Binary salt of a palladium(II) complex with (phosphono­methyl)phosphonic (medronic) acid comprising `handbell-like' [Pd{μ-CH₂(PO₃)₂}]₃ units

The asymmetric unit of the title compound, dipotassium bis­[hexa­aqua­nickel(II)] tris­(μ₂-methyl­enediphospho­nato)tripalla­dium(II) hexa­hydrate, K₂[Ni(H₂O)₆]₂[Pd₃{CH₂(PO₃)₂}₃]·6H₂O, consists of half a {[Pd{CH₂(PO₃)₂}]₃}⁶⁻ anion [one Pd atom (4e) and a methylene C atom (4e) occupy positions on a twofold axis] in a rare `handbell-like' arrangement, with K⁺ and [Ni(H₂O)₆]²⁺ cations to form the neutral complex, completed by three solvent water mol­ecules. The {[Pd{CH₂(PO₃)₂}]₃}⁶⁻ units exhibit close Pd...Pd separations of 3.0469 (4) Å and are packed via inter­molecular C—H...Pd hydrogen bonds. The [KO₉] and [NiO₆] units are assembled into sheets coplanar with (011) and stacked along the [100] direction. Within these sheets there are [K₄Ni₄O₈] and [K₂Ni₂O₄] loops. Successive alternation of the sheets and [Pd{CH₂(PO₃)₂}]₃ units parallel to [001] produces the three-dimensional packing, which is also supported by a dense network of hydrogen bonds involving the solvent water mol­ecules.

S1. Comment

Complexes comprising a Pd^II metallic centre coordinated by bioactive ligands are of considerable interest (Juribašić et al., 2011; Ruiz et al., 2005, 2006; Tušek-Božić et al., 2008) owing to their usefulness in the design of more effective and less harmful antineoplastic drugs than cis-platin [cis-diamminedichloridoplatinum(II)]. From this standpoint, the most promising class of ligands is the bisphosphonic acids. These have been widely adopted as antineoplastic drugs for the therapy of affected bone tissues embracing metastatic phenomena (Body et al., 1996; Boissier et al., 2000; Hughes et al. 1995; Lipton, 2003; Matczak-Jon & Videnova-Adrabińska, 2005; Matkovskaya et al., 2001). Some background to this is provided by previous investigations of the cytotoxic activity of mono- and binuclear complexes formed from the interaction of cis-platin with medronic acid and derivatives of bisphosphonic acids (Kozachkova et al., 2007; Margiotta et al., 2007, 2009). Mononuclear Pd^II species in this class of compounds consist of a six-membered [MOPCPO] chelate ring, while the rest of the coordination sites are occupied by ammonia or ammine N atoms (see Scheme 1). A similar but bidentate-bridging role of the methylenediphosphonate ligand is seen in binuclear complexes of Pd^II (see Scheme 2).

Fig. 1 shows the asymmetric unit of the title compound, (I), which consists of two Pd^II cations (Pd1 and Pd2), two deprotonated medronate dianions, one [Ni1(H₂O)₆]²⁺ complex cation and one K1 cation. Solvent water molecules occupy three independent locations and are positionally disordered. The three medronate anions act as chelating ligands, assembling three Pd atoms [Pd1, Pd1ⁱ and Pd2; symmetry code: (i) ??? Please complete] into a `handbell-like' [Pd{CH₂(PO₃)₂}]₃ unit (Fig. 2). To the best of our knowledge, this has not been observed previously for metal–organic compounds containing phosphonate ligands, but it occurs in the extended family of neutral [Pd(µ-O₂CR)]₃.solvent carboxylates (R = Me, Et, ^tBu, ⁱBu, CF₃, C₆H₂Me₃-2,4,6; solvent = H₂O, CH₂Cl₂, C₆H₆; Jain & Jain, 2010, and references therein). It is noteworthy that, amongst N-donor ligands, the neutral [Pd(µ-pz)₃] complex was reported to be fashioned in the same way (Umakoshi et al., 2003). This might indirectly testify to the effect that π-electron delocalization in carboxylate [O₂CR]^-, pyrazolate [C₃H₃N₂]^- and bisphosphonate [CH₂(PO₃)₂]^4- is similar.

The Pd—O bonds in (I) (Table 1) are typical for square-planar [PdO₄] coordination polyhedra. Remarkably, the Pd1···Pd1ⁱ separation is closer than the sum of the covalent radii [Reference?] and is 3.0473 (5) Å, which falls within the range observed for polynuclear complexes of Pd^II (and Pt^II) (Jain & Jain, 2010). The interplanar angle between the mean least-squares planes of the [Pd1O₄] and [Pd2O₄] units is 79.03 (4)°. From the set of adjacent P1···P2···P3···C1 angles, only the P1—C1—P2 angle is likely to have an impact on the Pd1···Pd1ⁱ separation owing to its `flexible' nature.

A view towards the (012) plane (Fig. 2b) presents the C—H···Pd supported packing of `handbell-like' [Pd(µ-CH₂(PO₃)₂]₃ units. The calculated H···Pd (2.9799 Å) contacts are too short to be regarded as metal–acceptor hydrogen bonds (Desiraju & Steiner, 2001), in agreement with those reported previously (Çayli et al., 2012). In terms of a graph-set description of hydrogen-bonding nets (Bernstein et al., 1995), R₂²(10) loops are seen in this packing.

The [KO₉] and [NiO₆] units are assembled via common alternating oxygen bridges and nodes into [K₄Ni₄O₈] and [K₂Ni₂O₄] loops in two-dimensional-sheets (Fig. 3a). The latter are shifted by ~ 1/4a and separated by around b from each other, embedding handbell-like [Pd(µ-CH₂(PO₃)₂]₃ units within the interplanar space (Fig. 3b).

The above-mentioned covalent and ionic–covalent interactions in (I) are complemented by a dense hydrogen-bonding network contributing to the general cohesion. Fig. 4 shows the centrosymmetric pattern of six hydrogen-bonded [Pd{µ-CH₂(PO₃)₂}]₃ units, two [Ni1(H₂O)₆] units and six water molecules. Referring again to a graph-set description of the hydrogen bonds, one can distinguish an R₄²(8) ring element employing adjacent [Ni1(H₂O)₆] units, while linkage of [CH₂(PO₃)₂] and [Ni(H₂O)₆] groups is described by C₂¹(7), C₂¹(8) and C₂¹(9) loops. Also, participation of the water molecules produces a unique [C₂¹(8)C₂²(8)] element.

Related literature

For related literature, see: Bernstein et al. (1995); Body et al. (1996); Boissier et al. (2000); Bruker (2001, 2007); Cooper et al. (2002); Desiraju & Steiner (2001); Hughes et al. (1995); Jain & Jain (2010); Juribašić et al. (2011); Kozachkova et al. (2007); Lipton (2003); Müller et al. (2006); Margiotta et al. (2007, 2009); Matczak-Jon & Videnova-Adrabińska (2005); Matkovskaya et al. (2001); Ruiz et al. (2005, 2006); Sheldrick (2008); Spek (2009); Tanski & Shalumova (2008); Tušek-Božić, Juribašić, Traldi, Scarcia & Furlani (2008); Umakoshi et al. (2003); Çayli et al. (2012).

S2. Experimental

A solution of AgNO₃ (0.3398 g, 2.0 mmol) in H₂O (5 ml) was added to a solution of PdCl₂ (0.0885 g, 0.5 mmol) in hydrochloric acid (0.1 M, 10 ml) and the resulting solution stirred at 276 (1) K for 30 min under protection from light until AgCl was precipitated. (Phosphomethyl)phosphonic acid (0.176 g, 1,0 mmol) and Ni(NO₃)₂.6H₂O (0.1454 g, 0.5 mmol) were added. The dark-red solution turned yellow and the pH was adjusted to ~3 with 0.1 M aqueous KOH. Chunky brown crystals of (I) appeared upon slow evaporation of a water solution at room temperature over a period of 3 d.

S3. Refinement

An a posteriori inspection of a data set with a twofold axis test by ROTAX (Cooper et al., 2002) suggested nonmerohedral twinning with the rotational matrix (1 -0.001 1.850/-0.001 -1 -0.001/0 0 -1), corresponding to the [100] reciprocal direction. The calculated twin fraction of the minor component was 0.101 (7), which explains why it was not detected during the data collection. However, the final residuals (R₁ = 0.04, wR₂ = 0.11, Δρ_min/Δρ_max = 0.99/-0.96 e Å^-3) and K = <F²_o>/<F_c²> indicated an array of unsplit reflections. The twin matrix was readily refound using the CELL_NOW indexing program (Bruker, 2001) and the diffracted intensities were integrated using SAINT-Plus (Bruker, 2007) on two separate domains with options as suggested by Tanski & Shalumova (2008). The resulting data set was scaled on a composite domain and corrected for absorption using the TWINABS program (Bruker, 2001). Refinements on [What?], treated in this way, resulted in a data set which converged with significantly lower residuals [R₁(all) = 0.03 and wR₂ = 0.05]. The solvent water O atoms were obviously involved in positional disorder, exhibiting abnormal anisotropic displacement parameters (ADPs). The starting positions for the disordered components were estimated from partition of the ADPs. The ADPs for the minor components were restrained to be equal to those for the major ones (Müller et al., 2006), as setting them free led to nonpositive defined values. Similarity restraints were applied to chemically equivalent bond lengths, and the angles involving disordered atoms O15 and O16 of the P1O₃ group were constrained to be equal [instruction SADI 0.02 in SHELXL97 (Sheldrick, 2008)]. The corresponding ADPs of both the minor and major components of the disorder were considered to be equal (instruction EADP).

C-bound H atoms were placed at their expected locations and allowed to ride in both coordinates and isotropic displacement parameters [C—H = 0.99 Å for methylene H atoms and U_iso(H) = 1.2U_eq(C)]. The locations of the H atoms of the [Ni(H₂O)₆] units and the major disordered solvent water O atoms were only accessible from a difference Fourier map after twin refinements. The O—H and H···H separations were restrained in an assumption of similarity for the entire structure, where applicable, and the U_iso(H) = 1.5U_eq(O) relation was used. Finally, a PLAT420 alert [hydrogen-bond criteria; PLATON (Spek, 2009)] was detected for atom H8 on O10, but all attempts to find an alternative candidate position, either from a diffrence Fourier map or an omit map, led to a single tolerable Q peak. Intentionally ingoring that while trying other peaks in a sphere of up to 1.2 Å [Diameter? Radius?] eventually resulted in the same location under diffrent combinations of restraint of positional and displacement parameters, as well as free refinements. Therefore, this warning was regarded as likely to be a rare artifact. The H atoms of the minor disordered component of the solvent water O atoms are still missing from this analysis, taking into account the twinning and their low X-ray scattering power.

Computing details

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT-Plus (Bruker, 2007); data reduction: SAINT-Plus (Bruker, 2007) and XPREP (Bruker, 2001); program(s) used to solve structure: DIRDIF (Beurskens et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level (colour code for the electronic version of the paper: Pd violet, Ni green, K light blue, P rose, O red, C grey and H empty spheres with a black outline). Hollow dotted ellipsoids and bonds are used to indicate the minor component of positionally disordered O atoms attributed to the phosphonate group and disordered water molecules. (See Table 1 for symmetry codes.)
	Fig. 2. A view of the `handbell-like' [Pd{µ-CH2(PO3)2}]3 unit. The Pd···Pd separations and the packing via C—H···Pd contacts are shown as dashed lines. (See Table 1 for symmetry codes.)
	Fig. 3. The arrangment of [K4Ni4O8] and [K2Ni2O4] loops, viewed (a) coplanar with (110) and (b) stacked along the [001] direction.
	Fig. 4. The hydrogen-bonding pattern involving [Pd{µ-CH2(PO3)2}]3 units (shown in two-coloured wireframe), [Ni(H2O)6]^2+ units and solvent water molecules (colour codes are the same as in the other figures). [See Table 1 for symmetry codes; additionally, (x) x + 1/2, y + 1/2, z.]

dipotassium bis[hexaaquanickel(II)] tris(µ₂-methylenediphosphonato)tripalladium(II) hexahydrate

Crystal data

K2[Ni(H2O)6]2[Pd3(CH2O6P2)3]·6H2O	F(000) = 2636
Mr = 1354.02	Dx = 2.421 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 8292 reflections
a = 23.6234 (11) Å	θ = 2.2–4.4°
b = 12.5467 (6) Å	µ = 3.03 mm^−1
c = 16.0458 (7) Å	T = 100 K
β = 128.934 (2)°	Prism, translucent brown
V = 3699.5 (3) Å^3	0.40 × 0.20 × 0.20 mm
Z = 4

Data collection

Bruker APEXII CCD area-detector diffractometer	3231 independent reflections
Radiation source: fine-focus sealed tube	3019 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.028
ϕ and ω scans	θmax = 25.0°, θmin = 2.0°
Absorption correction: multi-scan (TWINABS; Bruker, 2001)	h = −28→21
Tmin = 0.402, Tmax = 0.514	k = 0→14
3231 measured reflections	l = 0→19

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.022	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.052	w = 1/[σ^2(Fo^2) + (0.0215P)^2 + 12.6038P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max = 0.001
3231 reflections	Δρmax = 0.64 e Å^−3
302 parameters	Δρmin = −0.73 e Å^−3
30 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00016 (3)

Special details

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.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Pd2	0.5000	0.28430 (3)	0.7500	0.00858 (10)
Pd1	0.508025 (13)	−0.014356 (19)	0.85194 (2)	0.00949 (8)
Ni1	0.22771 (2)	0.03018 (3)	0.12525 (3)	0.01188 (11)
K1	0.30253 (4)	−0.06339 (7)	0.40720 (6)	0.02195 (19)
P3	0.41963 (4)	−0.19221 (7)	0.68260 (7)	0.01043 (18)
P2	0.42588 (5)	0.19795 (7)	0.83698 (7)	0.01338 (19)
P1	0.58907 (5)	0.19965 (7)	0.98078 (7)	0.0172 (2)
O6	0.42851 (11)	−0.12243 (17)	0.76931 (17)	0.0120 (5)
O2	0.58258 (12)	0.28751 (17)	0.90797 (17)	0.0134 (5)
O7	0.41563 (12)	−0.12636 (17)	0.59824 (17)	0.0126 (5)
O4	0.42650 (12)	0.08937 (18)	0.79376 (18)	0.0136 (5)
O1	0.59051 (12)	0.08742 (18)	0.94555 (19)	0.0209 (6)
O11	0.29079 (13)	−0.02100 (19)	0.0841 (2)	0.0194 (6)
H9	0.3297 (13)	−0.039 (3)	0.129 (2)	0.029*
H10	0.2713 (18)	−0.065 (3)	0.042 (2)	0.029*
O8	0.35301 (11)	−0.26142 (18)	0.63054 (17)	0.0131 (5)
O3	0.42557 (12)	0.29022 (18)	0.77246 (19)	0.0156 (5)
O5	0.36106 (14)	0.20930 (18)	0.8337 (2)	0.0207 (6)
O9	0.32024 (12)	0.06666 (19)	0.27536 (19)	0.0136 (5)
H5	0.3517 (17)	0.075 (3)	0.276 (3)	0.020*
H6	0.316 (2)	0.114 (3)	0.299 (3)	0.020*
O13	0.16263 (15)	0.0826 (2)	0.1582 (2)	0.0196 (6)
H13	0.157 (2)	0.1404 (17)	0.157 (3)	0.029*
H14	0.161 (2)	0.053 (3)	0.196 (3)	0.029*
O12	0.22566 (13)	0.18305 (19)	0.07699 (19)	0.0139 (5)
H11	0.1989 (15)	0.191 (3)	0.0180 (18)	0.021*
H12	0.2635 (11)	0.198 (3)	0.097 (3)	0.021*
O14	0.13578 (13)	−0.01202 (19)	−0.0278 (2)	0.0153 (5)
H15	0.0992 (18)	0.007 (3)	−0.039 (3)	0.023*
H16	0.128 (2)	−0.0744 (18)	−0.040 (3)	0.023*
O10	0.23456 (14)	−0.1128 (2)	0.1910 (2)	0.0289 (7)
H7	0.2064 (16)	−0.155 (3)	0.155 (3)	0.043*
H8	0.2722 (13)	−0.139 (4)	0.225 (3)	0.043*
C1	0.5095 (2)	0.2096 (3)	0.9722 (3)	0.0194 (8)
H1	0.5112	0.1528	1.0166	0.023*
H2	0.5101	0.2791	1.0020	0.023*
C2	0.5000	−0.2738 (3)	0.7500	0.0097 (9)
H3	0.5033	−0.3202	0.8028	0.012*	0.50
H4	0.4967	−0.3201	0.6972	0.012*	0.50
O15	0.6620 (3)	0.2149 (4)	1.0927 (3)	0.0097 (10)	0.723 (12)
O16	0.6423 (7)	0.2347 (10)	1.0985 (8)	0.0097 (10)	0.277 (12)
O17	0.2256 (2)	0.1673 (5)	0.4206 (4)	0.0248 (13)	0.723 (10)
H171	0.197 (4)	0.178 (6)	0.387 (6)	0.037*	0.723 (10)
O18	0.2222 (7)	0.1177 (13)	0.3931 (11)	0.0248 (13)	0.277 (10)
O19	0.0094 (3)	0.0077 (5)	0.1017 (6)	0.0206 (11)	0.518 (7)
O20	−0.0068 (4)	−0.0459 (6)	0.0767 (5)	0.0206 (11)	0.482 (7)
H192	0.018 (5)	−0.021 (10)	0.105 (10)	0.031*	0.482 (7)
O21	0.3561 (2)	0.4591 (3)	0.2069 (3)	0.0207 (8)	0.744 (4)
H181	0.359 (3)	0.398 (2)	0.199 (5)	0.031*	0.744 (4)
H182	0.361 (3)	0.488 (4)	0.168 (4)	0.031*	0.744 (4)
O22	0.3627 (5)	0.3859 (7)	0.2697 (8)	0.0207 (8)	0.256 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pd2	0.00899 (18)	0.00923 (19)	0.00764 (18)	0.000	0.00528 (16)	0.000
Pd1	0.00893 (14)	0.00943 (14)	0.00761 (14)	−0.00204 (10)	0.00400 (12)	−0.00151 (10)
Ni1	0.0098 (2)	0.0094 (2)	0.0121 (2)	−0.00125 (17)	0.0048 (2)	−0.00160 (17)
K1	0.0144 (4)	0.0341 (5)	0.0124 (4)	−0.0020 (3)	0.0061 (3)	0.0035 (4)
P3	0.0085 (4)	0.0098 (4)	0.0099 (4)	−0.0009 (3)	0.0043 (4)	−0.0024 (3)
P2	0.0187 (5)	0.0103 (4)	0.0176 (5)	−0.0035 (4)	0.0145 (4)	−0.0037 (4)
P1	0.0188 (5)	0.0126 (5)	0.0088 (4)	−0.0073 (4)	0.0032 (4)	−0.0006 (4)
O6	0.0089 (11)	0.0125 (12)	0.0129 (12)	−0.0034 (9)	0.0061 (10)	−0.0048 (10)
O2	0.0137 (12)	0.0124 (12)	0.0077 (12)	−0.0039 (9)	0.0037 (10)	0.0004 (9)
O7	0.0125 (12)	0.0109 (12)	0.0104 (11)	−0.0005 (9)	0.0052 (10)	−0.0007 (9)
O4	0.0123 (12)	0.0107 (12)	0.0138 (12)	−0.0002 (9)	0.0062 (10)	−0.0026 (10)
O1	0.0125 (12)	0.0114 (13)	0.0181 (13)	−0.0032 (10)	−0.0004 (11)	0.0011 (10)
O11	0.0119 (13)	0.0193 (14)	0.0203 (15)	−0.0028 (11)	0.0068 (12)	−0.0089 (11)
O8	0.0103 (12)	0.0120 (12)	0.0127 (12)	−0.0005 (9)	0.0051 (10)	−0.0029 (10)
O3	0.0190 (13)	0.0131 (12)	0.0229 (13)	0.0002 (10)	0.0172 (12)	0.0008 (10)
O5	0.0280 (14)	0.0135 (13)	0.0373 (16)	−0.0055 (11)	0.0285 (14)	−0.0071 (11)
O9	0.0129 (13)	0.0133 (13)	0.0163 (13)	−0.0014 (10)	0.0101 (12)	−0.0038 (10)
O13	0.0265 (14)	0.0124 (13)	0.0289 (16)	−0.0009 (12)	0.0218 (13)	0.0011 (12)
O12	0.0083 (12)	0.0162 (13)	0.0117 (12)	0.0007 (10)	0.0037 (11)	0.0007 (11)
O14	0.0116 (13)	0.0110 (12)	0.0190 (14)	−0.0038 (10)	0.0075 (12)	−0.0014 (11)
O10	0.0164 (14)	0.0141 (15)	0.0277 (16)	−0.0066 (11)	0.0002 (13)	0.0007 (12)
C1	0.034 (2)	0.0156 (18)	0.0166 (19)	−0.0091 (16)	0.0202 (18)	−0.0056 (15)
C2	0.009 (2)	0.011 (2)	0.011 (2)	0.000	0.007 (2)	0.000
O15	0.008 (2)	0.0102 (19)	0.0105 (14)	−0.0006 (16)	0.0051 (15)	−0.0027 (12)
O16	0.008 (2)	0.0102 (19)	0.0105 (14)	−0.0006 (16)	0.0051 (15)	−0.0027 (12)
O17	0.0174 (18)	0.030 (3)	0.024 (3)	0.007 (2)	0.012 (2)	0.015 (2)
O18	0.0174 (18)	0.030 (3)	0.024 (3)	0.007 (2)	0.012 (2)	0.015 (2)
O19	0.015 (3)	0.026 (3)	0.017 (3)	−0.004 (2)	0.008 (2)	−0.003 (2)
O20	0.015 (3)	0.026 (3)	0.017 (3)	−0.004 (2)	0.008 (2)	−0.003 (2)
O21	0.0332 (19)	0.0123 (16)	0.0228 (19)	0.0003 (15)	0.0205 (17)	0.0011 (14)
O22	0.0332 (19)	0.0123 (16)	0.0228 (19)	0.0003 (15)	0.0205 (17)	0.0011 (14)

Geometric parameters (Å, º)

Pd2—O2^i	2.004 (2)	P1—O2	1.542 (2)
Pd2—O2	2.004 (2)	P1—C1	1.802 (4)
Pd2—O3^i	2.006 (2)	O7—Pd1^i	2.013 (2)
Pd2—O3	2.006 (2)	O11—H9	0.76 (2)
Pd2—P2^i	3.0429 (9)	O11—H10	0.76 (2)
Pd2—P2	3.0429 (9)	O9—H5	0.75 (2)
Pd1—O6	1.999 (2)	O9—H6	0.75 (2)
Pd1—O1	2.001 (2)	O13—H13	0.73 (2)
Pd1—O4	2.004 (2)	O13—H14	0.73 (2)
Pd1—O7^i	2.013 (2)	O12—H11	0.74 (2)
Pd1—H1^ii	2.9795	O12—H12	0.76 (2)
Pd1—Pd1^i	3.0473 (5)	O14—H15	0.80 (2)
Ni1—O13	2.025 (2)	O14—H16	0.80 (2)
Ni1—O10	2.035 (3)	O10—H7	0.76 (2)
Ni1—O9	2.043 (2)	O10—H8	0.77 (2)
Ni1—O12	2.058 (2)	C1—H1	0.9900
Ni1—O11	2.074 (3)	C1—H2	0.9900
Ni1—O14	2.079 (2)	C2—P3^i	1.800 (3)
P3—O8	1.509 (2)	C2—H3	0.9900
P3—O7	1.537 (2)	C2—H4	0.9900
P3—O6	1.543 (2)	O17—O18	0.738 (13)
P3—C2	1.801 (3)	O17—H171	0.56 (6)
P2—O5	1.506 (2)	O18—H171	0.93 (7)
P2—O4	1.533 (2)	O19—O20	0.753 (6)
P2—O3	1.550 (2)	O19—H192	0.40 (14)
P2—C1	1.801 (4)	O20—H192	0.56 (7)
P1—O1	1.526 (3)	O21—H181	0.78 (3)
P1—O15	1.530 (4)	O21—H182	0.78 (3)
P1—O16	1.535 (10)	O22—H181	1.09 (5)
O2^i—Pd2—O2	177.70 (13)	O5—P2—C1	110.81 (16)
O2^i—Pd2—O3^i	92.21 (9)	O4—P2—C1	107.60 (15)
O2—Pd2—O3^i	87.71 (9)	O3—P2—C1	106.58 (15)
O2^i—Pd2—O3	87.71 (9)	O5—P2—Pd2	144.70 (11)
O2—Pd2—O3	92.20 (9)	O4—P2—Pd2	86.39 (9)
O3^i—Pd2—O3	175.75 (13)	C1—P2—Pd2	90.71 (11)
O2^i—Pd2—P2^i	79.08 (7)	O1—P1—O15	106.2 (2)
O2—Pd2—P2^i	101.77 (7)	O1—P1—O16	121.9 (5)
O3^i—Pd2—P2^i	26.97 (7)	O1—P1—O2	113.19 (14)
O3—Pd2—P2^i	156.59 (7)	O15—P1—O2	107.61 (18)
O2^i—Pd2—P2	101.76 (7)	O16—P1—O2	110.0 (5)
O2—Pd2—P2	79.07 (7)	O1—P1—C1	107.53 (15)
O3^i—Pd2—P2	156.59 (7)	O15—P1—C1	115.6 (3)
O3—Pd2—P2	26.96 (7)	O16—P1—C1	94.7 (5)
P2^i—Pd2—P2	138.29 (3)	O2—P1—C1	106.89 (15)
O6—Pd1—O1	175.32 (9)	P3—O6—Pd1	121.46 (13)
O6—Pd1—O4	84.50 (9)	P1—O2—Pd2	119.87 (13)
O1—Pd1—O4	97.63 (9)	P3—O7—Pd1^i	118.77 (13)
O6—Pd1—O7^i	91.36 (9)	P2—O4—Pd1	130.25 (13)
O1—Pd1—O7^i	86.60 (9)	P1—O1—Pd1	128.98 (14)
O4—Pd1—O7^i	175.67 (9)	Ni1—O11—H9	118 (3)
O6—Pd1—H1^ii	64.9	Ni1—O11—H10	111 (3)
O1—Pd1—H1^ii	110.5	H9—O11—H10	109 (4)
O4—Pd1—H1^ii	100.3	P2—O3—Pd2	117.10 (13)
O7^i—Pd1—H1^ii	79.0	Ni1—O9—H5	111 (3)
O6—Pd1—Pd1^i	81.77 (6)	Ni1—O9—H6	113 (3)
O1—Pd1—Pd1^i	102.20 (7)	H5—O9—H6	110 (4)
O4—Pd1—Pd1^i	93.73 (6)	Ni1—O13—H13	118 (3)
O7^i—Pd1—Pd1^i	84.40 (6)	Ni1—O13—H14	119 (3)
H1^ii—Pd1—Pd1^i	142.0	H13—O13—H14	115 (4)
O13—Ni1—O10	88.67 (11)	Ni1—O12—H11	114 (3)
O13—Ni1—O9	92.56 (10)	Ni1—O12—H12	109 (3)
O10—Ni1—O9	84.76 (10)	H11—O12—H12	110 (4)
O13—Ni1—O12	87.34 (10)	Ni1—O14—H15	111 (3)
O10—Ni1—O12	172.78 (11)	Ni1—O14—H16	117 (3)
O9—Ni1—O12	89.40 (10)	H15—O14—H16	100 (3)
O13—Ni1—O11	177.32 (11)	Ni1—O10—H7	119 (4)
O10—Ni1—O11	93.03 (12)	Ni1—O10—H8	116 (4)
O9—Ni1—O11	89.66 (10)	H7—O10—H8	108 (4)
O12—Ni1—O11	91.18 (10)	P2—C1—P1	112.80 (18)
O13—Ni1—O14	89.45 (10)	P2—C1—H1	109.0
O10—Ni1—O14	94.10 (10)	P1—C1—H1	109.0
O9—Ni1—O14	177.67 (10)	P2—C1—H2	109.0
O12—Ni1—O14	91.88 (9)	P1—C1—H2	109.0
O11—Ni1—O14	88.36 (10)	H1—C1—H2	107.8
O8—P3—O7	110.87 (13)	P3^i—C2—P3	110.7 (2)
O8—P3—O6	109.24 (12)	P3^i—C2—H3	109.5
O7—P3—O6	112.80 (13)	P3—C2—H3	109.5
O8—P3—C2	110.15 (15)	P3^i—C2—H4	109.5
O7—P3—C2	107.01 (11)	P3—C2—H4	109.5
O6—P3—C2	106.65 (11)	H3—C2—H4	108.1
O5—P2—O4	111.53 (13)	O18—O17—H171	91 (9)
O5—P2—O3	109.16 (14)	O20—O19—H192	47 (10)
O4—P2—O3	111.03 (13)	H181—O21—H182	104 (5)
O2^i—Pd2—P2—O5	−48.79 (19)	O6—P3—O7—Pd1^i	49.85 (17)
O2—Pd2—P2—O5	129.02 (19)	C2—P3—O7—Pd1^i	−67.13 (17)
O3^i—Pd2—P2—O5	−174.2 (2)	O5—P2—O4—Pd1	−134.69 (18)
O3—Pd2—P2—O5	11.2 (2)	O3—P2—O4—Pd1	103.32 (18)
P2^i—Pd2—P2—O5	−135.51 (18)	C1—P2—O4—Pd1	−13.0 (2)
O2^i—Pd2—P2—O4	74.38 (11)	Pd2—P2—O4—Pd1	76.64 (16)
O2—Pd2—P2—O4	−107.80 (11)	O6—Pd1—O4—P2	155.77 (18)
O3^i—Pd2—P2—O4	−51.1 (2)	O1—Pd1—O4—P2	−20.04 (19)
O3—Pd2—P2—O4	134.43 (18)	H1^ii—Pd1—O4—P2	92.5
P2^i—Pd2—P2—O4	−12.33 (9)	Pd1^i—Pd1—O4—P2	−122.89 (17)
O2^i—Pd2—P2—O3	−60.04 (17)	O15—P1—O1—Pd1	147.8 (3)
O2—Pd2—P2—O3	117.77 (17)	O16—P1—O1—Pd1	130.9 (6)
O3^i—Pd2—P2—O3	174.52 (17)	O2—P1—O1—Pd1	−94.3 (2)
P2^i—Pd2—P2—O3	−146.75 (15)	C1—P1—O1—Pd1	23.5 (2)
O2^i—Pd2—P2—C1	−178.02 (13)	O4—Pd1—O1—P1	13.5 (2)
O2—Pd2—P2—C1	−0.21 (13)	O7^i—Pd1—O1—P1	−167.4 (2)
O3^i—Pd2—P2—C1	56.5 (2)	H1^ii—Pd1—O1—P1	−90.5
O3—Pd2—P2—C1	−117.98 (19)	Pd1^i—Pd1—O1—P1	109.06 (18)
P2^i—Pd2—P2—C1	95.27 (12)	O5—P2—O3—Pd2	−173.15 (14)
O8—P3—O6—Pd1	−177.02 (13)	O4—P2—O3—Pd2	−49.78 (18)
O7—P3—O6—Pd1	−53.24 (18)	C1—P2—O3—Pd2	67.13 (18)
C2—P3—O6—Pd1	63.95 (18)	O2^i—Pd2—O3—P2	121.91 (15)
O4—Pd1—O6—P3	122.19 (16)	O2—Pd2—O3—P2	−60.39 (15)
O7^i—Pd1—O6—P3	−56.54 (15)	P2^i—Pd2—O3—P2	66.6 (3)
H1^ii—Pd1—O6—P3	−133.7	O5—P2—C1—P1	−178.70 (17)
Pd1^i—Pd1—O6—P3	27.60 (13)	O4—P2—C1—P1	59.1 (2)
O1—P1—O2—Pd2	55.40 (19)	O3—P2—C1—P1	−60.0 (2)
O15—P1—O2—Pd2	172.4 (3)	Pd2—P2—C1—P1	−27.31 (18)
O16—P1—O2—Pd2	−164.5 (6)	O1—P1—C1—P2	−64.7 (2)
C1—P1—O2—Pd2	−62.80 (19)	O15—P1—C1—P2	176.9 (2)
O3^i—Pd2—O2—P1	−125.36 (16)	O16—P1—C1—P2	169.7 (5)
O3—Pd2—O2—P1	58.89 (16)	O2—P1—C1—P2	57.1 (2)
P2^i—Pd2—O2—P1	−102.21 (14)	O8—P3—C2—P3^i	−177.54 (11)
P2—Pd2—O2—P1	35.22 (14)	O7—P3—C2—P3^i	61.86 (10)
O8—P3—O7—Pd1^i	172.72 (12)	O6—P3—C2—P3^i	−59.10 (10)

Symmetry codes: (i) −x+1, y, −z+3/2; (ii) −x+1, −y, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O21—H181···O8^iii	0.78 (3)	2.00 (4)	2.747 (4)	161 (6)
O21—H182···O14^iv	0.78 (3)	2.33 (4)	3.072 (4)	160 (5)
O17—H171···O3^v	0.56 (6)	2.40 (6)	2.954 (5)	173 (10)
O9—H5···O6^iii	0.75 (2)	1.97 (2)	2.712 (3)	170 (4)
O9—H5···O4^iii	0.75 (2)	2.61 (3)	3.048 (3)	119 (4)
O10—H8···O5^iii	0.77 (2)	1.90 (3)	2.653 (4)	166 (5)
O11—H9···O4^iii	0.76 (2)	2.24 (2)	2.962 (3)	158 (4)
O12—H11···O8^vi	0.74 (2)	1.97 (3)	2.693 (3)	165 (4)
O11—H10···O17^iii	0.76 (2)	1.99 (2)	2.748 (5)	171 (5)
O11—H10···O18^iii	0.76 (2)	2.00 (3)	2.693 (12)	151 (4)
O12—H12···O8^iii	0.76 (2)	1.99 (2)	2.740 (3)	169 (4)
O13—H13···O5^v	0.73 (2)	1.96 (2)	2.691 (3)	172 (4)
O13—H14···O21^vii	0.73 (2)	2.19 (2)	2.911 (4)	173 (5)
O13—H14···O22^vii	0.73 (2)	2.33 (3)	2.941 (10)	143 (4)
O13—H14···O18	0.73 (2)	2.65 (4)	3.116 (15)	124 (4)
O14—H15···O20^viii	0.80 (2)	1.92 (2)	2.724 (7)	175 (4)
O14—H15···O19^viii	0.80 (2)	2.09 (3)	2.839 (7)	155 (4)
O14—H16···O2^ix	0.80 (2)	1.93 (3)	2.709 (3)	165 (4)

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