Ammonium [(1S)-(endo,anti)]-(−)-3-bromo­camphor-8-sulfonate

In the title mol­ecular salt, NH₄⁺·C₁₀H₁₄BrO₄S⁻, the norbornane skeleton of the anion is composed of two five-membered rings in envelope conformations and a six-membered ring with one Br atom, one carbonyl O atom and a methyl group held in a boat conformation by a bridging methyl­ene group. Short intra­molecular C—H...O and C—H...Br inter­actions occur. In the crystal, the component ions are linked by inter­molecular N—H...O and C—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.027
• wR factor = 0.065
• Data-to-parameter ratio = 16.5

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT431_ALERT_2_C Short Inter HL..A Contact  Br1    ..  O1      ..       3.25 Ang.
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          4
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          4
PLAT915_ALERT_3_C Low Friedel Pair Coverage ......................      84.90 Perc.
PLAT042_ALERT_1_C Calc. and Reported MoietyFormula Strings  Differ          ?

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.50
           From the CIF: _reflns_number_total               2775
           Count of symmetry unique reflns         1620
           Completeness (_total/calc)            171.30%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1155
           Fraction of Friedel pairs measured     0.713
           Are heavy atom types Z>Si present        yes
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          5
PLAT791_ALERT_4_G Note: The Model has Chirality at C2     (Verify)          S
PLAT791_ALERT_4_G Note: The Model has Chirality at C3     (Verify)          R
PLAT791_ALERT_4_G Note: The Model has Chirality at C6     (Verify)          S
PLAT791_ALERT_4_G Note: The Model has Chirality at C10    (Verify)          R

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   6 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   5 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check


checkCIF publication errors

Alert level A
PUBL024_ALERT_1_A The number of authors is greater than 5.
              Please specify the role of each of the co-authors
              for your paper.

Author Response: Abbasi, Aziz-ur-Rehman and Jahangir synthesized and crystallized the title compound for x-ray analysis and performed the elemental analysis of the compound. Data collection, structure solution, structure refinement and writing the article of the title compound have been performed by the others.

   1 ALERT level A = Data missing that is essential or data in wrong format
   0 ALERT level G = General alerts. Data that may be required is missing

---

S1. Comment

3-Bromocamphor-8-sulfonic acid and its ammonium salts have extensively been used as chiral auxillaries for the optical resolution of a number of enantiomeric amines through diasteriomeric salt formation (Bálint et al., 1999; Zhao et al., 2002; Roy et al., 2009; Pellati et al., 2010).

In the bicyclo[2.2.1]heptane (norbornane) skeleton of the title compound, (I), (Fig. 1), the two five-membered rings have envelope conformations, with atom C2 displaced by 0.365 (3) Å from the C2–C6 plane [the puckering parameters (Cremer & Pople, 1975) are Q₂ = 0.573 (3) Å and ϕ₂ = 5.3 (3)°] and by 0.397 (3) Å from the C2/C3/C6/C9/C10 plane [the puckering parameters: Q₂ = 0.615 (3) Å and ϕ₂ = 181.6 (3)°] and the six-membered ring (C3–C6/C9/C10) adopts a boat conformation by the puckering parameters Q_T = 0.970 (3) Å, θ = 92.03 (18)° and ϕ = 357.34 (19) °.

In (I), the C—C single-bond lengths range from 1.491 (5) to 1.575 (4) Å, with a mean value of 1.535 (4) Å. In the bicyclo[2.2.1]heptane fragment, the angles between planes A (C3/C2/C6), B (C3–C6) and C (C3/C6/C9/C10) are as follows: A/B= 53.65 (19)°, A/C= 58.14 (18)° and B/C= 68.22 (13)°.

In the crystal, adjacent molecules of (I) are linked by intermolecular N—H···O and C—H···O hydrogen bonds (Table 1, Fig. 2).

Related literature

For further synthetic details, see: Smith et al. (2008). For other structures with the norbornane skeleton, see: Jauch et al. (1992); Ustabaş et al. (2006); Ersanlı et al. (2005). For the use of 3-bromocamphor-8-sulfonic acid and its ammonium salts as chiral auxillaries for the optical resolution of enantiomeric amines through diasteriomeric salt formation, see: Bálint et al. (1999); Pellati et al. (2010); Roy et al. (2009); Zhao et al. (2002). For puckering parameters, see: Cremer & Pople (1975).

S2. Experimental

3-Bromocamphor-8-sulfonic acid ammonium salt was prepared by modification in the reported method (Smith et al., 2008). 3-Bromocamphor-8-sulfonic acid (1 g) was dissolved in 15 ml of ethanol and then 6 ml of NH₃ solution were added. The mixture was stirred until a clear solution was observed (about 20 min). The solution was slowly concentrated on water bath to half the volume over a 2 h period. The concentrate was allowed to crystallize undisturbed for 48 h. The resulting colourless prisms of (I) were carefully separated by filteration and washed with three 0.5-ml portions of petroleum ether.

S3. Refinement

In the ammonium ion, H atoms bound to N atoms were located in difference Fourier maps and their positional parameters were refined freely using a DFIX instruction [N—H = 0.93 (3) Å] in SHELXL97, with U_iso(H) = 1.5U_eq(N). H atoms bound to C atoms were placed in idealized positions and refined using a riding model with C—H = 0.96, 0.97 and 0.98 Å for CH₃, CH₂ and CH, respectively. U_iso(H) values were set at 1.5U_eq(C) for the methyl groups, and 1.2U_eqU_eq(C) for other H atoms.

Computing details

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999), PARST (Nardelli, 1983) and PLATON (Spek, 2009).

Figures

	Fig. 1. View of (I) with displacement ellipsoids drawn at the 30% probability level.
	Fig. 2. The crystal packing of (I) viewed down the b-axis. The hydrogen-bonds are drawn as a dashed lines. H-atoms not involved in hydrogen bonds have been omitted for clarity.

Ammonium [(1S)-(endo,anti)]-(-)-(3-bromo-1,7- dimethyl-2-oxobicyclo[2.2.1]heptan-7-yl)methanesulfonate

Crystal data

NH4^+·C10H14BrO4S^−	F(000) = 336
Mr = 328.22	Dx = 1.677 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 3356 reflections
a = 7.2449 (2) Å	θ = 2.9–28.3°
b = 7.0049 (1) Å	µ = 3.33 mm^−1
c = 13.2428 (3) Å	T = 296 K
β = 104.704 (1)°	Prism, colourless
V = 650.06 (3) Å^3	0.42 × 0.14 × 0.11 mm
Z = 2

Data collection

Bruker Kappa APEXII CCD diffractometer	2775 independent reflections
Radiation source: sealed tube	2586 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.000
ϕ and ω scans	θmax = 27.5°, θmin = 3.3°
Absorption correction: part of the refinement model (ΔF) (XABS2; Parkin et al., 1995; quadratic fit to sin(θ)/λ - 18 parameters)	h = −9→9
Tmin = 0.336, Tmax = 0.711	k = −8→9
2775 measured reflections	l = 0→17

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)] = 0.027	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.065	w = 1/[σ^2(Fo^2) + (0.033P)^2 + 0.1814P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
2775 reflections	Δρmax = 0.35 e Å^−3
168 parameters	Δρmin = −0.47 e Å^−3
5 restraints	Absolute structure: Flack (1983), 1155 Freidel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.021 (7)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs 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
Br1	0.09450 (4)	0.00017 (4)	0.27520 (3)	0.0440 (1)
S1	0.65799 (9)	0.68509 (9)	0.36429 (5)	0.0242 (2)
O1	0.7216 (3)	0.8793 (3)	0.3541 (2)	0.0434 (8)
O2	0.8199 (3)	0.5560 (3)	0.39714 (16)	0.0332 (6)
O3	0.5283 (3)	0.6697 (4)	0.42972 (17)	0.0448 (8)
O4	0.2268 (4)	0.0517 (4)	0.0568 (2)	0.0596 (10)
C1	0.5311 (4)	0.6201 (4)	0.2339 (2)	0.0277 (8)
C2	0.4754 (4)	0.4086 (4)	0.2154 (2)	0.0213 (7)
C3	0.3597 (3)	0.3263 (4)	0.2899 (2)	0.0223 (7)
C4	0.1802 (4)	0.4500 (4)	0.2647 (2)	0.0272 (8)
C5	0.1351 (4)	0.4758 (5)	0.1462 (2)	0.0352 (9)
C6	0.3067 (4)	0.3804 (4)	0.1148 (2)	0.0310 (9)
C7	0.3318 (6)	0.4411 (6)	0.0112 (2)	0.0519 (13)
C8	0.6514 (4)	0.2949 (4)	0.2067 (2)	0.0316 (9)
C9	0.2719 (4)	0.1690 (5)	0.1248 (2)	0.0342 (9)
C10	0.3097 (4)	0.1283 (4)	0.2418 (2)	0.0298 (8)
N1	0.8032 (3)	0.1906 (4)	0.4952 (2)	0.0311 (7)
H1A	0.41550	0.69600	0.21450	0.0330*
H1B	0.60920	0.65480	0.18710	0.0330*
H3	0.42880	0.32500	0.36380	0.0270*
H4A	0.20390	0.57210	0.30010	0.0330*
H4B	0.07600	0.38650	0.28480	0.0330*
H5A	0.12590	0.61000	0.12770	0.0420*
H5B	0.01620	0.41320	0.11210	0.0420*
H7A	0.22080	0.40620	−0.04250	0.0780*
H7B	0.44200	0.37920	−0.00150	0.0780*
H7C	0.34880	0.57700	0.01080	0.0780*
H8A	0.74270	0.29220	0.27340	0.0470*
H8B	0.70750	0.35440	0.15630	0.0470*
H8C	0.61420	0.16680	0.18500	0.0470*
H10	0.42240	0.04610	0.26290	0.0360*
H1N	0.775 (5)	0.096 (4)	0.445 (2)	0.0470*
H2N	0.914 (4)	0.170 (6)	0.543 (2)	0.0470*
H3N	0.806 (5)	0.305 (4)	0.461 (3)	0.0470*
H4N	0.706 (4)	0.195 (6)	0.528 (3)	0.0470*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0329 (2)	0.0300 (2)	0.0673 (2)	−0.0085 (1)	0.0093 (1)	0.0087 (2)
S1	0.0199 (3)	0.0209 (3)	0.0303 (3)	−0.0028 (2)	0.0036 (2)	−0.0024 (3)
O1	0.0492 (13)	0.0217 (11)	0.0526 (15)	−0.0096 (9)	0.0007 (11)	−0.0030 (9)
O2	0.0246 (9)	0.0298 (11)	0.0393 (12)	0.0024 (7)	−0.0029 (8)	−0.0036 (8)
O3	0.0304 (10)	0.0674 (17)	0.0391 (13)	−0.0101 (11)	0.0133 (9)	−0.0175 (12)
O4	0.0552 (15)	0.060 (2)	0.0580 (16)	−0.0138 (12)	0.0042 (12)	−0.0336 (13)
C1	0.0241 (13)	0.0248 (14)	0.0298 (15)	−0.0018 (11)	−0.0010 (11)	0.0010 (11)
C2	0.0168 (12)	0.0239 (13)	0.0226 (13)	−0.0016 (10)	0.0041 (10)	−0.0026 (10)
C3	0.0170 (11)	0.0207 (12)	0.0274 (14)	−0.0020 (9)	0.0022 (10)	−0.0004 (10)
C4	0.0184 (11)	0.0235 (15)	0.0403 (16)	0.0017 (9)	0.0084 (10)	−0.0020 (11)
C5	0.0222 (12)	0.0368 (19)	0.0406 (16)	0.0024 (13)	−0.0030 (11)	0.0017 (14)
C6	0.0239 (13)	0.0409 (17)	0.0248 (15)	−0.0040 (12)	−0.0002 (11)	−0.0024 (12)
C7	0.056 (2)	0.070 (3)	0.0247 (17)	−0.0134 (18)	0.0011 (15)	0.0033 (15)
C8	0.0206 (13)	0.0359 (16)	0.0382 (17)	−0.0007 (12)	0.0074 (11)	−0.0104 (13)
C9	0.0198 (12)	0.0392 (17)	0.0405 (16)	−0.0051 (12)	0.0018 (11)	−0.0130 (14)
C10	0.0213 (12)	0.0212 (13)	0.0444 (17)	−0.0006 (10)	0.0039 (11)	−0.0016 (11)
N1	0.0266 (12)	0.0334 (13)	0.0329 (13)	0.0019 (11)	0.0066 (10)	0.0030 (11)

Geometric parameters (Å, º)

Br1—C10	1.945 (3)	C6—C7	1.491 (4)
S1—O1	1.454 (2)	C6—C9	1.514 (4)
S1—O2	1.457 (2)	C9—C10	1.530 (4)
S1—O3	1.435 (2)	C1—H1B	0.9700
S1—C1	1.797 (3)	C1—H1A	0.9700
O4—C9	1.201 (4)	C3—H3	0.9800
N1—H1N	0.92 (3)	C4—H4B	0.9700
N1—H2N	0.90 (3)	C4—H4A	0.9700
N1—H3N	0.92 (3)	C5—H5A	0.9700
N1—H4N	0.92 (3)	C5—H5B	0.9700
C1—C2	1.539 (4)	C7—H7A	0.9600
C2—C3	1.558 (4)	C7—H7B	0.9600
C2—C6	1.575 (4)	C7—H7C	0.9600
C2—C8	1.532 (4)	C8—H8B	0.9600
C3—C4	1.527 (4)	C8—H8C	0.9600
C3—C10	1.531 (4)	C8—H8A	0.9600
C4—C5	1.530 (4)	C10—H10	0.9800
C5—C6	1.558 (4)
O1—S1—O2	111.00 (13)	C3—C10—C9	102.4 (2)
O1—S1—O3	113.46 (15)	S1—C1—H1B	108.00
O1—S1—C1	104.17 (14)	S1—C1—H1A	108.00
O2—S1—O3	111.96 (14)	C2—C1—H1A	108.00
O2—S1—C1	107.84 (13)	C2—C1—H1B	108.00
O3—S1—C1	107.92 (14)	H1A—C1—H1B	107.00
H3N—N1—H4N	109 (3)	C10—C3—H3	114.00
H2N—N1—H4N	109 (3)	C4—C3—H3	114.00
H1N—N1—H3N	107 (3)	C2—C3—H3	115.00
H1N—N1—H4N	108 (3)	C5—C4—H4A	111.00
H1N—N1—H2N	113 (3)	C3—C4—H4B	111.00
H2N—N1—H3N	111 (3)	C3—C4—H4A	111.00
S1—C1—C2	116.52 (19)	C5—C4—H4B	111.00
C1—C2—C8	108.8 (2)	H4A—C4—H4B	109.00
C1—C2—C6	111.8 (2)	H5A—C5—H5B	109.00
C1—C2—C3	114.6 (2)	C4—C5—H5A	111.00
C6—C2—C8	110.7 (2)	C4—C5—H5B	111.00
C3—C2—C6	93.6 (2)	C6—C5—H5A	111.00
C3—C2—C8	116.6 (2)	C6—C5—H5B	111.00
C4—C3—C10	108.9 (2)	H7B—C7—H7C	109.00
C2—C3—C4	102.5 (2)	C6—C7—H7C	109.00
C2—C3—C10	100.4 (2)	C6—C7—H7A	110.00
C3—C4—C5	103.9 (2)	C6—C7—H7B	109.00
C4—C5—C6	104.2 (2)	H7A—C7—H7B	109.00
C7—C6—C9	114.9 (3)	H7A—C7—H7C	109.00
C2—C6—C7	119.5 (3)	C2—C8—H8B	109.00
C2—C6—C5	102.8 (2)	C2—C8—H8A	109.00
C5—C6—C9	103.6 (2)	H8A—C8—H8C	109.00
C2—C6—C9	99.2 (2)	C2—C8—H8C	109.00
C5—C6—C7	114.5 (3)	H8A—C8—H8B	109.00
O4—C9—C6	128.6 (3)	H8B—C8—H8C	110.00
O4—C9—C10	125.2 (3)	C9—C10—H10	109.00
C6—C9—C10	106.3 (2)	Br1—C10—H10	109.00
Br1—C10—C3	116.24 (18)	C3—C10—H10	109.00
Br1—C10—C9	111.62 (19)
O1—S1—C1—C2	169.7 (2)	C2—C3—C4—C5	39.1 (3)
O2—S1—C1—C2	51.7 (2)	C10—C3—C4—C5	−66.7 (3)
O3—S1—C1—C2	−69.4 (3)	C2—C3—C10—Br1	−159.47 (17)
S1—C1—C2—C3	54.3 (3)	C2—C3—C10—C9	−37.5 (3)
S1—C1—C2—C6	159.2 (2)	C4—C3—C10—Br1	−52.3 (3)
S1—C1—C2—C8	−78.2 (3)	C4—C3—C10—C9	69.7 (3)
C1—C2—C3—C4	61.2 (3)	C3—C4—C5—C6	−5.6 (3)
C1—C2—C3—C10	173.5 (2)	C4—C5—C6—C2	−29.3 (3)
C6—C2—C3—C4	−54.8 (2)	C4—C5—C6—C7	−160.5 (3)
C6—C2—C3—C10	57.5 (2)	C4—C5—C6—C9	73.6 (3)
C8—C2—C3—C4	−170.0 (2)	C2—C6—C9—O4	−144.1 (3)
C8—C2—C3—C10	−57.8 (3)	C2—C6—C9—C10	34.8 (3)
C1—C2—C6—C5	−67.8 (3)	C5—C6—C9—O4	110.3 (4)
C1—C2—C6—C7	60.4 (4)	C5—C6—C9—C10	−70.9 (3)
C1—C2—C6—C9	−174.0 (2)	C7—C6—C9—O4	−15.4 (5)
C3—C2—C6—C5	50.6 (2)	C7—C6—C9—C10	163.5 (3)
C3—C2—C6—C7	178.7 (3)	O4—C9—C10—Br1	−54.7 (4)
C3—C2—C6—C9	−55.7 (2)	O4—C9—C10—C3	−179.8 (3)
C8—C2—C6—C5	170.7 (2)	C6—C9—C10—Br1	126.4 (2)
C8—C2—C6—C7	−61.1 (4)	C6—C9—C10—C3	1.3 (3)
C8—C2—C6—C9	64.5 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O1^i	0.92 (3)	1.92 (3)	2.835 (4)	173 (3)
N1—H2N···O2^ii	0.90 (3)	2.05 (3)	2.899 (3)	157 (3)
N1—H3N···O2	0.92 (3)	1.97 (3)	2.887 (3)	176 (3)
N1—H4N···O3^iii	0.92 (3)	1.93 (3)	2.827 (3)	167 (4)
C4—H4B···Br1	0.97	2.71	3.221 (3)	113
C8—H8A···O2	0.96	2.44	3.104 (3)	126
C10—H10···O1^i	0.98	2.49	3.451 (4)	167

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