Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805029727/dn6241sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536805029727/dn6241Isup2.hkl |
CCDC reference: 287548
Key indicators
- Single-crystal X-ray study
- T = 295 K
- Mean (C-C) = 0.005 Å
- R factor = 0.041
- wR factor = 0.098
- Data-to-parameter ratio = 23.9
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ? PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density .... 3.20 PLAT480_ALERT_4_C Long H...A H-Bond Reported H4B .. CL1 .. 2.92 Ang.
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 3 ALERT level C = Check and explain 0 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 0 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion
The title compound was crystallized by slow evaporation of an aqueous solution of cytosine, tin(II) chloride and hydrochloric acid in a molar ratio of 10:5:1. White prismatic crystals of (I) were obtained after two weeks and were manually separated for single-crystal X-ray analysis.
All H atoms were located in difference Fourier maps but were introduced in calculated positions and treated as riding on their parent atoms, with C—H = 0.93 Å and N—H = 0.86 Å, and with Uiso(H) = 1.2Ueq(C,N). [Please check added text] The very large residual electronic density (3.066 e Å−3) observed in the structure has no chemical significance and might be regarded as spurious.
Data collection: KappaCCD Server Software (Nonius, 1998); cell refinement: DENZO and SCALEPAK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPAK; program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997), PLUTON (Spek, 1990) and ATOMS for Windows (Dowty, 1995); software used to prepare material for publication: WinGX (Farrugia, 1999).
(C4H6N3O)2[SnCl6] | Z = 1 |
Mr = 555.63 | F(000) = 270 |
Triclinic, P1 | Dx = 2.100 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 6.910 (5) Å | Cell parameters from 2533 reflections |
b = 7.090 (5) Å | θ = 2.3–30.1° |
c = 9.270 (5) Å | µ = 2.38 mm−1 |
α = 101.86 (5)° | T = 295 K |
β = 98.36 (5)° | Prism, white |
γ = 90.51 (5)° | 0.1 × 0.1 × 0.1 mm |
V = 439.4 (5) Å3 |
Nonius KappaCCD area-detector diffractometer | 2531 independent reflections |
Radiation source: fine-focus sealed tube | 2279 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.052 |
ϕ scans, and ω scans with κ offsets | θmax = 30.1°, θmin = 2.3° |
Absorption correction: multi-scan (SORTAV; Blessing 1995) | h = −9→9 |
Tmin = 0.717, Tmax = 0.792 | k = −9→9 |
2533 measured reflections | l = −13→4 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.098 | H-atom parameters constrained |
S = 1.08 | w = 1/[σ2(Fo2) + (0.02P)2] where P = (Fo2 + 2Fc2)/3 |
2531 reflections | (Δ/σ)max = 0.001 |
106 parameters | Δρmax = 3.07 e Å−3 |
0 restraints | Δρmin = −0.96 e Å−3 |
(C4H6N3O)2[SnCl6] | γ = 90.51 (5)° |
Mr = 555.63 | V = 439.4 (5) Å3 |
Triclinic, P1 | Z = 1 |
a = 6.910 (5) Å | Mo Kα radiation |
b = 7.090 (5) Å | µ = 2.38 mm−1 |
c = 9.270 (5) Å | T = 295 K |
α = 101.86 (5)° | 0.1 × 0.1 × 0.1 mm |
β = 98.36 (5)° |
Nonius KappaCCD area-detector diffractometer | 2531 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing 1995) | 2279 reflections with I > 2σ(I) |
Tmin = 0.717, Tmax = 0.792 | Rint = 0.052 |
2533 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 0 restraints |
wR(F2) = 0.098 | H-atom parameters constrained |
S = 1.08 | Δρmax = 3.07 e Å−3 |
2531 reflections | Δρmin = −0.96 e Å−3 |
106 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. |
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 | ||
Sn | 0.5000 | 0.5000 | 0.5000 | 0.02302 (11) | |
Cl1 | 0.33727 (13) | 0.80139 (12) | 0.56055 (10) | 0.0371 (2) | |
Cl2 | 0.31063 (12) | 0.43568 (13) | 0.25047 (8) | 0.03329 (19) | |
Cl3 | 0.24638 (14) | 0.33496 (14) | 0.58581 (11) | 0.0418 (2) | |
O2 | 0.6402 (4) | 0.8662 (4) | 0.1099 (3) | 0.0415 (6) | |
N3 | 0.3457 (4) | 0.9160 (4) | 0.1916 (3) | 0.0284 (6) | |
H3 | 0.4018 | 0.9886 | 0.2733 | 0.034* | |
N1 | 0.3670 (4) | 0.7133 (4) | −0.0345 (3) | 0.0327 (6) | |
H1 | 0.4342 | 0.6517 | −0.0988 | 0.039* | |
N4 | 0.0499 (4) | 0.9823 (5) | 0.2735 (3) | 0.0355 (7) | |
H4A | 0.1102 | 1.0572 | 0.3526 | 0.043* | |
H4B | −0.0754 | 0.9670 | 0.2611 | 0.043* | |
C2 | 0.4639 (5) | 0.8323 (5) | 0.0894 (4) | 0.0294 (6) | |
C5 | 0.0574 (5) | 0.7710 (5) | 0.0384 (4) | 0.0312 (7) | |
H5 | −0.0778 | 0.7499 | 0.0199 | 0.037* | |
C6 | 0.1699 (5) | 0.6871 (5) | −0.0612 (4) | 0.0332 (7) | |
H6 | 0.1110 | 0.6095 | −0.1505 | 0.040* | |
C4 | 0.1488 (4) | 0.8921 (5) | 0.1723 (4) | 0.0257 (6) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Sn | 0.02457 (16) | 0.02343 (16) | 0.01863 (15) | −0.00029 (10) | 0.00150 (10) | 0.00006 (10) |
Cl1 | 0.0354 (4) | 0.0300 (4) | 0.0389 (4) | 0.0084 (3) | −0.0021 (3) | −0.0039 (3) |
Cl2 | 0.0318 (4) | 0.0417 (5) | 0.0211 (4) | 0.0020 (3) | −0.0033 (3) | −0.0006 (3) |
Cl3 | 0.0411 (5) | 0.0451 (5) | 0.0404 (5) | −0.0110 (4) | 0.0122 (4) | 0.0081 (4) |
O2 | 0.0225 (11) | 0.0607 (18) | 0.0384 (14) | −0.0024 (11) | 0.0050 (10) | 0.0035 (13) |
N3 | 0.0231 (12) | 0.0325 (14) | 0.0258 (13) | −0.0025 (10) | −0.0007 (10) | 0.0004 (11) |
N1 | 0.0297 (14) | 0.0367 (15) | 0.0292 (14) | 0.0029 (12) | 0.0069 (11) | −0.0009 (12) |
N4 | 0.0273 (14) | 0.0453 (17) | 0.0311 (15) | −0.0001 (12) | 0.0056 (11) | 0.0009 (13) |
C2 | 0.0252 (14) | 0.0349 (16) | 0.0286 (15) | 0.0020 (12) | 0.0051 (12) | 0.0069 (13) |
C5 | 0.0232 (14) | 0.0337 (17) | 0.0329 (17) | −0.0008 (12) | 0.0001 (12) | 0.0009 (13) |
C6 | 0.0304 (16) | 0.0366 (18) | 0.0274 (16) | −0.0020 (13) | −0.0013 (13) | −0.0014 (13) |
C4 | 0.0222 (14) | 0.0282 (15) | 0.0270 (14) | 0.0005 (11) | 0.0029 (11) | 0.0071 (12) |
Sn—Cl3 | 2.4134 (17) | N1—C6 | 1.353 (4) |
Sn—Cl3i | 2.4134 (17) | N1—C2 | 1.359 (4) |
Sn—Cl1 | 2.4246 (18) | N1—H1 | 0.8600 |
Sn—Cl1i | 2.4246 (18) | N4—C4 | 1.305 (4) |
Sn—Cl2i | 2.4385 (18) | N4—H4A | 0.8600 |
Sn—Cl2 | 2.4385 (18) | N4—H4B | 0.8600 |
O2—C2 | 1.219 (4) | C5—C6 | 1.342 (5) |
N3—C4 | 1.351 (4) | C5—C4 | 1.414 (5) |
N3—C2 | 1.385 (4) | C5—H5 | 0.9300 |
N3—H3 | 0.8600 | C6—H6 | 0.9300 |
Cl3—Sn—Cl3i | 180.00 (4) | C6—N1—C2 | 123.1 (3) |
Cl3—Sn—Cl1 | 90.03 (6) | C6—N1—H1 | 118.5 |
Cl3i—Sn—Cl1 | 89.97 (6) | C2—N1—H1 | 118.5 |
Cl3—Sn—Cl1i | 89.97 (6) | C4—N4—H4A | 120.0 |
Cl3i—Sn—Cl1i | 90.03 (6) | C4—N4—H4B | 120.0 |
Cl1—Sn—Cl1i | 180.0 | H4A—N4—H4B | 120.0 |
Cl3—Sn—Cl2i | 90.45 (6) | O2—C2—N1 | 123.5 (3) |
Cl3i—Sn—Cl2i | 89.55 (6) | O2—C2—N3 | 121.9 (3) |
Cl1—Sn—Cl2i | 90.15 (6) | N1—C2—N3 | 114.6 (3) |
Cl1i—Sn—Cl2i | 89.85 (6) | C6—C5—C4 | 118.6 (3) |
Cl3—Sn—Cl2 | 89.55 (6) | C6—C5—H5 | 120.7 |
Cl3i—Sn—Cl2 | 90.45 (6) | C4—C5—H5 | 120.7 |
Cl1—Sn—Cl2 | 89.85 (6) | C5—C6—N1 | 121.4 (3) |
Cl1i—Sn—Cl2 | 90.15 (6) | C5—C6—H6 | 119.3 |
Cl2i—Sn—Cl2 | 180.0 | N1—C6—H6 | 119.3 |
C4—N3—C2 | 124.8 (3) | N4—C4—N3 | 120.1 (3) |
C4—N3—H3 | 117.6 | N4—C4—C5 | 122.5 (3) |
C2—N3—H3 | 117.6 | N3—C4—C5 | 117.4 (3) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3···Cl1ii | 0.86 | 2.46 | 3.265 (4) | 157 |
N1—H1···Cl2iii | 0.86 | 2.42 | 3.249 (4) | 162 |
N4—H4A···Cl3iv | 0.86 | 2.66 | 3.507 (4) | 169 |
N4—H4B···O2v | 0.86 | 2.26 | 3.032 (5) | 150 |
N4—H4B···Cl1vi | 0.86 | 2.92 | 3.490 (4) | 126 |
Symmetry codes: (ii) −x+1, −y+2, −z+1; (iii) −x+1, −y+1, −z; (iv) x, y+1, z; (v) x−1, y, z; (vi) −x, −y+2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | (C4H6N3O)2[SnCl6] |
Mr | 555.63 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 295 |
a, b, c (Å) | 6.910 (5), 7.090 (5), 9.270 (5) |
α, β, γ (°) | 101.86 (5), 98.36 (5), 90.51 (5) |
V (Å3) | 439.4 (5) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 2.38 |
Crystal size (mm) | 0.1 × 0.1 × 0.1 |
Data collection | |
Diffractometer | Nonius KappaCCD area-detector diffractometer |
Absorption correction | Multi-scan (SORTAV; Blessing 1995) |
Tmin, Tmax | 0.717, 0.792 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2533, 2531, 2279 |
Rint | 0.052 |
(sin θ/λ)max (Å−1) | 0.705 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.098, 1.08 |
No. of reflections | 2531 |
No. of parameters | 106 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 3.07, −0.96 |
Computer programs: KappaCCD Server Software (Nonius, 1998), DENZO and SCALEPAK (Otwinowski & Minor, 1997), DENZO and SCALEPAK, SIR2002 (Burla et al., 2003), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), PLUTON (Spek, 1990) and ATOMS for Windows (Dowty, 1995), WinGX (Farrugia, 1999).
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3···Cl1i | 0.86 | 2.46 | 3.265 (4) | 157 |
N1—H1···Cl2ii | 0.86 | 2.42 | 3.249 (4) | 162 |
N4—H4A···Cl3iii | 0.86 | 2.66 | 3.507 (4) | 169 |
N4—H4B···O2iv | 0.86 | 2.26 | 3.032 (5) | 150 |
N4—H4B···Cl1v | 0.86 | 2.92 | 3.490 (4) | 126 |
Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) −x+1, −y+1, −z; (iii) x, y+1, z; (iv) x−1, y, z; (v) −x, −y+2, −z+1. |
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Studies of metal ion–nucleid acid interactions are of great current interest, since metal ions play a crucial role in the structure and function of nucleic acid and genetic information transfer (Salam & Aoki, 2000)·The antitumour activity of organotin(IV) complexes is also known (Kabanos et al., 1992).
Cytosine (6-aminopyrimidin-2-one) is one of the pyrimidines found in deoxyribonucleic acids. It has been the subject of several investigations with the aim of studying the electrostatic properties of its monohydrate form (Weber & Craven,1990), the relative stabilities of its tautomeric forms (Kobayashi, 1998) and its hydration effects and hydrogen bonding (Sivanesan et al., 2000). It offers many metal binding modes, namely via atom N3 (Tran Qui & Bagieu, 1990), through atom N4 (Muller et al., 1998), bridging through atoms N3 and N4 (Wienkotter et al., 1995), via atom O2 only (Cervantes et al., 1990), with chelation by atoms N3 and O2 (Aoki & Saenger, 1984), and bridging through atoms N3 and O2 (Lippert et al., 1984) via stronger N3 with additional weaker O2 interactions (Palaniandavar et al., 1996). Only one crystal structure based on Sn and cytosine has been reported to date (Casellato, 1995). Here, we present a new organic–inorganic hybrid compound, (I), based on Sn and cytosine, and examine the hydrogen bonding in the crystal structure.
The title structure, (I), consists of hexachlorostannate(IV) anions arranged around an inversion centre and two protonated cytosine rings (Fig. 1). The anionic sheet is parallel to the (001) plane and the distance between two sheets is c. The cytosine is monoprotonated at atom N3, as previously reported for the tetrachlorodimethylstannate and nitrate compounds (Casellato, 1995; Cherouana et al., 2003). The internal angle at N3 [C2—N3—C4 = 124.85 (10)°] is larger than the value of 119.4° reported in unprotonated cytosine (McClure & Craven, 1973). A similar effect has been observed in the structure of cytosinium dihydrogenmonophosphate (Bagieu-Beucher, 1990). There are two crystallographically equivalent (cytosinium) cations in (I), and these cations form layers parallel to the (011) plane.
The Sn atom is six-coordinated and forms a quasi-regular octahedral arrangement (Bouacida et al., 2005a). This [SnCl6]2− octahedron alternates with the cationic layers along the c axis (Fig. 2). The bond lengths are similar to those found in other octahedral SnIV compounds (Bouacida et al., 2005b).
The crystal packing in (I) is governed by classical hydrogen bonds (Fig.3). Atoms N1, N3, N4 and C5 of the cytosine participate in the formation of strong inter- and intramolecular (N—H···Cl and N—H···O) hydrogen bonds with hexachlorostannate and cytosine (Table 1), resulting in the formation of a two-dimensionnal network.