metal-organic compounds
Dichlorido{(E)-2,4,6-trimethyl-N-[phenyl(2-pyridyl)methylidene]aniline-κ2N,N′}palladium(II)
aNano-Powder & Thin Film Technology Center, ITRI South, Tainan 709, Taiwan, Republic of China, and bDepartment of Chemistry, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
*Correspondence e-mail: mmhsueh@itri.org.tw
The title complex, [PdCl2(C21H20N2)], contains a PdII atom in a slightly distorted square-planar coordination environment defined by two N atoms from one 2,4,6-trimethyl-N-[phenyl(2-pyridyl)methylidene]aniline ligand and two Cl atoms, forming a five-membered ring (N—Pd—N—C—C).
Related literature
For the synthesis of pyridyl-imine ligands, see: Meneghetti et al. (1999). For the design and synthesis of metal-organic frameworks, see: Lai et al. (2005); Pelagattia et al. (2005); Zhang et al. (2008). For related structures, see: Hsueh et al. (2006); Zhang et al. (2008). For the application of the title compound in Suzuki–Miyaura reactions, see: Li (2003); Miyaura & Suzuki (1995); Na et al. (2004); Nicolaou et al. (2005); Rajagopal et al. (2002); Tomioka et al. (2004).
Experimental
Crystal data
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Data collection: SMART (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; 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.
Supporting information
https://doi.org/10.1107/S1600536810016466/pk2244sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810016466/pk2244Isup2.hkl
The title compound was prepared by the reaction of palladium(II) dichloride (17.733 mg, 0.1 mmol) with (E)-2,4,6-trimethyl-N-(phenyl(pyridin-2-yl)methylene)aniline (30.016 mg, 0.1 mmol) in EtOH (20 ml). The mixture was stirred at room temperature for 24 h. The mixture turned yellow immediately. After removal of solvents, dichloromethane (20 ml) was added and the solution was filtered through Celite. The filtrate was slowly evaporated at room temperature to yield yellow crystals suitable for X-ray analysis. Yield: 41.084 mg (86%). Analysis calculated for C21H20Cl2N2Pd: C 52.80, H 4.22, N 5.86%; found: C 52.65, H 4.17, N 5.93%.
All H atoms were initially located in a difference Fourier map. The methyl H atoms were then constrained to an ideal geometry with C—H distances of 0.96 Å and Uiso(H) = 1.5Ueq(C), but each group was allowed to rotate freely about its C—C bond. All other H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C—H distances in the range 0.95–1.00 Å and Uiso(H) = 1.2Ueq(C).
Recently, palladium-catalyzed Suzuki-Miyaura reactions involving cross-coupling of aryl halides with aryl
have emerged as the most important synthetic methods for the preparation of biaryl compounds (Miyaura et al., 1995; Na et al., 2004; Rajagopal et al., 2002; Li 2003; Tomioka et al., 2004; Nicolaou et al., 2005). Thus, because of its utility as an important synthetic methodology, a significant amount of research focus had been devoted to designing improved catalysts for the Suzuki-Miyaura cross-coupling reaction. It is noteworthy that there has been a continuing interest in the further development of more efficient and selective catalytic systems for the synthesis of biaryls. However, only a few examples of N,N' pyridyl-imine palladium complexes have been reported as catalysts in coupling reaction (Lai et al., 2005; Pelagattia et al., 2005). Herein, we report the synthesis and of the title palladium (II) complex that is certainly a potential catalyst in cross-coupling reactions.The structure of the title compound is a mononuclear configuration with the metal center bound to two N atoms (one from the imine group and one from the pyridine ring) and two Cl atoms (Fig. 1). The coordination geometry around PdII atom is slightly distorted square planar, and the distances of Pd(1)—N(1) and Pd(1)—N(2) are 2.025 (2) and 2.033 (2) Å, respectively. It is noticed that the trans angles (N2—Pd—Cl1 and N1—Pd—Cl2) in the PdN2Cl2 core do not deviate more than 8° from the ideal value of 180°. Moreover, the planes of the pyridine (N1—C1—C2—C3—C4—C5) and phenyl rings (C8—C9—C10—C11—C12 and C13—C14—C15—C16—C17—C18) are close to perpendicular, and the dihedral angles between them are 80.9 (3) and 82.8 (3)°, respectively. All bond distances and bond angles lie within normal ranges, which are essentially similar to the pyridyl-imine palladium (II) complex (Hsueh et al., 2006; Zhang et al., 2008).
For the synthesis of pyridyl-imine ligands, see: Meneghetti et al. (1999). For the design and synthesis of metal-organic frameworks, see: Lai et al. (2005); Pelagattia et al. (2005); Zhang et al. (2008). For related structures, see: Hsueh et al. (2006); Zhang et al. (2008). For the application of the title compound in Suzuki–Miyaura reactions, see: Li (2003); Miyaura & Suzuki (1995); Na et al. (2004); Nicolaou et al. (2005); Rajagopal et al. (2002); Tomioka et al. (2004).
Data collection: SMART (Bruker, 2007); cell
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).Fig. 1. A view of the molecular structure of the title compound with displacement ellipsoids shown at the 30% probability level. |
[PdCl2(C21H20N2)] | F(000) = 960 |
Mr = 477.69 | Dx = 1.581 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 4812 reflections |
a = 7.4807 (6) Å | θ = 2.9–2.6° |
b = 15.1483 (13) Å | µ = 1.20 mm−1 |
c = 17.7147 (15) Å | T = 298 K |
V = 2007.4 (3) Å3 | Parallelpiped, yellow |
Z = 4 | 0.35 × 0.33 × 0.22 mm |
Bruker SMART 1000 CCD diffractometer | 3956 independent reflections |
Radiation source: fine-focus sealed tube | 3871 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.024 |
φ and ω scans | θmax = 26.1°, θmin = 2.7° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −7→9 |
Tmin = 0.738, Tmax = 1.000 | k = −16→18 |
11233 measured reflections | l = −21→15 |
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)] = 0.019 | H-atom parameters constrained |
wR(F2) = 0.052 | w = 1/[σ2(Fo2) + (0.040P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.01 | (Δ/σ)max = 0.002 |
3956 reflections | Δρmax = 0.20 e Å−3 |
238 parameters | Δρmin = −0.52 e Å−3 |
0 restraints | Absolute structure: Flack (1983), 1670 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.02 (2) |
[PdCl2(C21H20N2)] | V = 2007.4 (3) Å3 |
Mr = 477.69 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 7.4807 (6) Å | µ = 1.20 mm−1 |
b = 15.1483 (13) Å | T = 298 K |
c = 17.7147 (15) Å | 0.35 × 0.33 × 0.22 mm |
Bruker SMART 1000 CCD diffractometer | 3956 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 3871 reflections with I > 2σ(I) |
Tmin = 0.738, Tmax = 1.000 | Rint = 0.024 |
11233 measured reflections |
R[F2 > 2σ(F2)] = 0.019 | H-atom parameters constrained |
wR(F2) = 0.052 | Δρmax = 0.20 e Å−3 |
S = 1.01 | Δρmin = −0.52 e Å−3 |
3956 reflections | Absolute structure: Flack (1983), 1670 Friedel pairs |
238 parameters | Absolute structure parameter: 0.02 (2) |
0 restraints |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 | ||
Pd1 | 0.262038 (18) | 0.612368 (9) | 0.476057 (8) | 0.02890 (6) | |
Cl1 | 0.41648 (8) | 0.68412 (4) | 0.56891 (3) | 0.04639 (14) | |
Cl2 | 0.19993 (9) | 0.49999 (4) | 0.55734 (3) | 0.04722 (15) | |
N1 | 0.3065 (2) | 0.70552 (11) | 0.39625 (10) | 0.0321 (4) | |
N2 | 0.1064 (2) | 0.56451 (11) | 0.39132 (10) | 0.0308 (3) | |
C1 | 0.4227 (3) | 0.77241 (15) | 0.39906 (14) | 0.0424 (5) | |
H1A | 0.4974 | 0.7776 | 0.4408 | 0.051* | |
C2 | 0.4354 (4) | 0.83417 (17) | 0.34181 (16) | 0.0527 (6) | |
H2A | 0.5191 | 0.8794 | 0.3446 | 0.063* | |
C3 | 0.3231 (4) | 0.82774 (16) | 0.28102 (14) | 0.0498 (6) | |
H3A | 0.3274 | 0.8696 | 0.2426 | 0.060* | |
C4 | 0.2022 (3) | 0.75775 (15) | 0.27725 (13) | 0.0418 (5) | |
H4A | 0.1258 | 0.7518 | 0.2362 | 0.050* | |
C5 | 0.1982 (3) | 0.69758 (13) | 0.33577 (11) | 0.0314 (4) | |
C6 | 0.0837 (3) | 0.61804 (13) | 0.33544 (11) | 0.0302 (4) | |
C7 | −0.0452 (3) | 0.60379 (14) | 0.27275 (12) | 0.0344 (4) | |
C8 | −0.2010 (4) | 0.65290 (18) | 0.27039 (14) | 0.0493 (6) | |
H8A | −0.2234 | 0.6950 | 0.3074 | 0.059* | |
C9 | −0.3241 (4) | 0.6395 (2) | 0.21285 (17) | 0.0622 (8) | |
H9A | −0.4306 | 0.6712 | 0.2123 | 0.075* | |
C10 | −0.2883 (4) | 0.5791 (2) | 0.15659 (15) | 0.0594 (7) | |
H10A | −0.3704 | 0.5701 | 0.1179 | 0.071* | |
C11 | −0.1303 (5) | 0.5321 (2) | 0.15769 (16) | 0.0674 (8) | |
H11A | −0.1052 | 0.4924 | 0.1191 | 0.081* | |
C12 | −0.0104 (4) | 0.54350 (19) | 0.21532 (15) | 0.0526 (7) | |
H12A | 0.0948 | 0.5108 | 0.2161 | 0.063* | |
C13 | 0.0126 (3) | 0.48204 (13) | 0.39711 (12) | 0.0316 (4) | |
C14 | −0.1580 (3) | 0.48020 (14) | 0.42893 (12) | 0.0364 (5) | |
C15 | −0.2372 (3) | 0.39752 (15) | 0.43887 (13) | 0.0451 (5) | |
H15A | −0.3513 | 0.3946 | 0.4596 | 0.054* | |
C16 | −0.1526 (4) | 0.32013 (15) | 0.41912 (13) | 0.0513 (7) | |
C17 | 0.0171 (4) | 0.32429 (15) | 0.38896 (14) | 0.0469 (6) | |
H17A | 0.0757 | 0.2723 | 0.3761 | 0.056* | |
C18 | 0.1027 (3) | 0.40533 (14) | 0.37726 (13) | 0.0392 (5) | |
C19 | −0.2509 (4) | 0.56211 (18) | 0.45550 (16) | 0.0563 (6) | |
H19A | −0.3451 | 0.5464 | 0.4897 | 0.084* | |
H19B | −0.3004 | 0.5928 | 0.4129 | 0.084* | |
H19C | −0.1667 | 0.5997 | 0.4808 | 0.084* | |
C20 | −0.2428 (7) | 0.23101 (19) | 0.43118 (19) | 0.0839 (11) | |
H20A | −0.3672 | 0.2399 | 0.4421 | 0.126* | |
H20B | −0.1871 | 0.2011 | 0.4727 | 0.126* | |
H20C | −0.2310 | 0.1959 | 0.3863 | 0.126* | |
C21 | 0.2913 (4) | 0.40809 (18) | 0.34700 (18) | 0.0607 (7) | |
H21A | 0.3515 | 0.4592 | 0.3664 | 0.091* | |
H21B | 0.2882 | 0.4109 | 0.2929 | 0.091* | |
H21C | 0.3541 | 0.3559 | 0.3625 | 0.091* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Pd1 | 0.02800 (8) | 0.02850 (8) | 0.03020 (9) | 0.00077 (6) | −0.00266 (6) | −0.00482 (5) |
Cl1 | 0.0497 (3) | 0.0470 (3) | 0.0424 (3) | −0.0033 (2) | −0.0130 (3) | −0.0131 (2) |
Cl2 | 0.0583 (4) | 0.0409 (3) | 0.0424 (3) | −0.0035 (2) | −0.0076 (3) | 0.0079 (2) |
N1 | 0.0311 (9) | 0.0286 (8) | 0.0366 (9) | −0.0025 (7) | 0.0017 (7) | −0.0065 (7) |
N2 | 0.0283 (8) | 0.0309 (8) | 0.0331 (9) | −0.0014 (7) | 0.0009 (7) | −0.0058 (7) |
C1 | 0.0406 (12) | 0.0392 (12) | 0.0472 (13) | −0.0095 (10) | −0.0008 (11) | −0.0067 (10) |
C2 | 0.0574 (16) | 0.0424 (13) | 0.0583 (15) | −0.0211 (12) | 0.0032 (13) | −0.0013 (12) |
C3 | 0.0617 (16) | 0.0399 (13) | 0.0478 (13) | −0.0088 (12) | 0.0065 (12) | 0.0057 (11) |
C4 | 0.0473 (14) | 0.0419 (12) | 0.0360 (11) | −0.0059 (10) | −0.0007 (10) | 0.0045 (9) |
C5 | 0.0307 (10) | 0.0310 (10) | 0.0325 (10) | −0.0008 (8) | 0.0022 (8) | −0.0056 (8) |
C6 | 0.0313 (10) | 0.0280 (9) | 0.0313 (10) | 0.0004 (9) | 0.0013 (8) | −0.0044 (8) |
C7 | 0.0379 (11) | 0.0348 (10) | 0.0306 (10) | −0.0073 (9) | −0.0021 (8) | −0.0017 (8) |
C8 | 0.0466 (15) | 0.0562 (14) | 0.0450 (13) | 0.0096 (12) | −0.0083 (11) | −0.0094 (11) |
C9 | 0.0431 (14) | 0.079 (2) | 0.0646 (18) | 0.0041 (13) | −0.0127 (13) | 0.0015 (15) |
C10 | 0.0598 (18) | 0.0728 (18) | 0.0457 (14) | −0.0164 (14) | −0.0216 (13) | −0.0035 (13) |
C11 | 0.076 (2) | 0.082 (2) | 0.0443 (15) | −0.0021 (17) | −0.0119 (15) | −0.0287 (15) |
C12 | 0.0534 (15) | 0.0607 (16) | 0.0439 (14) | 0.0069 (12) | −0.0049 (11) | −0.0176 (12) |
C13 | 0.0360 (11) | 0.0277 (10) | 0.0309 (10) | −0.0030 (8) | −0.0043 (8) | −0.0030 (8) |
C14 | 0.0372 (11) | 0.0379 (11) | 0.0342 (11) | −0.0042 (9) | −0.0007 (9) | −0.0016 (9) |
C15 | 0.0440 (12) | 0.0521 (13) | 0.0392 (11) | −0.0149 (12) | −0.0013 (10) | 0.0018 (9) |
C16 | 0.081 (2) | 0.0354 (12) | 0.0378 (12) | −0.0186 (12) | −0.0085 (12) | 0.0033 (10) |
C17 | 0.0682 (17) | 0.0292 (11) | 0.0433 (13) | −0.0007 (11) | −0.0094 (12) | −0.0043 (10) |
C18 | 0.0442 (12) | 0.0351 (11) | 0.0383 (12) | 0.0021 (9) | −0.0060 (9) | −0.0054 (9) |
C19 | 0.0447 (13) | 0.0544 (14) | 0.0696 (15) | 0.0053 (12) | 0.0157 (13) | −0.0040 (12) |
C20 | 0.130 (3) | 0.0479 (15) | 0.0738 (19) | −0.040 (2) | 0.011 (3) | 0.0052 (14) |
C21 | 0.0497 (15) | 0.0511 (15) | 0.0814 (19) | 0.0127 (12) | 0.0105 (14) | −0.0107 (14) |
Pd1—N1 | 2.0250 (18) | C10—H10A | 0.9300 |
Pd1—N2 | 2.0334 (17) | C11—C12 | 1.370 (4) |
Pd1—Cl2 | 2.2776 (6) | C11—H11A | 0.9300 |
Pd1—Cl1 | 2.2851 (5) | C12—H12A | 0.9300 |
N1—C1 | 1.336 (3) | C13—C18 | 1.389 (3) |
N1—C5 | 1.348 (3) | C13—C14 | 1.396 (3) |
N2—C6 | 1.291 (3) | C14—C15 | 1.397 (3) |
N2—C13 | 1.436 (3) | C14—C19 | 1.498 (3) |
C1—C2 | 1.383 (4) | C15—C16 | 1.377 (4) |
C1—H1A | 0.9300 | C15—H15A | 0.9300 |
C2—C3 | 1.369 (4) | C16—C17 | 1.378 (4) |
C2—H2A | 0.9300 | C16—C20 | 1.525 (3) |
C3—C4 | 1.395 (3) | C17—C18 | 1.400 (3) |
C3—H3A | 0.9300 | C17—H17A | 0.9300 |
C4—C5 | 1.381 (3) | C18—C21 | 1.509 (4) |
C4—H4A | 0.9300 | C19—H19A | 0.9600 |
C5—C6 | 1.479 (3) | C19—H19B | 0.9600 |
C6—C7 | 1.486 (3) | C19—H19C | 0.9600 |
C7—C8 | 1.384 (3) | C20—H20A | 0.9600 |
C7—C12 | 1.392 (3) | C20—H20B | 0.9600 |
C8—C9 | 1.389 (4) | C20—H20C | 0.9600 |
C8—H8A | 0.9300 | C21—H21A | 0.9600 |
C9—C10 | 1.379 (4) | C21—H21B | 0.9600 |
C9—H9A | 0.9300 | C21—H21C | 0.9600 |
C10—C11 | 1.380 (5) | ||
N1—Pd1—N2 | 80.04 (7) | C10—C11—C12 | 120.4 (3) |
N1—Pd1—Cl2 | 174.72 (5) | C10—C11—H11A | 119.8 |
N2—Pd1—Cl2 | 94.79 (5) | C12—C11—H11A | 119.8 |
N1—Pd1—Cl1 | 95.05 (5) | C11—C12—C7 | 120.3 (3) |
N2—Pd1—Cl1 | 172.09 (5) | C11—C12—H12A | 119.8 |
Cl2—Pd1—Cl1 | 90.21 (2) | C7—C12—H12A | 119.8 |
C1—N1—C5 | 119.2 (2) | C18—C13—C14 | 122.0 (2) |
C1—N1—Pd1 | 127.55 (16) | C18—C13—N2 | 118.19 (19) |
C5—N1—Pd1 | 113.20 (13) | C14—C13—N2 | 119.53 (18) |
C6—N2—C13 | 122.46 (17) | C15—C14—C13 | 117.2 (2) |
C6—N2—Pd1 | 114.68 (13) | C15—C14—C19 | 120.4 (2) |
C13—N2—Pd1 | 122.48 (13) | C13—C14—C19 | 122.3 (2) |
N1—C1—C2 | 122.0 (2) | C16—C15—C14 | 122.4 (2) |
N1—C1—H1A | 119.0 | C16—C15—H15A | 118.8 |
C2—C1—H1A | 119.0 | C14—C15—H15A | 118.8 |
C3—C2—C1 | 119.1 (2) | C15—C16—C17 | 118.9 (2) |
C3—C2—H2A | 120.5 | C15—C16—C20 | 121.0 (3) |
C1—C2—H2A | 120.5 | C17—C16—C20 | 120.2 (3) |
C2—C3—C4 | 119.3 (2) | C18—C17—C16 | 121.3 (2) |
C2—C3—H3A | 120.3 | C18—C17—H17A | 119.4 |
C4—C3—H3A | 120.3 | C16—C17—H17A | 119.4 |
C5—C4—C3 | 118.7 (2) | C13—C18—C17 | 118.3 (2) |
C5—C4—H4A | 120.7 | C13—C18—C21 | 121.4 (2) |
C3—C4—H4A | 120.7 | C17—C18—C21 | 120.3 (2) |
N1—C5—C4 | 121.65 (19) | C14—C19—H19A | 109.5 |
N1—C5—C6 | 115.08 (18) | C14—C19—H19B | 109.5 |
C4—C5—C6 | 123.19 (19) | H19A—C19—H19B | 109.5 |
N2—C6—C5 | 115.63 (17) | C14—C19—H19C | 109.5 |
N2—C6—C7 | 124.55 (18) | H19A—C19—H19C | 109.5 |
C5—C6—C7 | 119.82 (17) | H19B—C19—H19C | 109.5 |
C8—C7—C12 | 119.2 (2) | C16—C20—H20A | 109.5 |
C8—C7—C6 | 119.40 (19) | C16—C20—H20B | 109.5 |
C12—C7—C6 | 121.3 (2) | H20A—C20—H20B | 109.5 |
C7—C8—C9 | 120.1 (2) | C16—C20—H20C | 109.5 |
C7—C8—H8A | 119.9 | H20A—C20—H20C | 109.5 |
C9—C8—H8A | 119.9 | H20B—C20—H20C | 109.5 |
C8—C9—C10 | 119.9 (3) | C18—C21—H21A | 109.5 |
C8—C9—H9A | 120.0 | C18—C21—H21B | 109.5 |
C10—C9—H9A | 120.0 | H21A—C21—H21B | 109.5 |
C11—C10—C9 | 119.9 (2) | C18—C21—H21C | 109.5 |
C11—C10—H10A | 120.0 | H21A—C21—H21C | 109.5 |
C9—C10—H10A | 120.0 | H21B—C21—H21C | 109.5 |
Experimental details
Crystal data | |
Chemical formula | [PdCl2(C21H20N2)] |
Mr | 477.69 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 298 |
a, b, c (Å) | 7.4807 (6), 15.1483 (13), 17.7147 (15) |
V (Å3) | 2007.4 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.20 |
Crystal size (mm) | 0.35 × 0.33 × 0.22 |
Data collection | |
Diffractometer | Bruker SMART 1000 CCD |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.738, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11233, 3956, 3871 |
Rint | 0.024 |
(sin θ/λ)max (Å−1) | 0.619 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.019, 0.052, 1.01 |
No. of reflections | 3956 |
No. of parameters | 238 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.20, −0.52 |
Absolute structure | Flack (1983), 1670 Friedel pairs |
Absolute structure parameter | 0.02 (2) |
Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
Acknowledgements
Financial support from the Ministry of Economic Affairs, Taiwan, is appreciated.
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Recently, palladium-catalyzed Suzuki-Miyaura reactions involving cross-coupling of aryl halides with aryl boronic acids have emerged as the most important synthetic methods for the preparation of biaryl compounds (Miyaura et al., 1995; Na et al., 2004; Rajagopal et al., 2002; Li 2003; Tomioka et al., 2004; Nicolaou et al., 2005). Thus, because of its utility as an important synthetic methodology, a significant amount of research focus had been devoted to designing improved catalysts for the Suzuki-Miyaura cross-coupling reaction. It is noteworthy that there has been a continuing interest in the further development of more efficient and selective catalytic systems for the synthesis of biaryls. However, only a few examples of N,N' pyridyl-imine palladium complexes have been reported as catalysts in coupling reaction (Lai et al., 2005; Pelagattia et al., 2005). Herein, we report the synthesis and crystal structure of the title palladium (II) complex that is certainly a potential catalyst in cross-coupling reactions.
The structure of the title compound is a mononuclear configuration with the metal center bound to two N atoms (one from the imine group and one from the pyridine ring) and two Cl atoms (Fig. 1). The coordination geometry around PdII atom is slightly distorted square planar, and the distances of Pd(1)—N(1) and Pd(1)—N(2) are 2.025 (2) and 2.033 (2) Å, respectively. It is noticed that the trans angles (N2—Pd—Cl1 and N1—Pd—Cl2) in the PdN2Cl2 core do not deviate more than 8° from the ideal value of 180°. Moreover, the planes of the pyridine (N1—C1—C2—C3—C4—C5) and phenyl rings (C8—C9—C10—C11—C12 and C13—C14—C15—C16—C17—C18) are close to perpendicular, and the dihedral angles between them are 80.9 (3) and 82.8 (3)°, respectively. All bond distances and bond angles lie within normal ranges, which are essentially similar to the pyridyl-imine palladium (II) complex (Hsueh et al., 2006; Zhang et al., 2008).