Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270106053108/gz3036sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270106053108/gz3036Isup2.hkl |
CCDC reference: 638296
For the preparation of (I), L-cocaine hydrochloride (Sigma, lot No. 48 F0208) was dissolved in water to yield a 50 µg ml-1 solution. This solution (200 µl) was combined with 0.5% acidified (HCl) gold(III) chloride (HAuCl4·3H2O) (200 µl) and allowed to crystallize. Extremely long gold parallelepiped crystals formed (m.p. 452 K). A suitable crystal for X-ray analysis was cut from one of these long rods.
All H atoms for (I) were found in electron-density difference maps. The methyl H atoms were placed in ideally staggered positions, with C—H distances of 0.98 Å and Uiso(H) = 1.5Ueq(C). The methylene and methine H atoms were placed in geometrically idealized positions and constrained to ride on their parent C atoms, with C—H distances of 0.99 and 1.00 Å, respectively, and with Uiso(H) = 1.2Ueq(C). The ammonium H atom was similarly placed in an idealized position, with an N—H distance of 0.91 Å, and refined with Uiso(H) = 1.2Ueq(N).
Data collection: SMART (Bruker, 2006); cell refinement: SMART; data reduction: SAINT-Plus (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2004); program(s) used to refine structure: SHELXL97 (Sheldrick, 2004); molecular graphics: SHELXTL (Sheldrick, 2004); software used to prepare material for publication: SHELXTL.
(C17H22NO4)[AuCl4] | Dx = 1.953 Mg m−3 |
Mr = 643.12 | Melting point: 452 K |
Orthorhombic, P212121 | Cu Kα radiation, λ = 1.54178 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 14526 reflections |
a = 7.7358 (3) Å | θ = 3.0–68.5° |
b = 9.4543 (5) Å | µ = 17.33 mm−1 |
c = 29.9093 (13) Å | T = 295 K |
V = 2187.46 (17) Å3 | Parallelepiped, yellow |
Z = 4 | 0.45 × 0.21 × 0.08 mm |
F(000) = 1240 |
Bruker SMART CCD APEXII area-detector diffractometer | 3906 independent reflections |
Radiation source: fine-focus sealed tube | 3804 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.052 |
ϕ and ω scans | θmax = 68.5°, θmin = 3.0° |
Absorption correction: numerical and multi-scan [SHELXTL (Sheldrick, 2004) and SADABS (Bruker, 2005)] | h = −9→9 |
Tmin = 0.042, Tmax = 0.338 | k = −11→11 |
14526 measured reflections | l = −36→34 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.028 | H-atom parameters constrained |
wR(F2) = 0.070 | w = 1/[σ2(Fo2) + (0.0263P)2 + 0.9351P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max < 0.001 |
3906 reflections | Δρmax = 0.59 e Å−3 |
246 parameters | Δρmin = −0.96 e Å−3 |
0 restraints | Absolute structure: Flack (1983), with 1468 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.025 (14) |
(C17H22NO4)[AuCl4] | V = 2187.46 (17) Å3 |
Mr = 643.12 | Z = 4 |
Orthorhombic, P212121 | Cu Kα radiation |
a = 7.7358 (3) Å | µ = 17.33 mm−1 |
b = 9.4543 (5) Å | T = 295 K |
c = 29.9093 (13) Å | 0.45 × 0.21 × 0.08 mm |
Bruker SMART CCD APEXII area-detector diffractometer | 3906 independent reflections |
Absorption correction: numerical and multi-scan [SHELXTL (Sheldrick, 2004) and SADABS (Bruker, 2005)] | 3804 reflections with I > 2σ(I) |
Tmin = 0.042, Tmax = 0.338 | Rint = 0.052 |
14526 measured reflections |
R[F2 > 2σ(F2)] = 0.028 | H-atom parameters constrained |
wR(F2) = 0.070 | Δρmax = 0.59 e Å−3 |
S = 1.05 | Δρmin = −0.96 e Å−3 |
3906 reflections | Absolute structure: Flack (1983), with 1468 Friedel pairs |
246 parameters | Absolute structure parameter: 0.025 (14) |
0 restraints |
Experimental. Crystal mounted on cryoloop using Paratone-N |
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. |
x | y | z | Uiso*/Ueq | ||
Au1 | 1.48067 (3) | −0.08296 (2) | 0.827908 (6) | 0.04897 (9) | |
Cl1 | 1.4831 (3) | −0.26793 (18) | 0.77877 (5) | 0.0723 (4) | |
O1 | 0.4481 (8) | 0.5175 (7) | 0.89138 (15) | 0.0864 (16) | |
N1 | 1.1201 (7) | 0.4034 (5) | 0.83739 (15) | 0.0523 (10) | |
H1A | 1.1616 | 0.4136 | 0.8657 | 0.063* | |
C1 | 0.9621 (9) | 0.3070 (6) | 0.83835 (19) | 0.0570 (14) | |
H1 | 0.9962 | 0.2074 | 0.8401 | 0.068* | |
Cl2 | 1.18875 (19) | −0.0958 (2) | 0.83312 (6) | 0.0714 (4) | |
O2 | 0.7201 (6) | 0.5528 (5) | 0.91443 (13) | 0.0617 (10) | |
C2 | 0.8493 (9) | 0.3483 (7) | 0.87798 (19) | 0.0539 (14) | |
H2 | 0.7457 | 0.2887 | 0.8777 | 0.065* | |
Cl3 | 1.7706 (2) | −0.0551 (2) | 0.81918 (6) | 0.0739 (5) | |
C3 | 0.7920 (10) | 0.5049 (7) | 0.87294 (19) | 0.0602 (16) | |
H3 | 0.7043 | 0.5118 | 0.8494 | 0.072* | |
O3 | 1.0932 (7) | 0.3471 (7) | 0.92750 (16) | 0.0824 (16) | |
Cl4 | 1.4790 (3) | 0.0911 (2) | 0.88051 (6) | 0.0821 (4) | |
O4 | 0.8372 (7) | 0.2909 (5) | 0.95482 (16) | 0.0682 (13) | |
C4 | 0.9404 (9) | 0.5985 (6) | 0.86168 (18) | 0.0603 (15) | |
H4A | 1.0157 | 0.6069 | 0.8875 | 0.072* | |
H4B | 0.8977 | 0.6922 | 0.8544 | 0.072* | |
C5 | 1.0429 (10) | 0.5405 (6) | 0.82234 (17) | 0.0580 (14) | |
H5 | 1.1329 | 0.6072 | 0.8130 | 0.070* | |
C6 | 0.9317 (11) | 0.4944 (9) | 0.7824 (2) | 0.074 (2) | |
H6A | 0.9976 | 0.4989 | 0.7549 | 0.089* | |
H6B | 0.8307 | 0.5545 | 0.7796 | 0.089* | |
C7 | 0.8782 (12) | 0.3408 (10) | 0.7928 (2) | 0.079 (2) | |
H7A | 0.7534 | 0.3326 | 0.7946 | 0.095* | |
H7B | 0.9203 | 0.2769 | 0.7699 | 0.095* | |
C8 | 1.2631 (11) | 0.3534 (9) | 0.8075 (2) | 0.0745 (19) | |
H8A | 1.2221 | 0.3488 | 0.7772 | 0.112* | |
H8B | 1.3004 | 0.2612 | 0.8168 | 0.112* | |
H8C | 1.3585 | 0.4182 | 0.8092 | 0.112* | |
C9 | 0.5503 (9) | 0.5465 (6) | 0.92093 (18) | 0.0567 (14) | |
C10 | 0.5017 (10) | 0.5735 (6) | 0.96792 (18) | 0.0636 (15) | |
C11 | 0.3276 (12) | 0.5805 (9) | 0.9789 (2) | 0.0789 (19) | |
H11 | 0.2428 | 0.5779 | 0.9569 | 0.095* | |
C12 | 0.2836 (13) | 0.5915 (10) | 1.0241 (3) | 0.093 (3) | |
H12 | 0.1675 | 0.5976 | 1.0320 | 0.112* | |
C13 | 0.4045 (17) | 0.5937 (12) | 1.0569 (3) | 0.105 (4) | |
H13 | 0.3716 | 0.5986 | 1.0867 | 0.126* | |
C14 | 0.5712 (15) | 0.5886 (13) | 1.0458 (2) | 0.098 (3) | |
H14 | 0.6539 | 0.5902 | 1.0683 | 0.117* | |
C15 | 0.6257 (13) | 0.5810 (10) | 1.0012 (2) | 0.080 (2) | |
H15 | 0.7428 | 0.5810 | 0.9941 | 0.096* | |
C16 | 0.9428 (9) | 0.3258 (6) | 0.92225 (19) | 0.0543 (14) | |
C17 | 0.9164 (12) | 0.2851 (10) | 0.9998 (3) | 0.088 (3) | |
H17A | 1.0242 | 0.2350 | 0.9982 | 0.132* | |
H17B | 0.8398 | 0.2369 | 1.0199 | 0.132* | |
H17C | 0.9365 | 0.3795 | 1.0104 | 0.132* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Au1 | 0.03817 (12) | 0.06238 (13) | 0.04636 (12) | −0.00480 (9) | −0.00432 (8) | 0.01037 (9) |
Cl1 | 0.0674 (10) | 0.0800 (9) | 0.0696 (8) | −0.0057 (9) | 0.0116 (8) | −0.0080 (7) |
O1 | 0.074 (4) | 0.133 (5) | 0.053 (2) | 0.001 (3) | 0.002 (2) | −0.009 (3) |
N1 | 0.058 (3) | 0.059 (3) | 0.039 (2) | 0.001 (2) | 0.0005 (17) | 0.001 (2) |
C1 | 0.066 (4) | 0.050 (2) | 0.056 (3) | −0.004 (3) | 0.007 (3) | −0.012 (2) |
Cl2 | 0.0421 (7) | 0.0984 (11) | 0.0736 (9) | −0.0079 (8) | 0.0022 (6) | −0.0121 (10) |
O2 | 0.067 (3) | 0.076 (3) | 0.0423 (18) | 0.004 (2) | 0.0038 (17) | −0.0078 (18) |
C2 | 0.056 (4) | 0.060 (3) | 0.046 (3) | −0.013 (3) | 0.002 (3) | −0.005 (2) |
Cl3 | 0.0411 (7) | 0.1031 (13) | 0.0776 (10) | −0.0110 (8) | −0.0036 (6) | 0.0147 (9) |
C3 | 0.063 (4) | 0.075 (4) | 0.043 (3) | 0.018 (3) | 0.006 (3) | −0.005 (3) |
O3 | 0.067 (3) | 0.129 (5) | 0.051 (2) | −0.005 (3) | 0.001 (2) | 0.028 (3) |
Cl4 | 0.0770 (11) | 0.0890 (10) | 0.0803 (9) | −0.0171 (12) | −0.0051 (9) | −0.0206 (8) |
O4 | 0.076 (3) | 0.071 (3) | 0.058 (2) | −0.013 (2) | 0.014 (2) | 0.014 (2) |
C4 | 0.090 (4) | 0.044 (2) | 0.047 (3) | 0.004 (3) | 0.011 (3) | −0.002 (2) |
C5 | 0.077 (4) | 0.050 (2) | 0.047 (3) | 0.004 (3) | 0.010 (3) | 0.008 (2) |
C6 | 0.080 (5) | 0.102 (5) | 0.039 (3) | 0.028 (4) | 0.001 (3) | 0.003 (3) |
C7 | 0.077 (5) | 0.110 (6) | 0.050 (3) | −0.006 (4) | −0.001 (3) | −0.036 (4) |
C8 | 0.072 (5) | 0.096 (5) | 0.056 (3) | 0.019 (4) | 0.013 (3) | 0.003 (3) |
C9 | 0.068 (4) | 0.055 (3) | 0.047 (3) | 0.005 (3) | 0.006 (3) | 0.002 (2) |
C10 | 0.087 (5) | 0.054 (3) | 0.050 (3) | 0.013 (4) | 0.016 (3) | −0.001 (2) |
C11 | 0.095 (5) | 0.076 (4) | 0.066 (4) | −0.001 (5) | 0.018 (4) | −0.011 (4) |
C12 | 0.103 (6) | 0.092 (5) | 0.085 (5) | −0.007 (6) | 0.044 (5) | −0.032 (5) |
C13 | 0.178 (11) | 0.086 (5) | 0.051 (4) | −0.022 (7) | 0.038 (5) | −0.022 (4) |
C14 | 0.134 (8) | 0.112 (7) | 0.047 (4) | −0.007 (7) | 0.011 (4) | −0.018 (4) |
C15 | 0.107 (6) | 0.085 (5) | 0.048 (3) | −0.003 (5) | 0.007 (3) | −0.011 (4) |
C16 | 0.062 (4) | 0.051 (3) | 0.050 (3) | −0.007 (3) | 0.006 (3) | 0.008 (2) |
C17 | 0.088 (6) | 0.107 (6) | 0.068 (4) | 0.004 (5) | 0.016 (4) | 0.038 (4) |
Au1—Cl2 | 2.2669 (15) | C5—C6 | 1.535 (10) |
Au1—Cl3 | 2.2732 (15) | C5—H5 | 0.9800 |
Au1—Cl4 | 2.2766 (17) | C6—C7 | 1.542 (12) |
Au1—Cl1 | 2.2843 (16) | C6—H6A | 0.9700 |
O1—C9 | 1.217 (9) | C6—H6B | 0.9700 |
N1—C5 | 1.497 (7) | C7—H7A | 0.9700 |
N1—C8 | 1.500 (8) | C7—H7B | 0.9700 |
N1—C1 | 1.525 (8) | C8—H8A | 0.9600 |
N1—H1A | 0.9100 | C8—H8B | 0.9600 |
C1—C2 | 1.523 (8) | C8—H8C | 0.9600 |
C1—C7 | 1.541 (10) | C9—C10 | 1.477 (7) |
C1—H1 | 0.9800 | C10—C15 | 1.384 (11) |
O2—C9 | 1.330 (9) | C10—C11 | 1.389 (12) |
O2—C3 | 1.433 (7) | C11—C12 | 1.398 (10) |
C2—C16 | 1.523 (9) | C11—H11 | 0.9300 |
C2—C3 | 1.552 (9) | C12—C13 | 1.354 (15) |
C2—H2 | 0.9800 | C12—H12 | 0.9300 |
C3—C4 | 1.488 (10) | C13—C14 | 1.333 (17) |
C3—H3 | 0.9800 | C13—H13 | 0.9300 |
O3—C16 | 1.192 (9) | C14—C15 | 1.399 (10) |
O4—C16 | 1.314 (8) | C14—H14 | 0.9300 |
O4—C17 | 1.478 (10) | C15—H15 | 0.9300 |
C4—C5 | 1.521 (8) | C17—H17A | 0.9600 |
C4—H4A | 0.9700 | C17—H17B | 0.9600 |
C4—H4B | 0.9700 | C17—H17C | 0.9600 |
Cl2—Au1—Cl3 | 175.52 (8) | C7—C6—H6A | 110.7 |
Cl2—Au1—Cl4 | 89.17 (7) | C5—C6—H6B | 110.7 |
Cl3—Au1—Cl4 | 90.08 (7) | C7—C6—H6B | 110.7 |
Cl2—Au1—Cl1 | 90.66 (7) | H6A—C6—H6B | 108.8 |
Cl3—Au1—Cl1 | 90.37 (7) | C1—C7—C6 | 105.1 (6) |
Cl4—Au1—Cl1 | 176.33 (7) | C1—C7—H7A | 110.7 |
C5—N1—C8 | 112.8 (5) | C6—C7—H7A | 110.7 |
C5—N1—C1 | 101.7 (5) | C1—C7—H7B | 110.7 |
C8—N1—C1 | 114.5 (5) | C6—C7—H7B | 110.7 |
C5—N1—H1A | 109.2 | H7A—C7—H7B | 108.8 |
C8—N1—H1A | 109.2 | N1—C8—H8A | 109.5 |
C1—N1—H1A | 109.2 | N1—C8—H8B | 109.5 |
C2—C1—N1 | 108.7 (4) | H8A—C8—H8B | 109.5 |
C2—C1—C7 | 113.2 (6) | N1—C8—H8C | 109.5 |
N1—C1—C7 | 101.4 (5) | H8A—C8—H8C | 109.5 |
C2—C1—H1 | 111.1 | H8B—C8—H8C | 109.5 |
N1—C1—H1 | 111.1 | O1—C9—O2 | 123.1 (6) |
C7—C1—H1 | 111.1 | O1—C9—C10 | 124.4 (7) |
C9—O2—C3 | 119.7 (5) | O2—C9—C10 | 112.5 (6) |
C1—C2—C16 | 111.7 (6) | C15—C10—C11 | 120.0 (6) |
C1—C2—C3 | 109.4 (5) | C15—C10—C9 | 121.1 (7) |
C16—C2—C3 | 110.7 (5) | C11—C10—C9 | 118.7 (7) |
C1—C2—H2 | 108.3 | C10—C11—C12 | 118.0 (8) |
C16—C2—H2 | 108.3 | C10—C11—H11 | 121.0 |
C3—C2—H2 | 108.3 | C12—C11—H11 | 121.0 |
O2—C3—C4 | 107.9 (5) | C13—C12—C11 | 122.1 (9) |
O2—C3—C2 | 109.2 (5) | C13—C12—H12 | 118.9 |
C4—C3—C2 | 111.7 (5) | C11—C12—H12 | 118.9 |
O2—C3—H3 | 109.4 | C14—C13—C12 | 119.2 (7) |
C4—C3—H3 | 109.4 | C14—C13—H13 | 120.4 |
C2—C3—H3 | 109.4 | C12—C13—H13 | 120.4 |
C16—O4—C17 | 115.2 (6) | C13—C14—C15 | 122.1 (10) |
C3—C4—C5 | 111.3 (5) | C13—C14—H14 | 119.0 |
C3—C4—H4A | 109.4 | C15—C14—H14 | 119.0 |
C5—C4—H4A | 109.4 | C10—C15—C14 | 118.6 (9) |
C3—C4—H4B | 109.4 | C10—C15—H15 | 120.7 |
C5—C4—H4B | 109.4 | C14—C15—H15 | 120.7 |
H4A—C4—H4B | 108.0 | O3—C16—O4 | 123.5 (6) |
N1—C5—C4 | 106.7 (4) | O3—C16—C2 | 123.7 (6) |
N1—C5—C6 | 102.2 (5) | O4—C16—C2 | 112.6 (6) |
C4—C5—C6 | 114.3 (6) | O4—C17—H17A | 109.5 |
N1—C5—H5 | 111.0 | O4—C17—H17B | 109.5 |
C4—C5—H5 | 111.0 | H17A—C17—H17B | 109.5 |
C6—C5—H5 | 111.0 | O4—C17—H17C | 109.5 |
C5—C6—C7 | 105.1 (5) | H17A—C17—H17C | 109.5 |
C5—C6—H6A | 110.7 | H17B—C17—H17C | 109.5 |
C5—N1—C1—C2 | −72.3 (5) | C2—C1—C7—C6 | 87.9 (7) |
C8—N1—C1—C2 | 165.7 (5) | N1—C1—C7—C6 | −28.4 (7) |
C5—N1—C1—C7 | 47.1 (5) | C5—C6—C7—C1 | 0.0 (8) |
C8—N1—C1—C7 | −74.8 (6) | C3—O2—C9—O1 | −9.1 (9) |
N1—C1—C2—C16 | −63.0 (6) | C3—O2—C9—C10 | 168.9 (5) |
C7—C1—C2—C16 | −174.8 (6) | O1—C9—C10—C15 | 168.4 (7) |
N1—C1—C2—C3 | 59.8 (6) | O2—C9—C10—C15 | −9.6 (9) |
C7—C1—C2—C3 | −52.0 (7) | O1—C9—C10—C11 | −6.7 (10) |
C9—O2—C3—C4 | 144.1 (6) | O2—C9—C10—C11 | 175.3 (6) |
C9—O2—C3—C2 | −94.4 (6) | C15—C10—C11—C12 | −1.6 (12) |
C1—C2—C3—O2 | −167.1 (6) | C9—C10—C11—C12 | 173.6 (7) |
C16—C2—C3—O2 | −43.6 (7) | C10—C11—C12—C13 | −0.9 (14) |
C1—C2—C3—C4 | −47.9 (7) | C11—C12—C13—C14 | 1.7 (18) |
C16—C2—C3—C4 | 75.6 (6) | C12—C13—C14—C15 | 0 (2) |
O2—C3—C4—C5 | 170.4 (5) | C11—C10—C15—C14 | 3.1 (13) |
C2—C3—C4—C5 | 50.5 (7) | C9—C10—C15—C14 | −171.9 (9) |
C8—N1—C5—C4 | −164.0 (6) | C13—C14—C15—C10 | −2 (2) |
C1—N1—C5—C4 | 72.9 (5) | C17—O4—C16—O3 | 2.4 (11) |
C8—N1—C5—C6 | 75.7 (7) | C17—O4—C16—C2 | −172.7 (6) |
C1—N1—C5—C6 | −47.4 (6) | C1—C2—C16—O3 | 37.0 (9) |
C3—C4—C5—N1 | −64.8 (7) | C3—C2—C16—O3 | −85.2 (9) |
C3—C4—C5—C6 | 47.4 (7) | C1—C2—C16—O4 | −148.0 (5) |
N1—C5—C6—C7 | 29.1 (7) | C3—C2—C16—O4 | 89.9 (6) |
C4—C5—C6—C7 | −85.8 (6) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O3 | 0.91 | 2.02 | 2.756 (6) | 136 |
C11—H11···O3i | 0.93 | 2.62 | 3.24 (1) | 125 |
C17—H17B···O3ii | 0.96 | 2.60 | 3.542 (9) | 168 |
C5—H5···Cl2iii | 0.98 | 2.90 | 3.633 (6) | 132 |
C4—H4B···Cl3iv | 0.97 | 2.80 | 3.750 (6) | 171 |
C6—H6A···Cl3v | 0.97 | 2.90 | 3.842 (7) | 165 |
C8—H8B···Cl4 | 0.96 | 2.85 | 3.703 (8) | 149 |
C2—H2···Cl4i | 0.98 | 2.78 | 3.759 (6) | 173 |
Symmetry codes: (i) x−1, y, z; (ii) x−1/2, −y+1/2, −z+2; (iii) x, y+1, z; (iv) x−1, y+1, z; (v) −x+3, y+1/2, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | (C17H22NO4)[AuCl4] |
Mr | 643.12 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 295 |
a, b, c (Å) | 7.7358 (3), 9.4543 (5), 29.9093 (13) |
V (Å3) | 2187.46 (17) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 17.33 |
Crystal size (mm) | 0.45 × 0.21 × 0.08 |
Data collection | |
Diffractometer | Bruker SMART CCD APEXII area-detector diffractometer |
Absorption correction | Numerical and multi-scan [SHELXTL (Sheldrick, 2004) and SADABS (Bruker, 2005)] |
Tmin, Tmax | 0.042, 0.338 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 14526, 3906, 3804 |
Rint | 0.052 |
(sin θ/λ)max (Å−1) | 0.604 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.028, 0.070, 1.05 |
No. of reflections | 3906 |
No. of parameters | 246 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.59, −0.96 |
Absolute structure | Flack (1983), with 1468 Friedel pairs |
Absolute structure parameter | 0.025 (14) |
Computer programs: SMART (Bruker, 2006), SMART, SAINT-Plus (Bruker, 2005), SHELXS97 (Sheldrick, 2004), SHELXL97 (Sheldrick, 2004), SHELXTL (Sheldrick, 2004), SHELXTL.
Au1—Cl2 | 2.2669 (15) | Au1—Cl4 | 2.2766 (17) |
Au1—Cl3 | 2.2732 (15) | Au1—Cl1 | 2.2843 (16) |
Cl2—Au1—Cl3 | 175.52 (8) | Cl2—Au1—Cl1 | 90.66 (7) |
Cl2—Au1—Cl4 | 89.17 (7) | Cl3—Au1—Cl1 | 90.37 (7) |
Cl3—Au1—Cl4 | 90.08 (7) | Cl4—Au1—Cl1 | 176.33 (7) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O3 | 0.91 | 2.02 | 2.756 (6) | 136 |
C11—H11···O3i | 0.93 | 2.62 | 3.24 (1) | 125 |
C17—H17B···O3ii | 0.96 | 2.60 | 3.542 (9) | 168 |
C5—H5···Cl2iii | 0.98 | 2.90 | 3.633 (6) | 132 |
C4—H4B···Cl3iv | 0.97 | 2.80 | 3.750 (6) | 171 |
C6—H6A···Cl3v | 0.97 | 2.90 | 3.842 (7) | 165 |
C8—H8B···Cl4 | 0.96 | 2.85 | 3.703 (8) | 149 |
C2—H2···Cl4i | 0.98 | 2.78 | 3.759 (6) | 173 |
Symmetry codes: (i) x−1, y, z; (ii) x−1/2, −y+1/2, −z+2; (iii) x, y+1, z; (iv) x−1, y+1, z; (v) −x+3, y+1/2, −z+3/2. |
Cocaine is a complex tropane alkaloid which occurs naturally in the leaves of the coca plant, Erythroxylum coca. In the United States, cocaine is one of the most widely abused illicit drugs, second only to marijuana (Drug Enforcement Administration, 2006). Pharmacologically, cocaine acts as a central nervous system stimulant, and has been used medically as a local anesthetic. The structure of cocaine was originally determined by Willstätter & Müller (1898) by chemical means and verified by a crystal structure of L-cocaine hydrochloride by Gabe & Barnes (1963); this structure was redetermined by Zhu et al. in 1999.
The gold chloride microcrystal test has been widely utilized for over 100 years (Lyons, 1885) by forensic scientists in the general scheme of analysis for cocaine. Microcrystal tests are one of the fastest and simplest techniques for differentiating L-cocaine from its seven stereoisomers (Allen et al., 1981). Unlike some of the more sophisticated techniques such as mass spectrometry, microcrystal tests are inexpensive, and the only instrument required is a light microscope. This test involves the addition of a 5% w/v solution of chloroauric acid in water (HAuCl4·3H2O) to a dilute aqueous acidified (HCl) solution of suspected cocaine, followed by observation of the resulting crystals microscopically (American Society for Testing and Materials, 2003). However, the interpretation of the resulting microcrystalline precipitate has been empirical and subject to the training and experience of the analyst (McCrone, 1992). In our study, single-crystal X-ray diffraction was used to determine the absolute configuration of the gold(III) tetrachloride salt of L-cocaine, (I), which has the same powder diffraction profile as the microcrystalline material.
Fig. 1 shows the asymmetric unit of (I). Compared with the structure reported by Zhu et al. (1999), the main difference in the cocaine cation is the rotation of the methoxycarbonyl group about the C2—C16 bond in (I). The L-cocaine–HCl structure reported by Zhu et al. (1999) has the methoxycarbonyl group rotated [torsion angle -138.4 (8)°] to allow hydrogen bonding between the protonated N atom and the methoxy O atom. In the present structure, (I), this torsion angle [C3—C2—C16—O4 = 89.9 (6)°] allows the protonated N atom to be hydrogen-bonded to the carbonyl O atom [N1···O3 = 2.755 (6) Å, and N1—H1A···O3 = 136°]. According to potential energy calculations performed by Zhu et al. (1999), the energy minimum for the methoxycarbonyl group occurs at a torsion angle of approximatelyl 95–110°. The orientation of the methoxycarbonyl group found in (I) corresponds closely to the conformation found in the structure of (-)-norcocaine (Zhu et al., 1994), which exhibits similar hydrogen bonding between the protonated atom N1 and the carbonyl atom O3.
The [AuCl4]- anion of (I) was found to be a distorted square plane, with the Au atom 0.0056 (8) Å above the best least-squares plane of the five-atom moiety. Two opposing Cl- anions are above the best plane by 0.0784 (14) Å and the other two are below the plane by -0.0812 (14) Å. In a search of the Cambridge Structural Database (CSD, Version 5.27, update of May 2006; Allen, 2002), 89 structures containing the gold tetrachloride anion are found. However, only 24 show the `bowing' of the square-planar arrangement of the Au and the four Cl- anions. Of these, only one shows flexing of the Cl- anions slightly larger than that found here. Two opposing Cl- anions in the structure of tetra(methylthio)tetrathiafulvalene bis(tetrachloro-gold) (CSD refcode GEHSOB01; Jones, 1989) are above the best plane by 0.087 Å and the opposite two are below the plane by -0.078 Å. All of the other gold tetrachloride anions are more planar than that in (I), mostly forming a very nearly perfect square-planar arrangement about the Au atom.
In (I), the hydrogen bonding between atom N1 and the O atom of the methoxycarbonyl group (O3) is characterized by N1···O3 = 2.755 (6) Å and N1—H1A···O3 = 136°. In the structure of (-)-cocaine hydrochloride (Zhu et al., 1999), there is a hydrogen bond between atom N1 and the Cl- anion [3.058 (9) Å] and another weaker hydrogen bond between atom N1 and the methoxy O atom [2.894 (9) Å]. This latter hydrogen bond is made possible because of the rotation of the methoxycarbonyl group in this structure to present the methoxy O atom to the H atom on N1. In (I), since the methoxycarbonyl group is rotated by 131.5 (10)°, this hydrogen bond from N1 is to the carbonyl atom O3.
Fig. 2 illustrates the hydrogen bonding and close contacts of (I). Two intermolecular close contacts are present (Table 1) within the 2.7 Å range that we employ as standard for non-bonded C—H···O packing interactions (Steiner, 1997). Also, four close contacts exist to three of the four Cl- of the anion; atom Cl1 has no close contacts (see Table 1). However, a symmetry-related [AuCl4]- anion is located such that the Cl1···Au1(1 - x, -1/2 + y, 3/2 - z) distance is 4.3742 (16) Å and the Au1—Cl1···Au1(1 - x, -1/2 + y, 3/2 - z) angle is 172.38 (6)°. The interplanar angle between the best least-squares planes of two [AuCl4]- anions is 82.81 (4)°, which results in a herringbone pattern of the [AuCl4]- anions, with atom Cl1 pointing directly at the Au of an adjacent anion.