catena-Poly­[bromo(ω-thio­capro­lactam-κS)­gold(I)](Au—Au)

The title compound, [AuBr(C₆H₁₁NS)]_n, formed through an Au^IIIAu^I reduction process, presents a polymeric structure including Au chains with alternating Au—Au distances of 3.0898 (8) and 3.1181 (8) Å. The coordination geometry is best described on the basis of linear [AuBr(C₆H₁₁NS)] mol­ecules, which are associated into a one-dimensional polymer via a common aurophilic interaction.

S1. Comment

As an extension of our work on the extractive properties of ω-thiocaprolactam (1-azacycloheptane-2-thione, Hthcl) in liquid-liquid separation processes, we recently oriented our efforts toward gold. Au^I is classified as a soft acid and is known to coordinate a variety of soft bases, particularly S-containing ligands. For instance, thiourea gives a very stable water-soluble Au^I complex, [Au{S═C(NH₂)₂}₂]⁺, which is useful in the extraction of gold from ores (Chernyak et al., 1979). Moreover, Au compounds with S ligands are of current interest owing to their fascinating structural chemistry, and due to their wide variety of applications in classical and modern technologies (Schmidbaur Grohmann Olmos & Schier, 1999; Schmidbaur Grohmann & Olmos, 1999) and in medicine (Brown & Smith, 1980; Shaw, 1999). We previously reported the efficiency of Hthcl for binding late transition metals with a d¹⁰ electronic configuration, such as Hg^II (Nuñez Gaytán et al., 1998) and Cd^II and Ag^I (Bernès et al., 1999). We now report the preparation and characterization of the title compound, (I), the first Au^I complex including Hthcl as ligand. \sch

The asymmetric unit of (I) contains two Au^I ions, two Br⁻ anions and two S-coordinated Hthcl ligands, with all atoms lying on general positions (Fig. 1). The two Au^I cations present similar coordination geometries (Table 1). The Br and Hthcl moieties are trans-coordinated [Br—Au—S angles 172.75 (9) for Au1 and 170.69 (9)° for Au2], and a dimeric fragment is formed through an Au—Au single bond. These [AuBr(Hthcl)]₂ units are joined via an intermolecular Au···Au interaction [Au—Au1···Au 143.595 (18) and Au—Au2···Au 148.803 (17)°], forming a one-dimensional inorganic polymer based on an [Au1—Au2]_∞ chain running along a 2₁ axis parallel to b (Fig. 2). These chains are densely packed in the crystalline state, reaching a packing-index of 0.706 (Spek, 2003). The two metal centres are chemically identical Au^I cations, as evidenced from electrochemical reduction of (I) (see Experimental). On the other hand, the Hthcl ligands are unaffected by the polymeric character of (I) and retain the geometry of the free ligand (Mozzhukhin et al., 1993; Núñez Gaytán, 1997), characterized by a chair conformation for the seven-membered ring and an actual C═S bond [1.677 (13) and 1.689 (13) Å]. However, this bond is slightly weakened by coordination to Au, as reflected in the shift of 45 cm⁻¹ for the C═S stretching vibration (see Experimental).

Numerous homometallic polymeric species including an Au chain and monodentate ligands have been reported, which can be structurally classified as follows. The minimal empirical formula for the complex being [AuL₁L₂], the corresponding polymer may be either a homopolymer or a copolymer, which, in the crystalline state, is necessarily regular. For the former class, Au ions coordinate two different ligands L₁ and L₂, while in the latter, Au(L₁)₂ and Au(L₂)₂ fragments alternate along the chain. The same formula may even be crystallized in both forms, as reported with L₁ = Cl and L₂ = pyridine (Jones & Ahrens, 1998). An exhaustive classification of these compounds should consider the special case L₁ = L₂: the resulting homopolymer is then a cationic species (e.g. Jiang et al., 2000).

Compound (I) belongs to the homopolymer class. The arrangement of the ligands along the chain is characterized by the X—Au1—Au2—X torsion angles, where X is Br1, Br2, S1, S2, or a symmetry-related Au centre. All these angles are close to 0 or 90°. This feature extends along the polymeric chain, i.e. it can be observed for torsion angles about Au1—Au2ⁱ [symmetry code: (i) 1 − x, y + 1/2, 1/2 − z; Table 1]. Each independent Au atom thus apparently presents an almost square-planar geometry, with cis angles in the range 87.48 (4)–96.53 (9)° (Table 1). However, on the basis of orbital theory considerations, a tetrahedral geometry (6 s6p³-hybridized metal centre) is expected for a four-coordinate Au^I atom, rather than a square-planar geometry (5 d6s6p² hybridization). Clearly, the actual coordination geometry around the metal centres is linear. Compound (I) consists of linear [AuBr(Hthcl)] molecules, centred on common 6 s6p-hybridized Au^I ions, with aurophilic (i.e. non-covalent) intermolecular interactions. To a certain extent, this interpretation of the X-ray structure is analogous to that used for complexes of the copolymer class. A copolymer with formula [AuL₁L₂] may be re-formulated as [Au(L₁)₂]⁺·[Au(L₂)₂]⁻, with intermolecular aurophilic interactions. This description given for (I) is in full agreement with numerous reports on Au^I complexes with a linear geometry which present aurophilic interactions, a well documented phenomenon (Schmidbaur, 2000).

Some reports quantified these aurophilic interactions and concluded that they are similar in strength to hydrogen bonds, i.e. 7–11 kcal mol⁻¹ (Schmidbaur, 1995; Harwell et al., 1996; 1 kcal mol⁻¹ = 4.184 kJ mol⁻¹). From a structural point of view, it was established that two-coordinate Au^I complexes experience an attractive aurophilic interaction if the Au···Au separation is less than 3.6 Å (Pathaneni & Desiraju, 1993). This criterion is verified in the case of (I), with separations Au1—Au2 = 3.0898 (8) Å within the asymmetric unit and Au1···Au2ⁱ = 3.1181 (8) Å for the link between asymmetric units. These values are far from the Au···Au separation reported for metallic gold (2.877 Å; Wells, 1975), but are comparable with those found in related [AuL₁L₂] polymers based on an infinite chain of Au atoms. Hitherto, three such complexes have been structurally characterized, all with L₁ = Br. With L₂ = pyridine (Conzelmann et al., 1984), the Au···Au separations are 3.302 and 3.562 Å. With L₂ = o-xylylisocyano, one Au···Au distance is observed, of 3.348 Å (Ecken et al., 1998). Finally, with L₂ = tetrahydrothiophene (Ahrland et al., 1993), this separation is 3.353 Å. Shorter Au···Au distances are obtained by using bridging ligands, such as thiocarbamates (Bishop et al., 1998), which constrain the geometry of the Au chain (Au···Au 2.790 and 3.157 Å for the covalent bond and the aurophilic interaction, respectively).

A careful scrutiny of these geometrical features leads to a general conclusion for (I). Assuming a direct correlation between bond length and bond strength, the covalent bond and aurophilic interaction in (I) probably have very similar strengths. The above mentioned range, namely 7–11 kcal mol⁻¹ per Au···Au contact, thus seems to be underestimated, at least for (I) and related compounds. Another noteworthy conclusion related to liquid-liquid extraction of gold by means of Hthcl or related S-containing molecules, is that these aurophilic interactions may be sufficiently strong to persist in solution (Balch et al., 1990). The ¹³C NMR spectrum of (I) is complicated (see Experimental), which may result from partial decomposition into oligomers, conformational changes for Hthcl, thio-enolization of Hthcl, or a combination of these three phenomena.

Up to now, using Hthcl as ligand, we have obtained different solid-state structures with each d¹⁰ metal studied – monomer, cyclic oligomer or polymer. In the present case, a Au^III → Au^I reduction is observed during the course of the reaction (see Experimental), which is not surprising because (I) crystallizes slowly. On the other hand, the low yield obtained for a reaction which should be almost quantitative suggests the formation of other uncharacterized compounds, including Au^III complexes. This is supported by the isolation of a monomeric Au^III complex when using AuCl₃ (or HAuCl₄) as starting material (Núñez Gaytán et al., 2004). A more thorough rationalization of this complex behaviour of Hthcl towards Au^III will be the subject of future studies.

S2. Experimental

A 0.01 M solution of ω-thiocaprolactam in CHCl₃ was prepared. AuBr₃ (0.044 g, 0.1 mmol) was added to this solution (10 ml, 0.1 mmol of ω-thiocaprolactam). After stirring for 2 h at 300 K, the mixture was filtered and allowed to concentrate slowly in a test tube at 277 K. A slow rate of evaporation (several weeks) is essential for obtaining the title compound. A brown solid was collected after drying the crude product in air (yield 25.6%, 10.4 mg). Repeated crystallization of this solid by slow evaporation of an AcOEt solution at 300 K afforded suitable single crystals of (I). ATR/FT—IR (attenuated total reflectance/Fourier-transform infra-red spectroscopy) data were obtained on a Perkin-Elmer GX equipped with a diamond ATR sampling accessory (DuraSampl IR II from SensIR Technologies): ν_max(C═S) = 1546 cm⁻¹ for Hthcl, 1501 cm⁻¹ for (I); ν_max(N—H) = 3170 cm⁻¹ for Hthcl, 3364 cm⁻¹ for (I). ¹³C NMR (100 MHz, CH₃OD): 18 signals in the range 24.20–43.56 p.p.m.. None of these signals corresponds to free Hthcl; the signal for C═S is not detected, a common feature for this class of complexes (e.g. Raubenheimer et al., 1992). Electrochemical measurements were made using an EG&G model 273 potentiostat/galvanostat. A platinum disc working electrode, a platinum wire auxiliary electrode and a silver pseudoreference electrode (immersed in the supporting electrolyte and separated from the working solution by a fritted glass disc) were used in a three-electrode configuration. All experiments were done in 0.1 M TBAP (Please define) in CH₂Cl₂ under a dry N₂ atmosphere at 290 K with a scan rate of 50 mV s⁻¹. The peak potential for the chemically irreversible reduction of Au^I to Au⁰ is −0.745 V, referenced to the observed half-wave potential for the couple Cp₂Fe⁺/Cp₂Fe.

S3. Refinement

Due to the high µ × R value for the crystal of (I), absorption correction was applied through a ΔF refinement procedure instead of using collected ψ-scans data, which gave a somewhat worse final refinement [R₁ = 0.0476 for 2455 I>2σ(I), versus R₁ = 0.0430 for the refinement reported here]. The structure was first refined isotropically and all H atoms placed in idealized positions (R₁ = 0.0940). DIFABS (Walker & Stuart, 1983) from the WinGX system (Farrugia, 1999) was then applied to the raw diffraction data, and the model was refined to convergence. The accuracy of the applied correction is far from perfect, as evidenced by the high residual peak observed in the final difference map, 1.5 e Å⁻³ close to atom Au1. Unfortunately, the crystal shape was considered to be inappropriate for an accurate and error-free numerical absorption correction. H atoms were refined using a riding model, with constrained distances of N—H = 0.86 Å and C—H = 0.97 Å, and with U_iso(H) = 1.2U_eq(parent atom).

Computing details

Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXTL-Plus (Sheldrick, 1998); program(s) used to refine structure: SHELXTL-Plus; molecular graphics: SHELXTL-Plus and Mercury (Bruno et al., 2002); software used to prepare material for publication: SHELXTL-Plus.

Figures

	Fig. 1. Part of the polymeric structure of (I), showing the atom labelling for the asymmetric unit. Displacement ellipsoids are drawn at the 30% probability level. H atoms bonded to C atoms have been omitted for clarity. Dashed bonds indicate the direction of polymerization.
	Fig. 2. A view, along the a axis, of the unit cell of (I). H atoms have been omitted for clarity. [Symmetry codes: (i) 1 − x, y − 1/2, 1/2 − z; (ii) 1 − x, y + 1/2, 1/2 − z].

catena-Poly[bromo(ω-thiocaprolactam-κS)gold(I)](Au—Au)

Crystal data

[AuBr(C6H11NS)]	F(000) = 1472
Mr = 406.09	Dx = 2.808 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 72 reflections
a = 10.1039 (10) Å	θ = 4.2–12.3°
b = 11.3131 (16) Å	µ = 19.62 mm^−1
c = 17.4278 (19) Å	T = 296 K
β = 105.314 (9)°	Irregular prism, brown
V = 1921.4 (4) Å^3	0.32 × 0.12 × 0.10 mm
Z = 8

Data collection

Bruker P4 diffractometer	2455 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube, FN4	Rint = 0.035
Graphite monochromator	θmax = 25.0°, θmin = 2.1°
ω scans	h = −12→2
Absorption correction: part of the refinement model (ΔF) (Walker & Stuart, 1983)	k = −13→1
Tmin = 0.040, Tmax = 0.139	l = −20→20
4490 measured reflections	3 standard reflections every 97 reflections
3374 independent reflections	intensity decay: 1.5%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.043	H-atom parameters constrained
wR(F^2) = 0.106	w = 1/[σ^2(Fo^2) + (0.0476P)^2 + 9.115P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
3374 reflections	Δρmax = 1.51 e Å^−3
182 parameters	Δρmin = −1.31 e Å^−3
0 restraints	Extinction correction: SHELXL97 in SHELXTL-Plus (Sheldrick, 1998), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00047 (7)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Au1	0.40908 (5)	0.49442 (5)	0.21360 (3)	0.05113 (18)
Au2	0.54151 (5)	0.24807 (4)	0.21452 (3)	0.04742 (18)
Br1	0.31043 (13)	0.42248 (13)	0.31730 (9)	0.0608 (4)
Br2	0.33317 (14)	0.18068 (13)	0.11993 (8)	0.0606 (4)
S1	0.4768 (4)	0.5550 (3)	0.10464 (19)	0.0579 (8)
S2	0.7551 (3)	0.3001 (3)	0.28887 (18)	0.0523 (8)
N1	0.7234 (10)	0.5863 (11)	0.2037 (6)	0.058 (3)
H1A	0.6849	0.5639	0.2398	0.070*
C1	0.6441 (12)	0.5897 (10)	0.1310 (6)	0.045 (3)
C2	0.7081 (13)	0.6321 (12)	0.0670 (8)	0.057 (3)
H2A	0.7469	0.7100	0.0812	0.069*
H2B	0.6371	0.6392	0.0174	0.069*
C3	0.8201 (17)	0.5502 (14)	0.0543 (9)	0.076 (5)
H3A	0.7883	0.4693	0.0544	0.091*
H3B	0.8330	0.5658	0.0020	0.091*
C4	0.9557 (16)	0.5601 (16)	0.1139 (10)	0.082 (5)
H4A	0.9900	0.6397	0.1112	0.098*
H4B	1.0189	0.5064	0.0985	0.098*
C5	0.9585 (14)	0.5347 (15)	0.1994 (9)	0.071 (4)
H5A	0.9290	0.4539	0.2034	0.086*
H5B	1.0521	0.5416	0.2320	0.086*
C6	0.8691 (14)	0.6157 (15)	0.2312 (9)	0.075 (4)
H6A	0.8970	0.6127	0.2888	0.090*
H6B	0.8825	0.6960	0.2152	0.090*
N11	0.6388 (10)	0.3478 (9)	0.4047 (6)	0.050 (3)
H11A	0.5639	0.3273	0.3708	0.060*
C11	0.7507 (12)	0.3430 (11)	0.3810 (8)	0.048 (3)
C12	0.8859 (12)	0.3751 (13)	0.4393 (8)	0.062 (4)
H12A	0.9573	0.3735	0.4115	0.074*
H12B	0.8796	0.4554	0.4575	0.074*
C13	0.9273 (13)	0.2963 (15)	0.5101 (8)	0.068 (4)
H13A	1.0256	0.3035	0.5326	0.082*
H13B	0.9085	0.2151	0.4926	0.082*
C14	0.8563 (15)	0.3211 (14)	0.5754 (8)	0.067 (4)
H14A	0.8943	0.2686	0.6198	0.080*
H14B	0.8774	0.4015	0.5940	0.080*
C15	0.7021 (14)	0.3063 (13)	0.5511 (8)	0.062 (4)
H15A	0.6809	0.2248	0.5351	0.074*
H15B	0.6675	0.3211	0.5971	0.074*
C16	0.6278 (13)	0.3853 (13)	0.4848 (7)	0.057 (3)
H16A	0.5316	0.3879	0.4842	0.068*
H16B	0.6642	0.4648	0.4952	0.068*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Au1	0.0451 (3)	0.0487 (3)	0.0566 (3)	0.0039 (2)	0.0081 (2)	−0.0032 (2)
Au2	0.0537 (3)	0.0477 (3)	0.0421 (3)	0.0026 (2)	0.0148 (2)	0.0005 (2)
Br1	0.0508 (7)	0.0611 (8)	0.0729 (9)	0.0016 (7)	0.0207 (6)	0.0035 (7)
Br2	0.0645 (8)	0.0658 (9)	0.0475 (7)	−0.0067 (7)	0.0077 (6)	−0.0010 (7)
S1	0.062 (2)	0.063 (2)	0.0439 (17)	0.0011 (18)	0.0044 (15)	0.0008 (17)
S2	0.0499 (17)	0.062 (2)	0.0476 (17)	0.0001 (16)	0.0170 (14)	0.0016 (16)
N1	0.045 (6)	0.082 (8)	0.047 (6)	−0.002 (6)	0.012 (5)	0.002 (6)
C1	0.058 (7)	0.039 (6)	0.035 (6)	−0.007 (6)	0.010 (5)	−0.009 (5)
C2	0.062 (8)	0.060 (9)	0.054 (8)	−0.014 (7)	0.021 (6)	−0.002 (7)
C3	0.097 (12)	0.068 (10)	0.075 (10)	−0.021 (9)	0.044 (10)	−0.016 (9)
C4	0.076 (11)	0.085 (12)	0.094 (12)	0.003 (10)	0.038 (9)	−0.018 (10)
C5	0.046 (7)	0.095 (12)	0.088 (11)	0.005 (8)	0.043 (7)	0.018 (9)
C6	0.058 (8)	0.097 (12)	0.064 (9)	−0.016 (9)	0.004 (7)	0.011 (9)
N11	0.039 (5)	0.057 (7)	0.055 (6)	−0.002 (5)	0.014 (5)	0.002 (5)
C11	0.044 (7)	0.037 (6)	0.066 (8)	0.002 (6)	0.020 (6)	−0.002 (6)
C12	0.037 (7)	0.082 (10)	0.065 (9)	−0.011 (7)	0.011 (6)	−0.008 (8)
C13	0.045 (7)	0.095 (12)	0.059 (8)	0.001 (8)	0.005 (6)	0.000 (9)
C14	0.077 (10)	0.069 (10)	0.050 (8)	0.009 (8)	0.010 (7)	−0.008 (7)
C15	0.072 (9)	0.061 (9)	0.048 (7)	−0.006 (8)	0.008 (7)	−0.003 (7)
C16	0.045 (7)	0.076 (10)	0.058 (8)	0.005 (7)	0.027 (6)	−0.007 (7)

Geometric parameters (Å, º)

Au1—S1	2.287 (4)	C5—H5A	0.9700
Au1—Br1	2.4237 (15)	C5—H5B	0.9700
Au1—Au2	3.0898 (8)	C6—H6A	0.9700
Au1—Au2^i	3.1181 (8)	C6—H6B	0.9700
Au2—S2	2.282 (3)	N11—C11	1.303 (14)
Au2—Br2	2.4284 (14)	N11—C16	1.491 (15)
S1—C1	1.677 (13)	N11—H11A	0.8600
S2—C11	1.689 (13)	C11—C12	1.516 (17)
N1—C1	1.308 (14)	C12—C13	1.490 (19)
N1—C6	1.461 (16)	C12—H12A	0.9700
N1—H1A	0.8600	C12—H12B	0.9700
C1—C2	1.507 (17)	C13—C14	1.523 (18)
C2—C3	1.52 (2)	C13—H13A	0.9700
C2—H2A	0.9700	C13—H13B	0.9700
C2—H2B	0.9700	C14—C15	1.512 (19)
C3—C4	1.49 (2)	C14—H14A	0.9700
C3—H3A	0.9700	C14—H14B	0.9700
C3—H3B	0.9700	C15—C16	1.497 (18)
C4—C5	1.51 (2)	C15—H15A	0.9700
C4—H4A	0.9700	C15—H15B	0.9700
C4—H4B	0.9700	C16—H16A	0.9700
C5—C6	1.49 (2)	C16—H16B	0.9700
S1—Au1—Br1	172.75 (9)	H5A—C5—H5B	107.8
S1—Au1—Au2	92.88 (10)	N1—C6—C5	113.2 (13)
Br1—Au1—Au2	87.48 (4)	N1—C6—H6A	108.9
S1—Au1—Au2^i	90.38 (10)	C5—C6—H6A	108.9
Br1—Au1—Au2^i	93.62 (4)	N1—C6—H6B	108.9
Au2—Au1—Au2^i	143.595 (18)	C5—C6—H6B	108.9
S2—Au2—Br2	170.69 (9)	H6A—C6—H6B	107.7
S2—Au2—Au1	96.53 (9)	C11—N11—C16	126.4 (10)
Br2—Au2—Au1	89.03 (4)	C11—N11—H11A	116.8
S2—Au2—Au1^ii	88.98 (9)	C16—N11—H11A	116.8
Br2—Au2—Au1^ii	90.11 (4)	N11—C11—C12	118.8 (11)
Au1—Au2—Au1^ii	148.803 (17)	N11—C11—S2	123.8 (9)
C1—S1—Au1	110.1 (4)	C12—C11—S2	117.4 (9)
C11—S2—Au2	110.8 (4)	C13—C12—C11	114.7 (12)
C1—N1—C6	128.1 (11)	C13—C12—H12A	108.6
C1—N1—H1A	116.0	C11—C12—H12A	108.6
C6—N1—H1A	116.0	C13—C12—H12B	108.6
N1—C1—C2	117.0 (11)	C11—C12—H12B	108.6
N1—C1—S1	125.0 (9)	H12A—C12—H12B	107.6
C2—C1—S1	118.1 (9)	C12—C13—C14	115.0 (13)
C1—C2—C3	113.2 (12)	C12—C13—H13A	108.5
C1—C2—H2A	108.9	C14—C13—H13A	108.5
C3—C2—H2A	108.9	C12—C13—H13B	108.5
C1—C2—H2B	108.9	C14—C13—H13B	108.5
C3—C2—H2B	108.9	H13A—C13—H13B	107.5
H2A—C2—H2B	107.7	C15—C14—C13	115.1 (11)
C4—C3—C2	115.7 (13)	C15—C14—H14A	108.5
C4—C3—H3A	108.3	C13—C14—H14A	108.5
C2—C3—H3A	108.3	C15—C14—H14B	108.5
C4—C3—H3B	108.3	C13—C14—H14B	108.5
C2—C3—H3B	108.3	H14A—C14—H14B	107.5
H3A—C3—H3B	107.4	C16—C15—C14	114.8 (12)
C3—C4—C5	116.6 (13)	C16—C15—H15A	108.6
C3—C4—H4A	108.1	C14—C15—H15A	108.6
C5—C4—H4A	108.1	C16—C15—H15B	108.6
C3—C4—H4B	108.1	C14—C15—H15B	108.6
C5—C4—H4B	108.1	H15A—C15—H15B	107.5
H4A—C4—H4B	107.3	N11—C16—C15	114.0 (11)
C6—C5—C4	113.2 (13)	N11—C16—H16A	108.8
C6—C5—H5A	108.9	C15—C16—H16A	108.8
C4—C5—H5A	108.9	N11—C16—H16B	108.8
C6—C5—H5B	108.9	C15—C16—H16B	108.8
C4—C5—H5B	108.9	H16A—C16—H16B	107.7
S1—Au1—Au2—S2	86.70 (12)	C6—N1—C1—C2	−2 (2)
Br1—Au1—Au2—S2	−100.55 (9)	C6—N1—C1—S1	−179.7 (12)
Au2^i—Au1—Au2—S2	−7.86 (8)	Au1—S1—C1—N1	−2.0 (13)
S1—Au1—Au2—Br2	−85.81 (9)	Au1—S1—C1—C2	−179.9 (9)
Br1—Au1—Au2—Br2	86.94 (5)	N1—C1—C2—C3	65.1 (16)
Au2^i—Au1—Au2—Br2	179.62 (5)	S1—C1—C2—C3	−116.8 (12)
S1—Au1—Au2—Au1^ii	−174.43 (9)	C1—C2—C3—C4	−78.3 (16)
Br1—Au1—Au2—Au1^ii	−1.68 (5)	C2—C3—C4—C5	60 (2)
Au2^i—Au1—Au2—Au1^ii	91.01 (5)	C3—C4—C5—C6	−60 (2)
Au2—Au1—Au2^i—Au1^i	78.52 (5)	C1—N1—C6—C5	−65 (2)
Au2—Au1—Au2^i—Br2^i	−9.79 (5)	C4—C5—C6—N1	77.0 (17)
Au2—Au1—Au2^i—S2^i	179.47 (8)	C16—N11—C11—C12	1.6 (19)
Br1—Au1—Au2^i—Au1^i	169.18 (5)	C16—N11—C11—S2	−179.6 (10)
Br1—Au1—Au2^i—Br2^i	80.87 (5)	Au2—S2—C11—N11	−1.5 (12)
Br1—Au1—Au2^i—S2^i	−89.86 (9)	Au2—S2—C11—C12	177.2 (9)
S1—Au1—Au2^i—Au1^i	−16.86 (9)	N11—C11—C12—C13	63.1 (17)
S1—Au1—Au2^i—Br2^i	−105.17 (9)	S2—C11—C12—C13	−115.8 (12)
S1—Au1—Au2^i—S2^i	84.09 (12)	C11—C12—C13—C14	−79.4 (16)
Au2—Au1—S1—C1	−77.0 (5)	C12—C13—C14—C15	61.7 (19)
Au2^i—Au1—S1—C1	66.7 (5)	C13—C14—C15—C16	−60.5 (18)
Au1—Au2—S2—C11	63.5 (5)	C11—N11—C16—C15	−64.0 (17)
Au1^ii—Au2—S2—C11	−85.7 (5)	C14—C15—C16—N11	75.9 (15)

Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) −x+1, y−1/2, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Br2^i	0.86	2.83	3.442 (10)	130
N11—H11A···Br1	0.86	2.71	3.372 (10)	135

Symmetry code: (i) −x+1, y+1/2, −z+1/2.