N,N′-bis­[(3-hy­droxy-4(4H)-oxypyran-2-yl)meth­yl]-N,N′-dimethyl­ethylene-1,2-diammonium tetra­chloridoplatinate(II) dihydrate

The title compound (C₁₆H₂₂N₂O₆)[PtCl₄]·2H₂O, shows anti­proliferative activity in eight tumor cell lines. The asymmetric unit consists of one solvent water mol­ecule on a general position, and one half of each of the polyammonium cation and the tetrachloridoplatinate(II) anion, both of them located on centers of inversion. In the crystal, the cations are connected via hydrogen bonding between the carbonyl O atoms and the hydroxyl H atoms into zigzag chains that elongate in the c-axis direction. In addition, the carbonyl O atom is hydrogen-bonded to the water mol­ecule which, in turn, inter­acts with the [PtCl₄]²⁻ anion. Finally, the chains are linked by N—H⁺...Cl inter­actions into a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.023
• wR factor = 0.049
• Data-to-parameter ratio = 17.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT352_ALERT_3_C Short   N-H Bond (0.87A)   N1     -   H1N    ...       0.74 Ang.
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....         10

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT022_ALERT_3_G Ratio Unique / Expected Reflections (too) Low ..      0.878
PLAT042_ALERT_1_G Calc. and Reported MoietyFormula Strings  Differ          ?
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          2
PLAT790_ALERT_4_G Centre of Gravity not Within Unit Cell: Resd.  #          3
              H2 O
PLAT793_ALERT_4_G The Model has Chirality at N1      (Verify) ....          R
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600        362

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   2 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   7 ALERT level G = General information/check it is not something unexpected

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

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S1. Comment

Maltol (3-hydroxy-2-methyl-4-pyrone) is a natural compound, which exhibits interesting antineoplastic activities (Murakami et al., 2006). At the same time, linear polyamines are also known antitumor agents (Liang et al., 2006; Casero & Woster, 2001). For these reasons we synthesized and studied compound N,N'-bis((3-hydroxy-4-pyron-2-yl)methyl)-N,N'-dimethylethylendiamine (Malten) coupling two Maltol units to an aliphatic diamine. Malten has shown antiproliferative activity in eight tumor cell lines (Amatori et al.,2010; Amatori et al., 2012). In the asymmetric unit of the title compound half of the polyammonium cation [H₂Malten]²⁺ and of the tetrachloroplatinate(II) counterion are present, together with a crystallization water molecule. The two halves of each ion are related by a center of symmetry (Fig. 1). The [H₂Malten]²⁺ polyammonium chain, which joins the two aromatic rings, has an all-trans conformation and defines a plane which forms an angle of 65.4 (2)° with each of them. In the crystal lattice the [H₂Malten]²⁺ cations are each linked by two pairs of complementary O—H···O hydrogen bonds into centrosymmetric dimers, which are further linked into chains along the c axis (Fig. 2 and Table 1). Moreover, the carbonyl O atom (O2) is H-bonded to the lattice water molecule, which is also linked to the (PtCl₄)^2- anion by O—H···Cl interactions. Finally, the cations and anions are linked by N—H⁺···Cl interactions.

Related literature

For the antitumor activity of maltol (systematic name: 3-hydroxy-2-methyl-4-pyrone) and polyamines, see: Casero & Woster (2001); Liang et al. (2006); Murakami et al. (2006). For background to the synthesis, solution behaviour, structural properties and biological activity of N,N'-bis[(3-hydroxy-4-pyron-2-yl)methyl]-N,N'-dimethylethylendiamine (Malten), see: Amatori et al. (2010, 2012).

S2. Experimental

Malten^.2HClO₄ was dissolved in H₂O, K₂PtCl₄ was added and the pH adjusted to 3. Crystals suitable for X-ray analysis formed in one day at room temperature.

S3. Refinement

The O—H and N—H H atoms were located in the Fourier difference map and refined with varying coordinates isotropic. The C—H H atoms were introduced in calculated position and refined isotropic with U_iso(H) 1.2 times U_eq(C) (1.5 for methyl H atoms).

Computing details

Data collection: CrysAlis PRO (Oxford Diffraction 2009); cell refinement: CrysAlis PRO (Oxford Diffraction 2009); data reduction: CrysAlis PRO (Oxford Diffraction 2009); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: PARST97 (Nardelli, 1995).

Figures

	Fig. 1. Crystal structure of the title compound with labelling and displacement ellipsoids drawn at the 30% probability level. Symmetry codes: i) = -x + 2, -y, -z + 1; ii) = -x + 1, -y + 1, -z + 1.
	Fig. 2. Crystal structure of the title compound with view along the a axis. Intermolecular hydrogen bonding is shown as dashed lines.

N,N'-bis[(3-hydroxy-4(4H)-oxypyran-2-yl)methyl]-N, N'-dimethylethylene-1,2-diammonium tetrachloridoplatinate(II) dihydrate

Crystal data

(C16H22N2O6)[PtCl4]·2H2O	Z = 1
Mr = 711.28	F(000) = 346
Triclinic, P1	Dx = 2.083 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.4775 (4) Å	Cell parameters from 7279 reflections
b = 7.0037 (4) Å	θ = 4.1–29.2°
c = 13.1628 (8) Å	µ = 6.71 mm^−1
α = 88.810 (5)°	T = 150 K
β = 87.033 (5)°	Prismatic, light yellow
γ = 71.927 (6)°	0.32 × 0.22 × 0.20 mm
V = 566.92 (6) Å^3

Data collection

Oxford Diffraction Xcalibur3 diffractometer	2719 independent reflections
Radiation source: Enhance (Mo) X-ray Source	2694 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.044
Detector resolution: 16.4547 pixels mm^-1	θmax = 29.3°, θmin = 4.1°
ω scans	h = −8→8
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction 2009)	k = −9→9
Tmin = 0.164, Tmax = 0.262	l = −17→17
9431 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.023	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.049	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0253P)^2] where P = (Fo^2 + 2Fc^2)/3
2719 reflections	(Δ/σ)max < 0.001
158 parameters	Δρmax = 1.44 e Å^−3
0 restraints	Δρmin = −1.14 e Å^−3

Special details

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Pt1	1.0000	0.0000	0.5000	0.01531 (6)
Cl1	1.25762 (12)	0.12554 (11)	0.42237 (6)	0.01926 (15)
Cl2	0.82520 (13)	0.02992 (11)	0.34889 (6)	0.02098 (16)
O1	0.8029 (5)	0.6477 (4)	0.1284 (2)	0.0298 (6)
O2	0.8598 (4)	0.3386 (4)	−0.00821 (17)	0.0278 (5)
O3	0.3953 (4)	0.4312 (3)	0.22157 (16)	0.0218 (5)
N1	0.5757 (4)	0.6487 (4)	0.3876 (2)	0.0169 (5)
C1	0.4294 (6)	0.2757 (5)	0.1565 (3)	0.0261 (7)
H1	0.3424	0.1924	0.1649	0.031*
C2	0.5823 (6)	0.2365 (5)	0.0809 (3)	0.0263 (7)
H2	0.5998	0.1263	0.0394	0.032*
C3	0.7197 (5)	0.3601 (5)	0.0625 (2)	0.0224 (7)
C4	0.6815 (5)	0.5228 (5)	0.1358 (2)	0.0205 (6)
C5	0.5256 (5)	0.5510 (5)	0.2108 (2)	0.0187 (6)
C6	0.4731 (5)	0.7161 (5)	0.2869 (2)	0.0190 (6)
H6A	0.3166	0.7682	0.2984	0.023*
H6B	0.5233	0.8244	0.2595	0.023*
C7	0.4568 (5)	0.5266 (5)	0.4470 (2)	0.0181 (6)
H7A	0.4719	0.4039	0.4103	0.022*
H7B	0.3033	0.6018	0.4532	0.022*
C15	0.8152 (5)	0.5442 (5)	0.3735 (2)	0.0181 (6)
H15A	0.8821	0.6290	0.3351	0.027*
H15B	0.8389	0.4207	0.3376	0.027*
H15C	0.8778	0.5159	0.4388	0.027*
O1W	1.1440 (5)	−0.0251 (4)	0.1423 (2)	0.0343 (6)
H1N	0.559 (6)	0.742 (6)	0.417 (3)	0.028 (11)*
H1O	0.888 (7)	0.623 (6)	0.088 (3)	0.024 (11)*
H1WA	1.062 (9)	−0.020 (8)	0.194 (4)	0.059 (16)*
H1WB	1.128 (7)	−0.105 (7)	0.104 (3)	0.040 (13)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pt1	0.01339 (9)	0.01279 (9)	0.02021 (9)	−0.00476 (6)	0.00072 (6)	−0.00306 (6)
Cl1	0.0169 (4)	0.0185 (4)	0.0241 (4)	−0.0084 (3)	0.0032 (3)	−0.0031 (3)
Cl2	0.0223 (4)	0.0208 (4)	0.0219 (4)	−0.0092 (3)	−0.0040 (3)	−0.0009 (3)
O1	0.0347 (15)	0.0327 (14)	0.0275 (13)	−0.0200 (12)	0.0137 (12)	−0.0108 (11)
O2	0.0310 (14)	0.0309 (13)	0.0237 (12)	−0.0136 (11)	0.0074 (10)	−0.0087 (10)
O3	0.0236 (12)	0.0246 (12)	0.0197 (11)	−0.0112 (10)	−0.0005 (9)	−0.0021 (9)
N1	0.0197 (14)	0.0154 (13)	0.0168 (12)	−0.0074 (11)	0.0002 (10)	−0.0020 (10)
C1	0.0284 (19)	0.0261 (18)	0.0283 (17)	−0.0143 (15)	−0.0056 (15)	0.0001 (14)
C2	0.0310 (19)	0.0242 (17)	0.0271 (17)	−0.0134 (15)	0.0003 (15)	−0.0062 (13)
C3	0.0251 (18)	0.0222 (16)	0.0196 (15)	−0.0064 (13)	−0.0035 (13)	−0.0020 (12)
C4	0.0236 (17)	0.0208 (16)	0.0191 (15)	−0.0096 (13)	−0.0003 (13)	−0.0030 (12)
C5	0.0218 (16)	0.0177 (15)	0.0172 (14)	−0.0065 (13)	−0.0041 (13)	0.0014 (11)
C6	0.0220 (16)	0.0170 (15)	0.0170 (14)	−0.0047 (12)	−0.0027 (12)	0.0018 (11)
C7	0.0171 (15)	0.0176 (15)	0.0200 (15)	−0.0060 (12)	0.0006 (12)	0.0009 (11)
C15	0.0158 (15)	0.0189 (15)	0.0194 (14)	−0.0051 (12)	0.0007 (12)	−0.0008 (11)
O1W	0.0380 (17)	0.0383 (16)	0.0315 (15)	−0.0187 (13)	−0.0001 (13)	−0.0064 (12)

Geometric parameters (Å, º)

Pt1—Cl1^i	2.3018 (8)	C2—C3	1.431 (5)
Pt1—Cl1	2.3018 (8)	C2—H2	0.9300
Pt1—Cl2^i	2.3132 (7)	C3—C4	1.462 (4)
Pt1—Cl2	2.3132 (7)	C4—C5	1.348 (5)
O1—C4	1.345 (4)	C5—C6	1.491 (4)
O1—H1O	0.73 (4)	C6—H6A	0.9700
O2—C3	1.243 (4)	C6—H6B	0.9700
O3—C1	1.356 (4)	C7—C7^ii	1.526 (6)
O3—C5	1.363 (4)	C7—H7A	0.9700
N1—C15	1.499 (4)	C7—H7B	0.9700
N1—C7	1.501 (4)	C15—H15A	0.9600
N1—C6	1.514 (4)	C15—H15B	0.9600
N1—H1N	0.74 (4)	C15—H15C	0.9600
C1—C2	1.337 (5)	O1W—H1WA	0.84 (5)
C1—H1	0.9300	O1W—H1WB	0.79 (5)
Cl1^i—Pt1—Cl1	180.00 (4)	O1—C4—C3	119.7 (3)
Cl1^i—Pt1—Cl2^i	90.28 (3)	C5—C4—C3	121.2 (3)
Cl1—Pt1—Cl2^i	89.72 (3)	C4—C5—O3	121.9 (3)
Cl1^i—Pt1—Cl2	89.72 (3)	C4—C5—C6	124.4 (3)
Cl1—Pt1—Cl2	90.28 (3)	O3—C5—C6	113.7 (3)
Cl2^i—Pt1—Cl2	180.0	C5—C6—N1	112.9 (2)
C4—O1—H1O	115 (3)	C5—C6—H6A	109.0
C1—O3—C5	118.6 (3)	N1—C6—H6A	109.0
C15—N1—C7	113.3 (2)	C5—C6—H6B	109.0
C15—N1—C6	111.5 (2)	N1—C6—H6B	109.0
C7—N1—C6	110.8 (2)	H6A—C6—H6B	107.8
C15—N1—H1N	109 (3)	N1—C7—C7^ii	111.9 (3)
C7—N1—H1N	107 (3)	N1—C7—H7A	109.2
C6—N1—H1N	106 (3)	C7^ii—C7—H7A	109.2
C2—C1—O3	123.1 (3)	N1—C7—H7B	109.2
C2—C1—H1	118.5	C7^ii—C7—H7B	109.2
O3—C1—H1	118.5	H7A—C7—H7B	107.9
C1—C2—C3	121.5 (3)	N1—C15—H15A	109.5
C1—C2—H2	119.2	N1—C15—H15B	109.5
C3—C2—H2	119.2	H15A—C15—H15B	109.5
O2—C3—C2	125.6 (3)	N1—C15—H15C	109.5
O2—C3—C4	120.7 (3)	H15A—C15—H15C	109.5
C2—C3—C4	113.7 (3)	H15B—C15—H15C	109.5
O1—C4—C5	119.1 (3)	H1WA—O1W—H1WB	109 (5)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O···O2^iii	0.73 (4)	1.98 (4)	2.655 (4)	154 (4)
O1W—H1WB···O2^iv	0.79 (5)	2.07 (5)	2.853 (4)	171 (4)
O1W—H1WA···Cl2	0.84 (5)	2.45 (5)	3.282 (3)	174 (5)
N1—H1N···Cl1^v	0.74 (4)	2.79 (4)	3.380 (3)	139 (4)
N1—H1N···Cl1^vi	0.74 (4)	2.79 (4)	3.362 (3)	136 (4)

Symmetry codes: (iii) −x+2, −y+1, −z; (iv) −x+2, −y, −z; (v) −x+2, −y+1, −z+1; (vi) x−1, y+1, z.