Tetra­ethyl­ammonium dibromido­tricarbon­yl(o-toluidine)rhenate(I)

Alice Brink; Hendrik G Visser; Andreas Roodt

doi:10.1107/S1600536810050038

. 2010 Dec 4;67(Pt 1):m32–m33. doi: 10.1107/S1600536810050038

Tetraethylammonium dibromidotricarbonyl(o-toluidine)rhenate(I)

Alice Brink ^a,^*, Hendrik G Visser ^a, Andreas Roodt ^a

PMCID: PMC3050163 PMID: 21522556

Abstract

In the title compound, (C₈H₂₀N)[ReBr₂(C₇H₉N)(CO)₃], the Re^I atom is octahedrally surrounded by three carbonyl ligands orientated in a facial arrangement, two bromide ligands and an o-toluidine ligand. The amine lies trans to the carbonyl ligand and is substitutionally disordered over two positions in a 0.66 (1):0.34 (1) ratio. An array of C—H⋯O, C—H⋯Br and N—H⋯Br hydrogen-bonding interactions between the cations and the surrounding rhenate anions stabilize the crystal structure.

Related literature

For the synthesis of the Re^I–tricarbonyl synthon, see: Alberto et al. (1996 ▶); Brink et al. (2009 ▶). For related rhenium–tricarbonyl complexes, see: Mundwiler et al. (2004 ▶); Wang et al. (2003 ▶); Saw et al. (2006 ▶); Schutte et al. (2008 ▶, 2009 ▶, 2010 ▶); Wei et al. (2003 ▶); Schibli et al. (2000 ▶). For kinetic studies of related Re compounds, see: Smith et al. (1996 ▶); Abou-Hamdan et al. (1998 ▶). For related dibromido structures, see: Alberto et al. (1999 ▶); Abram et al. (1998 ▶).

Experimental

Crystal data

(C₈H₂₀N)[ReBr₂(C₇H₉N)(CO)₃]
M _r = 667.45
Monoclinic,
a = 10.776 (2) Å
b = 18.466 (4) Å
c = 11.745 (2) Å
β = 106.74 (3)°
V = 2238.2 (8) Å³
Z = 4
Mo Kα radiation
μ = 9.02 mm⁻¹
T = 100 K
0.42 × 0.32 × 0.08 mm

Data collection

Bruker X8 APEXII 4K Kappa CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.116, T _max = 0.532
45095 measured reflections
5371 independent reflections
4411 reflections with I > 2σ(I)
R _int = 0.072

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.086
S = 1.06
5371 reflections
270 parameters
H-atom parameters constrained
Δρ_max = 2.5 e Å⁻³
Δρ_min = −2.99 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT-Plus (Bruker, 2004 ▶); data reduction: SAINT-Plus and XPREP (Bruker, 2004 ▶); program(s) used to solve structure: SIR92 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 2004 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810050038/bt5421sup1.cif

e-67-00m32-sup1.cif^{(23.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810050038/bt5421Isup2.hkl

e-67-00m32-Isup2.hkl^{(257.7KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1C⋯Br2ⁱ	0.92	2.7	3.542 (4)	153
N1—H1B⋯Br1ⁱ	0.92	2.75	3.594 (4)	153
C121—H12C⋯O03ⁱⁱ	0.98	2.5	3.139 (10)	123
C35—H35B⋯O03ⁱⁱⁱ	0.99	2.39	3.196 (7)	138
C37—H37A⋯Br1^iv	0.99	2.92	3.911 (6)	174

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

Acknowledgments

Financial assistance from the University of the Free State (UFS), the UFS Advanced Biomolecular Cluster, SASOL and the South African National Research Foundation (SA-NRF/THRIP) is gratefully acknowledged. Part of this material is based on work supported by the SA–NRF/THRIP under grant No. GUN 2068915. Opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the SA–NRF.

supplementary crystallographic information

Comment

The structure forms part of an ongoing investigation aimed at determining the structural and kinetic behaviour of fac-rhenium tricarbonyl complexes. Various rhenium bi- and tridentate tricarbonyl ligands have been synthesized (Mundwiler et al., 2004, Wang et al., 2003, Saw et al., 2006, Schutte et al., 2009, 2008, 2010, Wei et al., 2003, Schibli et al., 2000). A few crystallographic studies on dibromido monodentate rhenium compounds have been reported in literature (Alberto et al., 1999, Abram et al., 1998).

The title complex crystallized as a distorted octahedral anionic Re^I compound with one tetraethylammonium counter ion in the asymmetric unit (Fig. 1). The coordinated amine lies in an axial position below the equatorial plane, defined as Br1—Br2—C02—C03, and trans to a carbonyl ligand. It is disordered over two positions and the plane through the aromatic carbons lies at an angle of 35.2 (2)° to the equatorial plane. The Re—N bond distance (2.241 (4) Å) is longer than for the rhenium acetonitrile analogue (2.150 (6) Å) (Abram et al., 1998).

The longer Re—Br bond lengths (2.6390 (7) Å and 2.6370 (8) Å) are induced by the facially coordinated carbonyl ligands and compares well with related structures (Abram et al., 1998, Schutte et al., 2010). Intermolecular C—H···O, C—H···Br and N—H···Br hydrogen-bonding interactions are observed between rhenate anions and neighboring cations.

Experimental

[NEt₄]₂[Re(CO)₃Br₃] (0.13 mmol) (synthesized according to Alberto et al. (1996)) was dissolved in 6 ml methanol. The ligand 2-(o-tolyliminomethyl)phenol (0.14 mmol) (for related synthesis see Brink et al., 2009), containing 10% o-toluidine as byproduct, was dissolved in 6 ml MeOH and slowly added. The reaction mixture was stirred for 2 h at room temperature. Crystals of the title complex whereby the Re bonded preferentially to the amine were obtained by the slow evaporation of the solvent at 4°C.