organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

S-2-Amino-5-(di­methyl­ammonio)phenyl sulfo­thio­ate

aFaculty of Textile Technology, Laboratory of Applied Chemistry, University of Zagreb, Prilaz baruna Filipovića 28a, HR-10000 Zagreb, Croatia
*Correspondence e-mail: gpavlov@ttf.hr

(Received 8 April 2009; accepted 29 April 2009; online 7 May 2009)

The title compound, C8H12N2O3S2, has been isolated as an inter­mediate in the synthesis of methyl­ene blue dye, the best known phenothia­zine dye, and structurally characterized as a zwitterion. The crystal structure is dominated by inter­molecular N—H⋯O hydrogen bonds between the amine and sulfothio­ate groups, with graph-set motif C(9)R22(8), involving anti­parallel chains and a centrosymmetric eight-membered ring. A hydrogen bond with graph-set motif R22(14) between the ammonium and sulfothio­ate groups completes the two-dimensional network in the ab plane. Inter­molecular C—H⋯O hydrogen bonds are also present in the crystal.

Related literature

For methyl­ene blue dye, see: Bernthasen (1889[Bernthasen, A. (1889). Annalen, 251, 1-97.]); Zollinger (1991[Zollinger, H. (1991). Colour Chemistry, 2nd ed. Weinheim: VCH.]); Hunger (2003[Hunger, K. (2003). Industrial Dyes: Chemistry, Properties, Application. Weinheim: Wiley-VCH.]). For its preparation, see: Leventis et al. (1997[Leventis, N., Chen, M. & Sortiriou-Leventis, C. (1997). Tetrahedron, 53, 10083-10092.]). For the synthesis of the title compound, see: Bogert & Updike (1927[Bogert, M. T. & Updike, I. A. (1927). J. Am. Chem. Soc. 49, 1373-1382.]); Bennett & Bell (1943[Bennett, G. M. & Bell, E. V. (1943). Organic Syntheses, Collected Vol. 2, p. 223. New York: John Wiley & Sons.]). For bond-length data, see: Trinajstić (1968[Trinajstić, N. (1968). Tetrahedron Lett. 12, 1529-1532.]); Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L. & Orpen, A. G. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]).

[Scheme 1]

Experimental

Crystal data
  • C8H12N2O3S2

  • Mr = 248.32

  • Monoclinic, P 21 /n

  • a = 12.0593 (1) Å

  • b = 7.3651 (1) Å

  • c = 12.2312 (1) Å

  • β = 95.0766 (8)°

  • V = 1082.09 (2) Å3

  • Z = 4

  • Cu Kα radiation

  • μ = 4.41 mm−1

  • T = 296 K

  • 0.48 × 0.37 × 0.29 mm

Data collection
  • Xcalibur Nova diffractometer with enhance (Cu) X-ray source and Onyx CCD

  • Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008[Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]) Tmin = 0.628, Tmax = 1.000 (expected range = 0.175–0.279)

  • 5132 measured reflections

  • 2153 independent reflections

  • 2006 reflections with I > 2σ(I)

  • Rint = 0.015

Refinement
  • R[F2 > 2σ(F2)] = 0.034

  • wR(F2) = 0.092

  • S = 1.07

  • 2153 reflections

  • 150 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.33 e Å−3

  • Δρmin = −0.19 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H11N⋯O1i 0.87 (3) 2.36 (3) 3.136 (3) 148 (2)
N1—H21N⋯O1ii 0.82 (2) 2.28 (2) 3.010 (2) 148 (2)
N2—H12N⋯O3iii 0.88 (2) 1.89 (2) 2.769 (2) 175 (2)
C5—H5⋯O3i 0.93 2.55 3.376 (2) 148
C8—H8A⋯O2iv 0.96 2.41 3.209 (3) 141
Symmetry codes: (i) x, y-1, z; (ii) -x+2, -y, -z+1; (iii) -x+1, -y, -z+1; (iv) [x-{\script{1\over 2}}, -y-{\script{1\over 2}}, z+{\script{1\over 2}}].

Data collection: CrysAlis CCD (Oxford Diffraction, 2008[Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]); cell refinement: CrysAlis RED (Oxford Diffraction, 2008[Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

Phenothiazine dyes are class of colorants with application in various fields of which the methylene blue is the most well known (Zollinger, 1991; Hunger, 2003). Commercially, methylene blue is produced by oxidation of 4-N,N-dimethylaminoaniline with Na2Cr2O7 in the presence of Na2S2O3, followed by the further oxidation in the presence of N,N-dimethylaniline, usually without isolation of intermediate 4-N,N-dimethylaminoaniline-2-tiosulfuric acid (Leventis et al., 1997). Namely, this compound was first described in 1889 (Bernthasen, 1889) and in the last hundred years reported by several authors. Moreover, in the literature the compound is described as phenyl O-hydrogen sulfothioate acid but the possibility of zwitterionic form (I) (Scheme 1) was not reported. Following one of the known method for preparation of 4-N,N-dimethylaminoaniline-2-tiosulfuric acid (Bogert & Updike, 1927), we isolated S-2-amino-5-(dimethylammonio)phenyl sulfothioate (I) determined by single-crystal structure analysis (Scheme, Fig. 1).

The single S—S bond distance value of sulfothioate group is 2.0985 (5) Å. The S—C bond in (I) is 1.768 (2) Å, reflecting aprox. 20% of π bond character according to N. Trinajstić (Trinajstić, 1968). The Car—N bond formed by amine group has significantπ character (1.360 (3) Å). On the contrary, C—N bonds of the N,N-dimethylammonio groups are essentially single bonds (N2—C7 1.491 (2) Å and N2—C8 1.501 (2) Å). The values observed are in accordance with the literature data (Allen et al., 1987).

The relative orientation of the sulfothioate group to the phenyl ring is defined by the torsion angle S2—S1—C3—C4 (92.93 (13)°). The twist around Car-Nsp3 bond is described by Car—Car—Nsp3—Csp3 torsion angle of 73.97 (18)° (for the atom sequence C6—C1—N2—C8).

The rather complex hydrogen bond network in (I) (Table 1, Fig. 2) is characterized by the N—H···O and the C—H···O intermolecular hydrogen bonds. The atom N1 acts as double proton donor and the atoms O1 and O3 as double proton acceptors (Table 1). The C—H···O intermolecular hydrogen bonds are formed between Car-H groups along with the C8 atom of 5-N,N-dimethylammonio cation and O atoms of S—SO3- fragment.

At the unitary level antiparallel infinite chains are formed by the N1—H11N···O1i (i = x, -y, z) hydrogen bonds between amino and sulfothioate groups (Table 1, Fig. 2). The R22(8) rings are formed via N1—H11N···O1i (i = x, -y, z) and N1—H21N···O1ii (ii = 2 - x, -y, 1 - z) hydrogen bonds, thus N1 amino group participates in bifurcated hydrogen bond. The combination of these two primary motifs, chain and ring, generates a new 14-membered ring of the second level of graph-set notation: N2=R22(14) involving N+2-H···O3 hydrogen bond. Consequently, the crystal structure can be described as the two-dimensional-network in the (ab) plane.

Related literature top

For methylene blue dye, see: Bernthasen (1889); Zollinger (1991); Hunger (2003). For its preparation, see: (Leventis et al., 1997). For the synthesis of the title compound, see: Bogert & Updike (1927); Bennett & Bell (1943) . For bond-length data, see: Trinajstić (1968); Allen et al. (1987).

Experimental top

N,N-dimethylaniline was dissolved in aqueous HCl and nitrosilated with NaNO2 (Bennett & Bell, 1943). The resulting crude 4-nitroso-N,N-dimethylaniline hydrochloride was isolated and dissolved in aqueous acetic acid. The cold water solution of Na2S2O3 was added and the reaction mixture was stirred at 273 - 278 K for several h (Bogert & Updike, 1927), and left for two days at room temperature. The crude product was filtered off, and crystallized from water. The obtained crystals of S-2-amino-5-(dimethylammonium)phenyl sulfothioate (I) were in the form of blue prisms. Spectroscopic analysis, IR (ATR, cm-1): 3451 (m), 3342 (m), 3034 (w), 2657 (m), 1616 (s), 1504 (s), 1458 (m), 1400 (m), 1319 (w), 1242 (s), 1161 (s), 1134 (s), 1003 (s), 906 (m), 880 (w), 822 (m), 675 (w), 622 (s), 544 (m). 1H NMR (300 MHz, DMSO-d6):δ 8.99 (br s, 2H), 7.18 (s, 1H), 7.10–7.03 (m, 2H), 2.99 (s, 6H). Analysis, calculated for C8H12N2O3S2: C 38.69, H 4.87, N 11.28%; found: C 38.65, H 4.91, N 11.21%.

Refinement top

Hydrogen atoms bonded to the nitrogen atoms of amino and ammonio groups were found in the difference Fourier electron-density maps and refined freely. All hydrogen atoms attached to the carbon atoms were generated at calculated positions and refined by applying the riding model (Uiso (H) = 1.2 Ueq (C) and Csp2-H distance 0.93 Å; Csp3-H 0.96 Å and Uiso (H) = 1.5 Ueq (C).

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis RED (Oxford Diffraction, 2008); data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXL97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. Crystal structure of (I) viewed down the c axis. Hydrogen bonds are drawn by dashed lines.
[Figure 3] Fig. 3. The zwitterionic and acid forms of the title compound.
S-2-amino-5-(dimethylammonio)phenyl sulfothioate top
Crystal data top
C8H12N2O3S2F(000) = 520
Mr = 248.32Dx = 1.524 Mg m3
Monoclinic, P21/nCu Kα radiation, λ = 1.54184 Å
a = 12.0593 (1) ÅCell parameters from 4267 reflections
b = 7.3651 (1) Åθ = 3.6–76.1°
c = 12.2312 (1) ŵ = 4.41 mm1
β = 95.0766 (8)°T = 296 K
V = 1082.09 (2) Å3Prism, blue
Z = 40.48 × 0.37 × 0.29 mm
Data collection top
κ geometry Xcalibur Nova
diffractometer with enhance (Cu) X-ray source and Onyx CCD
2153 independent reflections
Radiation source: fine-focus sealed tube2006 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.015
Detector resolution: 10.4323 pixels mm-1θmax = 75.0°, θmin = 4.9°
Enhance (Cu) X–ray Source scansh = 1315
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2008)
k = 95
Tmin = 0.628, Tmax = 1.000l = 1514
5132 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.092H atoms treated by a mixture of independent and constrained refinement
S = 1.07 w = 1/[σ2(Fo2) + (0.0551P)2 + 0.3077P]
where P = (Fo2 + 2Fc2)/3
2153 reflections(Δ/σ)max < 0.001
150 parametersΔρmax = 0.33 e Å3
0 restraintsΔρmin = 0.19 e Å3
Crystal data top
C8H12N2O3S2V = 1082.09 (2) Å3
Mr = 248.32Z = 4
Monoclinic, P21/nCu Kα radiation
a = 12.0593 (1) ŵ = 4.41 mm1
b = 7.3651 (1) ÅT = 296 K
c = 12.2312 (1) Å0.48 × 0.37 × 0.29 mm
β = 95.0766 (8)°
Data collection top
κ geometry Xcalibur Nova
diffractometer with enhance (Cu) X-ray source and Onyx CCD
2153 independent reflections
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2008)
2006 reflections with I > 2σ(I)
Tmin = 0.628, Tmax = 1.000Rint = 0.015
5132 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0340 restraints
wR(F2) = 0.092H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.33 e Å3
2153 reflectionsΔρmin = 0.19 e Å3
150 parameters
Special details top

Experimental. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
S10.85191 (3)0.04337 (6)0.62282 (3)0.04476 (15)
S20.83204 (3)0.15312 (5)0.46396 (3)0.03773 (14)
O10.92392 (11)0.27914 (18)0.46826 (12)0.0521 (3)
O20.83442 (12)0.00876 (19)0.38531 (12)0.0556 (3)
O30.72379 (11)0.24407 (18)0.45543 (11)0.0506 (3)
N10.83654 (15)0.3588 (3)0.56480 (16)0.0531 (4)
H11N0.832 (2)0.469 (4)0.539 (2)0.060 (7)*
H21N0.891 (2)0.295 (3)0.556 (2)0.057 (7)*
N20.43258 (11)0.05829 (19)0.68128 (11)0.0369 (3)
H12N0.3836 (17)0.113 (3)0.6345 (17)0.042 (5)*
C10.53946 (13)0.1301 (2)0.64861 (12)0.0354 (3)
C20.63340 (13)0.0239 (2)0.65023 (13)0.0371 (3)
H20.63060.09710.67150.045*
C30.73290 (13)0.0974 (2)0.62006 (13)0.0375 (3)
C40.73946 (14)0.2821 (2)0.59014 (13)0.0391 (3)
C50.64152 (14)0.3866 (2)0.59039 (14)0.0413 (4)
H50.64330.50870.57120.050*
C60.54366 (14)0.3119 (2)0.61841 (13)0.0388 (3)
H60.47990.38320.61720.047*
C70.42090 (16)0.1431 (2)0.67521 (17)0.0491 (4)
H7A0.46960.19790.73220.074*
H7B0.34530.17620.68450.074*
H7C0.44030.18480.60500.074*
C80.40933 (16)0.1240 (3)0.79311 (15)0.0491 (4)
H8A0.41200.25430.79480.074*
H8B0.33680.08380.80910.074*
H8C0.46430.07600.84700.074*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0369 (2)0.0545 (3)0.0423 (2)0.01012 (16)0.00067 (16)0.00048 (17)
S20.0361 (2)0.0368 (2)0.0409 (2)0.00114 (14)0.00620 (15)0.00381 (14)
O10.0461 (7)0.0505 (7)0.0602 (8)0.0109 (6)0.0076 (6)0.0049 (6)
O20.0643 (8)0.0537 (8)0.0503 (7)0.0016 (6)0.0127 (6)0.0157 (6)
O30.0435 (7)0.0476 (7)0.0594 (8)0.0071 (5)0.0029 (5)0.0075 (6)
N10.0463 (9)0.0465 (9)0.0690 (11)0.0051 (7)0.0192 (8)0.0029 (8)
N20.0344 (7)0.0419 (7)0.0347 (7)0.0012 (5)0.0046 (5)0.0001 (5)
C10.0344 (7)0.0402 (8)0.0320 (7)0.0011 (6)0.0046 (6)0.0004 (6)
C20.0394 (8)0.0361 (8)0.0363 (7)0.0021 (6)0.0060 (6)0.0030 (6)
C30.0354 (7)0.0425 (8)0.0348 (7)0.0034 (6)0.0047 (6)0.0003 (6)
C40.0415 (8)0.0425 (9)0.0336 (7)0.0026 (7)0.0060 (6)0.0006 (6)
C50.0487 (9)0.0349 (8)0.0409 (8)0.0005 (7)0.0067 (7)0.0016 (6)
C60.0394 (8)0.0393 (8)0.0377 (8)0.0060 (6)0.0040 (6)0.0011 (6)
C70.0486 (9)0.0449 (10)0.0551 (10)0.0079 (7)0.0114 (8)0.0048 (8)
C80.0509 (10)0.0567 (10)0.0418 (9)0.0005 (8)0.0154 (7)0.0067 (8)
Geometric parameters (Å, º) top
S1—C31.7683 (16)C2—C31.395 (2)
S1—S22.0986 (6)C2—H20.9300
S2—O21.4358 (13)C3—C41.413 (2)
S2—O11.4428 (13)C4—C51.410 (2)
S2—O31.4627 (13)C5—C61.373 (2)
N1—C41.360 (2)C5—H50.9300
N1—H11N0.87 (3)C6—H60.9300
N1—H21N0.83 (3)C7—H7A0.9600
N2—C11.4805 (19)C7—H7B0.9600
N2—C71.491 (2)C7—H7C0.9600
N2—C81.501 (2)C8—H8A0.9600
N2—H12N0.88 (2)C8—H8B0.9600
C1—C21.375 (2)C8—H8C0.9600
C1—C61.391 (2)
C3—S1—S2100.49 (5)C2—C3—S1118.90 (13)
O2—S2—O1116.10 (8)C4—C3—S1120.36 (12)
O2—S2—O3111.22 (8)N1—C4—C5120.80 (16)
O1—S2—O3112.69 (8)N1—C4—C3121.86 (16)
O2—S2—S1109.13 (7)C5—C4—C3117.32 (15)
O1—S2—S1100.93 (6)C6—C5—C4121.37 (15)
O3—S2—S1105.69 (6)C6—C5—H5119.3
C4—N1—H11N116.4 (17)C4—C5—H5119.3
C4—N1—H21N120.4 (17)C5—C6—C1120.29 (15)
H11N—N1—H21N121 (2)C5—C6—H6119.9
C1—N2—C7115.00 (13)C1—C6—H6119.9
C1—N2—C8111.61 (13)N2—C7—H7A109.5
C7—N2—C8109.99 (14)N2—C7—H7B109.5
C1—N2—H12N102.0 (13)H7A—C7—H7B109.5
C7—N2—H12N111.7 (13)N2—C7—H7C109.5
C8—N2—H12N105.9 (13)H7A—C7—H7C109.5
C2—C1—C6120.13 (15)H7B—C7—H7C109.5
C2—C1—N2121.91 (14)N2—C8—H8A109.5
C6—C1—N2117.94 (14)N2—C8—H8B109.5
C1—C2—C3120.15 (15)H8A—C8—H8B109.5
C1—C2—H2119.9N2—C8—H8C109.5
C3—C2—H2119.9H8A—C8—H8C109.5
C2—C3—C4120.73 (15)H8B—C8—H8C109.5
C3—S1—S2—O261.58 (9)S2—S1—C3—C288.47 (13)
C3—S1—S2—O1175.65 (8)S2—S1—C3—C492.94 (13)
C3—S1—S2—O358.12 (8)C2—C3—C4—N1177.24 (16)
C7—N2—C1—C221.8 (2)S1—C3—C4—N11.3 (2)
C8—N2—C1—C2104.36 (18)C2—C3—C4—C51.0 (2)
C7—N2—C1—C6159.86 (15)S1—C3—C4—C5179.60 (12)
C8—N2—C1—C673.96 (18)N1—C4—C5—C6178.39 (17)
C6—C1—C2—C30.9 (2)C3—C4—C5—C60.1 (2)
N2—C1—C2—C3179.22 (14)C4—C5—C6—C10.7 (2)
C1—C2—C3—C41.6 (2)C2—C1—C6—C50.2 (2)
C1—C2—C3—S1179.85 (12)N2—C1—C6—C5178.16 (14)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H11N···O1i0.87 (3)2.36 (3)3.136 (3)148 (2)
N1—H21N···O1ii0.82 (2)2.28 (2)3.010 (2)148 (2)
N2—H12N···O3iii0.88 (2)1.89 (2)2.769 (2)175 (2)
C5—H5···O3i0.932.553.376 (2)148
C8—H8A···O2iv0.962.413.209 (3)141
Symmetry codes: (i) x, y1, z; (ii) x+2, y, z+1; (iii) x+1, y, z+1; (iv) x1/2, y1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC8H12N2O3S2
Mr248.32
Crystal system, space groupMonoclinic, P21/n
Temperature (K)296
a, b, c (Å)12.0593 (1), 7.3651 (1), 12.2312 (1)
β (°) 95.0766 (8)
V3)1082.09 (2)
Z4
Radiation typeCu Kα
µ (mm1)4.41
Crystal size (mm)0.48 × 0.37 × 0.29
Data collection
Diffractometerκ geometry Xcalibur Nova
diffractometer with enhance (Cu) X-ray source and Onyx CCD
Absorption correctionMulti-scan
(CrysAlis RED; Oxford Diffraction, 2008)
Tmin, Tmax0.628, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
5132, 2153, 2006
Rint0.015
(sin θ/λ)max1)0.626
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.092, 1.07
No. of reflections2153
No. of parameters150
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.33, 0.19

Computer programs: CrysAlis CCD (Oxford Diffraction, 2008), CrysAlis RED (Oxford Diffraction, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H11N···O1i0.87 (3)2.36 (3)3.136 (3)148 (2)
N1—H21N···O1ii0.82 (2)2.28 (2)3.010 (2)148 (2)
N2—H12N···O3iii0.88 (2)1.89 (2)2.769 (2)175 (2)
C5—H5···O3i0.932.55003.376 (2)148
C8—H8A···O2iv0.962.41003.209 (3)141
Symmetry codes: (i) x, y1, z; (ii) x+2, y, z+1; (iii) x+1, y, z+1; (iv) x1/2, y1/2, z+1/2.
 

Acknowledgements

This research was supported by the Ministry of Science and Technology of the Republic of Croatia (grant No. 117–0000000–3283 and 098–1191344–2943).

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L. & Orpen, A. G. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CrossRef Google Scholar
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