A potential anti-cancer agent: 5-chloro-7-iodo-8-hy-droxy-quinolinium dichlorido(5-chloro-7-iodo-quinolin-8-olato-κN,O)palladium(II) dihydrate.

The title Pd(II) coordination compound, (C(9)H(6)ClINO)[PdCl(2)(C(9)H(4)ClINO)]·2H(2)O, was prepared as a potential anti-cancer agent. Its structure is ionic and consists of a square-planar [PdCl(2)(CQ)](-) complex anion (CQ is 5-chloro-7-iodo-quinolin-8-olate), with the Pd(II) atom surrounded by two chloride ligands in a cis configuration and one N,O-bidentate CQ mol-ecule, a protonated anion of CQ as counter-cation and two non-coordinated water mol-ecules. The water mol-ecules are involved in O-H⋯O and N-H⋯O hydrogen bonds, which inter-connect the HCQ(+) cations into a chain parallel to [010]. Apart from these inter-actions, the structure is also stabilized by face-to-face π-π inter-actions [centroid-centroid = 3.546 (3) Å], which occur between the phenolic parts of the complex anions and cations.

Related literature

For background to square-planar complexes of platinum and palladium as potential chemotherapeutics, see: Bielawska et al. (2010 ▶); Bruijnincx & Sadler (2008 ▶); Ding et al. (2005 ▶); Garoufis et al. (2009 ▶). For structures of CQ complexes, see: Di Vaira et al. (2004 ▶) for [Cu(CQ)2] and [Zn(CQ)2(H2O)]·H2O·THF; Miyashita et al. (2005 ▶) for [ReCl2(CQ)O(PPh3)]. The structure of [Pd(8-HQ)2] (8-HQ = 8-hy­droxy­quinoline) was previously described by Prout & Wheeler (1966 ▶). For other related structures, see: Cui et al. (2009 ▶); Guney et al. (2011 ▶); Screnci & McKeage (1999 ▶); Yue et al. (2008 ▶); Kapteijn et al. (1996 ▶); Fazeli et al. (2009 ▶); Gniewek et al. (2006 ▶). Structures of complexes containing other halogen-derivatives of 8-HQ may also be found in the Cambridge Structural Database, see: Allen (2002 ▶). For π–π inter­actions, see: Janiak (2000 ▶).

Experimental

Crystal data

(C9H6ClINO)[PdCl2(C9H4ClINO)]·2H2O

M = 824.31

Monoclinic,

a = 34.3212 (10) Å

b = 7.7028 (2) Å

c = 18.4128 (5) Å

β = 104.455 (3)°

V = 4713.7 (2) Å3

Z = 8

Mo Kα radiation

μ = 3.89 mm−1

T = 293 K

0.44 × 0.14 × 0.07 mm

Data collection

Oxford Diffraction Xcalibur Sapphire2 diffractometer

Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2007 ▶) T min = 0.555, T max = 1.000

24287 measured reflections

4641 independent reflections

3888 reflections with I > 2σ(I)

R int = 0.049

Refinement

R[F 2 > 2σ(F 2)] = 0.032

wR(F 2) = 0.080

S = 1.14

4641 reflections

287 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.61 e Å−3

Δρmin = −0.87 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2007 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2007 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶) and CALC-OH (Nardelli, 1999 ▶); molecular graphics: DIAMOND (Brandenburg, 2001 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811040803/ff2030sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811040803/ff2030Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

(C9H6ClINO)[PdCl2(C9H4ClINO)]·2H2O	F(000) = 3104
Mr = 824.31	Dx = 2.323 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 14809 reflections
a = 34.3212 (10) Å	θ = 3.0–29.6°
b = 7.7028 (2) Å	µ = 3.89 mm−1
c = 18.4128 (5) Å	T = 293 K
β = 104.455 (3)°	Needle, orange-red
V = 4713.7 (2) Å3	0.44 × 0.14 × 0.07 mm
Z = 8

Oxford Diffraction Xcalibur Sapphire2 diffractometer	4641 independent reflections
Radiation source: fine-focus sealed tube	3888 reflections with I > 2σ(I)
graphite	Rint = 0.049
Detector resolution: 8.3438 pixels mm-1	θmax = 26.0°, θmin = 3.0°
ω scans	h = −42→42
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2007)	k = −9→9
Tmin = 0.555, Tmax = 1.000	l = −22→22
24287 measured reflections

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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.080	H atoms treated by a mixture of independent and constrained refinement
S = 1.14	w = 1/[σ2(Fo2) + (0.0265P)2 + 28.2625P] where P = (Fo2 + 2Fc2)/3
4641 reflections	(Δ/σ)max = 0.002
287 parameters	Δρmax = 0.61 e Å−3
0 restraints	Δρmin = −0.87 e Å−3

Experimental. CrysAlis RED, Oxford Diffraction (2007), Analytical numeric absorption correction using a multifaceted crystal model.

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	Occ. (<1)
I1	0.699063 (11)	0.67835 (5)	0.58026 (2)	0.04530 (12)
Pd1	0.627824 (11)	0.95775 (5)	0.77655 (2)	0.02970 (11)
Cl1	0.59303 (5)	1.0787 (2)	0.85369 (8)	0.0471 (4)
Cl2	0.68728 (4)	1.0204 (2)	0.86375 (8)	0.0483 (4)
I2	0.611094 (11)	0.16194 (5)	0.507511 (19)	0.03868 (11)
Cl3	0.53299 (5)	0.6203 (2)	0.43378 (8)	0.0515 (4)
Cl4	0.54308 (4)	0.4700 (3)	0.72671 (9)	0.0574 (4)
O1	0.65529 (10)	0.8421 (5)	0.70322 (19)	0.0343 (8)
O2	0.69038 (11)	0.2391 (6)	0.6466 (2)	0.0469 (10)
H2	0.6854	0.1925	0.6052	0.070*
N1	0.57824 (12)	0.9057 (6)	0.6950 (2)	0.0329 (10)
C13	0.60872 (16)	0.6631 (7)	0.5168 (3)	0.0345 (12)
H3	0.6161	0.6098	0.4769	0.041*
N2	0.69550 (14)	0.4180 (6)	0.7764 (3)	0.0373 (11)
H2N	0.7156 (18)	0.398 (8)	0.761 (3)	0.045*
C12	0.63853 (15)	0.7155 (6)	0.5801 (3)	0.0288 (10)
C14	0.56918 (16)	0.6898 (7)	0.5132 (3)	0.0346 (12)
C11	0.62914 (14)	0.7916 (6)	0.6417 (3)	0.0274 (10)
C28	0.70063 (18)	0.4935 (8)	0.8424 (3)	0.0459 (15)
H28	0.7265	0.5133	0.8719	0.055*
C29	0.65883 (15)	0.3807 (7)	0.7305 (3)	0.0310 (11)
C19	0.58701 (14)	0.8219 (6)	0.6352 (3)	0.0279 (10)
C25	0.62410 (15)	0.4374 (7)	0.7528 (3)	0.0315 (11)
C23	0.58380 (15)	0.3332 (7)	0.6341 (3)	0.0331 (11)
H23	0.5587	0.3198	0.6008	0.040*
C18	0.54040 (16)	0.9481 (8)	0.6920 (3)	0.0441 (14)
H8	0.5346	1.0081	0.7319	0.053*
C22	0.61854 (15)	0.2761 (6)	0.6136 (3)	0.0302 (11)
C24	0.58658 (15)	0.4075 (7)	0.7019 (3)	0.0337 (11)
C21	0.65593 (15)	0.2950 (7)	0.6611 (3)	0.0304 (11)
C16	0.51643 (16)	0.8190 (8)	0.5717 (3)	0.0418 (13)
H6	0.4953	0.7889	0.5311	0.050*
C15	0.55647 (15)	0.7739 (7)	0.5712 (3)	0.0328 (11)
C27	0.66770 (19)	0.5433 (8)	0.8681 (3)	0.0451 (14)
H27	0.6713	0.5941	0.9151	0.054*
C26	0.62989 (17)	0.5169 (7)	0.8236 (3)	0.0388 (13)
H26	0.6077	0.5519	0.8403	0.047*
C17	0.50877 (17)	0.9044 (9)	0.6298 (3)	0.0538 (16)
H7	0.4825	0.9349	0.6292	0.065*
O4A	0.7649 (2)	0.3424 (13)	0.7353 (5)	0.0556 (18)	0.50
H1O4	0.7444	0.3321	0.6986	0.083*	0.50
H2O4	0.7819	0.2658	0.7303	0.083*	0.50
O4B	0.7706 (2)	0.4711 (14)	0.7626 (5)	0.0556 (18)	0.50
O3	0.72251 (16)	0.1567 (7)	0.5263 (3)	0.0780 (16)
H2O3	0.7047	0.0789	0.5129	0.117*
H1O3	0.7125	0.2474	0.5028	0.117*

	U11	U22	U33	U12	U13	U23
I1	0.0356 (2)	0.0526 (2)	0.0522 (2)	0.00153 (17)	0.01937 (17)	−0.00573 (18)
Pd1	0.0312 (2)	0.0324 (2)	0.02578 (18)	−0.00258 (17)	0.00749 (15)	0.00048 (16)
Cl1	0.0538 (9)	0.0550 (9)	0.0381 (7)	0.0005 (7)	0.0218 (7)	−0.0047 (6)
Cl2	0.0436 (8)	0.0610 (9)	0.0350 (7)	−0.0094 (7)	−0.0002 (6)	−0.0030 (7)
I2	0.0445 (2)	0.0382 (2)	0.03188 (18)	−0.00183 (16)	0.00673 (15)	0.00035 (15)
Cl3	0.0471 (9)	0.0655 (10)	0.0352 (7)	−0.0147 (7)	−0.0020 (6)	−0.0088 (7)
Cl4	0.0315 (7)	0.0886 (12)	0.0561 (9)	0.0108 (8)	0.0184 (7)	0.0014 (9)
O1	0.0263 (18)	0.045 (2)	0.0298 (18)	−0.0024 (16)	0.0042 (15)	−0.0069 (16)
O2	0.036 (2)	0.066 (3)	0.041 (2)	0.012 (2)	0.0132 (18)	0.006 (2)
N1	0.028 (2)	0.039 (2)	0.032 (2)	−0.0007 (19)	0.0082 (18)	0.0029 (19)
C13	0.045 (3)	0.033 (3)	0.026 (2)	−0.003 (2)	0.010 (2)	0.001 (2)
N2	0.028 (2)	0.044 (3)	0.036 (2)	−0.004 (2)	−0.0001 (19)	0.008 (2)
C12	0.028 (3)	0.027 (3)	0.034 (2)	0.002 (2)	0.011 (2)	0.001 (2)
C14	0.039 (3)	0.034 (3)	0.026 (2)	−0.006 (2)	0.000 (2)	0.001 (2)
C11	0.028 (3)	0.028 (3)	0.025 (2)	−0.001 (2)	0.003 (2)	0.006 (2)
C28	0.043 (3)	0.044 (3)	0.040 (3)	−0.012 (3)	−0.011 (3)	0.006 (3)
C29	0.027 (3)	0.033 (3)	0.031 (3)	−0.006 (2)	0.001 (2)	0.007 (2)
C19	0.028 (3)	0.028 (3)	0.028 (2)	−0.003 (2)	0.008 (2)	−0.001 (2)
C25	0.035 (3)	0.029 (3)	0.030 (2)	−0.002 (2)	0.008 (2)	0.007 (2)
C23	0.026 (3)	0.036 (3)	0.034 (3)	−0.003 (2)	0.003 (2)	0.002 (2)
C18	0.033 (3)	0.058 (4)	0.044 (3)	0.004 (3)	0.015 (3)	−0.006 (3)
C22	0.034 (3)	0.030 (3)	0.026 (2)	−0.002 (2)	0.005 (2)	0.002 (2)
C24	0.024 (2)	0.040 (3)	0.039 (3)	−0.002 (2)	0.013 (2)	0.007 (2)
C21	0.028 (3)	0.035 (3)	0.030 (2)	−0.001 (2)	0.010 (2)	0.005 (2)
C16	0.028 (3)	0.054 (4)	0.039 (3)	−0.003 (3)	0.000 (2)	0.001 (3)
C15	0.030 (3)	0.036 (3)	0.031 (3)	−0.003 (2)	0.005 (2)	0.007 (2)
C27	0.059 (4)	0.045 (3)	0.028 (3)	0.000 (3)	0.005 (3)	−0.004 (2)
C26	0.044 (3)	0.042 (3)	0.032 (3)	0.000 (3)	0.013 (2)	0.005 (2)
C17	0.027 (3)	0.079 (5)	0.054 (4)	0.001 (3)	0.008 (3)	−0.004 (3)
O4A	0.030 (3)	0.082 (6)	0.055 (4)	0.009 (4)	0.010 (3)	0.010 (4)
O4B	0.030 (3)	0.082 (6)	0.055 (4)	0.009 (4)	0.010 (3)	0.010 (4)
O3	0.083 (4)	0.075 (4)	0.063 (3)	−0.007 (3)	−0.007 (3)	−0.007 (3)

I1—C12	2.096 (5)	C28—H28	0.9300
Pd1—N1	2.009 (4)	C29—C21	1.420 (7)
Pd1—O1	2.035 (3)	C29—C25	1.423 (7)
Pd1—Cl1	2.2711 (14)	C19—C15	1.416 (7)
Pd1—Cl2	2.3107 (14)	C25—C26	1.409 (7)
I2—C22	2.099 (5)	C25—C24	1.410 (7)
Cl3—C14	1.749 (5)	C23—C24	1.354 (7)
Cl4—C24	1.735 (5)	C23—C22	1.408 (7)
O1—C11	1.316 (6)	C23—H23	0.9300
O2—C21	1.347 (6)	C18—C17	1.407 (8)
O2—H2	0.8200	C18—H8	0.9300
N1—C18	1.327 (7)	C22—C21	1.369 (7)
N1—C19	1.373 (6)	C16—C17	1.338 (8)
C13—C14	1.358 (8)	C16—C15	1.419 (7)
C13—C12	1.405 (7)	C16—H6	0.9300
C13—H3	0.9300	C27—C26	1.366 (8)
N2—C28	1.319 (7)	C27—H27	0.9300
N2—C29	1.360 (6)	C26—H26	0.9300
N2—H2N	0.82 (6)	C17—H7	0.9300
C12—C11	1.385 (7)	O4A—H1O4	0.8502
C14—C15	1.409 (7)	O4A—H2O4	0.8499
C11—C19	1.440 (7)	O3—H2O3	0.8488
C28—C27	1.384 (9)	O3—H1O3	0.8483
N1—Pd1—O1	82.12 (15)	C26—C25—C24	125.5 (5)
N1—Pd1—Cl1	94.01 (12)	C26—C25—C29	117.7 (5)
O1—Pd1—Cl1	175.98 (10)	C24—C25—C29	116.7 (5)
N1—Pd1—Cl2	175.90 (12)	C24—C23—C22	120.6 (5)
O1—Pd1—Cl2	94.44 (10)	C24—C23—H23	119.7
Cl1—Pd1—Cl2	89.47 (6)	C22—C23—H23	119.7
C11—O1—Pd1	111.8 (3)	N1—C18—C17	121.5 (5)
C21—O2—H2	109.5	N1—C18—H8	119.2
C18—N1—C19	119.4 (4)	C17—C18—H8	119.2
C18—N1—Pd1	128.3 (4)	C21—C22—C23	121.1 (5)
C19—N1—Pd1	112.3 (3)	C21—C22—I2	121.1 (4)
C14—C13—C12	120.6 (5)	C23—C22—I2	117.8 (4)
C14—C13—H3	119.7	C23—C24—C25	121.6 (5)
C12—C13—H3	119.7	C23—C24—Cl4	119.5 (4)
C28—N2—C29	123.7 (5)	C25—C24—Cl4	118.8 (4)
C28—N2—H2N	118 (4)	O2—C21—C22	124.6 (5)
C29—N2—H2N	118 (4)	O2—C21—C29	117.4 (4)
C11—C12—C13	122.1 (5)	C22—C21—C29	118.0 (5)
C11—C12—I1	119.3 (4)	C17—C16—C15	120.6 (5)
C13—C12—I1	118.6 (4)	C17—C16—H6	119.7
C13—C14—C15	121.8 (5)	C15—C16—H6	119.7
C13—C14—Cl3	119.1 (4)	C14—C15—C19	116.5 (5)
C15—C14—Cl3	119.0 (4)	C14—C15—C16	126.9 (5)
O1—C11—C12	125.6 (4)	C19—C15—C16	116.6 (5)
O1—C11—C19	118.6 (4)	C26—C27—C28	119.3 (5)
C12—C11—C19	115.7 (4)	C26—C27—H27	120.4
N2—C28—C27	120.3 (5)	C28—C27—H27	120.4
N2—C28—H28	119.9	C27—C26—C25	120.9 (5)
C27—C28—H28	119.9	C27—C26—H26	119.6
N2—C29—C21	120.2 (5)	C25—C26—H26	119.6
N2—C29—C25	117.9 (5)	C16—C17—C18	120.2 (5)
C21—C29—C25	121.8 (4)	C16—C17—H7	119.9
N1—C19—C15	121.7 (4)	C18—C17—H7	119.9
N1—C19—C11	115.2 (4)	H1O4—O4A—H2O4	107.7
C15—C19—C11	123.1 (4)	H2O3—O3—H1O3	105.2

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O3	0.82	2.18	2.782 (7)	131.
N2—H2N···O4A	0.82 (6)	1.92 (6)	2.737 (10)	174 (6)
N2—H2N···O4B	0.82 (6)	1.96 (6)	2.683 (9)	146 (6)
O4A—H1O4···O2	0.85	2.00	2.787 (10)	155.
C28—H28···O3i	0.93	2.48	3.347 (8)	155.

Pd1—N1	2.009 (4)
Pd1—O1	2.035 (3)
Pd1—Cl1	2.2711 (14)
Pd1—Cl2	2.3107 (14)

N1—Pd1—O1	82.12 (15)
N1—Pd1—Cl1	94.01 (12)
O1—Pd1—Cl1	175.98 (10)
N1—Pd1—Cl2	175.90 (12)
O1—Pd1—Cl2	94.44 (10)
Cl1—Pd1—Cl2	89.47 (6)

Table 2

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O3	0.82	2.18	2.782 (7)	131
N2—H2N⋯O4A	0.82 (6)	1.92 (6)	2.737 (10)	174 (6)
N2—H2N⋯O4B	0.82 (6)	1.96 (6)	2.683 (9)	146 (6)
O4A—H1O4⋯O2	0.85	2.00	2.787 (10)	155
C28—H28⋯O3i	0.93	2.48	3.347 (8)	155

Symmetry code: (i) .