Dibromidobis[1-(2,4,6-trimethyl­phen­yl)-1,4,5,6-tetra­hydro­pyrimidine-κN3]palladium(II)

Mao, P.; Liu, X.; Yang, L.; Yuan, J.; Song, M.

doi:10.1107/S1600536810050968

metal-organic compounds

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Volume 67| Part 1| January 2011| Page m62

https://doi.org/10.1107/S1600536810050968

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Dibromidobis[1-(2,4,6-trimethylphenyl)-1,4,5,6-tetrahydropyrimidine-κN³]palladium(II)

Pu Mao,^a Xiujun Liu,^b Liangru Yang,^b Jinwei Yuan ^b and Maoping Song ^a ^*

^aDepartment of Chemistry, Zhengzhou University, Zhengzhou 450001, People's Republic of China, and ^bSchool of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, People's Republic of China
^*Correspondence e-mail: henangongda@yahoo.com

(Received 5 November 2010; accepted 5 December 2010; online 11 December 2010)

In the title complex, [PdBr₂(C₁₃H₁₈N₂)₂], the Pd^II atom is situated on an inversion center. The tetrahydropyrimidine group of the N-(2,4,6-trimethylphenyl)-1,4,5,6-tetrahydropyrimidine ligand is twisted from the square (PdN₂Br₂) coordination plane with a C—N—Pd—Br torsion angle of 81.8 (4)°; this is different from the angle of 43.47 (14)°, reported in a closely related structure, dichloridobis(1-methyl-1,4,5,6-tetrahydropyrimidine)palladium(II).

Related literature

For the related structure, dichlorobis(1-methyl-1,4,5,6-tetrahydropyrimidine)palladium(II), see: Chang & Lee (2007 ).

Experimental

Crystal data

[PdBr₂(C₁₃H₁₈N₂)₂]
M_r = 670.81
Monoclinic, P 2₁ /c
a = 7.1348 (14) Å
b = 21.308 (4) Å
c = 8.9704 (18) Å
β = 94.60 (3)°
V = 1359.4 (5) Å³
Z = 2
Mo Kα radiation
μ = 3.64 mm⁻¹
T = 293 K
0.20 × 0.20 × 0.20 mm

Data collection

Rigaku Saturn 724 CCD area-detector diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2006 ) T_min = 0.530, T_max = 0.530
6809 measured reflections
2393 independent reflections
1931 reflections with I > 2σ(I)
R_int = 0.034

Refinement

R[F² > 2σ(F²)] = 0.045
wR(F²) = 0.114
S = 1.08
2393 reflections
154 parameters
H-atom parameters constrained
Δρ_max = 0.76 e Å⁻³
Δρ_min = −0.50 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2006); cell refinement: CrystalClear; data reduction: CrystalClear; 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: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536810050968/su2226sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810050968/su2226Isup2.hkl

checkCIF report

Comment top

Our group is interested in the preparation of new N-heterocyclic carbene (NHC) ligands based on substituted 1,4,5,6-tetrahydropyrimidine and their palladium complexes. In the course of preparing the palladium complex of a bidentate NHC ligand, we observed that the reaction of the corresponding tetrahydropyrimidine salt and Pd(OAc)₂, unexpectedly, under unoptimized reaction conditions, afforded the title compound.

In the title compound the Pd atom is situated on a center of inversion (Fig. 1). The organic ligands twist away from the square (PdN2Br2) coordination plane with a C1—N1—Pd1—Br1 torsion angle of 81.8 (4)°. The corresponding angle in the closely related structure, dichlorobis(1-methyl-1,4,5,6-tetrahydropyrimidine)palladium(II) [Chang & Lee, 2007], is 43.47 (14)°.

Related literature top

For the related structure, dichlorobis(1-methyl-1,4,5,6-tetrahydropyrimidine)palladium(II), see: Chang & Lee (2007).

Experimental top

Pd(OAc)₂ (101 mg, 0.45 mmol) was added to a solution of N,N-methylene-N',N'-bis-2,4,6-trimethylphenyl-1,4,5,6-tetrahydropyrimidine (260 mg, 0.45 mmol) in DMSO (3 ml). The mixture was then heated at 333 K for 5 h. After cooling, the solvent was removed completely under vacuum. The residue was then dissolved in CHCl₃, and filtered. Evaporation of the filtrate afforded an orange solid (yield 200 mg, 66%). Crystals of the title complex, suitable for structural analysis, were obtained by vapor diffusion of diethyl ether into an acetonitrile solution containing the solid.

Structure description top

For the related structure, dichlorobis(1-methyl-1,4,5,6-tetrahydropyrimidine)palladium(II), see: Chang & Lee (2007).

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2006); cell refinement: CrystalClear (Rigaku/MSC, 2006); data reduction: CrystalClear (Rigaku/MSC, 2006); 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: SHELXL97 (Sheldrick, 2008).

Figures top

Fig. 1. The molecular structure of the title molecule, showing 30% probability displacement ellipsoids.

Dibromidobis[1-(2,4,6-trimethylphenyl)-1,4,5,6-tetrahydropyrimidine- κN³]palladium(II) top

Crystal data top

[PdBr₂(C₁₃H₁₈N₂)₂]	F(000) = 672
M_r = 670.81	D_x = 1.639 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3263 reflections
a = 7.1348 (14) Å	θ = 2.5–27.9°
b = 21.308 (4) Å	µ = 3.64 mm⁻¹
c = 8.9704 (18) Å	T = 293 K
β = 94.60 (3)°	Prismatic, colourless
V = 1359.4 (5) Å³	0.20 × 0.20 × 0.20 mm
Z = 2

Data collection top

Rigaku CCD area-detector diffractometer	2393 independent reflections
Radiation source: fine-focus sealed tube	1931 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.034
ω scans	θ_max = 25.0°, θ_min = 2.5°
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2006)	h = −8→5
T_min = 0.530, T_max = 0.530	k = −18→25
6809 measured reflections	l = −9→10

Refinement top

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.114	H-atom parameters constrained
S = 1.08	w = 1/[σ²(F_o²) + (0.0553P)²] where P = (F_o² + 2F_c²)/3
2393 reflections	(Δ/σ)_max < 0.001
154 parameters	Δρ_max = 0.76 e Å⁻³
0 restraints	Δρ_min = −0.50 e Å⁻³

Crystal data top

[PdBr₂(C₁₃H₁₈N₂)₂]	V = 1359.4 (5) Å³
M_r = 670.81	Z = 2
Monoclinic, P2₁/c	Mo Kα radiation
a = 7.1348 (14) Å	µ = 3.64 mm⁻¹
b = 21.308 (4) Å	T = 293 K
c = 8.9704 (18) Å	0.20 × 0.20 × 0.20 mm
β = 94.60 (3)°

Data collection top

Rigaku CCD area-detector diffractometer	2393 independent reflections
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2006)	1931 reflections with I > 2σ(I)
T_min = 0.530, T_max = 0.530	R_int = 0.034
6809 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.045	0 restraints
wR(F²) = 0.114	H-atom parameters constrained
S = 1.08	Δρ_max = 0.76 e Å⁻³
2393 reflections	Δρ_min = −0.50 e Å⁻³
154 parameters

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pd1	0.5000	0.5000	0.0000	0.0445 (2)
Br1	0.27385 (9)	0.45987 (3)	−0.19525 (7)	0.0700 (2)
N1	0.3804 (6)	0.44800 (17)	0.1532 (5)	0.0502 (11)
N2	0.4027 (6)	0.36304 (16)	0.3218 (5)	0.0513 (11)
C1	0.2139 (8)	0.4701 (2)	0.2167 (6)	0.0595 (16)
H1A	0.1044	0.4545	0.1570	0.071*
H1B	0.2111	0.5156	0.2118	0.071*
C2	0.2026 (10)	0.4506 (2)	0.3718 (7)	0.0722 (19)
H2A	0.0783	0.4607	0.4015	0.087*
H2B	0.2929	0.4747	0.4348	0.087*
C3	0.2385 (8)	0.3831 (2)	0.3997 (7)	0.0659 (17)
H3A	0.2622	0.3757	0.5062	0.079*
H3B	0.1290	0.3589	0.3638	0.079*
C4	0.4604 (8)	0.3983 (2)	0.2102 (6)	0.0534 (14)
H4	0.5700	0.3855	0.1695	0.064*
C5	0.5155 (7)	0.3102 (2)	0.3749 (6)	0.0461 (12)
C6	0.4605 (8)	0.2496 (2)	0.3291 (6)	0.0541 (14)
C7	0.5759 (8)	0.1998 (2)	0.3757 (6)	0.0586 (15)
H7	0.5389	0.1592	0.3491	0.070*
C8	0.7456 (8)	0.2088 (3)	0.4614 (7)	0.0631 (16)
C9	0.7929 (8)	0.2699 (2)	0.5081 (7)	0.0628 (15)
H9	0.9027	0.2766	0.5691	0.075*
C10	0.6784 (8)	0.3208 (2)	0.4650 (7)	0.0561 (14)
C11	0.2792 (9)	0.2376 (3)	0.2354 (7)	0.0757 (18)
H11A	0.1756	0.2527	0.2871	0.114*
H11B	0.2649	0.1933	0.2180	0.114*
H11C	0.2817	0.2590	0.1415	0.114*
C12	0.8751 (9)	0.1538 (3)	0.5026 (9)	0.087 (2)
H12A	0.9802	0.1548	0.4423	0.130*
H12B	0.8074	0.1152	0.4855	0.130*
H12C	0.9194	0.1567	0.6063	0.130*
C13	0.7335 (9)	0.3853 (3)	0.5220 (8)	0.081 (2)
H13A	0.7528	0.4123	0.4390	0.122*
H13B	0.8477	0.3826	0.5861	0.122*
H13C	0.6352	0.4021	0.5773	0.122*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pd1	0.0507 (4)	0.0410 (3)	0.0427 (4)	0.0089 (2)	0.0098 (3)	0.0122 (2)
Br1	0.0733 (5)	0.0738 (4)	0.0615 (5)	−0.0017 (3)	−0.0030 (3)	0.0054 (3)
N1	0.054 (3)	0.045 (2)	0.053 (3)	0.0112 (19)	0.012 (2)	0.0117 (19)
N2	0.066 (3)	0.038 (2)	0.052 (3)	0.0043 (19)	0.016 (2)	0.0131 (18)
C1	0.060 (4)	0.046 (3)	0.075 (4)	0.014 (2)	0.023 (3)	0.010 (3)
C2	0.084 (5)	0.061 (3)	0.076 (5)	0.027 (3)	0.034 (4)	0.016 (3)
C3	0.078 (4)	0.055 (3)	0.070 (4)	0.013 (3)	0.040 (4)	0.011 (3)
C4	0.056 (4)	0.052 (3)	0.054 (3)	0.005 (2)	0.020 (3)	0.005 (2)
C5	0.048 (3)	0.041 (3)	0.049 (3)	0.008 (2)	0.006 (2)	0.010 (2)
C6	0.068 (4)	0.042 (3)	0.053 (3)	0.004 (2)	0.005 (3)	0.004 (2)
C7	0.071 (4)	0.036 (3)	0.069 (4)	0.004 (2)	0.006 (3)	0.004 (2)
C8	0.058 (4)	0.056 (3)	0.077 (4)	0.011 (3)	0.017 (3)	0.019 (3)
C9	0.049 (4)	0.061 (3)	0.077 (4)	0.002 (3)	−0.006 (3)	0.011 (3)
C10	0.057 (4)	0.039 (3)	0.073 (4)	−0.002 (2)	0.005 (3)	0.006 (2)
C11	0.085 (5)	0.057 (3)	0.081 (5)	0.006 (3)	−0.017 (4)	−0.016 (3)
C12	0.070 (5)	0.070 (4)	0.121 (6)	0.023 (3)	0.014 (4)	0.031 (4)
C13	0.073 (4)	0.054 (3)	0.115 (6)	−0.012 (3)	−0.009 (4)	−0.006 (3)

Geometric parameters (Å, º) top

Pd1—N1ⁱ	2.008 (4)	C5—C6	1.402 (7)
Pd1—N1	2.008 (4)	C6—C7	1.386 (7)
Pd1—Br1ⁱ	2.4391 (9)	C6—C11	1.507 (8)
Pd1—Br1	2.4391 (9)	C7—C8	1.394 (8)
N1—C4	1.289 (6)	C7—H7	0.9300
N1—C1	1.437 (6)	C8—C9	1.401 (8)
N2—C4	1.343 (6)	C8—C12	1.519 (7)
N2—C5	1.442 (6)	C9—C10	1.394 (7)
N2—C3	1.474 (6)	C9—H9	0.9300
C1—C2	1.461 (8)	C10—C13	1.508 (7)
C1—H1A	0.9700	C11—H11A	0.9600
C1—H1B	0.9700	C11—H11B	0.9600
C2—C3	1.478 (7)	C11—H11C	0.9600
C2—H2A	0.9700	C12—H12A	0.9600
C2—H2B	0.9700	C12—H12B	0.9600
C3—H3A	0.9700	C12—H12C	0.9600
C3—H3B	0.9700	C13—H13A	0.9600
C4—H4	0.9300	C13—H13B	0.9600
C5—C10	1.380 (7)	C13—H13C	0.9600

N1ⁱ—Pd1—N1	180.000 (1)	C6—C5—N2	119.1 (5)
N1ⁱ—Pd1—Br1ⁱ	90.30 (14)	C7—C6—C5	118.1 (5)
N1—Pd1—Br1ⁱ	89.70 (14)	C7—C6—C11	120.0 (5)
N1ⁱ—Pd1—Br1	89.70 (13)	C5—C6—C11	121.8 (5)
N1—Pd1—Br1	90.30 (14)	C6—C7—C8	122.0 (5)
Br1ⁱ—Pd1—Br1	180.0	C6—C7—H7	119.0
C4—N1—C1	117.8 (4)	C8—C7—H7	119.0
C4—N1—Pd1	121.7 (3)	C7—C8—C9	118.0 (5)
C1—N1—Pd1	120.0 (3)	C7—C8—C12	120.9 (5)
C4—N2—C5	119.1 (4)	C9—C8—C12	121.1 (6)
C4—N2—C3	119.6 (4)	C10—C9—C8	121.2 (6)
C5—N2—C3	120.9 (4)	C10—C9—H9	119.4
N1—C1—C2	113.2 (4)	C8—C9—H9	119.4
N1—C1—H1A	108.9	C5—C10—C9	118.9 (4)
C2—C1—H1A	108.9	C5—C10—C13	122.1 (5)
N1—C1—H1B	108.9	C9—C10—C13	118.9 (5)
C2—C1—H1B	108.9	C6—C11—H11A	109.5
H1A—C1—H1B	107.7	C6—C11—H11B	109.5
C1—C2—C3	114.5 (5)	H11A—C11—H11B	109.5
C1—C2—H2A	108.6	C6—C11—H11C	109.5
C3—C2—H2A	108.6	H11A—C11—H11C	109.5
C1—C2—H2B	108.6	H11B—C11—H11C	109.5
C3—C2—H2B	108.6	C8—C12—H12A	109.5
H2A—C2—H2B	107.6	C8—C12—H12B	109.5
N2—C3—C2	109.6 (4)	H12A—C12—H12B	109.5
N2—C3—H3A	109.7	C8—C12—H12C	109.5
C2—C3—H3A	109.7	H12A—C12—H12C	109.5
N2—C3—H3B	109.7	H12B—C12—H12C	109.5
C2—C3—H3B	109.7	C10—C13—H13A	109.5
H3A—C3—H3B	108.2	C10—C13—H13B	109.5
N1—C4—N2	127.1 (5)	H13A—C13—H13B	109.5
N1—C4—H4	116.5	C10—C13—H13C	109.5
N2—C4—H4	116.5	H13A—C13—H13C	109.5
C10—C5—C6	121.6 (4)	H13B—C13—H13C	109.5
C10—C5—N2	119.2 (4)

Br1ⁱ—Pd1—N1—C4	−73.6 (4)	C3—N2—C5—C6	85.6 (7)
Br1—Pd1—N1—C4	106.4 (4)	C10—C5—C6—C7	−0.7 (8)
Br1ⁱ—Pd1—N1—C1	98.2 (4)	N2—C5—C6—C7	177.0 (4)
Br1—Pd1—N1—C1	−81.8 (4)	C10—C5—C6—C11	177.7 (5)
C4—N1—C1—C2	24.7 (8)	N2—C5—C6—C11	−4.7 (8)
Pd1—N1—C1—C2	−147.4 (4)	C5—C6—C7—C8	−2.2 (8)
N1—C1—C2—C3	−48.5 (8)	C11—C6—C7—C8	179.4 (5)
C4—N2—C3—C2	−18.5 (8)	C6—C7—C8—C9	3.9 (8)
C5—N2—C3—C2	154.1 (5)	C6—C7—C8—C12	−176.1 (5)
C1—C2—C3—N2	44.1 (8)	C7—C8—C9—C10	−2.9 (9)
C1—N1—C4—N2	1.8 (9)	C12—C8—C9—C10	177.2 (5)
Pd1—N1—C4—N2	173.8 (4)	C6—C5—C10—C9	1.7 (8)
C5—N2—C4—N1	−177.5 (5)	N2—C5—C10—C9	−176.0 (5)
C3—N2—C4—N1	−4.7 (9)	C6—C5—C10—C13	−176.5 (5)
C4—N2—C5—C10	75.9 (7)	N2—C5—C10—C13	5.8 (8)
C3—N2—C5—C10	−96.7 (6)	C8—C9—C10—C5	0.1 (8)
C4—N2—C5—C6	−101.8 (6)	C8—C9—C10—C13	178.4 (6)

Symmetry code: (i) −x+1, −y+1, −z.

Experimental details

Crystal data
Chemical formula	[PdBr₂(C₁₃H₁₈N₂)₂]
M_r	670.81
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	7.1348 (14), 21.308 (4), 8.9704 (18)
β (°)	94.60 (3)
V (Å³)	1359.4 (5)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	3.64
Crystal size (mm)	0.20 × 0.20 × 0.20

Data collection
Diffractometer	Rigaku CCD area-detector
Absorption correction	Multi-scan (CrystalClear; Rigaku/MSC, 2006)
T_min, T_max	0.530, 0.530
No. of measured, independent and observed [I > 2σ(I)] reflections	6809, 2393, 1931
R_int	0.034
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.114, 1.08
No. of reflections	2393
No. of parameters	154
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.76, −0.50

Computer programs: CrystalClear (Rigaku/MSC, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Acknowledgements

The authors thank Mr H. Qian for technical assistance. This research was supported by the National Natural Science Foundation of the People's Republic of China (grant No. 20902017).

References

Chang, C.-F. & Lee, H. M. (2007). Acta Cryst. E63, m167–m168. Web of Science CSD CrossRef IUCr Journals Google Scholar
Rigaku/MSC (2006). CrystalClear. Rigaku/MSC Inc., Tokyo, Japan. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar

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