Bis(pentane-2,4-dionato)bis[2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide]nickel(II)

[N,N0-Bis(2-hydroxynaphthylmethylene)-1,2-ethanediaminato]zinc(II) Chen et al. (2005) 10.1107/S1600536805026796 YAWZOM Diazidobis(2,20-biimidazole)copper(II) Liu et al. (2007) 10.1107/S1600536807047873 SILZIX Dichlorido(1,10-phenanthroline)copper(II) Liu (2007) 10.1107/S1600536807056735 MISSAJ Diazidobis(2,20-biimidazole)cobalt(II) Li et al. (2008) 10.1107/S1600536807062873 MIRYAO Diazidobis(2,20-biimidazole)manganese(II) Zhang et al. (2008) 10.1107/S1600536808017984 MODBUD Diazidobis(2,20-biimidazole)iron(II) Hao et al. (2008a) 10.1107/S1600536808018539 MODFOB Bis(pentane-2,4-dionato)bis[2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide]nickel(II) Hao et al. (2008b) 10.1107/S1600536808018552 MODFUH

In the title compound, [Ni(C 5 H 7 O 2 ) 2 (C 12 H 16 N 3 O 2 )], the Ni II cation is hexacoordinated by four O and two N atoms, showing a slightly distorted octahedral geometry. The Ni II cation lies on an inversion centre, as a consequence of which the asymmetric unit comprises one half-molecule. The four O atoms belonging to two pentane-2,4-dionate ligands lie in the equatorial plane and two pyridyl N atoms occupy the axial coordination sites.

Experimental
Crystal data [Ni(C 5  Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus; 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: SHELXTL. r e t r a c t e d Design of different kinds of metal-radical coordination architectures with appropriate organic radicals and coligands has been an important subject during the last decade because of their potential use for molecule-based magnetic materials and optical devices (Caneschi et al., 1989;Tsukuda et al., 2002;Vostrikova et al., 2000;Kuchar et al., 2003). The organic species, such as tridentate nitronyl nitroxide radical, and bidentate nitroxide radical could results in a large number of building blocks with the potential applications. In this paper, we report the structure of the title compound, (I).
The Ni II cation is hexacoordinated with four O and two N atoms showing the slightly distorted octahedral geometry ( Fig. 1). The Ni II cation lies on an inversion centre. The four oxygen atoms belonging to two pentane-2,4-dionate lie in the equatorial plane and the two nitrogen atoms occupy the axial coordination sites. The Ni-N and Ni-O bond lengths are in the range of 2.154 (2)-2.154 (2) and 2.0239 (17)-2.0292 (16) /%A, respectively (Table 1).

S3. Refinement
All H atoms were placed in calculated positions with C-H = 0.93Å and refined as riding with U iso (H) = 1.2U eq (carrier).

Figure 1
The molecular structure of (I) around Ni II , drawn with the 30% probability displacement ellipsoids for the non-hydrogen atoms.

Bis(pentane-2,4-dionato)bis[2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide]nickel(II)
Crystal data  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.