supplementary materials


HTML versionpdf versioncif file3d viewstructure factorssupplementary materialsCIF check reportsimilar papers Open access

wm2700 scheme

Acta Cryst. (2012). E68, m1513    [ doi:10.1107/S1600536812047022 ]

cis-{2,6-Bis[(di-tert-butylphosphanyl)methyl]cyclohexyl-[kappa]3P,C1,P'}chloridopalladium(II)

D. Olsson, J. M. Janse van Rensburg and O. F. Wendt

Abstract top

The PdII atom in the title compound, [Pd(C24H49P2)Cl], has a distorted square-planar CClP2 coordination geometry with the P,C,P'-tridentate ligand forming two five-membered metallacycles. The cyclohexane ring is aligned with the PdII coordination plane due to C-H activation in an equatorial position, giving a tri-equatorial conformation of the cyclohexyl ring.

Comment top

In this study we report the crystal structure of {cis-1,3-bis[(di-tert-butylphosphanyl)methyl]cyclohexane}palladium(II) chloride, [PdCl(C24H49P2)], (I).

Compound (I) belongs to a family of C(sp3)—H activated (PCP)-complexes, showing interesting catalytic performance in C—C coupling reactions (Ohff et al., 1997; Sjövall et al., 2002; Nilsson & Wendt, 2005; Olsson & Wendt, 2009). Structural data for the corresponding bromide and iodide analogues have been reported previously (Sjövall et al., 2002; Olsson et al., 2007b).

Aromatic backbones are by far the most commonly occurring for palladium (PCP)-complexes, but complexes based on an aliphatic backbone are receiving increasing attention. Aliphatic (PCP)-type ligands that are coordinated to transition metals have been published recently for metals such as rhodium (Kuznetsov et al., 2006), nickel (Castonguay et al., 2006; Pandarus & Zargarian, 2007), platinum (Olsson et al. 2007a) and iridium (Arunachalampillai et al., 2009; Jonasson et al. 2011).

In the structure of (I) the PdII atom exhibits a pseudo-square-planar coordination geometry (Fig. 1). Comparison to the analogous iodido and bromido complexes indicates the expected Pd—halogen bond lengths decrease. The Pd—P bond lengths are around 2.3 Å in all complexes with a trans orientation of the P atoms; in (I) the P1—Pd1—P2 angle is 166.495 (15) ° . The (PCP)-tridentate ligand and the PdII atom form two five-membered metalla rings. As is usually observed in these systems, the bis-chelating system displays two acute P—Pd—C1 angles of around 83–84°. Bond lengths are Pd1—Cl1, 2.4405 (4) Å, Pd1—P1, 2.3233 (4) Å, Pd1—P2, 2.3226 (4) Å and Pd1—C1, 2.0808 (16) Å.

The cyclohexane ring is aligned with the palladium coordination plane forming the usual tri-equatorial conformation (Fig. 1).

Related literature top

C(sp3)—H activated (PCP)-complexes with catalytic performance in C—C coupling reactions were reported by Ohff et al. (1997); Sjövall et al. (2002); Nilsson & Wendt (2005); Olsson & Wendt (2009). Metal complexes with (PCP)-type ligands containing an aliphatic backbone have been reported for Rh (Kuznetsov et al., 2006), Ni (Castonguay et al., 2006; Pandarus & Zargarian, 2007), Pt (Olsson et al. 2007a), Ir (Arunachalampillai et al., 2009; Jonasson et al. 2011). The crystal structures of the bromide and iodide analogues of the title compound were determined by Sjövall et al. (2002) and Olsson et al. (2007b).

Experimental top

All procedures were performed under vacuum or nitrogen. The (PCP)H ligand was prepared according to the published procedure (Sjövall et al., 2002). A solution of the ligand (0.536 g, 1.337 mmol) in 20 ml THF was mixed with a solution of PdCl2(PhCN)2 (0.500 g, 1.304 mmol) in 30 ml THF in a high-pressure glass vessel and the mixture was heated at 353 K for 8 h. Evaporation of all volatiles gave a crude, light yellow product in almost quantitative yield. Recrystallization from hexane gave 0.483 g (69%) of crystals suitable for X-ray crystallographic analysis. 1H-NMR (benzene-d6): δ 2.15–0.80 (m region, 13H, CH & CH2), 1.37 (m, 36H, coalesced virtual triplets). 31P{1H} NMR (benzene-d6): δ 70.6 (s).

Refinement top

The H atoms were positioned geometrically and treated as riding on their parent atoms with C–H distances of 0.93–0.97 Å and Uiso(H) = 1.2Ueq - 1.5Ueq. The highest difference peak in the Fourier map is located 1.25 Å from H26A and the lowest is located 0.60 Å from P2.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (CrystalMaker, 2011); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) with atom labels (methyl groups labels omitted) and 40% probability displacement ellipsoids. H-atoms were omitted for clarity.
cis-{2,6-Bis[(di-tert- butylphosphanyl)methyl]cyclohexyl- κ3P,C1,P'}chloridopalladium(II) top
Crystal data top
[Pd(C24H49P2)Cl]F(000) = 1144
Mr = 541.42Dx = 1.349 Mg m−3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 14595 reflections
a = 11.9467 (2) Åθ = 2.2–33.0°
b = 14.6159 (2) ŵ = 0.93 mm−1
c = 15.5190 (3) ÅT = 293 K
β = 100.339 (2)°Prism, colourless
V = 2665.80 (8) Å30.15 × 0.10 × 0.05 mm
Z = 4
Data collection top
Oxford Diffraction XCalibur 3
diffractometer		9297 independent reflections
Radiation source: Enhance (Mo) X-ray Source6699 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.024
Detector resolution: 16.1829 pixels mm-1θmax = 33.0°, θmin = 2.2°
ω scansh = −18→18
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2006)		k = −20→22
Tmin = 0.941, Tmax = 1.000l = −17→23
26794 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.028Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.070H-atom parameters constrained
S = 0.96 w = 1/[σ2(Fo2) + (0.040P)2]
where P = (Fo2 + 2Fc2)/3
9297 reflections(Δ/σ)max = 0.004
253 parametersΔρmax = 1.28 e Å−3
0 restraintsΔρmin = −0.56 e Å−3
Crystal data top
[Pd(C24H49P2)Cl]V = 2665.80 (8) Å3
Mr = 541.42Z = 4
Monoclinic, P21/nMo Kα radiation
a = 11.9467 (2) ŵ = 0.93 mm−1
b = 14.6159 (2) ÅT = 293 K
c = 15.5190 (3) Å0.15 × 0.10 × 0.05 mm
β = 100.339 (2)°
Data collection top
Oxford Diffraction XCalibur 3
diffractometer		9297 independent reflections
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2006)		6699 reflections with I > 2σ(I)
Tmin = 0.941, Tmax = 1.000Rint = 0.024
26794 measured reflectionsθmax = 33.0°
Refinement top
R[F2 > 2σ(F2)] = 0.028H-atom parameters constrained
wR(F2) = 0.070Δρmax = 1.28 e Å−3
S = 0.96Δρmin = −0.56 e Å−3
9297 reflectionsAbsolute structure: ?
253 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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
xyzUiso*/Ueq
Pd10.395006 (10)0.557045 (8)0.252150 (7)0.01343 (4)
Cl10.36623 (3)0.67441 (3)0.35789 (3)0.02067 (8)
P10.20462 (4)0.53783 (3)0.18983 (3)0.01455 (8)
P20.59247 (3)0.55763 (3)0.28541 (3)0.01541 (8)
C10.41983 (14)0.46752 (12)0.15303 (11)0.0188 (3)
H10.42260.50650.10210.023*
C20.32136 (14)0.40129 (11)0.12327 (11)0.0197 (3)
H20.31760.35970.17220.024*
C30.33987 (15)0.34263 (12)0.04548 (10)0.0210 (3)
H3A0.27940.29770.03320.025*
H3B0.33560.3813−0.00580.025*
C40.45339 (16)0.29375 (12)0.06192 (11)0.0268 (4)
H4A0.46420.26210.00910.032*
H4B0.45390.24850.10770.032*
C50.55085 (15)0.36146 (12)0.08926 (10)0.0215 (3)
H5A0.55510.40290.04110.026*
H5B0.62220.32830.10250.026*
C60.53358 (15)0.41664 (12)0.16956 (11)0.0211 (3)
H60.53130.37310.21720.025*
C70.20875 (14)0.45253 (11)0.10369 (11)0.0196 (3)
H7A0.14610.40990.10160.024*
H7B0.20110.48260.04720.024*
C80.63117 (14)0.48257 (12)0.20024 (11)0.0204 (3)
H8A0.64600.51900.15130.024*
H8B0.69960.44860.22360.024*
C110.11083 (13)0.48541 (11)0.26177 (10)0.0172 (3)
C120.16985 (16)0.39565 (12)0.29573 (12)0.0255 (4)
H12A0.24580.40850.32540.038*
H12B0.17260.35540.24730.038*
H12C0.12800.36700.33570.038*
C13−0.00951 (14)0.46389 (13)0.21394 (12)0.0252 (4)
H13A−0.04700.51970.19260.038*
H13B−0.05140.43470.25360.038*
H13C−0.00570.42380.16560.038*
C140.10502 (15)0.54682 (12)0.34093 (11)0.0242 (4)
H14A0.18070.56030.37090.036*
H14B0.06400.51580.38010.036*
H14C0.06660.60280.32140.036*
C150.13876 (14)0.64162 (11)0.12899 (10)0.0195 (3)
C160.03613 (16)0.62126 (13)0.05651 (12)0.0290 (4)
H16A0.05770.57760.01620.044*
H16B0.01140.67680.02580.044*
H16C−0.02480.59670.08220.044*
C170.10405 (16)0.71136 (12)0.19252 (12)0.0261 (4)
H17A0.16780.72410.23800.039*
H17B0.04280.68700.21790.039*
H17C0.07970.76680.16160.039*
C180.23380 (16)0.68321 (12)0.08639 (12)0.0271 (4)
H18A0.25610.64000.04610.041*
H18B0.29810.69750.13100.041*
H18C0.20650.73800.05560.041*
C210.66048 (14)0.50577 (12)0.39318 (11)0.0200 (3)
C220.61384 (17)0.40707 (12)0.39274 (12)0.0286 (4)
H22A0.63670.37320.34580.043*
H22B0.53230.40870.38460.043*
H22C0.64360.37800.44750.043*
C230.79068 (15)0.50157 (16)0.40666 (12)0.0321 (4)
H23A0.81330.46930.35870.048*
H23B0.81940.47030.46050.048*
H23C0.82090.56260.40920.048*
C240.62365 (15)0.55715 (12)0.46951 (11)0.0235 (3)
H24A0.54210.56010.46040.035*
H24B0.65430.61800.47260.035*
H24C0.65150.52550.52330.035*
C250.65819 (14)0.67117 (11)0.26587 (11)0.0199 (3)
C260.77759 (15)0.66373 (13)0.24310 (13)0.0304 (4)
H26A0.77520.62420.19340.046*
H26B0.82900.63900.29220.046*
H26C0.80320.72340.22940.046*
C270.66061 (16)0.73466 (12)0.34422 (12)0.0268 (4)
H27A0.58560.73910.35800.040*
H27B0.68590.79430.33020.040*
H27C0.71190.71050.39380.040*
C280.57787 (16)0.71338 (13)0.18684 (12)0.0276 (4)
H28A0.50270.71870.20010.041*
H28B0.57580.67480.13650.041*
H28C0.60520.77290.17470.041*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pd10.01082 (6)0.01346 (6)0.01586 (6)0.00033 (5)0.00199 (4)−0.00143 (5)
Cl10.01600 (19)0.0219 (2)0.02365 (19)0.00088 (15)0.00219 (15)−0.00764 (16)
P10.01157 (19)0.01407 (19)0.01712 (19)−0.00003 (14)0.00017 (15)−0.00109 (14)
P20.01061 (18)0.01640 (19)0.01917 (19)0.00028 (16)0.00255 (15)−0.00093 (16)
C10.0188 (8)0.0192 (8)0.0188 (8)0.0020 (6)0.0049 (6)−0.0017 (6)
C20.0209 (9)0.0182 (8)0.0196 (8)0.0019 (6)0.0025 (7)−0.0014 (6)
C30.0259 (9)0.0197 (8)0.0175 (8)0.0008 (7)0.0042 (7)−0.0034 (6)
C40.0362 (11)0.0236 (9)0.0209 (8)0.0085 (8)0.0056 (8)−0.0020 (7)
C50.0229 (9)0.0228 (9)0.0197 (8)0.0079 (7)0.0062 (7)0.0017 (7)
C60.0217 (9)0.0217 (8)0.0195 (8)0.0049 (7)0.0022 (7)−0.0007 (6)
C70.0163 (8)0.0215 (9)0.0203 (8)−0.0024 (6)0.0011 (6)−0.0014 (6)
C80.0156 (8)0.0221 (9)0.0243 (8)0.0041 (6)0.0058 (7)0.0012 (7)
C110.0130 (7)0.0148 (8)0.0246 (8)−0.0013 (6)0.0057 (6)−0.0009 (6)
C120.0247 (9)0.0215 (9)0.0319 (10)0.0015 (7)0.0097 (8)0.0040 (7)
C130.0167 (9)0.0281 (10)0.0312 (9)−0.0050 (7)0.0051 (7)−0.0033 (7)
C140.0229 (9)0.0274 (10)0.0234 (8)−0.0038 (7)0.0074 (7)−0.0028 (7)
C150.0183 (8)0.0168 (8)0.0213 (8)0.0009 (6)−0.0021 (6)0.0009 (6)
C160.0272 (10)0.0241 (9)0.0302 (9)0.0025 (8)−0.0097 (8)0.0021 (8)
C170.0263 (10)0.0181 (9)0.0315 (10)0.0055 (7)−0.0014 (8)0.0006 (7)
C180.0288 (10)0.0225 (9)0.0300 (9)0.0003 (8)0.0052 (8)0.0073 (7)
C210.0148 (8)0.0236 (9)0.0208 (8)0.0022 (7)0.0012 (6)−0.0007 (7)
C220.0385 (11)0.0218 (9)0.0228 (9)0.0025 (8)−0.0020 (8)0.0023 (7)
C230.0180 (9)0.0516 (13)0.0254 (9)0.0069 (9)0.0000 (7)0.0019 (9)
C240.0240 (9)0.0258 (9)0.0209 (8)−0.0009 (7)0.0044 (7)0.0000 (7)
C250.0145 (8)0.0199 (8)0.0258 (8)−0.0019 (6)0.0047 (6)0.0003 (7)
C260.0191 (9)0.0281 (10)0.0462 (11)−0.0043 (7)0.0120 (8)0.0042 (9)
C270.0234 (9)0.0204 (9)0.0363 (10)−0.0062 (7)0.0044 (8)−0.0022 (8)
C280.0265 (10)0.0236 (9)0.0324 (10)−0.0019 (7)0.0046 (8)0.0078 (8)
Geometric parameters (Å, º) top
Pd1—C12.0808 (16)C14—H14A0.9600
Pd1—P22.3226 (4)C14—H14B0.9600
Pd1—P12.3233 (4)C14—H14C0.9600
Pd1—Cl12.4405 (4)C15—C171.526 (2)
P1—C71.8352 (17)C15—C161.537 (2)
P1—C111.8810 (16)C15—C181.538 (2)
P1—C151.8828 (17)C16—H16A0.9600
P2—C81.8394 (17)C16—H16B0.9600
P2—C211.8827 (17)C16—H16C0.9600
P2—C251.8835 (17)C17—H17A0.9600
C1—C21.530 (2)C17—H17B0.9600
C1—C61.530 (2)C17—H17C0.9600
C1—H10.9800C18—H18A0.9600
C2—C71.522 (2)C18—H18B0.9600
C2—C31.529 (2)C18—H18C0.9600
C2—H20.9800C21—C241.532 (2)
C3—C41.513 (2)C21—C231.533 (2)
C3—H3A0.9700C21—C221.546 (2)
C3—H3B0.9700C22—H22A0.9600
C4—C51.529 (3)C22—H22B0.9600
C4—H4A0.9700C22—H22C0.9600
C4—H4B0.9700C23—H23A0.9600
C5—C61.529 (2)C23—H23B0.9600
C5—H5A0.9700C23—H23C0.9600
C5—H5B0.9700C24—H24A0.9600
C6—C81.522 (2)C24—H24B0.9600
C6—H60.9800C24—H24C0.9600
C7—H7A0.9700C25—C271.526 (2)
C7—H7B0.9700C25—C261.534 (2)
C8—H8A0.9700C25—C281.544 (2)
C8—H8B0.9700C26—H26A0.9600
C11—C131.528 (2)C26—H26B0.9600
C11—C141.533 (2)C26—H26C0.9600
C11—C121.537 (2)C27—H27A0.9600
C12—H12A0.9600C27—H27B0.9600
C12—H12B0.9600C27—H27C0.9600
C12—H12C0.9600C28—H28A0.9600
C13—H13A0.9600C28—H28B0.9600
C13—H13B0.9600C28—H28C0.9600
C13—H13C0.9600
C1—Pd1—P283.84 (5)C11—C13—H13C109.5
C1—Pd1—P182.82 (5)H13A—C13—H13C109.5
P2—Pd1—P1166.495 (15)H13B—C13—H13C109.5
C1—Pd1—Cl1174.27 (5)C11—C14—H14A109.5
P2—Pd1—Cl196.201 (14)C11—C14—H14B109.5
P1—Pd1—Cl196.853 (14)H14A—C14—H14B109.5
C7—P1—C11104.62 (7)C11—C14—H14C109.5
C7—P1—C15104.21 (8)H14A—C14—H14C109.5
C11—P1—C15112.70 (7)H14B—C14—H14C109.5
C7—P1—Pd1103.48 (6)C17—C15—C16109.18 (14)
C11—P1—Pd1116.43 (5)C17—C15—C18108.71 (14)
C15—P1—Pd1113.65 (5)C16—C15—C18108.39 (14)
C8—P2—C21105.91 (8)C17—C15—P1110.59 (11)
C8—P2—C25104.13 (8)C16—C15—P1114.69 (12)
C21—P2—C25111.83 (8)C18—C15—P1105.05 (11)
C8—P2—Pd1102.38 (6)C15—C16—H16A109.5
C21—P2—Pd1117.07 (5)C15—C16—H16B109.5
C25—P2—Pd1113.80 (5)H16A—C16—H16B109.5
C2—C1—C6110.78 (14)C15—C16—H16C109.5
C2—C1—Pd1114.66 (11)H16A—C16—H16C109.5
C6—C1—Pd1114.96 (11)H16B—C16—H16C109.5
C2—C1—H1105.1C15—C17—H17A109.5
C6—C1—H1105.1C15—C17—H17B109.5
Pd1—C1—H1105.1H17A—C17—H17B109.5
C7—C2—C3111.48 (13)C15—C17—H17C109.5
C7—C2—C1110.69 (13)H17A—C17—H17C109.5
C3—C2—C1112.39 (14)H17B—C17—H17C109.5
C7—C2—H2107.3C15—C18—H18A109.5
C3—C2—H2107.3C15—C18—H18B109.5
C1—C2—H2107.3H18A—C18—H18B109.5
C4—C3—C2112.57 (14)C15—C18—H18C109.5
C4—C3—H3A109.1H18A—C18—H18C109.5
C2—C3—H3A109.1H18B—C18—H18C109.5
C4—C3—H3B109.1C24—C21—C23109.83 (14)
C2—C3—H3B109.1C24—C21—C22107.91 (14)
H3A—C3—H3B107.8C23—C21—C22108.62 (15)
C3—C4—C5110.85 (14)C24—C21—P2110.58 (11)
C3—C4—H4A109.5C23—C21—P2113.75 (12)
C5—C4—H4A109.5C22—C21—P2105.90 (11)
C3—C4—H4B109.5C21—C22—H22A109.5
C5—C4—H4B109.5C21—C22—H22B109.5
H4A—C4—H4B108.1H22A—C22—H22B109.5
C4—C5—C6111.11 (14)C21—C22—H22C109.5
C4—C5—H5A109.4H22A—C22—H22C109.5
C6—C5—H5A109.4H22B—C22—H22C109.5
C4—C5—H5B109.4C21—C23—H23A109.5
C6—C5—H5B109.4C21—C23—H23B109.5
H5A—C5—H5B108.0H23A—C23—H23B109.5
C8—C6—C5112.41 (14)C21—C23—H23C109.5
C8—C6—C1110.62 (14)H23A—C23—H23C109.5
C5—C6—C1111.44 (14)H23B—C23—H23C109.5
C8—C6—H6107.4C21—C24—H24A109.5
C5—C6—H6107.4C21—C24—H24B109.5
C1—C6—H6107.4H24A—C24—H24B109.5
C2—C7—P1109.10 (11)C21—C24—H24C109.5
C2—C7—H7A109.9H24A—C24—H24C109.5
P1—C7—H7A109.9H24B—C24—H24C109.5
C2—C7—H7B109.9C27—C25—C26109.96 (15)
P1—C7—H7B109.9C27—C25—C28108.08 (14)
H7A—C7—H7B108.3C26—C25—C28108.45 (14)
C6—C8—P2108.99 (11)C27—C25—P2110.88 (12)
C6—C8—H8A109.9C26—C25—P2113.98 (12)
P2—C8—H8A109.9C28—C25—P2105.21 (11)
C6—C8—H8B109.9C25—C26—H26A109.5
P2—C8—H8B109.9C25—C26—H26B109.5
H8A—C8—H8B108.3H26A—C26—H26B109.5
C13—C11—C14109.63 (14)C25—C26—H26C109.5
C13—C11—C12108.94 (14)H26A—C26—H26C109.5
C14—C11—C12107.99 (14)H26B—C26—H26C109.5
C13—C11—P1113.85 (12)C25—C27—H27A109.5
C14—C11—P1110.77 (11)C25—C27—H27B109.5
C12—C11—P1105.41 (11)H27A—C27—H27B109.5
C11—C12—H12A109.5C25—C27—H27C109.5
C11—C12—H12B109.5H27A—C27—H27C109.5
H12A—C12—H12B109.5H27B—C27—H27C109.5
C11—C12—H12C109.5C25—C28—H28A109.5
H12A—C12—H12C109.5C25—C28—H28B109.5
H12B—C12—H12C109.5H28A—C28—H28B109.5
C11—C13—H13A109.5C25—C28—H28C109.5
C11—C13—H13B109.5H28A—C28—H28C109.5
H13A—C13—H13B109.5H28B—C28—H28C109.5
Acknowledgements top

Financial support from the Swedish Research Council and the Knut and Alice Wallenberg Foundation is gratefully acknowledged. We also thank the Crafoord foundation for a post-doctoral grant to JMJvR.

references
References top

Arunachalampillai, A., Olsson, D. & Wendt, O. F. (2009). Dalton Trans. pp. 8626–8630.

Castonguay, A., Sui-Seng, C., Zargarian, D. & Beauchamp, A. L. (2006). Organometallics, 25, 602–608.

CrystalMaker (2011). CrystalMaker. CrystalMaker Software Ltd, Oxfordshire, England. URL: www.CrystalMaker.com.

Jonasson, K. J., Ahlsten, N. & Wendt, O. F. (2011). Inorg. Chim. Acta, 379, 76–80.

Kuznetsov, V. F., Lough, A. J. & Gusev, D. G. (2006). Inorg. Chim. Acta, 359, 2806–2811.

Nilsson, P. & Wendt, O. F. (2005). J. Organomet. Chem. 690, 4197–4202.

Ohff, M., Ohff, A., van der Boom, M. E. & Milstein, D. (1997). J. Am. Chem. Soc. 119, 11687–11688.

Olsson, D., Arunachalampillai, A. & Wendt, O. F. (2007a). Dalton Trans. pp. 5427–5433.

Olsson, D., Janse van Rensburg, J. M. & Wendt, O. F. (2007b). Acta Cryst. E63, m1969.

Olsson, D. & Wendt, O. F. (2009). J. Organomet. Chem. 694, 3112–3115.

Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.

Pandarus, V. & Zargarian, D. (2007). Chem. Commun. pp. 978–980.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Sjövall, S., Wendt, O. F. & Andersson, C. (2002). J. Chem. Soc. Dalton Trans. pp. 1396–1400.