[1,1′-Bis(diphenyl­phosphino)ferrocene]carbon­yl[dihydro­bis(pyrazol-1-yl)borato]hydridoruthenium(II) acetone solvate

Seong Huh; Alan J Lough

doi:10.1107/S1600536808037100

. 2008 Nov 13;64(Pt 12):m1544–m1545. doi: 10.1107/S1600536808037100

[1,1′-Bis(diphenylphosphino)ferrocene]carbonyl[dihydrobis(pyrazol-1-yl)borato]hydridoruthenium(II) acetone solvate

Seong Huh ^a,^*, Alan J Lough ^b

PMCID: PMC2960072 PMID: 21581157

Abstract

In the title compound, [FeRu(C₁₇H₁₄P)₂(C₆H₈BN₄)H(CO)]·C₃H₆O, the Ru^II ion is coordinated in a distorted octahedral environment involving a hydride ligand, a carbonyl ligand and two bidentate ligands. Of the two bidentate ligands, the bulky 1,1′-bis(diphenylphosphino)ferrocene (dppf) ligand chelates with a larger bite angle of 101.90 (2)°, whereas the bite angle of the [H₂Bpz₂]⁻ ligand (pz = pyrazolyl) is 85.67 (7)°. The latter ligand creates an RuN₄B six-membered ring with a boat conformation, which puckers towards the site of the small hydride ligand. The hydride ligand is cis with respect to the carbonyl ligand and trans to one of the P atoms of the dppf ligand. In the crystal structure, there are weak intermolecular C—H⋯O hydrogen bonds between complex molecules and acetone solvent molecules.

Related literature

For background information on Ru^II complexes, see: Buriez et al. (1999 ▶); Han et al. (1996 ▶); Hill et al. (1998 ▶); Huh et al. (1996 ▶); Na et al. (1996 ▶); Sánchez-Delgado et al. (1986 ▶). For related structures, see: Huh et al. (1999 ▶, 2000 ▶).

Experimental

Crystal data

[FeRu(C₁₇H₁₄P)₂(C₆H₈BN₄)H(CO)]·C₃H₆O
M _r = 889.49
Monoclinic,
a = 9.0730 (2) Å
b = 29.9785 (5) Å
c = 14.7960 (3) Å
β = 94.617 (1)°
V = 4011.38 (14) Å³
Z = 4
Mo Kα radiation
μ = 0.86 mm⁻¹
T = 100 (1) K
0.20 × 0.20 × 0.12 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: multi-scan (DENZO-SMN; Otwinowski & Minor, 1997 ▶) T _min = 0.847, T _max = 0.904
41892 measured reflections
11681 independent reflections
7603 reflections with I > 2σ(I)
R _int = 0.064

Refinement

R[F ² > 2σ(F ²)] = 0.038
wR(F ²) = 0.079
S = 0.94
11681 reflections
508 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.60 e Å⁻³
Δρ_min = −0.50 e Å⁻³

Data collection: COLLECT (Nonius, 2002 ▶); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997 ▶); data reduction: DENZO-SMN; program(s) used to solve structure: SIR92 (Altomare et al., 1994 ▶); program(s) used to refine structure: SHELXTL (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808037100/is2360sup1.cif

e-64-m1544-sup1.cif^{(31KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808037100/is2360Isup2.hkl

e-64-m1544-Isup2.hkl^{(366.3KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Ru1—H1	1.60 (2)
Ru1—C1	1.832 (2)
Ru1—N1	2.1469 (17)
Ru1—N3	2.1514 (18)
Ru1—P1	2.3025 (6)
Ru1—P2	2.4813 (6)

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C10—H10A⋯O1S	1.00	2.45	3.426 (3)	166
C32—H32A⋯O1Sⁱ	0.95	2.45	3.251 (3)	142

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work was supported by Hankuk University of Foreign Studies Research Fund of 2008.

supplementary crystallographic information

Comment

Hydridocarbonyl Ru^II polyphophine complexes are excellent catalyst precursors for the homogeneous hydrogenation of carbonyl groups such as aldehydes and ketones under molecular hydrogen atomosphere (Sánchez-Delgado et al., 1986; Huh et al., 1996; Na et al., 1996). Poly(azolyl)borate Ru^II complexes are also versatile organometallic catalyst precursors for various organic reactions (Buriez et al., 1999). Most of the poly(azolyl)borate complexes possess potentially tridentate hydrotris(pyrazol-1-yl)borate derivatives (Buriez et al., 1999). However, Hill et al. (1998) reported Ru^II complexes with a bidentate dihydrobis(pyrazol-1-yl)borate ligand, [H₂Bpz₂]^- (pz = pyrazolyl), and their reactivity with various unsaturated organic groups. We have also structurally characterized two hydridocarbonyl Ru^II complexes bearing a bidentate dihydrobis(pyrazol-1-yl)borate ligand (Huh et al., 1999; 2000). These compounds are potentially efficient catalyst precursors for the homogeneous hydrogenation of aldehydes and ketones.

As the dihydrobis(pyrazol-1-yl)borate ligand usually occupies no more than two coordination sites of a transition metal ion, it may be advantageous to introduce additional chelate ligands to further control the electronic and steric factors of the Ru^II complex (Huh et al., 1996). In this regard, we successfully prepared and characterized a new Ru^II compound with two different bidentate ligands. A ligand displacement reaction of RuH(PPh₃)₂(η²-H₂Bpz₂)(CO) by 1,1'-bis(diphenylphosphino)ferrocene (dppf) yielded the title compound RuH(CO)(dppf)(η²-H₂Bpz₂).CH₃COCH₃, (I), which contains two different bidentate ligands, a neutral dppf ligand with two P donor atoms and an anionic [H₂Bpz₂]^- ligand with two N donor atoms. The two mutually trans-positioned PPh₃ ligands of the starting Ru^II complex were successfully replaced by the dppf ligand.

The dppf ligand coordinates to the Ru^II ion in the normal bidentate chelation mode as shown in Figure 1. The dppf ligand is bulkier than the [H₂Bpz₂]^- ligand and hence the bite angle for the dppf ligand, P1—Ru1—P2, is 101.90 (2)°. This value is not significantly different from that in the known structure of [RuH(dppf)(NCCH₃)(PPh₃)(CO)]⁺, 102.15 (9)° (Han et al., 1996). The N1—Ru1—N3 bite angle is much smaller with a value of 85.67 (7)° A six-membered ring consisting of atoms of Ru1/N1—N4/B1 is in a boat conformation which is puckered towards the hydride ligand.

The longer Ru1—P2 bond (compared to Ru1—P1) may be attributed to the stronger trans effect of the hydride ligand than nitrogen donor atom of [H₂Bpz₂]^-. The overall coordination environment of Ru^II ion is a distorted octahedral geometry. The two cyclopentadienyl rings of the dppf ligand show a staggered geometry.

Experimental

A reaction mixture of RuH(PPh₃)₂(η²-H₂Bpz₂)(CO) (207 mg, 0.258 mmol; Hill et al. 1998) and dppf (213 mg, 0.516 mmol) in 40 ml CH₂Cl₂ was heated under reflux in a nitrogen atmosphere for 22 h. The resulting solution was evaporated to dryness after filtration. The crude solids were dissolved in a minimum amount of acetone and stored at 258 K. X-ray quality yellow block crystals were obtained. The crystals were collected, washed with hexane and air-dried. Anal. Calcd for C₄₁H₃₇BN₄FeOP₂Ru.C₃H₆O: C, 59.41; H, 4.87; N, 6.30. Found: C, 59.32; H, 4.77; N, 6.23. IR (KBr): ν(BH₂) 2408, 2365, 2342, 2279, ν(CO) 1924 cm^{-1. 1}H NMR (CDCl₃, 298 K, TMS, Bruker AMX 500, 500 MHz): δ -6.28 (dd, 1H, ²J = 127.9, 26.4 Hz) p.p.m..