trans-Carbonyl­chloridobis(ethyl­diphenyl­phosphine-κP)rhodium(I)

Fabio Lorenzini; Brian O Patrick; Brian R James

doi:10.1107/S1600536807065877

. 2007 Dec 12;64(Pt 1):m179–m180. doi: 10.1107/S1600536807065877

trans-Carbonylchloridobis(ethyldiphenylphosphine-κP)rhodium(I)

Fabio Lorenzini ^a, Brian O Patrick ^a, Brian R James ^a,^*

PMCID: PMC2915114 PMID: 21200527

Abstract

The title compound, [RhCl(C₁₄H₁₅P)₂(CO)], crystallizes with two almost identical molecules in the asymmetric unit. The molecules have the Rh^I atom in a square-planar geometry. The crystal structure involves intermolecular C—H⋯O hydrogen bonds.

Related literature

For related literature, see: Beck et al. (1999 ▶); Higham et al. (2004 ▶); Hoye et al. (1993 ▶); Lorenzini et al. (2007a ▶,b ▶,c ▶); O’Connor & Wilkinson (1969 ▶); Vallarino (1957 ▶); Vaska & Di Luzio (1961 ▶, 1962 ▶).

Experimental

Crystal data

[RhCl(C₁₄H₁₅P)₂(CO)]
M _r = 594.83
Monoclinic,
a = 9.8557 (14) Å
b = 16.385 (2) Å
c = 16.381 (2) Å
β = 90.216 (6)°
V = 2645.3 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.89 mm⁻¹
T = 173.0 (1) K
0.15 × 0.15 × 0.07 mm

Data collection

Bruker X8 APEXII diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2003 ▶) T _min = 0.701, T _max = 0.940
41680 measured reflections
12665 independent reflections
8610 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.080
S = 0.98
12665 reflections
668 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.45 e Å⁻³
Δρ_min = −0.36 e Å⁻³
Absolute structure: Flack (1983 ▶), 6047 Friedel pairs
Flack parameter: 0.04 (4)

Data collection: SAINT (Bruker, 1997 ▶); cell refinement: SAINT; data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536807065877/ng2391sup1.cif

e-64-0m179-sup1.cif^{(39.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807065877/ng2391Isup2.hkl

e-64-0m179-Isup2.hkl^{(606.7KB, hkl)}

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

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

C57—Rh1	1.803 (13)
Cl1—Rh1	2.386 (3)
C58—Rh2	1.770 (17)
Cl2—Rh2	2.409 (4)
P1—Rh1	2.3161 (11)
P2—Rh1	2.3207 (11)
P3—Rh2	2.3154 (11)
P4—Rh2	2.3132 (11)

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C57—Rh1—P1	89.8 (4)
C57—Rh1—P2	89.8 (4)
P1—Rh1—P2	178.85 (7)
C57—Rh1—Cl1	178.9 (4)
P1—Rh1—Cl1	89.65 (9)
P2—Rh1—Cl1	90.70 (9)
C58—Rh2—P4	91.4 (5)
C58—Rh2—P3	89.2 (5)
P4—Rh2—P3	179.25 (7)
C58—Rh2—Cl2	177.0 (5)
P4—Rh2—Cl2	89.25 (12)
P3—Rh2—Cl2	90.22 (11)

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C22—H22⋯O2ⁱ	0.95	2.64	3.424 (18)	140
C48—H48⋯O1Bⁱⁱ	0.95	2.68	3.51 (3)	145
C4—H4⋯O1Bⁱⁱⁱ	0.95	2.71	3.51 (3)	142

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The authors thank the Natural Sciences and Engineering Research Council of Canada for financial support via a Discovery Grant.

supplementary crystallographic information

Comment

We have recently reported the syntheses of water-soluble Rh^I—THP complexes (THP is tris(hydroxymethyl)phosphine, P(CH₂OH)₃) (Lorenzini et al., 2007a). During a subsequent study of the general reactivity of such complexes with other potential ligands, we discovered a remarkable reaction of RhCl(cod)(THP), where cod = 1,5-cyclooctadiene, with several PRR'₂ phosphines (R = or ≠ R'), that generates, concomitantly with R'H, the phosphine-phosphinite derivatives RhCl(PRR'₂)[P,P—R'(R)POCH₂P(CH₂OH)₂] in two isomeric cis- and trans-forms (cis and trans refer to the disposition of the P-atoms with the R and R' substituents) (Lorenzini et al., 2007b). Such reactions, when investigated under a hydrogen atmosphere, led to the serendipitous isolation of the dihydrido complexes cis,mer-Rh(H)₂Cl(PRR'₂)₃, where R = Me, R' = Ph, or R = Cy, R' = Ph (Lorenzini et al., 2007c). ³¹P{¹H} NMR data suggested the presence of traces of trans-RhCl(CO)(PRR'₂)₂ in some of the isolated RhCl(PRR'₂)[P,P—R'(R)POCH₂P(CH₂OH)₂] complexes and in the in situ preparative solutions of the phosphine-phosphinite and dihydrido species (Lorenzini et al., 2007b). The carbonyl ligand is thought to arise via decarbonylation of formaldehyde which can be readily formed from transition metal-THP species (Higham et al., 2004; Hoye et al., 1993); the Wilkinson-type complex such as RhCl(PPh₃)₃ is well known to decarbonylate aldehydes with formation of trans-RhCl(CO)(PPh₃)₂ (Beck et al., 1999). The suggested formation of trans-RhCl(CO)(PRR'₂)₂ has now been confirmed by X-ray structural analysis of a single-crystal of trans-RhCl(CO)(PEtPh₂)₂ that was precipitated in trace yield during the reaction of RhCl(cod)(THP) with PEtPh₂, under a hydrogen atmosphere.

The complex trans-RhCl(CO)(PPh₃)₂ was first reported 50 years ago (Vallarino, 1957), but it was not until the Ir analogue (Vaska's compound) was synthesized (Vaska & Di Luzio, 1961) and shown to oxidatively add H₂ and other small molecules (Vaska & Di Luzio, 1962) that interest in such d⁸ square-planar molecules intensified. According to the Cambridge Crystallography Data Base, there have been 125 crystallographically characterized complexes of the type trans-RhCl(CO)(P-phosphine)₂, where (P-phosphine)₂ represents two monodentate ligands or one bidentate phosphine ligand but there are none containing PEtPh₂. Indeed, in spite of the vast literature on the chemistry of Rh-phosphine complexes, we can find no other example of any isolated Rh-complex containing PEtPh₂, although an in situ RhCl/PEtPh₂ species has been noted (O'Connor & Wilkinson, 1969).

Experimental

General. The RhCl(cod)(THP) complex was synthesized by our recently reported method; (Lorenzini et al., 2007a) and PEtPh₂ was used as received from Strem Chemicals. The Rh-phosphine reaction was carried out under Ar or H₂ using standard Schlenk techniques. Acetone-d₆ and CD₃OD (Cambridge Isotope Laboratory) were used as received. ³¹P{¹H}-NMR spectra were measured in acetone-d₆ and CD₃OD at room temperature (~300 K) on a Bruker AV400 spectrometer. External 85% aq H₃PO₄ were used as references (d = doublet, m = multiplet).

Trans-RhCl(CO)(PEtPh₂)₂. Addition of PEtPh₂ (12 µL, 0.057 mmol) in acetone-d₆ (0.3 ml) to a yellow CD₃OD solution (0.3 ml) of RhCl(cod)(THP) (10 mg, 0.026 mmol) at room temperature under Ar results in the immediate formation of a brown solution. The Ar is then replaced by H₂ and the vessel shaken, this resulting in a yellow solution. Over 12 h, a minute quantity of X-ray quality, yellow prism crystals of trans-RhCl(CO)(PEtPh₂)₂ deposit from the solution; the ³¹P{¹H} of the yellow solution shows the doublet resonance of the title compound (δ 27.49, d, J_PRh = 123.4 Hz) and also resonances at δ 36.64 (dd, 2P, J_PRh = 112.0, J_PP = 21.0 Hz, trans-P), and 18.29 (m, 1P, P-trans to Cl) thought to be due to RhCl(PEtPh₂)₃.