(Acetato-κ2 O,O′)[2′-(di-tert-butyl­phosphanyl)-1,1′-biphenyl-κ2 P,C 2]palladium(II)

Charmaine Arderne; Cedric W Holzapfel

doi:10.1107/S1600536812040068

. 2012 Sep 26;68(Pt 10):m1308. doi: 10.1107/S1600536812040068

(Acetato-κ² O,O′)[2′-(di-tert-butylphosphanyl)-1,1′-biphenyl-κ² P,C ²]palladium(II)

Charmaine Arderne ^a,^*, Cedric W Holzapfel ^a

PMCID: PMC3470176 PMID: 23125620

Abstract

The structure of the title compound, [Pd(C₂H₃O₂)(C₂₀H₂₆P)], shows a distorted square-planar geometry for the Pd^II atom, with significant deviations being evident owing to the asymmetric coordination mode of the acetate ligand. A weak intramolecular C—H⋯O interaction is noted. The crystal studied was a racemic twin.

Related literature

For related structures and catalytic literature on palladium complexes, see: Ormondi et al. (2011 ▶); van Blerk & Holzapfel (2009 ▶); Zim & Buchwald (2005 ▶); Williams et al. (2008 ▶).

Experimental

Crystal data

[Pd(C₂H₃O₂)(C₂₀H₂₆P)]
M _r = 462.82
Orthorhombic,
a = 9.800 (3) Å
b = 14.2392 (4) Å
c = 14.7772 (5) Å
V = 2062.1 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.99 mm⁻¹
T = 100 K
0.25 × 0.19 × 0.14 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (AXSCALE; Bruker, 2010 ▶) T _min = 0.790, T _max = 0.874
24048 measured reflections
5179 independent reflections
5077 reflections with I > 2σ(I)
R _int = 0.018

Refinement

R[F ² > 2σ(F ²)] = 0.014
wR(F ²) = 0.034
S = 1.06
5179 reflections
243 parameters
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.19 e Å⁻³
Absolute structure: not determined

Data collection: APEX2 (Bruker, 2010 ▶); cell refinement: SAINT (Bruker, 2010 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: OLEX2 (Dolomanov et al., 2009 ▶); software used to prepare material for publication: PLATON (Spek, 2009 ▶) and publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812040068/tk5150sup1.cif

e-68-m1308-sup1.cif^{(28.2KB, cif)}

Supplementary material file. DOI: 10.1107/S1600536812040068/tk5150Isup2.mol

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812040068/tk5150Isup3.hkl

e-68-m1308-Isup3.hkl^{(248.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected geometric parameters (Å, °).

Pd1—P1	2.2285 (7)
Pd1—O1	2.2109 (12)
Pd1—O2	2.1657 (11)
Pd1—C18	1.9686 (15)

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P1—Pd1—O1	113.61 (3)
P1—Pd1—O2	173.58 (3)
P1—Pd1—C18	86.37 (4)
O1—Pd1—O2	60.19 (4)
O1—Pd1—C18	159.59 (5)
O2—Pd1—C18	99.69 (5)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4B⋯O1	0.98	2.25	3.169 (2)	156

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Acknowledgments

The authors acknowledge the University of Johannesburg for the use of their facilities and for funding this project.

supplementary crystallographic information

Comment

Our continued studies of palladium catalysed reactions (Ormondi et al., 2011; Williams et al., 2008; van Blerk & Holzapfel, 2009) includes a comparison of the efficiency of a wide range of palladocycles compared against the title compound (I), acetato-(2'-di-t-butylphosphanyl-1,1'-biphenyl-2yl)palladium(II). Compound (I) is an efficient and stable catalyst introduced by Zim & Buchwald (2005). We now report the crystal structure of (I) as part of a structure–activity study.

There is significant deviation from the ideal square planar geometry around the Pd atom as a result of its coordination to the acetate moiety. This distorted geometry is evident from the deviations in bond angles from 90°. The data in Table 1 demonstrate the deviations in the coordination geometry. A weak intramolecular C—H···O interaction is noted (Fig. 2 and Table 2).

Experimental

A solution of 2-(biphenyl)-di-tert-butylphosphine (298 mg; 1 mmol) and palladium acetate (224 mg; 1 mmol) in 15 ml of chloroform was refluxed under argon for 3 h. The solvent was evaporated in vacuo to leave a colourless crystalline residue (464 mg; ca 100%). The solid was taken up in dichloromethane (3 ml) and the solution diluted with cyclohexane (10 ml). The solvent was allowed to slowly evaporate in a stream of nitrogen until the solution was reduced to 3 ml. This resulted in the formation of well formed yellow blocks of the title compound (I) (288 mg; m.p. 409–414 K).