Tetra-kis(pyridine-2-carboxyl-ato-κN,O)palladium(IV) dihydrate.

The asymmetric unit of the title compound, [Pd(C(6)H(4)NO(2))(4)]·2H(2)O, consists of a quarter of a neutral Pd(IV) complex and half of a solvent water mol-ecule. In the complex, the Pd(IV) ion is located on a fourfold inversion axis and eight-coordinated in a distorted dodeca-hedral environment by four N and four O atoms from four symmetry-related pyridine-2-carboxyl-ate (pic) anionic ligands. In the crystal, the water mol-ecule is involved in O-H⋯O hydrogen bonding, and weak inter-molecular C-H⋯O hydrogen bonds occur. There are also inter-molecular π-π inter-actions between adjacent pyridine rings, with a centroid-centroid distance of 3.715 (3) Å.

Related literature

For details of polyhedra with coordination number eight, see: Lippard & Russ (1968 ▶); Muetterties & Guggenberger (1974 ▶). For the synthesis and structure of the Pd(II)–pic complex, [Pd(pic)2], see: Qin et al. (2002 ▶). For the crystal structures of eight-coordinated M(III, IV)–pic complexes (M = Nb, Er or Bi), see: Ooi et al. (1996 ▶); Soares-Santos et al. (2003 ▶); Callens et al. (2008 ▶). For the crystal structures of Pd(II) in an environment of eight O atoms, see: Izarova et al. (2009 ▶).

Experimental

Crystal data

[Pd(C6H4NO2)4]·2H2O

M = 630.84

Tetragonal,

a = 11.1621 (5) Å

c = 9.5880 (9) Å

V = 1194.59 (14) Å3

Z = 2

Mo Kα radiation

μ = 0.85 mm−1

T = 296 K

0.23 × 0.14 × 0.07 mm

Data collection

Bruker SMART 1000 CCD diffractometer

Absorption correction: multi-scan (; Bruker, 2000 ▶) T min = 0.804, T max = 0.942

8399 measured reflections

1485 independent reflections

1074 reflections with I > 2σ(I)

R int = 0.045

Refinement

R[F 2 > 2σ(F 2)] = 0.034

wR(F 2) = 0.104

S = 1.21

1485 reflections

89 parameters

H-atom parameters constrained

Δρmax = 0.76 e Å−3

Δρmin = −1.00 e Å−3

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT (Bruker, 2000 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809039270/is2464sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809039270/is2464Isup2.hkl

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

[Pd(C6H4NO2)4]·2H2O	Dx = 1.754 Mg m−3
Mr = 630.84	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P42/n	Cell parameters from 3500 reflections
Hall symbol: -P 4bc	θ = 2.6–28.3°
a = 11.1621 (5) Å	µ = 0.85 mm−1
c = 9.5880 (9) Å	T = 296 K
V = 1194.59 (14) Å3	Block, colorless
Z = 2	0.23 × 0.14 × 0.07 mm
F(000) = 636

Bruker SMART 1000 CCD diffractometer	1485 independent reflections
Radiation source: fine-focus sealed tube	1074 reflections with I > 2σ(I)
graphite	Rint = 0.045
φ and ω scans	θmax = 28.3°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −14→14
Tmin = 0.804, Tmax = 0.942	k = −14→10
8399 measured reflections	l = −12→12

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.104	H-atom parameters constrained
S = 1.21	w = 1/[σ2(Fo2) + (0.031P)2 + 2.1364P] where P = (Fo2 + 2Fc2)/3
1485 reflections	(Δ/σ)max < 0.001
89 parameters	Δρmax = 0.76 e Å−3
0 restraints	Δρmin = −1.00 e Å−3

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
Pd1	0.2500	0.2500	0.2500	0.02277 (17)
O1	0.0856 (2)	0.3186 (3)	0.3193 (3)	0.0380 (7)
O2	−0.0577 (3)	0.3299 (3)	0.4796 (4)	0.0570 (10)
N1	0.1892 (3)	0.1367 (3)	0.4471 (4)	0.0334 (8)
C1	0.2408 (4)	0.0371 (4)	0.4990 (5)	0.0416 (10)
H1	0.3108	0.0087	0.4581	0.050*
C2	0.1927 (4)	−0.0243 (4)	0.6114 (5)	0.0449 (11)
H2	0.2298	−0.0930	0.6454	0.054*
C3	0.0889 (4)	0.0180 (5)	0.6722 (5)	0.0491 (12)
H3	0.0561	−0.0210	0.7489	0.059*
C4	0.0343 (4)	0.1187 (4)	0.6182 (4)	0.0406 (10)
H4	−0.0360	0.1482	0.6574	0.049*
C5	0.0863 (4)	0.1755 (4)	0.5038 (5)	0.0366 (10)
C6	0.0317 (4)	0.2821 (4)	0.4335 (5)	0.0371 (9)
O3	0.7500	0.2500	0.1567 (7)	0.092 (2)
H3O	0.7183	0.3148	0.1215	0.137*

	U11	U22	U33	U12	U13	U23
Pd1	0.02072 (19)	0.02072 (19)	0.0269 (3)	0.000	0.000	0.000
O1	0.0315 (15)	0.0398 (17)	0.0426 (17)	0.0077 (12)	−0.0017 (14)	0.0034 (14)
O2	0.0388 (19)	0.066 (2)	0.066 (2)	0.0183 (16)	0.0149 (17)	0.0011 (19)
N1	0.0312 (18)	0.0364 (19)	0.0326 (18)	0.0020 (14)	0.0007 (15)	0.0005 (15)
C1	0.040 (3)	0.035 (2)	0.049 (3)	0.0050 (18)	0.000 (2)	0.003 (2)
C2	0.053 (3)	0.040 (3)	0.042 (3)	−0.004 (2)	−0.007 (2)	0.006 (2)
C3	0.052 (3)	0.056 (3)	0.040 (3)	−0.006 (2)	0.001 (2)	0.006 (2)
C4	0.039 (2)	0.056 (3)	0.027 (2)	−0.004 (2)	0.0044 (18)	−0.006 (2)
C5	0.035 (2)	0.034 (2)	0.041 (2)	−0.0023 (17)	−0.0010 (18)	−0.0059 (19)
C6	0.032 (2)	0.038 (2)	0.041 (2)	−0.0005 (18)	0.0022 (19)	−0.006 (2)
O3	0.121 (6)	0.064 (4)	0.090 (5)	0.002 (4)	0.000	0.000

Pd1—O1i	2.097 (3)	N1—C1	1.347 (5)
Pd1—O1ii	2.097 (3)	C1—C2	1.386 (6)
Pd1—O1iii	2.097 (3)	C1—H1	0.9300
Pd1—O1	2.097 (3)	C2—C3	1.380 (7)
Pd1—N1ii	2.373 (3)	C2—H2	0.9300
Pd1—N1iii	2.373 (3)	C3—C4	1.380 (7)
Pd1—N1i	2.373 (3)	C3—H3	0.9300
Pd1—N1	2.373 (3)	C4—C5	1.393 (6)
O1—C6	1.314 (5)	C4—H4	0.9300
O2—C6	1.215 (5)	C5—C6	1.497 (6)
N1—C5	1.343 (5)	O3—H3O	0.87
O1i—Pd1—O1ii	95.77 (5)	N1ii—Pd1—N1	74.42 (17)
O1i—Pd1—O1iii	143.04 (17)	N1iii—Pd1—N1	129.37 (10)
O1ii—Pd1—O1iii	95.77 (5)	N1i—Pd1—N1	129.37 (10)
O1i—Pd1—O1	95.77 (5)	C6—O1—Pd1	123.4 (3)
O1ii—Pd1—O1	143.04 (17)	C5—N1—C1	118.8 (4)
O1iii—Pd1—O1	95.77 (5)	C5—N1—Pd1	113.3 (3)
O1i—Pd1—N1ii	71.43 (12)	C1—N1—Pd1	127.7 (3)
O1ii—Pd1—N1ii	72.07 (12)	N1—C1—C2	122.0 (4)
O1iii—Pd1—N1ii	145.42 (12)	N1—C1—H1	119.0
O1—Pd1—N1ii	78.64 (12)	C2—C1—H1	119.0
O1i—Pd1—N1iii	78.64 (12)	C3—C2—C1	118.9 (4)
O1ii—Pd1—N1iii	71.43 (12)	C3—C2—H2	120.5
O1iii—Pd1—N1iii	72.07 (12)	C1—C2—H2	120.5
O1—Pd1—N1iii	145.42 (12)	C2—C3—C4	119.5 (5)
N1ii—Pd1—N1iii	129.37 (10)	C2—C3—H3	120.3
O1i—Pd1—N1i	72.07 (12)	C4—C3—H3	120.3
O1ii—Pd1—N1i	145.42 (12)	C3—C4—C5	118.8 (4)
O1iii—Pd1—N1i	78.64 (12)	C3—C4—H4	120.6
O1—Pd1—N1i	71.43 (12)	C5—C4—H4	120.6
N1ii—Pd1—N1i	129.37 (10)	N1—C5—C4	121.9 (4)
N1iii—Pd1—N1i	74.42 (17)	N1—C5—C6	115.0 (4)
O1i—Pd1—N1	145.42 (12)	C4—C5—C6	123.1 (4)
O1ii—Pd1—N1	78.64 (12)	O2—C6—O1	122.9 (4)
O1iii—Pd1—N1	71.43 (12)	O2—C6—C5	121.3 (4)
O1—Pd1—N1	72.07 (12)	O1—C6—C5	115.8 (4)
O1i—Pd1—O1—C6	−141.3 (3)	N1iii—Pd1—N1—C1	24.3 (4)
O1ii—Pd1—O1—C6	−33.7 (3)	N1i—Pd1—N1—C1	127.2 (4)
O1iii—Pd1—O1—C6	73.9 (3)	C5—N1—C1—C2	−1.9 (7)
N1ii—Pd1—O1—C6	−71.6 (3)	Pd1—N1—C1—C2	−176.7 (3)
N1iii—Pd1—O1—C6	140.4 (3)	N1—C1—C2—C3	−0.1 (7)
N1i—Pd1—O1—C6	149.9 (3)	C1—C2—C3—C4	1.3 (7)
N1—Pd1—O1—C6	5.6 (3)	C2—C3—C4—C5	−0.4 (7)
O1i—Pd1—N1—C5	71.4 (4)	C1—N1—C5—C4	2.8 (6)
O1ii—Pd1—N1—C5	155.0 (3)	Pd1—N1—C5—C4	178.3 (3)
O1iii—Pd1—N1—C5	−104.9 (3)	C1—N1—C5—C6	−176.3 (4)
O1—Pd1—N1—C5	−2.2 (3)	Pd1—N1—C5—C6	−0.7 (4)
N1ii—Pd1—N1—C5	80.7 (3)	C3—C4—C5—N1	−1.6 (7)
N1iii—Pd1—N1—C5	−150.8 (3)	C3—C4—C5—C6	177.4 (4)
N1i—Pd1—N1—C5	−47.9 (3)	Pd1—O1—C6—O2	173.0 (3)
O1i—Pd1—N1—C1	−113.6 (4)	Pd1—O1—C6—C5	−7.9 (5)
O1ii—Pd1—N1—C1	−29.9 (4)	N1—C5—C6—O2	−175.7 (4)
O1iii—Pd1—N1—C1	70.2 (4)	C4—C5—C6—O2	5.2 (7)
O1—Pd1—N1—C1	172.9 (4)	N1—C5—C6—O1	5.1 (6)
N1ii—Pd1—N1—C1	−104.3 (4)	C4—C5—C6—O1	−173.9 (4)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3O···O2iv	0.87	2.04	2.879 (5)	161
C1—H1···O2v	0.93	2.55	3.233 (5)	131
C2—H2···O3vi	0.93	2.59	3.420 (6)	149

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3O⋯O2i	0.87	2.04	2.879 (5)	161
C1—H1⋯O2ii	0.93	2.55	3.233 (5)	131
C2—H2⋯O3iii	0.93	2.59	3.420 (6)	149

Symmetry codes: (i) ; (ii) ; (iii) .