1,1'-Methyl­enedipyridinium tetra­chloridocuprate(II) and bis­[tetra­chloridoaurate(III)] hybrid salts by X-ray powder diffraction

In order to explore the potential propensity of the 1,1'-methyl­enedipyridinium dication to form organic-inorganic hybrid ionic compounds by reaction with the appropriate halide metal salt, the organic-inorganic hybrid salts 1,1'-methyl­enedipyridinium tetra­chloridocuprate(II), (C₁₁H₁₂N₂)[CuCl₄], (I), and 1,1'-methyl­enedipyridinium bis­[tetra­chloridoaurate(III)], (C₁₁H₁₂N₂)[AuCl₄]₂, (II), were obtained by treatment of 1,1'-methyl­enedipyridinium dichloride with CuCl₂ and Na[AuCl₄], respectively. Both hybrid salts were isolated as pure compounds, fully characterized by multinuclear NMR spectroscopy and their mol­ecular structures confirmed by powder X-ray diffraction studies. The crystal structures consist of discrete 1,1'-methyl­enedipyridinium dications and [CuCl₄]^2- and [AuCl₄]^- anions for (I) and (II), respectively. As expected, the dications form a butterfly shape; the Cu^II centre of [CuCl₄]^2- has a distorted tetra­hedral configuration and the Au^III centre of [AuCl₄]^- shows a square-planar coordination. The ionic species of (I) and the dication of (II) each have twofold axial symmetry, while the two [AuCl₄]^- anions are located on a mirror-plane site. Both crystal structures are stabilized by inter­molecular C-H...Cl hydrogen bonds and also by Cl...[pi] inter­actions. It is noteworthy that, while the average inter­molecular centroid-centroid pyridinium ring distance in (I) is 3.643 (8) Å, giving strong evidence for noncovalent [pi]-[pi] ring inter­actions, for (II), the shortest centroid-centroid distance between pyridinium rings of 5.502 (9) Å is too long for any significant [pi]-[pi] ring inter­actions, which might be due to the bulk of the two [AuCl₄]^- anions.

S1. Comment

Over the past decade, research in the design of organic–inorganic hybrid ionic materials has steadily increased, because of the potential applications particularly in the areas of crystal engineering, supramolecular chemistry and materials science (Kimizuka & Kunitake, 1996; Mitzi et al., 1999; Bonhomme & Kanatzidis, 1998; Wachhold & Kanatzidis, 2000); these materials also have applications as optical semiconductors (Kagan et al., 1999; Li et al., 2008). Although the first preparation of the 1,1'-methylenedipyridinium dication, [(C₅H₅N)₂CH₂]²⁺, goes back to more than a century ago (Baer & Prescott, 1896), its potential affinity to form organic–inorganic hybrid salts has not been well exploited. However, countable organic–inorganic hybrid salts of 1,1'-methylenedipyridinium with mixed halo-osmium(IV) anions were previously reported and structurally characterized, motivated by the investigations of octahedrally coordinated complexes: e.g. trans-[(C₅H₅N)₂CH₂][OsF₄Cl₂].H₂O (Bruhn & Preetz, 1995a), the isomeric pair fac- and mer-[(C₅H₅N)₂CH₂][OsCl₃F₃] (Bruhn & Preetz, 1995b), the two isomers cis- and trans-[(C₅H₅N)₂CH₂][OsCl₄F₂] (Bruhn & Preetz, 1996), and cis-[(C₅H₅N)₂CH₂][OsBr₂F₄] (Höhling & Preetz, 1998). The related complex salt [(C₅H₅N)₂CH₂][Cu(NCS)₄] was also later described (Niu et al., 2008). This motivated us to synthesize a series of new organic–inorganic hybrid salts based on the 1,1'-methylenedipyridinium dication, which might have some applications in the field of materials science (Bonhomme & Kanatzidis, 1998; Wachhold & Kanatzidis, 2000). Very recently, we reported the synthesis and molecular structure characterizations of the complex salts [(C₅H₅N)₂CH₂][MCl₄] (M = Zn or Cd; Al-Ktaifani & Rukiah, 2011) and [(C₅H₅N)₂CH₂][PtCl_n] (n = 4 or 6; Al-Ktaifani & Rukiah, 2012). In this article, the synthesis of 1,1'-methylenedipyridinium tetrachlorocuprate(II), [(C₅H₅N)₂CH₂][CuCl₄], (I), and 1,1'-methylenedipyridinium bis[tetrachloroaurate(III)], [(C₅H₅N)₂CH₂][AuCl₄]₂, (II), and their characterizations by multinuclear NMR spectroscopy and powder X-ray diffraction study are presented.

Compounds (I) and (II) have a tendency to crystallize in the form of a very fine yellow powder. Since no single crystal of sufficient thickness and quality could be obtained, a crystal structure determination by powder X-ray diffraction was attempted. The crystal and molecular structures of (I) and (II) show discrete organic dications and a [CuCl₄]^2- anion for (I) and two [AuCl₄]^- anions for (II). A view of the molecular structures of the two compounds with the atomic labelling is shown in Fig. 1. The asymmetric unit of (I) contains one half of the 1,1'-methylenedipyridinium dication and one half of a tetrachlorocuprate(II) anion, while the asymmetric unit of (II) contains one half of a 1,1'-methylenedipyridinium dication and two half tetrachloroaurate anions. In (I), the methylene C atom and the Cu^II atom are located on a twofold axis. The Cu^II centre is four-coordinated in a distorted tetrahedral configuration by four Cl atoms [the largest Cl—Cu—Cl angle is 134.26 (18)°, while the smallest is 96.9 (3)°] with almost equal Cu—Cl bond distances [2.249 (5)–2.254 (4) Å] (Table 1), which is comparable to [observations] that observed for [(C₂H₅)₄N)][(CH₃)₄N)][CuCl₄] (Mahoui et al., 1996). For (II), the methylene C atom is also located on a twofold axis, while the two Au^III centres and two Cl atoms of each [AuCl₄]^- anion are located on a mirror plane. Both Au^III centres have square-planar coordinations and the Au—Cl bond lengths [2.241 (15)–2.285 (9) Å] and angles (90°) are in good agreement with normal values (Table 3) and very close to their corresponding average value in the related salt (C₂₄H₁₈N₆)[AuCl₄]₂ (Abedi et al., 2011). For both structures, the dication exhibits a butterfly shape consisting of two pyridine rings bound to the methylene group via their N atoms and shows similar features, C—C and N—C bond lengths and C—C—C, N—C—N and N—C—C angles to the corresponding ones in the related hybrid salts [(C₅H₅N)₂CH₂][MCl₄] (M = Zn, Cd or Pt; Al-Ktaifani & Rukiah, 2011, 2012).

In the crystal structures of (I) and (II), weak intermolecular C—H···Cl hydrogen bonds (Tables 2 and 4) link the molecules to form a one-dimensional chain along the a axis (Fig. 2). These hydrogen bonds may be effective in the stabilization of the structures of (I) and (II). The crystal packing of (I) is also further stabilized by noncovalent π–π interactions (Hunter & Sanders, 1990; Janiak, 2000) between pyridinium rings of adjacent dications [Cg1···Cg1(-x, -y, -z+1) = 3.643 (8) Å, where Cg1 is the centroid of the N1/C2–C6 ring]. In a similar manner, the relatively short Cu1—Cl1···Cg1(x, y, z) distances [3.515 (7) Å] are also strong evidence for noncovalent Cl—π interaction (Imai et al., 2008). In contrast to (I), for (II), the shortest intermolecular centroid–centroid distance between pyridinium rings [5.502 (9) Å] is too long for any significant π–π ring interactions (Janiak, 2000), which might be attributed to the bulk of the two [AuCl₄]^- anions. However, the Au1—Cl2···Cg1(x, y, z+1) and Au2—Cl6···Cg1(-x, -y+1, z) distances [3.87 (2) and 3.57 (2) Å, respectively] also suggest Cl—π interactions (Imai et al., 2008), which might play an effective role in controlling crystal packing. The Au^III···Au^III distance [4.245 (6) Å] in (II) is longer than the sum of the van der Waals radii for gold (3.4 Å; Bondi, 1964), suggesting there is no significant Au···Au interaction.

Related literature

For related literature, see: Abedi et al. (2011); Al-Ktaifani & Rukiah (2011, 2012); Almarzoqi et al. (1986); Altomare et al. (2009); Baer & Prescott (1896); Bondi (1964); Bonhomme & Kanatzidis (1998); Boultif & Louër (2004); Bruhn & Preetz (1995a, 1995b, 1996); Favre-Nicolin & Černý (2002); Finger et al. (1994); Höhling & Preetz (1998); Hunter & Sanders (1990); Imai et al. (2008); Janiak (2000); Kagan et al. (1999); Kimizuka & Kunitake (1996); Larson & Von Dreele (2004); Li et al. (2008); Mahoui et al. (1996); Mitzi et al. (1999); Niu et al. (2008); Stephens (1999); Thompson et al. (1987); Toby (2001); Von Dreele (1997); Wachhold & Kanatzidis (2000).

S2. Experimental

All reactions and manipulations were carried out in air with reagent-grade solvents. [(C₅H₅N)₂CH₂]Cl₂.H₂O was prepared according to the literature method of Almarzoqi et al. (1986). CuCl₂ (BDH, Germany) and Na[AuCl₄] (Merck, Germany) were commercial samples and used as received. ¹H and ¹³C{¹H} NMR spectra were recorded on a Bruker Bio spin 400 spectrometer. Microanalysis was performed using EURO EA. Powder X-ray diffraction was performed on a Stoe transmission diffractometer (Stadi-P).

For the synthesis of (I), a solution of [(C₅H₅N)₂CH₂]Cl₂.H₂O (0.22 g, 0.82 mmol) in H₂O (3 ml) was added to a solution of CuCl₂ (0.114 g, 0.82 mmol) in H₂O (3 ml) at room temperature and stirred overnight. The solvent was then removed in vacuum to afford quantitatively product (I), which was washed with EtOH to afford a yellow powder [yield 237 mg, 75%; m.p. 493 K (with decomposition)]. For the synthesis of (II), a solution of [(C₅H₅N)₂CH₂]Cl₂.H₂O (0.05 g, 0.19 mmol) in H₂O (3 ml) was added to a solution of Na[AuCl₄] (0.130 g, 0.38 mmol) in H₂O (3 ml) with rapid stirring at ambient temperature. The resulting solution was stirred for 18 h to give an orange–yellow precipitate. The obtained product was filtered off and washed with EtOH to give an orange–yellow powder (yield 115 mg, 71%; m.p. 561 K).

Both salts were obtained as air-stable yellow powdery products and were highly insoluble in common organic solvents. However, although (I) is water soluble, (II) is not, but each has a good solubility in dimethyl sulfoxide (DMSO). The obtained organic–inorganic hybrid salts (I) and (II) were isolated as pure products and fully characterized by multinuclear NMR and elemental analyses, and their molecular structures were confirmed by powder X-ray diffraction studies. Analytical data for C₁₁H₁₂CuCl₄N₂, (I): found C 35.54, H 3.20, N 7.39%; required C 34.99, H 3.21, N 7.41%. ¹H NMR (DMSO-d₆): δ 7.46 (s, 2H, CH₂), 8.33 (m, 4H, py), 8.80 (m, 2H, py), 9.72 (m, 4H, py); ¹³C{¹H} NMR (DMSO-d₆): δ 76.81 (CH₂), 129.23 (py), 146.48 (py), 149.20 (py). Analytical data for C₁₁H₁₂Au₂Cl₈N₂, (II), found C 15.05, H 1.32, N 2.94%; required C 15.45, H 1.42, N 3.29%. ¹H NMR (DMSO-d₆): δ 7.26 (s, 2H, CH₂), 8.33 (m, 4H, py), 8.80 (m, 2H, py), 9.45 (m, 4H, py). ¹³C{¹H} NMR (DMSO-d₆): δ 77.53 (CH₂), 129.21 (py), 146.32 (py), 149.27 (py).

S3. Refinement

Pattern indexing was performed with the program DicVol6.0 (Boultif & Louër, 2004). The first 20 lines of powder pattern were completely indexed on the basis of a monoclinic system for (I) and an orthorhombic system for (II). The figures of merit are sufficiently acceptable to support the obtained indexing results [M(20) = 16.5, F(20) = 34.2(0.0072, 81)] for (I) and [M(20) = 20.4, F(20) = 30.7(0.0085, 77)] for (II). The best estimated space groups were C2/c in the monoclinic system for (I) and Ima2 in the orthorhombic system for (II).

The initial structure of (I) was solved ab initio by direct methods using the program EXPO2009 (Altomare et al., 2009), while the direct space method was used by the program FOX (Favre-Nicolin & Černý, 2002) for determination of the initial structure of (II). The models found by these programs were introduced in the program GSAS (Larson & Von Dreele, 2004) implemented in EXPGUI (Toby, 2001) for Rietveld refinements. The background was refined using a shifted Chebyshev polynomial with 20 coefficients. The Thompson–Cox–Hastings (Thompson et al., 1987) pseudo-Voigt profile function was used with axial divergence asymmetry correction (Finger et al., 1994) and microstrain broadening as described by Stephens (1999). The two asymmetry parameters of this function, S/L and D/L, were both fixed at 0.022 during the Rietveld refinement. Intensities were corrected from absorption effects with a µd value of 0.9500 for (I) and 0.7646 for (II) (µ is the absorption coefficient and d is the sample thickness, these values were determined experimentally). A spherical harmonics correction (Von Dreele, 1997) of intensities for preferred orientation was applied in the final refinement with 18 coefficients for (I) and eight coefficients for (II). The use of the preferred orientation correction leads to better molecular geometry with better agreement factors. Planar group restraints to the pyridinium ring including their H atoms were applied for both structures. Non-H atoms were not restrained for (I), but for (II) a restraint on bond length for the distance between the carbon of methylene and the nitrogen of the pyridinium ring was applied to a normal value for this bond (1.49 Å). Before the final refinement, H atoms were introduced from geometrical arguments. The coordinates of these H atoms were not refined for both structures. The final refinement cycles were performed using anisotropic atomic displacement parameters for Cu and Cl atoms for (I) and for Au atoms only for (II). Anisotropic atomic displacement parameters for C and N atoms were used for both structures (I) and (II), while fixed global isotropic atomic displacement parameters [0.050 Ų for (I) and 0.075 Ų for (II)] were introduced for H atoms. The final Rietveld plot of the X-ray diffraction pattern for both structures (I) and (II) is given in Fig. 3.

Computing details

For both compounds, data collection: WinXPOW (Stoe & Cie, 1999); cell refinement: GSAS (Larson & Von Dreele, 2004); data reduction: WinXPOW (Stoe & Cie, 1999). Program(s) used to solve structure: EXPO2009 (Altomare et al., 2009) for (I); FOX (Favre-Nicolin & Černý, 2002) for (II). For both compounds, program(s) used to refine structure: GSAS (Larson & Von Dreele, 2004); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

	Fig. 1. The molecular structure of (a) (I) and (b) (II), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii. [Symmetry codes: (i) -x, y, -z+3/2; (ii) -x, -y+1, z; (iii) -x+1/2, y, z.]
	Fig. 2. Portion of packing diagram of (a) (I) and (b) (II). Hydrogen bonds between molecules are indicated by dashed lines. [Symmetry codes: (i) -x-1/2, y-1/2, -z+3/2; (ii) -x, -y+1, z-1.]
	Fig. 3. The final Rietveld plot for (a) (I) and (b) (II). Observed data points are indicated by dots and the best-fit profile (upper trace) and difference pattern (lower trace) are solid lines. The vertical bars indicate the positions of Bragg peaks.

(I) 1,1'-Methylenedipyridinium tetrachloridocuprate(II)

Crystal data

(C11H12N2)[CuCl4]	Z = 4
Mr = 377.59	F(000) = 756
Monoclinic, C2/c	Dx = 1.735 Mg m^−3
Hall symbol: -C 2yc	Cu Kα1 radiation, λ = 1.5406 Å
a = 9.90009 (11) Å	µ = 8.79 mm^−1
b = 9.94558 (11) Å	T = 298 K
c = 15.0359 (2) Å	Particle morphology: Fine powder
β = 102.4903 (8)°	Yellow
V = 1445.43 (4) Å^3	flat sheet, 8 × 8 mm

Data collection

Stoe Stadi-P Transmission diffractometer	Scan method: step
Radiation source: sealed X-ray tube	Absorption correction: for a cylinder mounted on the ϕ axis (GSAS; Larson & Von Dreele, 2004)
Curved Ge(111) monochromator	Tmin = 0.125, Tmax = 0.230
Specimen mounting: powder loaded between two Mylar foils	2θmin = 8.005°, 2θmax = 89.985°, 2θstep = 0.02°
Data collection mode: transmission

Refinement

Least-squares matrix: full	Profile function: CW Profile function number 4 with 21 terms Pseudovoigt profile coefficients as parameterized in (Thompson et al., 1987. Asymmetry correction of Finger et al.(Finger et al., 1994). Microstrain broadening by Stephens(Stephens, 1999). #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 11.436 #4(GP) = 0.000 #5(LX) = 1.026 #6(ptec) = 0.38 #7(trns) = 0.00 #8(shft) = 0.0000 #9(sfec) = 0.00 #10(S/L) = 0.0220 #11(H/L) = 0.0220 #12(eta) = 0.6000 #13(S400 ) = 1.1E-02 #14(S040 ) = 8.6E-03 #15(S004 ) = 3.0E-04 #16(S220 ) = -8.2E-05 #17(S202 ) = 5.8E-03 #18(S022 ) = 1.7E-03 #19(S301 ) = 7.4E-03 #20(S103 ) = 9.2E-04 #21(S121 ) = -3.1E-03 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0
Rp = 0.036	204 parameters
Rwp = 0.050	24 restraints
Rexp = 0.028	H-atom parameters not refined
R(F^2) = 0.02794	(Δ/σ)max = 0.01
χ^2 = 3.497	Background function: GSAS Background function number 1 with 20 terms. Shifted Chebyshev function of 1st kind 1: 860.116 2: -781.679 3: 388.997 4: -133.128 5: 39.2963 6: 19.0075 7: -14.0294 8: -20.4168 9: 15.3452 10: 2.09773 11: -7.87826 12: 7.40464 13: -4.29641 14: -3.88420 15: 2.15214 16: -1.57637 17: -2.29974 18: 0.428549 19: -0.344594 20: 1.25930
4100 data points

Special details

Experimental. The sample was ground lightly in a mortar, loaded between two Mylar foils and fixed in the sample holder with a mask of 8.0 mm internal diameter.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cu1	0.0	0.5000 (3)	0.75	0.03709
Cl1	−0.1734 (4)	0.3496 (4)	0.7128 (3)	0.0384
Cl2	−0.0682 (5)	0.6432 (4)	0.6332 (4)	0.05123
N1	−0.0374 (11)	0.0151 (10)	0.6663 (8)	0.027 (4)*
C1	0.0	−0.059 (3)	0.75	0.036 (9)*
C2	0.0641 (12)	0.0960 (12)	0.6428 (11)	0.032 (6)*
C3	0.0318 (11)	0.1670 (11)	0.5643 (10)	0.019 (5)*
C4	−0.1002 (14)	0.1581 (12)	0.5092 (9)	0.035 (5)*
C5	−0.1994 (12)	0.0707 (12)	0.5328 (10)	0.040 (5)*
C6	−0.1678 (12)	0.0047 (12)	0.6133 (10)	0.031 (4)*
H1a	−0.078	−0.121	0.748	0.05*
H2	0.1569	0.1038	0.6836	0.05*
H3	0.1019	0.2267	0.5467	0.05*
H4	−0.1234	0.2094	0.4517	0.05*
H5	−0.2942	0.0665	0.4947	0.05*
H6	−0.2368	−0.0548	0.6321	0.05*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.035 (3)	0.023 (3)	0.050 (4)	0.0	−0.000 (3)	0.0
Cl1	0.030 (4)	0.036 (4)	0.044 (5)	−0.013 (2)	−0.001 (3)	0.009 (3)
Cl2	0.057 (4)	0.041 (3)	0.048 (5)	−0.004 (3)	−0.008 (4)	0.010 (3)

Geometric parameters (Å, º)

Cu1—Cl1	2.254 (4)	C2—H2	0.99
Cu1—Cl1^i	2.254 (4)	C3—C4	1.391 (17)
Cu1—Cl2	2.249 (5)	C3—H3	0.99
Cu1—Cl2^i	2.249 (5)	C4—C5	1.413 (14)
C1—N1	1.437 (16)	C4—H4	0.99
C1—N1^i	1.437 (16)	C5—C6	1.353 (18)
C1—H1a	0.98	C5—H5	0.99
C1—H1a^i	0.98	C6—N1	1.367 (15)
N1—C2	1.392 (15)	C6—H6	0.99
C2—C3	1.353 (18)
Cl1—Cu1—Cl1^i	96.9 (3)	N1—C2—C3	118.4 (9)
Cl1—Cu1—Cl2	98.20 (17)	N1—C2—H2	120.7
Cl1—Cu1—Cl2^i	134.26 (18)	C3—C2—H2	120.8
Cl1^i—Cu1—Cl2	134.26 (18)	C2—C3—C4	120.0 (8)
Cl1^i—Cu1—Cl2^i	98.20 (17)	C2—C3—H3	119.9
Cl2—Cu1—Cl2^i	101.4 (3)	C4—C3—H3	120.0
C1—N1—C2	117.1 (11)	C3—C4—C5	120.3 (9)
C1—N1—C6	120.3 (10)	C3—C4—H4	119.9
C2—N1—C6	122.6 (10)	C5—C4—H4	119.7
N1—C1—N1^i	118 (2)	C4—C5—C6	119.0 (9)
N1—C1—H1a	104	C4—C5—H5	120.3
N1—C1—H1a^i	114	C6—C5—H5	120.3
N1^i—C1—H1a	114	N1—C6—C5	119.4 (9)
N1^i—C1—H1a^i	104	N1—C6—H6	120.1
H1a—C1—H1a^i	102	C5—C6—H6	120.3
C2—N1—C1—N1^i	63.2 (13)	C2—N1—C6—C5	2.8 (19)
C6—N1—C1—N1^i	−116.8 (12)	N1—C2—C3—C4	0.0 (19)
C1—N1—C2—C3	−180.0 (14)	C2—C3—C4—C5	−2.7 (19)
C6—N1—C2—C3	0.0 (19)	C3—C4—C5—C6	5.5 (19)
C1—N1—C6—C5	−177.2 (15)	C4—C5—C6—N1	−5.4 (19)

Symmetry code: (i) −x, y, −z+3/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1a···Cl1^ii	0.98	2.67	3.518 (9)	145

Symmetry code: (ii) −x−1/2, y−1/2, −z+3/2.

(II) 1,1'-methylenedipyridinium bis[tetrachloridoaurate(III)]

Crystal data

(C11H12N2)[AuCl4]2	F(000) = 1544
Mr = 849.79	Dx = 2.707 Mg m^−3
Orthorhombic, Ima2	Cu Kα1 radiation, λ = 1.5406 Å
Hall symbol: I 2 -2a	µ = 35.51 mm^−1
a = 15.61545 (11) Å	T = 298 K
b = 17.6525 (3) Å	Particle morphology: Fine powder
c = 7.56300 (6) Å	Yellow
V = 2084.76 (4) Å^3	flat sheet, 8 × 8 mm
Z = 4

Data collection

Stoe Stadi-P Transmission diffractometer	Scan method: step
Radiation source: sealed X-ray tube	Absorption correction: for a cylinder mounted on the ϕ axis (GSAS; Larson & Von Dreele, 2004)
Curved Ge(111) monochromator	Tmin = 0.181, Tmax = 0.307
Specimen mounting: powder loaded between two Mylar foils	2θmin = 5.009°, 2θmax = 91.989°, 2θstep = 0.02°
Data collection mode: transmission

Refinement

Least-squares matrix: full	Profile function: CW Profile function number 4 with 18 terms Pseudo-Voigt profile coefficients as parameterized in (Thompson et al., 1987. Asymmetry correction of Finger et al.(Finger et al., 1994). Microstrain broadening by Stephens(Stephens, 1999). #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 11.888 #4(GP) = 0.000 #5(LX) = 2.215 #6(ptec) = 0.48 #7(trns) = 0.00 #8(shft) = 0.0000 #9(sfec) = 0.00 #10(S/L) = 0.0220 #11(H/L) = 0.0220 #12(eta) = 0.6000 #13(S400 ) = 1.6E-03 #14(S040 ) = 2.5E-03 #15(S004 ) = 3.2E-02 #16(S220 ) = 1.3E-03 #17(S202 ) = 3.2E-03 #18(S022 ) = 1.0E-02 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0
Rp = 0.032	106 parameters
Rwp = 0.043	26 restraints
Rexp = 0.017	H-atom parameters not refined
R(F^2) = 0.02683	(Δ/σ)max = 0.01
χ^2 = 6.760	Background function: GSAS Background function number 1 with 20 terms. Shifted Chebyshev function of 1st kind 1: 2249.30 2: -2057.31 3: 1081.89 4: -319.563 5: 41.2634 6: 143.494 7: -127.983 8: 17.1685 9: 19.1074 10: 18.8027 11: -64.6250 12: 53.3320 13: -21.3102 14: -12.9331 15: 20.9392 16: -11.0088 17: 0.222426 18: 8.10512 19: -19.3986 20: -19.1439
4350 data points

Special details

Experimental. The sample was ground lightly in a mortar, loaded between two Mylar foils and fixed in the sample holder with a mask of 8.0 mm internal diameter.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Au1	0.25	0.37044 (18)	0.749 (2)	0.02178
Au2	0.25	0.60436 (16)	0.619 (2)	0.03127
Cl1	0.25	0.4669 (11)	0.948 (3)	0.051 (8)*
Cl2	0.1038 (6)	0.3696 (7)	0.734 (3)	0.036 (4)*
Cl3	0.25	0.2726 (11)	0.561 (3)	0.036 (6)*
Cl4	0.25	0.5230 (12)	0.389 (3)	0.070 (9)*
Cl5	0.25	0.6878 (11)	0.852 (3)	0.050 (6)*
Cl6	0.1046 (6)	0.6001 (6)	0.610 (3)	0.041 (4)*
C1	0.0	0.5	−0.001 (2)	0.053 (19)*
C2	0.0618 (8)	0.4080 (8)	0.194 (3)	0.061 (16)*
C3	0.0643 (8)	0.3409 (9)	0.281 (2)	0.032 (12)*
C4	−0.0090 (8)	0.2965 (8)	0.280 (3)	0.048 (11)*
C5	−0.0803 (8)	0.3180 (8)	0.184 (3)	0.051 (15)*
C6	−0.0794 (8)	0.3865 (8)	0.095 (3)	0.025 (11)*
N1	−0.0081 (11)	0.4291 (9)	0.108 (2)	0.048 (10)*
H1c1	−0.04587	0.50123	−0.08959	0.075*
H1c2	0.11216	0.44191	0.19636	0.075*
H1c3	0.11478	0.32635	0.35274	0.075*
H1c4	−0.00903	0.24743	0.34319	0.075*
H1c5	−0.13145	0.28482	0.1791	0.075*
H1c6	−0.12917	0.40382	0.02453	0.075*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Au1	0.015 (2)	0.034 (4)	0.017 (2)	0.0	0.0	−0.012 (2)
Au2	0.028 (2)	0.017 (4)	0.048 (3)	0.0	0.0	0.006 (2)

Geometric parameters (Å, º)

Au1—Cl1	2.272 (17)	C2—C3	1.355 (16)
Au1—Cl2	2.285 (9)	C2—N1	1.326 (17)
Au1—Cl2^i	2.285 (9)	C2—H1c2	0.99
Au1—Cl3	2.241 (15)	C3—C4	1.387 (15)
Au2—Cl4	2.255 (18)	C3—H1c3	0.99
Au2—Cl5	2.299 (15)	C4—C5	1.384 (16)
Au2—Cl6	2.272 (9)	C4—H1c4	0.99
Au2—Cl6^i	2.272 (9)	C5—C6	1.382 (16)
C1—N1	1.503 (11)	C5—H1c5	0.99
C1—N1^ii	1.503 (11)	C6—N1	1.346 (19)
C1—H1c1	0.98	C6—H1c6	0.99
C1—H1c1^ii	0.98
Cl1—Au1—Cl2	92.2 (3)	C3—C2—N1	120.6 (10)
Cl1—Au1—Cl2^i	92.2 (3)	C3—C2—H1c2	119.9
Cl1—Au1—Cl3	178.1 (7)	N1—C2—H1c2	119.5
Cl2—Au1—Cl2^i	174.2 (7)	C2—C3—C4	117.8 (8)
Cl2—Au1—Cl3	87.9 (3)	C2—C3—H1c3	121.0
Cl2^i—Au1—Cl3	87.9 (3)	C4—C3—H1c3	121.0
Cl4—Au2—Cl5	179.7 (9)	C3—C4—C5	120.8 (8)
Cl4—Au2—Cl6	87.5 (3)	C3—C4—H1c4	119.5
Cl4—Au2—Cl6^i	87.5 (3)	C5—C4—H1c4	119.6
Cl5—Au2—Cl6	92.5 (3)	C4—C5—C6	119.1 (8)
Cl5—Au2—Cl6^i	92.5 (3)	C4—C5—H1c5	120.3
Cl6—Au2—Cl6^i	175.0 (7)	C6—C5—H1c5	120.6
N1—C1—N1^ii	113.7 (19)	C5—C6—N1	117.5 (9)
N1—C1—H1c1	109.3	C5—C6—H1c6	121.5
N1—C1—H1c1^ii	114.6	N1—C6—H1c6	121.0
N1^ii—C1—H1c1	114.6	C1—N1—C2	115.8 (12)
N1^ii—C1—H1c1^ii	109.3	C1—N1—C6	119.7 (10)
H1c1—C1—H1c1^ii	93.8	C2—N1—C6	124.0 (11)
C2—N1—C1—N1^ii	−70.4 (16)	N1—C2—C3—C4	−2 (2)
C6—N1—C1—N1^ii	118.2 (14)	C2—C3—C4—C5	4 (3)
C1—N1—C2—C3	−173.1 (13)	C3—C4—C5—C6	−3 (3)
C1—N1—C6—C5	173.6 (13)	C4—C5—C6—N1	0 (2)
C2—N1—C6—C5	3 (2)	C6—N1—C2—C3	−2 (2)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1C1···Cl2^iii	0.98	2.79	3.456 (18)	126
C6—H1C6···Cl5^iii	0.99	2.81	3.492 (19)	127

Symmetry code: (iii) −x, −y+1, z−1.