Tris(1,10-phenanthroline-κ2 N,N′)nickel(II) hexa­oxido-μ-peroxido-disulfate­(VI) N,N-dimethyl­formamide disolvate monohydrate

Miguel Angel Harvey; Sebastián Suarez; Fabio Doctorovich; Ricardo Baggio

doi:10.1107/S1600536812050775

. 2012 Dec 22;69(Pt 1):m63–m64. doi: 10.1107/S1600536812050775

Tris(1,10-phenanthroline-κ² N,N′)nickel(II) hexaoxido-μ-peroxido-disulfate(VI) N,N-dimethylformamide disolvate monohydrate

Miguel Angel Harvey ^a,^b,^*, Sebastián Suarez ^c,^*, Fabio Doctorovich ^c, Ricardo Baggio ^d

PMCID: PMC3588241 PMID: 23476355

Abstract

The asymmetric unit of the title complex, [Ni(C₁₂H₈N₂)₃]S₂O₈·2C₃H₇NO·H₂O, consists of a complex [Ni(phen)₃]²⁺ cation and one isolated pds anion, with two DMF molecules and one water molecule as solvates (where phen is 1,10-phenanthroline, pds is the hexaoxido-μ-peroxoido-disulfate dianion and DMF is dimethylformamide). The [Ni(phen)₃]²⁺ cation is regular, with an almost ideal Ni^II bond-valence sum of 2.07 v.u. The group, as well as the water solvent molecule, are well behaved in terms of crystallographic order, but the remaining three molecules in the structure display different kinds of disorder, viz. the two DMF molecules mimic a twofold splitting and the pds anion has both S atoms clamped at well-determined positions but with a not-too-well-defined central part. These peculiar behaviours are a consequence of the hydrogen-bonding interactions: the outermost SO₃ parts of the pds anion are heavily connected to the complex cations via C—H⋯O hydrogen bonding, generating an [Ni(phen)₃]pds network and providing for the stability of the terminal pds sites. Also, the water solvent molecule is strongly bound to the structure (being a donor of two strong bonds and an acceptor of one) and is accordingly perfectly ordered. The peroxide O atoms in the pds middle region, instead, appear as much less restrained into their sites, which may explain their tendency to disorder. The cation–anion network leaves large embedded holes, amounting to about 28% of the total crystal volume, which are occupied by the DMF molecules. The latter are weakly interacting with the rest of the structure, which renders them much more labile and, accordingly, prone to disorder.

Related literature

For information on structures with coordinated pds, see: Youngme et al. (2007 ▶); Manson et al. (2009 ▶); Harrison & Hathaway (1980 ▶); Blackman et al. (1991 ▶); Harvey et al. (2011 ▶) and references therein. For examples of structurers with non-coordinating pds groups, see Baffert et al. (2009 ▶); Harvey et al. (2004 ▶, 2005 ▶); Youngme et al. (2008 ▶); Singh et al. (2009 ▶). For details of bond-valence analysis and the vector bond-valence model, see: Brown & Altermatt (1985 ▶) and Harvey et al. (2006 ▶), respectively.

Experimental

Crystal data

[Ni(C₁₂H₈N₂)₃](S₂O₈)·2C₃H₇NO·H₂O
M _r = 955.65
Triclinic,
a = 10.4832 (3) Å
b = 12.2221 (4) Å
c = 18.0044 (6) Å
α = 79.691 (3)°
β = 76.725 (3)°
γ = 76.190 (3)°
V = 2161.41 (12) Å³
Z = 2
Mo Kα radiation
μ = 0.62 mm⁻¹
T = 294 K
0.18 × 0.11 × 0.11 mm

Data collection

Oxford Diffraction Gemini CCD S Ultra diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009 ▶) T _min = 0.945, T _max = 0.952
31646 measured reflections
10070 independent reflections
6165 reflections with I > 2σ(I)
R _int = 0.041

Refinement

R[F ² > 2σ(F ²)] = 0.056
wR(F ²) = 0.170
S = 1.04
10070 reflections
647 parameters
246 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.65 e Å⁻³
Δρ_min = −0.73 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Click here for additional data file.^{(48KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812050775/br2216sup1.cif

e-69-00m63-sup1.cif^{(48KB, cif)}

Click here for additional data file.^{(492.4KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812050775/br2216Isup2.hkl

e-69-00m63-Isup2.hkl^{(492.4KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1WA⋯O6ⁱ	0.85 (5)	2.02 (6)	2.839 (7)	160 (10)
O1W—H1WB⋯O1D′ⁱ	0.85 (7)	1.90 (7)	2.668 (10)	149 (7)
C3B—H3B⋯O1W ⁱⁱ	0.93	2.54	3.305 (8)	139
C1B—H1B⋯O3ⁱⁱ	0.93	2.55	3.192 (6)	126
C3A—H3A⋯O8	0.93	2.59	3.271 (6)	130
C3C—H3C⋯O1ⁱⁱⁱ	0.93	2.43	3.337 (6)	164
C5A—H5A⋯O3	0.93	2.58	3.505 (7)	170
C5C—H5C⋯O2ⁱⁱⁱ	0.93	2.53	3.365 (7)	150
C6B—H6B⋯O1ⁱ	0.93	2.53	3.434 (5)	163
C6C—H6C⋯O2^iv	0.93	2.56	3.409 (6)	151
C8C—H8C⋯O3^iv	0.93	2.30	3.197 (6)	162
C10A—H10A⋯O8^v	0.93	2.48	3.220 (6)	137
C10C—H10C⋯O1E′	0.93	2.59	3.228 (19)	126

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) .

Acknowledgments

The authors acknowledge the ANPCyT (project No. PME 2006–01113) for the purchase of the Oxford Gemini CCD diffractometer and the Spanish Research Council (CSIC) for provision of a free-of-charge license to the Cambridge Structural Database (Allen, 2002 ▶).

supplementary crystallographic information

Comment

The binding behavior of peroxodisulfate (pds) towards a number of transition metal metal cations (Cd(II), Hg(II), Cu(II), Mn(III), Zn(II), Ag(II)) has been well documentated in the literature Youngme et al., 2007; Manson et al., 2009., Blackman et al., 1991; Harrison et al., 1980; Harvey et al., 2011, and references therein) but its rather elusive character as a ligand has also been evidenced in many other structures where the anion wouldn't coordinate, thus acting as a balancing counterion or, in occasions, just as a neutral co-crystallization agent in the form of peroxodisulfuric acid. Among the cations being reluctant towards pds coordination it must be mentioned the case of Cd (Harvey et al., 2005); Co(III) (Singh et al., 2009); Zn(II) (Harvey et al., 2004), Cu(II) (Youngme et al., 2008), Mn(IV) (Baffert et al., 2009), and even the more stringent case of Ni, of which no crystal structure with pds had been reported up to date: in particular, all our previous experiments aimed to produce such a complex had so far been unsuccessful.

Therefore, we present herein the first Ni^II-pds structure, where the anion did not enter into the Ni^II coordination sphere but behaves instead as a stabilizing counteranion: [Ni(phen)₃]²⁺.(pds).2DMF.(H₂O), where (phen: 1,10-phenanthroline; pds: peroxidisulfate dianion; DMF: dimethylformamide).

The asymmetric unit of the complex consists of a globular [Ni(phen)₃]²⁺ nucleus (Fig 1a), one isolated pds anion, two DMF and one water molecules as solvates.

The [Ni(phen)₃]²⁺ cationic centre is absolutely regular and does not differ from the more than 100 similar groups which appear in the v5.33 version of the CSD (Allen, 2002). The Bond Valence Sum for the Ni^II cation in the title compound (Brown and Altermatt, 1985) is almost ideal (2.07 v.u.), and the regularity in the NiN₆ coordination sphere is shown by the tight range of similar parameters (d(Ni-N): 2.087 (3)-2.100 (3)Å; N-Ni-N cis angles: 79.04 (12)-79.71 (12)° (chelating); 92.79 (12)-96.46 (12)° (non-chelating); N-Ni-N trans angles: 172.06 (12)-170.20 (12)°), but it can perhaps be best assessed by the geometric disposition of the three Bond Valence Vectors associated to the three chelating phen ligands (for details, see Harvey et al., 2006) which define an absolute planar array (sum of internal angles: 360.00°), and a theoretical (almost nil) resultant vector ( 0.017 v.u.). The cationic group as well as the water solvate are well behaved in terms of crystallographic order, but the remaining three groups in the structure display different kinds of disorder, as explained in detail in the refinement section, the two DMF mimicking different kinds of two-fold splitting (Figs. 1c,1d) with occupation factors of 0.546 (12)/0.454 (12) and 0.520 (12)/0.480 (12), respectively. In the case of pds this occurs in a more complicated fashion, having both S's "clamped" at two well determined positions (Fig 1b) and a not-so-well-defined central part (Occupation for O4,O5:0.641 (3)).

These peculiar behaviours may be better understood by inspection of Table 1, which gives the H-bonding interactions, and their representation in Fig 2. It is clearly seen therein that the outermost SO₃ parts of the pds anion are strongly connected to the cationic centres via H-bonding (10 donors out of 13 correspond to these groups), generating a sort of stable [Ni(phen)₃]-pds network and acting as a clamp for the terminal SO₃ groups. The oxygens in the pds middle region, instead, are much less restrained to their sites, and this could explain some tendency to disorder. Similar mobility restrictions apply to the water solvate, donor of two strong bonds (Table 1, entries 1 and 2) and acceptor of one (3rd entry). On the other hand, the above cationic-anionic network leaves large embedded holes (about 28% of the total crystal volume, as calculated by PLATON, Spek, 2009). These holes are occupied by the DMF molecules (in light tracing in Fig 2). Analysis of the acceptors in Table 1 and inspection of Figure 2 reaveals that they hardly interact with the rest of the structure, being thus labile and, accordingly, prone to disorder.

Experimental

The title compound was prepared by adding DMF to a solid, equimolar mixture of [Ni(CH₃COO)₂].4H₂O, K₂S₂O₈ and phen.H₂O in such a way that phen final concentration was 0.500 M. Crystals suitable for X-ray diffraction developed in a few hours.