139.1 (14) | C1—N1—C6B—C5B | −90 (6) |
C25—Pd1—N2—C1B | 143.5 (14) | C11—N1—C6B—C5B | 0 (5) |
N1—Pd1—N2—C1B | −27.5 (14) | Pd1—N1—C6B—C5B | 158 (3) |
C24—Pd1—N2—C6 | 161.4 (3) | N2—C1B—C6B—N1 | −8 (4) |
C25—Pd1—N2—C6 | 165.9 (2) | C2B—C1B—C6B—N1 | 177 (2) |
N1—Pd1—N2—C6 | −5.2 (2) | N2—C1B—C6B—C5B | 176 (2) |
C24—Pd1—N2—C17 | −14.5 (5) | C2B—C1B—C6B—C5B | 1 (3) |
C25—Pd1—N2—C17 | −10.1 (3) | C7B—C5B—C6B—N1 | 147 (4) |
N1—Pd1—N2—C17 | 178.8 (2) | C4B—C5B—C6B—N1 | −102 (4) |
C6B—N1—C1—C6 | −81 (4) | C7B—C5B—C6B—C1B | −38 (2) |
C11—N1—C1—C6 | 179.5 (3) | C4B—C5B—C6B—C1B | 74 (2) |
Pd1—N1—C1—C6 | −7.1 (4) | C6B—C5B—C7B—C9B | −63 (2) |
C6B—N1—C1—C2 | 96 (4) | C4B—C5B—C7B—C9B | −170.2 (18) |
C11—N1—C1—C2 | −3.7 (6) | C6B—C5B—C7B—C8B | 163 (2) |
Pd1—N1—C1—C2 | 169.7 (4) | C4B—C5B—C7B—C8B | 56 (3) |
N1—C1—C2—C10 | −16.3 (7) | C6B—C5B—C7B—C2B | 55.9 (16) |
C6—C1—C2—C10 | 160.8 (3) | C4B—C5B—C7B—C2B | −51.6 (16) |
N1—C1—C2—C3 | 111.9 (5) | C10B—C2B—C7B—C5B | 176.2 (14) |
C6—C1—C2—C3 | −71.0 (4) | C1B—C2B—C7B—C5B | −56.1 (15) |
N1—C1—C2—C7 | −144.3 (4) | C3B—C2B—C7B—C5B | 52.6 (14) |
C6—C1—C2—C7 | 32.8 (3) | C10B—C2B—C7B—C9B | −61.7 (18) |
C10—C2—C3—C4 | −158.1 (3) | C1B—C2B—C7B—C9B | 66.1 (19) |
C1—C2—C3—C4 | 69.8 (4) | C3B—C2B—C7B—C9B | 174.8 (17) |
C7—C2—C3—C4 | −32.7 (4) | C10B—C2B—C7B—C8B | 66 (2) |
C2—C3—C4—C5 | −0.1 (4) | C1B—C2B—C7B—C8B | −166 (2) |
C3—C4—C5—C6 | −69.8 (4) | C3B—C2B—C7B—C8B | −58 (2) |
C3—C4—C5—C7 | 34.6 (4) | C1—N1—C11—C12 | −80.3 (4) |
C1B—N2—C6—C1 | 86 (3) | C6B—N1—C11—C12 | −99.3 (18) |
C17—N2—C6—C1 | 179.5 (3) | Pd1—N1—C11—C12 | 107.1 (3) |
Pd1—N2—C6—C1 | 3.4 (4) | C1—N1—C11—C16 | 102.6 (4) |
C1B—N2—C6—C5 | −89 (3) | C6B—N1—C11—C16 | 83.6 (18) |
C17—N2—C6—C5 | 4.5 (6) | Pd1—N1—C11—C16 | −70.1 (4) |
Pd1—N2—C6—C5 | −171.6 (3) | C16—C11—C12—C13 | −2.1 (6) |
N1—C1—C6—N2 | 2.6 (5) | N1—C11—C12—C13 | −179.2 (3) |
C2—C1—C6—N2 | −175.1 (3) | C11—C12—C13—C14 | 0.2 (6) |
N1—C1—C6—C5 | 179.0 (3) | C12—C13—C14—C15 | 0.6 (6) |
C2—C1—C6—C5 | 1.2 (4) | C13—C14—C15—C16 | 0.5 (6) |
C7—C5—C6—N2 | 139.1 (4) | C12—C11—C16—C15 | 3.1 (5) |
C4—C5—C6—N2 | −114.3 (5) | N1—C11—C16—C15 | −179.7 (3) |
C7—C5—C6—C1 | −36.3 (4) | C14—C15—C16—C11 | −2.3 (6) |
C4—C5—C6—C1 | 70.3 (4) | C1B—N2—C17—C18 | −118.4 (16) |
C6—C5—C7—C9 | −61.8 (4) | C6—N2—C17—C18 | −143.2 (3) |
C4—C5—C7—C9 | −170.2 (4) | Pd1—N2—C17—C18 | 32.4 (4) |
C6—C5—C7—C8 | 172.0 (6) | C1B—N2—C17—C22 | 64.0 (16) |
C4—C5—C7—C8 | 63.6 (7) | C6—N2—C17—C22 | 39.2 (4) |
C6—C5—C7—C2 | 54.9 (3) | Pd1—N2—C17—C22 | −145.2 (2) |
C4—C5—C7—C2 | −53.5 (3) | C22—C17—C18—C19 | −2.1 (5) |
C10—C2—C7—C5 | 175.8 (3) | N2—C17—C18—C19 | −179.8 (3) |
C1—C2—C7—C5 | −53.8 (3) | C17—C18—C19—C20 | 0.4 (5) |
C3—C2—C7—C5 | 52.5 (3) | C18—C19—C20—C21 | 0.9 (5) |
C10—C2—C7—C9 | −66.1 (5) | C19—C20—C21—C22 | −0.6 (5) |
C1—C2—C7—C9 | 64.3 (4) | C20—C21—C22—C17 | −1.1 (5) |
C3—C2—C7—C9 | 170.6 (3) | C18—C17—C22—C21 | 2.4 (4) |
C10—C2—C7—C8 | 59.6 (7) | N2—C17—C22—C21 | 180.0 (3) |
C1—C2—C7—C8 | −170.0 (6) | C25—Pd1—C24—C23 | −115.0 (3) |
C3—C2—C7—C8 | −63.7 (6) | N1—Pd1—C24—C23 | 55.7 (3) |
C6—N2—C1B—C2B | 96 (4) | N2—Pd1—C24—C23 | −109.3 (4) |
C17—N2—C1B—C2B | −4 (4) | N1—Pd1—C24—C25 | 170.71 (16) |
Pd1—N2—C1B—C2B | −159 (3) | N2—Pd1—C24—C25 | 5.7 (5) |
C6—N2—C1B—C6B | −77 (3) | C23—C24—C25—C26 | −147.5 (3) |
C17—N2—C1B—C6B | −177.4 (19) | Pd1—C24—C25—C26 | 109.2 (3) |
Pd1—N2—C1B—C6B | 28 (3) | C23—C24—C25—Pd1 | 103.3 (3) |
N2—C1B—C2B—C10B | −37 (4) | C24—Pd1—C25—C26 | −112.3 (3) |
C6B—C1B—C2B—C10B | 137 (2) | N1—Pd1—C25—C26 | −136.0 (3) |
N2—C1B—C2B—C3B | 114 (3) | N2—Pd1—C25—C26 | 69.7 (3) |
C6B—C1B—C2B—C3B | −72 (2) | N1—Pd1—C25—C24 | −23.8 (4) |
N2—C1B—C2B—C7B | −140 (3) | N2—Pd1—C25—C24 | −178.00 (16) |
C6B—C1B—C2B—C7B | 34 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3A···N3i | 0.99 | 2.58 | 3.566 (6) | 174 |
C4—H4B···N4ii | 0.99 | 2.60 | 3.429 (5) | 141 |
Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) −x, −y, −z. |
Experimental details
Crystal data | |
Chemical formula | [Pd(C22H24N2)(C4H2N2)] |
Mr | 500.91 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 150 |
a, b, c (Å) | 11.8073 (13), 10.0751 (12), 21.453 (3) |
β (°) | 116.024 (8) |
V (Å3) | 2293.3 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.83 |
Crystal size (mm) | 0.55 × 0.25 × 0.25 |
Data collection | |
Diffractometer | Enraf-Nonius CAD4 |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7053, 5235, 4462 |
Rint | 0.076 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.086, 1.04 |
No. of reflections | 5235 |
No. of parameters | 317 |
No. of restraints | 33 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.83, −1.46 |
Computer programs: Locally modified CAD4-Version 5 Software (Enraf-Nonius, 1989), SET4 (de Boer & Duisenberg, 1984), HELENA (Spek, 1997), DIRDIF99 (Beurskens et al. 1999), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2000), PLATON.
Pd1—C24 | 2.037 (3) | N2—C6 | 1.271 (5) |
Pd1—C25 | 2.047 (3) | C1—C6 | 1.495 (5) |
Pd1—N1 | 2.157 (2) | C23—C24 | 1.435 (4) |
Pd1—N2 | 2.157 (2) | C24—C25 | 1.441 (4) |
N1—C1 | 1.281 (5) | C25—C26 | 1.433 (4) |
C24—Pd1—C25 | 41.31 (11) | N3—C23—C24 | 179.0 (3) |
C25—Pd1—N1 | 159.63 (10) | C23—C24—C25 | 119.7 (3) |
C24—Pd1—N2 | 162.56 (11) | C26—C25—C24 | 118.4 (3) |
N1—Pd1—N2 | 77.31 (9) | N4—C26—C25 | 179.1 (4) |
C1—N1—C11—C12 | −80.3 (4) | C6—N2—C17—C18 | −143.2 (3) |
C1—N1—C11—C16 | 102.6 (4) | C6—N2—C17—C22 | 39.2 (4) |
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Group ten complexes of chiral bicyclic nitrogen ligands have been used in the study of homogeneous hydrogenation, polymerization and other catalytic reactions (Schleis et al., 1998; van Asselt et al., 1997; van Asselt & Elsevier, 1992). The reactivity and selectivity in these zerovalent complexes can be controlled by varying the groups on the nitrogen or by changing the electron-poor alkene (van Asselt et al., 1994).
The Y-shaped trigonal-planar geometry of the title complex, (I), is shown in Figure 1 with selected geometric parameters presented in Table 1. The palladium centre is coordinated to two imine nitrogen atoms attached to a camphor backbone, and to the alkenic carbon atoms of fumaronitrile. The metal distances [Pd—N 2.157 (2) and 2.157 (2) Å, Pd—C 2.037 (3), 2.047 (3) Å] are comparable to those found in dimethyl-{2-(phenylimino)-3- (2,6-dimethylphenylimino)-1,7,7-trimethylbicyclo(2.2.1)heptane-2,3-diylidene}- palladium(II), (II) (Schleis et al., 1998). The metal distances in (I) are more symmetrical than in (II) due to the more crowded coordination sphere of the 2,6-dimethylphenyl group in the latter. The phenyl rings in (I) are tilted, relative to the PdN2C2 plane, to a greater extent than in (II) [dihedral angle between aryl rings and PdN2C2 plane are 74.54 (16) and 35.54 (14)° in (I), compared to 69.6 and 87.6° in (II)]. Presumably there are unfavourable interactions between the methyl groups on either the camphor backbone or phenyl ring in (II) [the latter being absent in (I)]. \sch
The disposition of the nitrogen atoms ensures a cis orientation at the metal; constrained σ-donating ligands are known to induce small bite angles in similar systems (Tatsumi et al., 1981). The N1—Pd1—N2 bite angle of 77.31 (9)° is comparable to that found in (II) [77.2 (1)°] and is of a similar magnitude to related complexes in the Cambridge Structural Database (Allen & Kennard, 1993). The imine C═N bonds of 1.281 (5) and 1.271 (4) Å are marginally different, one of them is slightly longer than those found in (II) [1.272 (5) and 1.273 (5) Å].
The C═C bond distance in the fumaronitrile ligand [1.441 (4) Å] is longer than in the free ligand [1.249 (10) Å, Britton & Gleason, 1982], due to coordination to palladium; the π-back bond donation from the filled metal orbital to the empty π* orbital in the alkene causes an elongation of this bond. There is a concomitant shortening of the C—C(N) single bonds from 1.480 (8) Å in the free ligand to 1.435 (4)/1.433 (4) Å in (I). The secondary effect (of ligand coordination) is a bending of the substituents away from the metal plane, which has been quantified by Ittel & Ibers (1976). Two angles, designated α and β/β', describe deviations of the alkene ligands from the metal plane. Their values, 66.3 (3) and 57.7 (3)/55.8 (3)°, correlate well with those in other bidentate systems, for example 59.3 (8), 60.8 (6)/59.9 (5)° for the tetracyanoethane ligand in [Pd(C23H16N6)] (Kranenburg et al., 1997). The olefinic carbon atoms are notionally sp2 hydridized, as shown by the C—C—C angles of 119.7 (3) and 118.6 (3)°. The cyano groups are linear [C—C≡N 179.0 (3) and 179.3 (4)°] and form very weak C—H···N hydrogen bond contacts, H3A···N3i of 2.58 Å, H4B···N4ii of 2.60 Å [symmetry operators (i) x, 1/2 - y, -1/2 + z; (ii) -x, -y, -z].