Bis(tert-butyl-3-oxobutanoato)dipyridine­nickel(II) benzene solvate

The title compound, [Ni(C₈H₁₃O₃)₂(C₅H₅N)₂]·C₆H₆, a potential metal–organic chemical vapour deposition (MOCVD) precursor, crystallizes with half a molecule of the complex and half a molecule of benzene in the asymmetric unit, both molecules being centrosymmetric. The Ni atom is at the origin (0, 0, 0), while the centroid of the benzene solvent mol­ecule is at another centre of symmetry (0, , ). The Ni atom has a distorted octa­hedral environment, with four O atoms from the bidentate tert-butyl-3-oxobutanoate ligand units in the axial positions and the two N atoms of the pyridine ligands at the apical positions. C—H...π contacts [3.021 (4) Å] between solvent benzene and the pyridine ligand, along with π–π stacking inter­actions [3.896 (1) Å] between adjacent pyridine ligands, result in a packing motif along the c axis.

Key indicators

• Single-crystal X-ray study
• T = 292 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.031
• wR factor = 0.086
• Data-to-parameter ratio = 15.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        200 Deg.
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C11
PLAT244_ALERT_4_C Low   'Solvent' Ueq as Compared to Neighbors for        C16
PLAT331_ALERT_2_C Small Average Phenyl C-C Dist.   C16    -C18           1.36 Ang.

Alert level G
PLAT794_ALERT_5_G Check Predicted Bond Valency for Ni1         (2)       2.07
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          2

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

Based on the methodology suggested for making thin films via chemical vapour deposition (CVD) by Williams (1989), several metal-organic (MO) CVD precursors have been synthesized and characterized (Dharmaprakash et al., 2006; Neelgund et al., 2007). In our attempts to synthesize less volatile hydrate precursors, the title compound has been prepared and its structure determined by X-ray diffraction.

The Ni atom is six co-ordinated with the participation of the ketonic O atoms of two bidentate tert-butyl-3-oxobutanoate ligands in the basal plane and with the N atoms of the two pyridine molecules in anti positions to each other, resulting in a distorted octahedral geometry [Fig. 1]. The Ni atom and solvent benzene molecule lie on the inversion centres at (0 0 0) and (0 1/2 1/2) respectively. Selected bond Ni—O/Ni—N distances are Ni1—O1 [2.024 (1) Å], Ni1—O2 [2.062 (1) Å] and Ni1—N1 [2.104 (1) Å].

Pairs of centrosymmetrically related pyridine ligands are involved in intermolecular π···π interactions [Cg···Cg = 3.896 (1)Å Cg = centroid of the pyridine ring (N1/C1/C2/C3/C4/C5), symmetry code (-x, 1 - y, -z)], with each such pair linked to a solvent benzene molecule via C18—H18···π interactions [H18···Cg = 3.021 (4) Å, symmetry code (-x + 1, -y, -z)], stabilizing the crystal packing in (I) [Fig. 2]. The supramolecular assembly is thus brought by an infinite chain of C—H···π and π···π interactions along the c axis [Fig. 2].

Related literature

For a background to chemical vapour deposition (CVD) and the synthesis of metal–organic (MO) CVD precursors, see: Williams (1989), Dharmaprakash et al. (2006, and references therein); Neelgund et al. (2007).

S2. Experimental

The compound was synthesized by dissolving Ni(NO₃)₂.6H₂O (2.9 g, 10 mmol) in 30% ethanol (30 ml). To this solution, (3.26 ml, 20 mmol) tert-butyl-3-oxobutanoate was added, maintaining the pH at 6.5 by adding KOH dissolved in 30% ethanol and the mixture was stirred for 30 minutes at 4 °C. The precipitate formed was filtered off, suction-dried and recrystallized to obtain block shaped crystals from a mixture of pyridine and benzene (2:1 v/v).

S3. Refinement

Hydrogen atoms were fixed geometrically and treated as riding atoms, with C—H distance of 0.93Å (Csp²), 0.96Å (Csp³) and with U_iso(H) = 1.5U_eq(C) for methyl H atoms and 1.2U_eq(C) for other H atoms. The disordered benzene solvent was subjected to restrained refinement using DFIX 1.400 0.002 command for the distances C16—C17 and C16—C18 respectively.

Computing details

Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS86 (Sheldrick, 1985); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2006) and CAMERON (Watkin et al., 1993); software used to prepare material for publication: PLATON (Spek, 2003).

Figures

	Fig. 1. The asymmetric unit of (I) showing 30% probability dispacement ellipsoids of (I). The octahedral coordination at the Ni atom is shown shaded. Hydrogen atoms are omitted for clarity.
	Fig. 2. : Molecular packing of (I) showing the infinite chain of C–H···π and π···π interactions.

Bis(tert-butyl-3-oxobutanoato)dipyridinenickel(II) benzene solvate

Crystal data

[Ni(C8H13O3)2(C5H5N)2]·C6H6	Z = 1
Mr = 609.37	F(000) = 324
Triclinic, P1	Dx = 1.257 Mg m^−3
Hall symbol: -P 1	Melting point: 124 K
a = 8.3748 (11) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.8057 (12) Å	Cell parameters from 622 reflections
c = 12.5949 (17) Å	θ = 0.9–28.0°
α = 99.205 (2)°	µ = 0.65 mm^−1
β = 93.504 (2)°	T = 292 K
γ = 117.338 (2)°	Block, pale blue
V = 804.81 (19) Å^3	0.54 × 0.43 × 0.21 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer	3031 independent reflections
Radiation source: fine-focus sealed tube	2913 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.020
φ and ω scans	θmax = 25.7°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
Tmin = 0.722, Tmax = 0.876	k = −10→10
8193 measured reflections	l = −15→15

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.086	H-atom parameters constrained
S = 1.10	w = 1/[σ^2(Fo^2) + (0.0481P)^2 + 0.1788P] where P = (Fo^2 + 2Fc^2)/3
3031 reflections	(Δ/σ)max < 0.001
191 parameters	Δρmax = 0.27 e Å^−3
2 restraints	Δρmin = −0.32 e Å^−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
Ni1	0.0000	0.0000	0.0000	0.03488 (11)
O1	0.23256 (15)	0.17167 (15)	−0.04472 (10)	0.0424 (3)
O2	0.14118 (16)	0.04802 (16)	0.15216 (10)	0.0437 (3)
N1	0.06342 (19)	−0.20147 (18)	−0.05506 (12)	0.0405 (3)
O3	0.16353 (19)	0.06159 (19)	0.33340 (10)	0.0563 (3)
C9	0.0652 (2)	0.0073 (2)	0.23278 (14)	0.0415 (4)
C6	0.2545 (2)	0.1808 (2)	−0.14322 (15)	0.0411 (4)
C8	−0.1222 (3)	−0.0968 (2)	0.23407 (15)	0.0482 (4)
H8	−0.1596	−0.1099	0.3016	0.058*
C5	−0.0671 (3)	−0.3621 (2)	−0.10124 (16)	0.0500 (4)
H5	−0.1875	−0.3844	−0.1075	0.060*
C1	0.2349 (2)	−0.1730 (3)	−0.04644 (16)	0.0496 (4)
H1	0.3272	−0.0617	−0.0136	0.059*
C11	0.3635 (3)	0.1579 (3)	0.35310 (17)	0.0591 (5)
C2	0.2816 (3)	−0.3003 (3)	−0.08382 (19)	0.0611 (5)
H2	0.4028	−0.2755	−0.0770	0.073*
C4	−0.0311 (3)	−0.4962 (3)	−0.1399 (2)	0.0661 (6)
H4	−0.1256	−0.6070	−0.1716	0.079*
C7	0.4466 (3)	0.3003 (3)	−0.15884 (19)	0.0603 (5)
H7A	0.4866	0.4157	−0.1164	0.090*
H7B	0.4496	0.3050	−0.2344	0.090*
H7C	0.5256	0.2563	−0.1357	0.090*
C12	0.4337 (4)	0.3310 (3)	0.3181 (2)	0.0760 (7)
H12A	0.4097	0.3104	0.2402	0.114*
H12B	0.5624	0.3991	0.3423	0.114*
H12C	0.3736	0.3933	0.3497	0.114*
C14	0.4380 (4)	0.0438 (4)	0.2969 (2)	0.0771 (7)
H14A	0.3888	−0.0649	0.3209	0.116*
H14B	0.5682	0.1029	0.3148	0.116*
H14C	0.4041	0.0210	0.2196	0.116*
C3	0.1455 (4)	−0.4647 (3)	−0.1313 (2)	0.0699 (6)
H3	0.1728	−0.5536	−0.1574	0.084*
C13	0.4045 (4)	0.1869 (4)	0.4768 (2)	0.0907 (9)
H13A	0.3537	0.2568	0.5107	0.136*
H13B	0.5338	0.2461	0.4994	0.136*
H13C	0.3519	0.0760	0.4980	0.136*
C16	0.9918 (6)	0.3375 (5)	0.4840 (3)	0.1279 (14)
H16	0.9844	0.2273	0.4716	0.153*
C17	0.9913 (8)	0.4253 (8)	0.5856 (3)	0.155 (2)
H17	0.9879	0.3752	0.6457	0.186*
C18	1.0046 (8)	0.4301 (8)	0.4024 (3)	0.155 (2)
H18	1.0105	0.3795	0.3330	0.186*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.02993 (16)	0.03302 (17)	0.03890 (18)	0.01287 (12)	0.00500 (11)	0.00705 (12)
O1	0.0350 (6)	0.0391 (6)	0.0473 (7)	0.0129 (5)	0.0073 (5)	0.0088 (5)
O2	0.0375 (6)	0.0467 (7)	0.0421 (6)	0.0167 (5)	0.0035 (5)	0.0089 (5)
N1	0.0383 (7)	0.0375 (7)	0.0453 (8)	0.0177 (6)	0.0073 (6)	0.0088 (6)
O3	0.0547 (8)	0.0633 (9)	0.0406 (7)	0.0211 (7)	0.0011 (6)	0.0088 (6)
C9	0.0478 (9)	0.0370 (8)	0.0395 (9)	0.0212 (8)	0.0037 (7)	0.0058 (7)
C6	0.0393 (9)	0.0341 (8)	0.0550 (10)	0.0197 (7)	0.0149 (7)	0.0130 (7)
C8	0.0506 (10)	0.0490 (10)	0.0448 (10)	0.0216 (9)	0.0145 (8)	0.0137 (8)
C5	0.0447 (10)	0.0395 (9)	0.0582 (11)	0.0151 (8)	0.0078 (8)	0.0062 (8)
C1	0.0402 (9)	0.0475 (10)	0.0613 (11)	0.0215 (8)	0.0073 (8)	0.0104 (8)
C11	0.0554 (12)	0.0583 (12)	0.0532 (11)	0.0224 (10)	−0.0076 (9)	0.0045 (9)
C2	0.0577 (12)	0.0687 (14)	0.0743 (14)	0.0420 (11)	0.0181 (10)	0.0206 (11)
C4	0.0702 (14)	0.0413 (10)	0.0772 (14)	0.0224 (10)	0.0109 (11)	0.0008 (10)
C7	0.0438 (10)	0.0610 (12)	0.0724 (14)	0.0174 (9)	0.0196 (10)	0.0244 (11)
C12	0.0670 (15)	0.0547 (13)	0.0864 (17)	0.0168 (11)	−0.0042 (13)	0.0073 (12)
C14	0.0720 (15)	0.0850 (17)	0.0809 (16)	0.0476 (14)	−0.0065 (13)	0.0095 (13)
C3	0.0892 (17)	0.0598 (13)	0.0805 (16)	0.0514 (13)	0.0237 (13)	0.0125 (11)
C13	0.0869 (19)	0.106 (2)	0.0571 (14)	0.0357 (17)	−0.0196 (13)	0.0033 (14)
C16	0.115 (3)	0.143 (4)	0.121 (3)	0.069 (3)	−0.003 (2)	0.000 (3)
C17	0.229 (6)	0.184 (5)	0.093 (3)	0.126 (5)	0.039 (3)	0.042 (3)
C18	0.217 (6)	0.206 (6)	0.078 (2)	0.131 (5)	0.037 (3)	0.019 (3)

Geometric parameters (Å, º)

Ni1—O1	2.0243 (11)	C2—C3	1.370 (3)
Ni1—O1^i	2.0243 (11)	C2—H2	0.9300
Ni1—O2^i	2.0626 (12)	C4—C3	1.368 (3)
Ni1—O2	2.0626 (12)	C4—H4	0.9300
Ni1—N1	2.1041 (14)	C7—H7A	0.9600
Ni1—N1^i	2.1041 (14)	C7—H7B	0.9600
O1—C6	1.275 (2)	C7—H7C	0.9600
O2—C9	1.245 (2)	C12—H12A	0.9600
N1—C5	1.332 (2)	C12—H12B	0.9600
N1—C1	1.333 (2)	C12—H12C	0.9600
O3—C9	1.353 (2)	C14—H14A	0.9600
O3—C11	1.470 (3)	C14—H14B	0.9600
C9—C8	1.411 (3)	C14—H14C	0.9600
C6—C8^i	1.380 (3)	C3—H3	0.9300
C6—C7	1.512 (2)	C13—H13A	0.9600
C8—C6^i	1.380 (3)	C13—H13B	0.9600
C8—H8	0.9300	C13—H13C	0.9600
C5—C4	1.371 (3)	C16—C17	1.387 (6)
C5—H5	0.9300	C16—C18	1.391 (6)
C1—C2	1.375 (3)	C16—H16	0.9300
C1—H1	0.9300	C17—C18^ii	1.243 (6)
C11—C12	1.512 (3)	C17—H17	0.9300
C11—C14	1.517 (3)	C18—C17^ii	1.243 (6)
C11—C13	1.529 (3)	C18—H18	0.9300
O1—Ni1—O1^i	180.00 (7)	C3—C2—C1	118.5 (2)
O1—Ni1—O2^i	90.70 (5)	C3—C2—H2	120.8
O1^i—Ni1—O2^i	89.30 (5)	C1—C2—H2	120.8
O1—Ni1—O2	89.30 (5)	C3—C4—C5	119.1 (2)
O1^i—Ni1—O2	90.70 (5)	C3—C4—H4	120.4
O2^i—Ni1—O2	180.00 (8)	C5—C4—H4	120.4
O1—Ni1—N1	89.06 (5)	C6—C7—H7A	109.5
O1^i—Ni1—N1	90.94 (5)	C6—C7—H7B	109.5
O2^i—Ni1—N1	89.84 (5)	H7A—C7—H7B	109.5
O2—Ni1—N1	90.16 (5)	C6—C7—H7C	109.5
O1—Ni1—N1^i	90.94 (5)	H7A—C7—H7C	109.5
O1^i—Ni1—N1^i	89.06 (5)	H7B—C7—H7C	109.5
O2^i—Ni1—N1^i	90.16 (5)	C11—C12—H12A	109.5
O2—Ni1—N1^i	89.84 (5)	C11—C12—H12B	109.5
N1—Ni1—N1^i	180.00 (7)	H12A—C12—H12B	109.5
C6—O1—Ni1	123.90 (11)	C11—C12—H12C	109.5
C9—O2—Ni1	123.11 (11)	H12A—C12—H12C	109.5
C5—N1—C1	117.60 (16)	H12B—C12—H12C	109.5
C5—N1—Ni1	120.88 (12)	C11—C14—H14A	109.5
C1—N1—Ni1	121.52 (12)	C11—C14—H14B	109.5
C9—O3—C11	122.78 (15)	H14A—C14—H14B	109.5
O2—C9—O3	120.71 (16)	C11—C14—H14C	109.5
O2—C9—C8	127.34 (16)	H14A—C14—H14C	109.5
O3—C9—C8	111.94 (15)	H14B—C14—H14C	109.5
O1—C6—C8^i	126.91 (16)	C4—C3—C2	119.06 (19)
O1—C6—C7	114.90 (16)	C4—C3—H3	120.5
C8^i—C6—C7	118.18 (17)	C2—C3—H3	120.5
C6^i—C8—C9	125.26 (17)	C11—C13—H13A	109.5
C6^i—C8—H8	117.4	C11—C13—H13B	109.5
C9—C8—H8	117.4	H13A—C13—H13B	109.5
N1—C5—C4	122.65 (19)	C11—C13—H13C	109.5
N1—C5—H5	118.7	H13A—C13—H13C	109.5
C4—C5—H5	118.7	H13B—C13—H13C	109.5
N1—C1—C2	123.11 (18)	C17—C16—C18	113.6 (4)
N1—C1—H1	118.4	C17—C16—H16	123.2
C2—C1—H1	118.4	C18—C16—H16	123.2
O3—C11—C12	111.15 (18)	C18^ii—C17—C16	120.9 (4)
O3—C11—C14	109.53 (18)	C18^ii—C17—H17	119.5
C12—C11—C14	112.4 (2)	C16—C17—H17	119.5
O3—C11—C13	101.87 (19)	C17^ii—C18—C16	125.4 (4)
C12—C11—C13	110.6 (2)	C17^ii—C18—H18	117.3
C14—C11—C13	110.8 (2)	C16—C18—H18	117.3
O2^i—Ni1—O1—C6	−16.16 (13)	C11—O3—C9—C8	174.11 (17)
O2—Ni1—O1—C6	163.84 (13)	Ni1—O1—C6—C8^i	9.6 (2)
N1—Ni1—O1—C6	73.67 (13)	Ni1—O1—C6—C7	−171.77 (12)
N1^i—Ni1—O1—C6	−106.33 (13)	O2—C9—C8—C6^i	3.9 (3)
O1—Ni1—O2—C9	163.87 (13)	O3—C9—C8—C6^i	−175.27 (17)
O1^i—Ni1—O2—C9	−16.13 (13)	C1—N1—C5—C4	−0.4 (3)
N1—Ni1—O2—C9	−107.07 (13)	Ni1—N1—C5—C4	178.80 (16)
N1^i—Ni1—O2—C9	72.93 (13)	C5—N1—C1—C2	0.7 (3)
O1—Ni1—N1—C5	−144.94 (14)	Ni1—N1—C1—C2	−178.42 (16)
O1^i—Ni1—N1—C5	35.06 (14)	C9—O3—C11—C12	62.2 (2)
O2^i—Ni1—N1—C5	−54.24 (14)	C9—O3—C11—C14	−62.7 (2)
O2—Ni1—N1—C5	125.76 (14)	C9—O3—C11—C13	179.96 (19)
O1—Ni1—N1—C1	34.18 (14)	N1—C1—C2—C3	−0.6 (3)
O1^i—Ni1—N1—C1	−145.82 (14)	N1—C5—C4—C3	−0.2 (3)
O2^i—Ni1—N1—C1	124.88 (14)	C5—C4—C3—C2	0.3 (4)
O2—Ni1—N1—C1	−55.12 (14)	C1—C2—C3—C4	0.0 (4)
Ni1—O2—C9—O3	−171.36 (12)	C18—C16—C17—C18^ii	2.4 (10)
Ni1—O2—C9—C8	9.6 (2)	C17—C16—C18—C17^ii	−2.6 (10)
C11—O3—C9—O2	−5.1 (3)

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