trans-Bromido(pyrimidinyl-κC 5)bis(triphenylphosphane-κP)palladium(II)

In the title complex, [PdBr(C4H3N2)(C18H15P)2], the geometry around the Pd atom is distorted square-planar with the Pd atom displaced by 0.0334 (14) Å from the BrP2C plane. The two Ph3P ligands are in trans positions, defining a P—Pd—P angle of 171.78 (5)°, while the pyrimidinyl and bromide ligands are trans to each other [C—Pd—Br = 174.63 (14)°].

In the title complex, [PdBr(C 4 H 3 N 2 )(C 18 H 15 P) 2 ], the geometry around the Pd atom is distorted square-planar with the Pd atom displaced by 0.0334 (14) Å from the BrP 2 C plane. The two Ph 3 P ligands are in trans positions, defining a P-Pd-P angle of 171.78 (5) , while the pyrimidinyl and bromide ligands are trans to each other  ].
To synthesize the pyrimidinyl metal compound, [Pd(PPh 3 ) 4 ] was used to react with 5-bromopyrimidine in dichloromethane at room temperature. As a result, a two triphenylphosphine displaced complex [Pd(Br)(C 4 H 3 N 2 )(PPh 3 ) 2 ] was isolated with 97% yield. The X-ray crystal structure analysis has been carried out to provide structural information.
The molecular structure of the title compound is shown in Fig. 1. The palladium atom has a distorted square planar environment, being displaced by 0.0396Å from the least-squares plane and with all angles about the Pd center within ± 2.6° of 90°. The Pd-C1 bond distance, 2.000 (5) Å, is longer than other Pd II -carbon(carbonyl) distances, and similar to Pd-C(carbene) distances (Cardin et al., 1972). Two PPh 3 ligands are in trans position: P1-Pd-P2, 171.78 (5)°, while the pyrimidinyl ligand and bromide are trans to each other: C1-Pd-Br, 174.63 (14)°. The phosphorus atoms approach tetrahedral geometry as expected. The largest angular deviation from ideal tetrahedral geometry is 119.31 (16)° for C5-P1-Pd.
The mean Pd-N distance (> 4.25Å) indicates no bonding interaction between the nitrogen atom and the palladium metal atom. Within the pyrimidinyl ligand itself, the geometry is consistent with a significant partial double bond character in the C-C and C-N bonds. The C-N bond distances (1.315 (7) ~1.351 (6) Å) are typical for a C-N bond having partial double bond character and are certainly much shorter than the normal C-N (1.47 Å) single bond. The Pd-C1 (2.000 (5) Å), Pd-P (2.3175 (13), 2.3325 (13) Å) and Pd-Br (2.4907 (6) Å) lengths are in agreement with reported values (Yih et al., 2008(Yih et al., , 2009).
TThe 31 P{ 1 H} NMR spectra of (I) shows a singlet resonances at δ 24.2. In the 1 H NMR spectra, the 2,6-H and 4-H protons of the pyrimidinyl group exhibit two singlet resonances at δ 7.75 and at δ 8.05. The 13 C{ 1 H} NMR spectra of (I) reveals two singlets at δ 151.9 and at δ 161.4 which are assigned to the 4-C and 2,6-C carbon atom of the pyrimidinyl group.
There is a triplet resonance at δ 154.4 ( 2 J P-C = 5.91 Hz), which is assigned to the 1-C of pyrimidinyl group. In the FAB mass spectra, base peak with the typical Pd isotope distribution is in agreement with the [M + ] molecular mass of (I).

Refinement
H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95Å and with U iso (H) = 1.2 times U eq (C). Fig. 1. The molecular structure of (I), with 50% probability displacement ellipsoids.