Di-μ-bromido-bis­({2-[(4,6-dimethyl­pyrimidin-2-yl)disulfan­yl]-4,6-dimethyl­pyrimidine-κ2 N 1,S 2}copper(I))

Ruthairat Nimthong; Chaveng Pakawatchai; Yupa Wattanakanjana

doi:10.1107/S1600536812016315

. 2012 Apr 21;68(Pt 5):m645. doi: 10.1107/S1600536812016315

Di-μ-bromido-bis({2-[(4,6-dimethylpyrimidin-2-yl)disulfanyl]-4,6-dimethylpyrimidine-κ² N ¹,S ²}copper(I))

Ruthairat Nimthong ^a, Chaveng Pakawatchai ^a,^*, Yupa Wattanakanjana ^b

PMCID: PMC3344368 PMID: 22590134

Abstract

The title dinuclear complex, [Cu₂Br₂(C₁₂H₁₄N₄S₂)₂], is located about an inversion center. The Cu^I ion is coordinated in a distorted tetrahedral geometry by two bridging Br atoms in addition to an N and an S atom from the 2-[(4,6-dimethylpyrimidin-2-yl)disulfanyl]-4,6-dimethylpyrimidine ligand. In the crystal, π–π stacking interactions are observed with a centroid–centroid distance of 3.590 (2) Å.

Related literature

For potential applications of heterocyclic thioamides and their metal complexes, see: Battistuzzi & Peyronel (1981 ▶); Holm & Solomon (1996 ▶); Cox et al. (2006 ▶); Falcomer et al. (2006 ▶); Sevier & Kaiser (2006 ▶); Saxena et al. (2009 ▶). For related structures, see: Lemos et al. (2001 ▶); Aslanidis et al. (2004 ▶); Freeman et al. (2008 ▶).

Experimental

Crystal data

[Cu₂Br₂(C₁₂H₁₄N₄S₂)₂]
M _r = 843.68
Monoclinic,
a = 15.3351 (7) Å
b = 15.3898 (7) Å
c = 14.3398 (7) Å
β = 109.178 (1)°
V = 3196.4 (3) Å³
Z = 4
Mo Kα radiation
μ = 4.12 mm⁻¹
T = 293 K
0.21 × 0.18 × 0.10 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: integration (SADABS; Bruker, 2003 ▶) T _min = 0.425, T _max = 0.662
12339 measured reflections
2732 independent reflections
2344 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.028
wR(F ²) = 0.077
S = 1.04
2732 reflections
181 parameters
55 restraints
H-atom parameters constrained
Δρ_max = 0.37 e Å⁻³
Δρ_min = −0.31 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT (Bruker, 2003 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97 and publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812016315/lh5449sup1.cif

e-68-0m645-sup1.cif^{(20.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812016315/lh5449Isup2.hkl

e-68-0m645-Isup2.hkl^{(134.2KB, hkl)}

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

Acknowledgments

We gratefully acknowledge financial support from the Center for Innovation in Chemistry (PERCH–CIC), the Commission on Higher Education, Ministry of Education, the Department of Chemistry and the Graduate School, Prince of Songkla University.

supplementary crystallographic information

Comment

The studies of cooordination multidentate ligands such as heterocyclic thioamides, in complexes of closed-shell d¹⁰ metal ions, have been shown attention from a number of researchers (Saxena et al., 2009; Cox et al., 2006; Falcomer et al., 2006) because of their interesting biochemical properties and presence in active sites of many metalloproteins (Holm & Solomon, 1996; Battistuzzi & Peyronel, 1981). Particularly, the formation of disulfide bonds is an essential step in the folding and assembly of the extracellular domains of many membrane and secreted proteins which are important features of the structure of many proteins (Sevier & Kaiser, 2006).

The molecular structure of the title compound is shown in Fig. 1. The complex is dinuclear in which the Cu^I ions adopt distorted tetrahedral geometries. There is a binuclear µ,µ'-dibromobridged CuBr₂Cu core. The Cu—S and Cu—N distances are similar to those reported for other thioamide containing complexes (Aslanidis et al., 2004; Lemos et al., 2001) and the disulfide bond distances is shorter than that reported in a related compound with a disulfide bond (Freeman et al., 2008). The 'bite' angle S—Cu—N angle is 90.77 (7)°. The molecule lies on a crystallographic inversion center which is at the center of the CuBr₂Cu core with a Cu···Cu separation of 2.7802 (7) Å. This value is close the sum of the van der Waals radii for two Cu atoms (2.8 Å). In the crystal π–π stacking interactions with a centroid to centroid distance of 3.590 (2) Å are observed (Fig. 2). In addition, fairly short C(sp³)—H···N intermolecular distances (H···N = 2.67 Å, C(sp³)—N = 3.41 Å and C(sp³)—H···N = 134.2°) are observed (Fig. 3).

Experimental

4,6-Dimethyl-2-pyrimidinethiol, dmpymtH, (0.07 g, 0.50 mmol) was dissolved in 30 cm³ of methanol at 343-348K. CuBr (0.1 g, 0.70 mmol) was added and the mixture was stirred for 5 h. The resulting clear solution was filtered off and left to evaporate at room temperature. The crystalline complex, which was deposited upon standing for several days, was filtered off and dried in vacuo (yield 75%).