organic compounds
of 2-amino-4,6-dimethoxypyrimidinium thiophene-2-carboxylate
aSchool of Chemistry, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu, India, bDepartment of Chemistry, Howard University, 525 College Street NW, Washington, DC 20059, USA, and cDepartment of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA
*Correspondence e-mail: tommtrichy@yahoo.co.in
In the title salt, C6H10N3O2+·C5H3O2S−, the 2-amino-4,6-dimethoxypyrimidinium cation interacts with the carboxylate group of the thiophene-2-carboxylate anion through a pair of N—H⋯O hydrogen bonds, forming an R22(8) ring motif. These motifs are centrosymmetrically paired via N—H⋯O hydrogen bonds, forming a complementary DDAA array. The separate DDAA arrays are linked by π–π stacking interactions between the pyrimidine rings, as well as by a number of weak C—H⋯O and N—H⋯O interactions. In the anion, the dihedral angle between the ring plane and the CO2 group is 11.60 (3)°. In the cation, the C atoms of methoxy groups deviate from the ring plane by 0.433 (10) Å.
CCDC reference: 1405154
1. Related literature
For the role played by non-covalent interactions in molecular recognition porcesses, see: Desiraju (1989). For aminopryimidine–carboxylate interactions in protein–nucleic acid recognition and protein–drug binding inteactions, see: Hunt et al. (1980); Alkorta & Elguero (2003). For 1:1 salts between 2-aminopyrimidine and mono- and dicarboxylic acids, see: Etter & Adsmond (1990). For self-assembly of 2-aminopyrimidine compounds, see: Scheinbeim & Schempp (1976). For carboxylic acid and 2-amino heterocyclic ring system synthons, see: Lynch & Jones (2004). For crystal structures of related salts, see: Ebenezer et al. (2012); Jennifer & Muthiah (2014). DDAA arrays have been observed in trimethoprim hydrogen glutarate (Robert et al., 2001), trimethoprim formate (Umadevi et al., 2002), trimethoprim-m-chlorobenzoate (Raj et al., 2003), pyrimethaminium 3,5-dinitrobenzoate (Subashini et al., 2007) and 2-amino-4,6-dimethoxypyrimidinum-salicylate (Thanigaimani et al., 2007).
2. Experimental
2.1. Crystal data
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2.3. Refinement
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Data collection: CrysAlis PRO (Agilent, 2012); cell CrysAlis PRO; data reduction: CrysAlis RED (Agilent, 2012); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007; Palatinus & van der Lee, 2008; Palatinus et al., 2012); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2.
Supporting information
CCDC reference: 1405154
10.1107/S2056989015010907/hg5442sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S2056989015010907/hg5442Isup2.hkl
Supporting information file. DOI: 10.1107/S2056989015010907/hg5442Isup3.cml
The π—π stacking interactions between the pyrimidine ring of one array with a neighbouring array, with an observed interplanar distance of 3.356 Å, a centroid (Cg1)-to-centroid (Cg1) distance of 3.4689 (12) Å (where Cg1 equals the centroid of the ring N1/C1/N2/C2/C3/C4, Fig 3) and slip angle (the angle between the centroid vector and the normal to the plane) of 14.68°, which are typical aromatic stacking values (Hunter, 1994). In addition, a number of weak C—H···O and N—H···O intermolecular interactions are also observed which contribute to crystal packing stability (Table 2).
of C6H10N3O2+ C5H3O2S-, (I), contains one 2-amino-4,6-dimethoxypyrimidinium cation and one thiophene-2-carboxylate anion (Fig 1). Protonation of the cation occurs at N1, providing a C1/N1/C2 angle of 119.39 (16)° compared to the C1/N2/C4 angle (115.99 (16)°) of the unprotonated N2 atom. The carboxylate group of the thiophene-2-carboxylate anion interacts with the protonated atom N1 and the 2-amino group of the pyrimidine moiety through a pair of N—H···O hydrogen bonds, forming an eight membered R22(8) ring motif. These motifs are centrosymmetrically paired via N—H···O hydrogen bonds to produce a DDAA (D = donor in hydrogen bonds, A = acceptor in hydrogen bonds) array of quadruple hydrogen bonds represented by the graph-set notation R22(8), R42(8) and R22(8) (Fig. 2). This type of array has also been identified in trimethoprim hydrogen glutarate (Robert et al., 2001), trimethoprim formate (Umadevi et al., 2002), trimethoprim- m-chlorobenzoate (Raj et al., 2003), pyrimethaminium 3,5-dinitrobenzoate (Subashini et al., 2007) and 2-amino-4,6-dimethoxypyrimidinum-salicylate (Thanigaimani et al., 2007). An infinite number of several such quadruple arrays are interconnected and stabilized byA hot methanolic solution of 2-amino-4,6-dimethoxy pyrimidine (38 mg, Aldrich) and thiophene-2-carboxylic acid (32 mg, Aldrich) was warmed for half an hour over a water bath. The mixture was cooled slowly and kept at room temperature. After a few days colourless crystals were obtained.
Crystal data, data collection and structure
details are summarized in Table 1. All of the H atoms were placed in their calculated positions andthen refined using the riding model with atom—H lengths of 0.95Å (CH), 0.98Å (CH3)or 0.88Å (NH, NH2). Isotropic displacement parameters for these atoms were set to 1.2 (CH, NH, NH2) or 1.5 (CH3) times Ueq of the parent atom. Idealised Me refined as rotating groups.Data collection: CrysAlis PRO (Agilent, 2012); cell
CrysAlis PRO (Agilent, 2012); data reduction: CrysAlis RED (Agilent, 2012); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007; Palatinus & van der Lee, 2008; Palatinus et al., 2012); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).Fig. 1. : The asymmetric unit of the title compound, showing 30% probability displacement ellipsoids. | |
Fig. 2. : A view of DDAA array along the b axis formed by independent N—H···O hydrogen bonds. Symmetry codes are given in Table 1. Dashed lines represent hydrogen bonds. | |
Fig. 3. : A view of infinite number of DDAA arrays interconnected by π–π stacking interactions indicated by dotted lines. Cg1···Cg1 = 3.4689 (12) Å, where Cg1 represents the centroid of the ring N1/C1/N2/C2/C3/C4. |
C6H10N3O2+·C5H3O2S− | F(000) = 592 |
Mr = 283.30 | Dx = 1.465 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 6.7335 (3) Å | Cell parameters from 2092 reflections |
b = 7.6307 (4) Å | θ = 4.0–32.4° |
c = 25.0638 (10) Å | µ = 0.27 mm−1 |
β = 93.928 (4)° | T = 173 K |
V = 1284.78 (10) Å3 | Irregular, colourless |
Z = 4 | 0.32 × 0.28 × 0.14 mm |
Agilent Eos Gemini diffractometer | 4245 independent reflections |
Radiation source: Enhance (Mo) X-ray Source | 3071 reflections with I > 2σ(I) |
Detector resolution: 16.0416 pixels mm-1 | Rint = 0.028 |
ω scans | θmax = 32.7°, θmin = 3.3° |
Absorption correction: multi-scan (CrysAlis RED; Agilent, 2012) | h = −7→9 |
Tmin = 0.789, Tmax = 1.000 | k = −11→10 |
8844 measured reflections | l = −36→33 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.062 | H-atom parameters constrained |
wR(F2) = 0.186 | w = 1/[σ2(Fo2) + (0.0861P)2 + 0.9218P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max < 0.001 |
4245 reflections | Δρmax = 0.79 e Å−3 |
174 parameters | Δρmin = −0.55 e Å−3 |
0 restraints |
C6H10N3O2+·C5H3O2S− | V = 1284.78 (10) Å3 |
Mr = 283.30 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 6.7335 (3) Å | µ = 0.27 mm−1 |
b = 7.6307 (4) Å | T = 173 K |
c = 25.0638 (10) Å | 0.32 × 0.28 × 0.14 mm |
β = 93.928 (4)° |
Agilent Eos Gemini diffractometer | 4245 independent reflections |
Absorption correction: multi-scan (CrysAlis RED; Agilent, 2012) | 3071 reflections with I > 2σ(I) |
Tmin = 0.789, Tmax = 1.000 | Rint = 0.028 |
8844 measured reflections |
R[F2 > 2σ(F2)] = 0.062 | 0 restraints |
wR(F2) = 0.186 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.79 e Å−3 |
4245 reflections | Δρmin = −0.55 e Å−3 |
174 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.3208 (2) | 0.1426 (2) | 0.38775 (6) | 0.0280 (3) | |
O2 | 0.2312 (2) | 0.1346 (2) | 0.57319 (6) | 0.0324 (4) | |
N1 | 0.5394 (2) | 0.2619 (2) | 0.44749 (6) | 0.0228 (3) | |
H1 | 0.6074 | 0.2925 | 0.4202 | 0.027* | |
N2 | 0.5086 (2) | 0.2608 (2) | 0.54146 (6) | 0.0240 (3) | |
N3 | 0.7832 (3) | 0.3787 (3) | 0.50524 (7) | 0.0329 (4) | |
H3A | 0.8323 | 0.4043 | 0.5377 | 0.039* | |
H3B | 0.8504 | 0.4053 | 0.4775 | 0.039* | |
C1 | 0.6093 (3) | 0.3005 (3) | 0.49820 (8) | 0.0230 (4) | |
C2 | 0.3645 (3) | 0.1761 (3) | 0.43926 (8) | 0.0223 (4) | |
C3 | 0.2549 (3) | 0.1307 (3) | 0.48120 (8) | 0.0257 (4) | |
H3 | 0.1315 | 0.0706 | 0.4763 | 0.031* | |
C4 | 0.3372 (3) | 0.1789 (3) | 0.53174 (8) | 0.0242 (4) | |
C5 | 0.1469 (3) | 0.0367 (3) | 0.37450 (9) | 0.0333 (5) | |
H5A | 0.1320 | 0.0186 | 0.3357 | 0.050* | |
H5B | 0.0286 | 0.0966 | 0.3862 | 0.050* | |
H5C | 0.1617 | −0.0769 | 0.3926 | 0.050* | |
C6 | 0.3184 (4) | 0.1689 (4) | 0.62628 (9) | 0.0352 (5) | |
H6A | 0.3659 | 0.2903 | 0.6284 | 0.053* | |
H6B | 0.4305 | 0.0890 | 0.6342 | 0.053* | |
H6C | 0.2182 | 0.1507 | 0.6523 | 0.053* | |
S1 | −0.15194 (10) | 0.54563 (10) | 0.26469 (2) | 0.0427 (2) | |
O1A | −0.0066 (2) | 0.4332 (2) | 0.41417 (6) | 0.0326 (4) | |
O2A | −0.2775 (2) | 0.3607 (3) | 0.36279 (6) | 0.0361 (4) | |
C1A | 0.0377 (5) | 0.6516 (4) | 0.23842 (10) | 0.0434 (6) | |
H1A | 0.0295 | 0.7014 | 0.2036 | 0.052* | |
C2A | 0.2037 (4) | 0.6582 (4) | 0.27227 (11) | 0.0431 (6) | |
H2A | 0.3227 | 0.7142 | 0.2631 | 0.052* | |
C3A | 0.1860 (3) | 0.5737 (3) | 0.32322 (8) | 0.0268 (4) | |
H3AA | 0.2874 | 0.5637 | 0.3513 | 0.032* | |
C4A | −0.0153 (3) | 0.5071 (3) | 0.32345 (8) | 0.0253 (4) | |
C5A | −0.1048 (3) | 0.4276 (3) | 0.37009 (8) | 0.0250 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0286 (7) | 0.0348 (8) | 0.0209 (7) | −0.0082 (6) | 0.0042 (5) | −0.0050 (6) |
O2 | 0.0321 (8) | 0.0437 (10) | 0.0228 (7) | −0.0045 (7) | 0.0110 (6) | 0.0022 (6) |
N1 | 0.0241 (7) | 0.0250 (8) | 0.0196 (7) | −0.0027 (6) | 0.0044 (6) | 0.0006 (6) |
N2 | 0.0269 (8) | 0.0271 (8) | 0.0185 (7) | 0.0015 (6) | 0.0054 (6) | 0.0015 (6) |
N3 | 0.0316 (9) | 0.0479 (12) | 0.0193 (8) | −0.0135 (8) | 0.0023 (7) | −0.0005 (8) |
C1 | 0.0267 (9) | 0.0229 (9) | 0.0198 (8) | 0.0003 (7) | 0.0039 (7) | 0.0016 (7) |
C2 | 0.0241 (9) | 0.0214 (9) | 0.0217 (8) | −0.0009 (7) | 0.0032 (7) | −0.0006 (7) |
C3 | 0.0241 (9) | 0.0279 (10) | 0.0256 (9) | −0.0034 (7) | 0.0062 (7) | 0.0015 (8) |
C4 | 0.0275 (9) | 0.0243 (9) | 0.0217 (9) | 0.0032 (7) | 0.0079 (7) | 0.0029 (7) |
C5 | 0.0321 (10) | 0.0379 (12) | 0.0296 (11) | −0.0087 (9) | 0.0009 (8) | −0.0066 (9) |
C6 | 0.0372 (11) | 0.0494 (14) | 0.0202 (9) | 0.0037 (10) | 0.0101 (8) | −0.0003 (9) |
S1 | 0.0476 (4) | 0.0578 (5) | 0.0226 (3) | 0.0000 (3) | 0.0015 (2) | 0.0018 (3) |
O1A | 0.0325 (8) | 0.0457 (10) | 0.0194 (7) | −0.0082 (7) | −0.0006 (6) | 0.0043 (6) |
O2A | 0.0340 (8) | 0.0530 (11) | 0.0213 (7) | −0.0147 (7) | 0.0015 (6) | 0.0006 (7) |
C1A | 0.0661 (17) | 0.0416 (14) | 0.0241 (11) | 0.0038 (12) | 0.0141 (11) | 0.0050 (10) |
C2A | 0.0517 (15) | 0.0439 (15) | 0.0354 (13) | −0.0110 (11) | 0.0155 (11) | 0.0029 (11) |
C3A | 0.0409 (11) | 0.0239 (9) | 0.0170 (8) | −0.0072 (8) | 0.0112 (7) | 0.0013 (7) |
C4A | 0.0311 (10) | 0.0277 (10) | 0.0171 (8) | 0.0014 (8) | 0.0026 (7) | 0.0002 (7) |
C5A | 0.0291 (9) | 0.0277 (10) | 0.0186 (8) | −0.0026 (7) | 0.0034 (7) | −0.0002 (7) |
O1—C2 | 1.329 (2) | C5—H5B | 0.9800 |
O1—C5 | 1.443 (3) | C5—H5C | 0.9800 |
O2—C4 | 1.343 (2) | C6—H6A | 0.9800 |
O2—C6 | 1.441 (3) | C6—H6B | 0.9800 |
N1—H1 | 0.8800 | C6—H6C | 0.9800 |
N1—C1 | 1.357 (2) | S1—C1A | 1.683 (3) |
N1—C2 | 1.351 (3) | S1—C4A | 1.708 (2) |
N2—C1 | 1.352 (2) | O1A—C5A | 1.249 (2) |
N2—C4 | 1.321 (3) | O2A—C5A | 1.272 (3) |
N3—H3A | 0.8800 | C1A—H1A | 0.9500 |
N3—H3B | 0.8800 | C1A—C2A | 1.357 (4) |
N3—C1 | 1.315 (3) | C2A—H2A | 0.9500 |
C2—C3 | 1.370 (3) | C2A—C3A | 1.443 (3) |
C3—H3 | 0.9500 | C3A—H3AA | 0.9500 |
C3—C4 | 1.396 (3) | C3A—C4A | 1.448 (3) |
C5—H5A | 0.9800 | C4A—C5A | 1.481 (3) |
C2—O1—C5 | 116.97 (16) | H5A—C5—H5C | 109.5 |
C4—O2—C6 | 117.66 (17) | H5B—C5—H5C | 109.5 |
C1—N1—H1 | 120.3 | O2—C6—H6A | 109.5 |
C2—N1—H1 | 120.3 | O2—C6—H6B | 109.5 |
C2—N1—C1 | 119.40 (16) | O2—C6—H6C | 109.5 |
C4—N2—C1 | 115.98 (17) | H6A—C6—H6B | 109.5 |
H3A—N3—H3B | 120.0 | H6A—C6—H6C | 109.5 |
C1—N3—H3A | 120.0 | H6B—C6—H6C | 109.5 |
C1—N3—H3B | 120.0 | C1A—S1—C4A | 92.37 (12) |
N2—C1—N1 | 122.80 (18) | S1—C1A—H1A | 123.6 |
N3—C1—N1 | 118.20 (17) | C2A—C1A—S1 | 112.83 (19) |
N3—C1—N2 | 119.00 (18) | C2A—C1A—H1A | 123.6 |
O1—C2—N1 | 111.98 (16) | C1A—C2A—H2A | 122.5 |
O1—C2—C3 | 126.99 (18) | C1A—C2A—C3A | 115.0 (2) |
N1—C2—C3 | 121.02 (18) | C3A—C2A—H2A | 122.5 |
C2—C3—H3 | 122.3 | C2A—C3A—H3AA | 126.4 |
C2—C3—C4 | 115.38 (18) | C2A—C3A—C4A | 107.1 (2) |
C4—C3—H3 | 122.3 | C4A—C3A—H3AA | 126.4 |
O2—C4—C3 | 115.91 (18) | C3A—C4A—S1 | 112.68 (14) |
N2—C4—O2 | 118.68 (18) | C3A—C4A—C5A | 125.34 (18) |
N2—C4—C3 | 125.40 (17) | C5A—C4A—S1 | 121.78 (16) |
O1—C5—H5A | 109.5 | O1A—C5A—O2A | 124.37 (18) |
O1—C5—H5B | 109.5 | O1A—C5A—C4A | 117.69 (18) |
O1—C5—H5C | 109.5 | O2A—C5A—C4A | 117.92 (18) |
H5A—C5—H5B | 109.5 | ||
O1—C2—C3—C4 | 178.67 (19) | C6—O2—C4—N2 | −4.2 (3) |
N1—C2—C3—C4 | −0.2 (3) | C6—O2—C4—C3 | 174.98 (19) |
C1—N1—C2—O1 | −177.64 (17) | S1—C1A—C2A—C3A | 0.3 (3) |
C1—N1—C2—C3 | 1.3 (3) | S1—C4A—C5A—O1A | −167.06 (17) |
C1—N2—C4—O2 | 179.44 (18) | S1—C4A—C5A—O2A | 11.8 (3) |
C1—N2—C4—C3 | 0.4 (3) | C1A—S1—C4A—C3A | −1.39 (18) |
C2—N1—C1—N2 | −1.8 (3) | C1A—S1—C4A—C5A | 173.67 (19) |
C2—N1—C1—N3 | 177.7 (2) | C1A—C2A—C3A—C4A | −1.3 (3) |
C2—C3—C4—O2 | −179.84 (19) | C2A—C3A—C4A—S1 | 1.7 (2) |
C2—C3—C4—N2 | −0.7 (3) | C2A—C3A—C4A—C5A | −173.1 (2) |
C4—N2—C1—N1 | 0.9 (3) | C3A—C4A—C5A—O1A | 7.3 (3) |
C4—N2—C1—N3 | −178.5 (2) | C3A—C4A—C5A—O2A | −173.8 (2) |
C5—O1—C2—N1 | 174.26 (18) | C4A—S1—C1A—C2A | 0.6 (2) |
C5—O1—C2—C3 | −4.7 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1Ai | 0.88 | 2.83 | 3.479 (2) | 132 |
N1—H1···O2Ai | 0.88 | 1.76 | 2.637 (2) | 175 |
N3—H3A···O1Aii | 0.88 | 2.04 | 2.826 (2) | 148 |
N3—H3B···O1Ai | 0.88 | 1.92 | 2.798 (2) | 173 |
C5—H5B···O1A | 0.98 | 2.68 | 3.369 (3) | 128 |
C6—H6B···O1iii | 0.98 | 2.52 | 3.434 (3) | 155 |
C1A—H1A···O1iv | 0.95 | 2.60 | 3.365 (3) | 138 |
C1A—H1A···O2Av | 0.95 | 2.60 | 3.383 (3) | 140 |
Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y+1, −z+1; (iii) −x+1, −y, −z+1; (iv) −x+1/2, y+1/2, −z+1/2; (v) −x−1/2, y+1/2, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1Ai | 0.88 | 2.83 | 3.479 (2) | 132.2 |
N1—H1···O2Ai | 0.88 | 1.76 | 2.637 (2) | 174.7 |
N3—H3A···O1Aii | 0.88 | 2.04 | 2.826 (2) | 147.7 |
N3—H3B···O1Ai | 0.88 | 1.92 | 2.798 (2) | 172.8 |
C5—H5B···O1A | 0.98 | 2.68 | 3.369 (3) | 127.9 |
C6—H6B···O1iii | 0.98 | 2.52 | 3.434 (3) | 155.0 |
C1A—H1A···O1iv | 0.95 | 2.60 | 3.365 (3) | 137.5 |
C1A—H1A···O2Av | 0.95 | 2.60 | 3.383 (3) | 140.4 |
Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y+1, −z+1; (iii) −x+1, −y, −z+1; (iv) −x+1/2, y+1/2, −z+1/2; (v) −x−1/2, y+1/2, −z+1/2. |
Acknowledgements
PTM is thankful to the UGC, New Delhi, for a UGC–BSR one-time grant to Faculty. JPJ acknowledges the NSF–MRI program (grant No. 1039027) for funds to purchase the X-ray diffractometer.
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