Hexakis(1H-imidazole-[kappa]N³)­nickel(II) bis­[O,O'-diiso­propyl di­thio­phos­phate(1-)]

In the title complex, [Ni(Im)₆](ⁱPr-dtp)₂ or [Ni(C₃H₄N₂)₆](C₆H₁₄O₂PS₂)₂, the coordination around the Ni atom, located on an inversion centre, is octhahedral with all positions being occupied by tertiary N atoms of the imidazole moieties. Hydro­gen bonds link the anions and cations into a two-dimensional network in the bc plane.

S1. Comment

Imidazole is of considerable interest as a ligand in that its presence in many biological systems (for example in the histidyl residue of proteins) provides a potential binding site for metal ions. Imidazole itself is a monodentate ligand and forms complexes with metal ions through its tertiary N atom. Some complexes of imidazole and its derivatives with transition et al. ions have been reported (Brooks & Davidson, 1960; Inoue et al., 1966; Rao & Li, 1966; Eilbeck et al., 1967; Davis & Smith, 1971). Complexes of copper(II) and cobalt(II) with carboxylate and imidazole ligands have been studied as models for metalloproteins since they both contain functionalities in the side chain (Sigel, 1980; Bernarducci et al., 1983; Abuhijleh & Woods, 1992). In addition, some of these copper(II) compounds were found to have a variety of pharmacological activities (Tamura et al., 1987) and superoxide dismutase activities (Bhirud & Srivastava, 1990). Some complexes of zinc(II) play an important role in biological organisms, especially in enzymatic reactions (Vallee & Wacker, 1970). \scheme1

The asymmetric unit of the title complex, (I), is formed by one half of the hexakis(1H-imidazole)nickel(II) molecule, with the Ni atom located at the center of symmetry, and one bis(O,O'-diisopropyl dithiophosphate) anion. The Ni1—N1, Ni1—N3 and Ni1—N5 bond distances agree with those of hexakis(imidazole)nickel(II) disalicylate [2.141 (1), 2.120 (1) and 2.124 (1) Å, respectively; Jian et al., 1999] and hexakis(imidazoole)nickel(II) bis(4-methoxybenzoate) [2.141 (2), 2.127 (2) and 2.140 (2) Å, respectively; Wang et al., 2000]. The environment around the Ni atom is octahedral, with the N1, N1A, N3, N3A, N5 and N5A atoms occupying all the positions. The two P—S bond lengths of the anions are nearly the same. These bond lengths are different from those when the dialkyl dithiophosphate ligand is coordinated through its S atoms, e.g. 1.99 and 1.98 Å in Ni{(EtO)₂PS₂}(py)₂ (Ooi & Fernando, 1967), and 2.005 (6), 1.925 (6), 1.997 (8) and 1.926 (9) Å in Zn{(ⁱPrO)₂PS₂}₂(bipy) (Harrison et al., 1986). The P—O and C—C bond lengths of the O,O'-diisopropyl dithiophosphate anions are comparable with the reported values, while the O—C distances are shorter (Hoskins & Tiekink, 1985; Sanz-Aparicio et al., 1986).

All the N—H atoms from the hexakis(imidazole)nickel(II) moiety form N—H···S intermolecular hydrogen bonds with the S atoms of the O,O'-diisopropyl dithiophosphate anions (Table 2). One of the S atoms also shows short S···S contacts [S2···S2(-x, y, 1/2 − z) 3.350 (2)°]. Hydrogen bonds link the anions and cations into a two-dimensional network parallel to the bc plane, with no interactions in the stacking (i.e. a) direction.

S2. Experimental

The title compound was prepared by the addition of imidazole (0.06 mmol) to a solution of nickel(II) bis(O,O'-diisopropyl dithiophosphate) in EtOH (50 ml). The mixture was heated until dissolved, after which it was cooled and filtered. Light-blue single crystals suitable for X-ray analysis were obtained by recrystalization from anhydrous EtOH solution.

S3. Refinement

After checking their presence in the difference map, all H atoms were fixed geometrically and allowed to ride on their attached atoms. The highest peak and deepest hole are located 0.94 and 0.78 Å, respectively, from the S1 atom.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 1990).

Figures

Fig. 1. The structure of the title compound showing 50% probability displacement ellipsoids and the atom-numbering scheme.

Structure of hexakis(imidazole)nickel(II) bis(O,O'-disopropyl dithiophosphate)

Crystal data

[Ni(C3H4N2)6](C6H14O2PS2)2	F(000) = 1880
Mr = 893.73	Dx = 1.369 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 24.7585 (4) Å	Cell parameters from 6747 reflections
b = 11.4460 (2) Å	θ = 1.8–28.4°
c = 16.5815 (1) Å	µ = 0.76 mm^−1
β = 112.689 (1)°	T = 293 K
V = 4335.32 (11) Å^3	Slab, light blue
Z = 4	0.40 × 0.34 × 0.12 mm

Data collection

Siemens SMART CCD area-detector diffractometer	5353 independent reflections
Radiation source: fine-focus sealed tube	3099 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.076
Detector resolution: 8.33 pixels mm^-1	θmax = 28.5°, θmin = 1.8°
ω scans	h = −13→33
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	k = −15→14
Tmin = 0.750, Tmax = 0.914	l = −22→21
15098 measured reflections

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)] = 0.072	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.227	H-atom parameters constrained
S = 1.07	w = 1/[σ^2(Fo^2) + (0.1162P)^2] where P = (Fo^2 + 2Fc^2)/3
5353 reflections	(Δ/σ)max < 0.001
241 parameters	Δρmax = 1.32 e Å^−3
0 restraints	Δρmin = −0.65 e Å^−3

Special details

Experimental. The data collection covered over a hemisphere of reciprocal space by a combination of three sets of exposures; each set had a different ϕ angle (0, 88 and 180°) for the crystal and each exposure of 30 s covered 0.3° in ω. The crystal-to-detector distance was 4 cm and the detector swing angle was −35°. Crystal decay was monitored by repeating fifty initial frames at the end of data collection and analysing the duplicate reflections, and was found to be negligible.

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	0.0371 (2)
P1	0.14921 (5)	0.46690 (10)	0.26680 (8)	0.0454 (3)
S1	0.20489 (6)	0.36125 (13)	0.35270 (10)	0.0687 (4)
S2	0.06624 (6)	0.44270 (12)	0.24482 (11)	0.0688 (4)
O1	0.16492 (17)	0.4433 (3)	0.1831 (2)	0.0709 (10)
O2	0.15978 (16)	0.5992 (3)	0.2924 (3)	0.0731 (11)
N1	−0.01946 (16)	−0.1496 (3)	0.0614 (2)	0.0424 (8)
N2	−0.00617 (19)	−0.3123 (3)	0.1358 (2)	0.0540 (10)
H2B	0.0093	−0.3772	0.1599	0.065*
N3	0.06504 (17)	0.0480 (3)	0.1214 (2)	0.0451 (9)
N4	0.13288 (19)	0.1472 (4)	0.2238 (3)	0.0604 (11)
H4A	0.1591	0.1993	0.2484	0.073*
N5	−0.06053 (16)	0.1037 (3)	0.0312 (2)	0.0418 (8)
N6	−0.09742 (19)	0.2365 (3)	0.0890 (3)	0.0552 (10)
H6A	−0.0993	0.2918	0.1228	0.066*
C1	−0.0626 (2)	−0.1628 (4)	0.0923 (3)	0.0527 (12)
H1A	−0.0931	−0.1105	0.0829	0.063*
C2	−0.0546 (2)	−0.2634 (4)	0.1388 (3)	0.0565 (12)
H2A	−0.0778	−0.2924	0.1669	0.068*
C3	0.0139 (2)	−0.2433 (4)	0.0891 (3)	0.0475 (11)
H3A	0.0470	−0.2589	0.0773	0.057*
C4	−0.0487 (2)	0.1823 (4)	0.0927 (3)	0.0491 (11)
H4B	−0.0113	0.1984	0.1336	0.059*
C5	−0.1426 (2)	0.1895 (4)	0.0235 (3)	0.0581 (13)
H5A	−0.1819	0.2090	0.0062	0.070*
C6	−0.1195 (2)	0.1084 (4)	−0.0122 (3)	0.0512 (11)
H6B	−0.1409	0.0621	−0.0599	0.061*
C7	0.0993 (2)	0.1386 (4)	0.1382 (3)	0.0560 (12)
H7A	0.1004	0.1912	0.0961	0.067*
C8	0.1175 (3)	0.0586 (5)	0.2636 (3)	0.0752 (18)
H8A	0.1329	0.0426	0.3232	0.090*
C9	0.0762 (3)	−0.0022 (4)	0.2016 (3)	0.0668 (15)
H9A	0.0577	−0.0684	0.2111	0.080*
C10	0.1442 (3)	0.5124 (5)	0.1070 (4)	0.0752 (17)
H10A	0.1340	0.5890	0.1235	0.090*
C11	0.1968 (4)	0.5296 (7)	0.0829 (6)	0.127 (4)
H11A	0.2287	0.5609	0.1321	0.191*
H11B	0.1869	0.5828	0.0346	0.191*
H11C	0.2081	0.4558	0.0667	0.191*
C12	0.0908 (5)	0.4643 (7)	0.0383 (4)	0.140 (4)
H12A	0.0605	0.4572	0.0606	0.210*
H12B	0.0993	0.3888	0.0209	0.210*
H12C	0.0780	0.5158	−0.0113	0.210*
C13	0.2153 (3)	0.6572 (6)	0.3143 (5)	0.086 (2)
H13A	0.2377	0.6159	0.2855	0.103*
C14	0.2500 (5)	0.6592 (8)	0.4085 (5)	0.145 (4)
H14A	0.2583	0.5806	0.4299	0.218*
H14B	0.2284	0.6983	0.4377	0.218*
H14C	0.2861	0.7000	0.4198	0.218*
C15	0.1997 (4)	0.7780 (6)	0.2739 (7)	0.157 (4)
H15A	0.1770	0.7706	0.2124	0.236*
H15B	0.2350	0.8206	0.2828	0.236*
H15C	0.1774	0.8191	0.3010	0.236*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.0469 (5)	0.0286 (4)	0.0359 (4)	0.0061 (3)	0.0163 (3)	−0.0018 (3)
P1	0.0466 (7)	0.0460 (6)	0.0464 (7)	−0.0095 (5)	0.0208 (6)	−0.0039 (5)
S1	0.0510 (8)	0.0691 (9)	0.0718 (9)	−0.0099 (6)	0.0081 (7)	0.0034 (7)
S2	0.0472 (8)	0.0536 (8)	0.1079 (12)	0.0056 (6)	0.0324 (8)	0.0240 (7)
O1	0.079 (3)	0.080 (3)	0.055 (2)	0.013 (2)	0.027 (2)	0.0074 (19)
O2	0.068 (2)	0.0472 (19)	0.116 (3)	−0.0150 (17)	0.048 (2)	−0.011 (2)
N1	0.054 (2)	0.0321 (17)	0.0384 (19)	0.0051 (16)	0.0152 (18)	0.0000 (14)
N2	0.078 (3)	0.0388 (19)	0.0349 (19)	0.0050 (19)	0.010 (2)	0.0069 (15)
N3	0.053 (2)	0.0351 (18)	0.044 (2)	0.0082 (17)	0.0152 (18)	−0.0055 (15)
N4	0.062 (3)	0.049 (2)	0.055 (2)	0.0019 (19)	0.006 (2)	−0.0146 (19)
N5	0.052 (2)	0.0361 (18)	0.0419 (19)	0.0099 (16)	0.0226 (18)	−0.0003 (14)
N6	0.073 (3)	0.045 (2)	0.056 (2)	0.016 (2)	0.033 (2)	−0.0054 (18)
C1	0.064 (3)	0.048 (3)	0.049 (3)	0.008 (2)	0.026 (2)	0.007 (2)
C2	0.074 (3)	0.054 (3)	0.044 (3)	−0.004 (3)	0.026 (3)	0.004 (2)
C3	0.055 (3)	0.041 (2)	0.041 (2)	0.005 (2)	0.012 (2)	0.0003 (18)
C4	0.057 (3)	0.041 (2)	0.054 (3)	0.007 (2)	0.026 (2)	−0.0057 (19)
C5	0.055 (3)	0.059 (3)	0.064 (3)	0.024 (2)	0.026 (3)	0.009 (2)
C6	0.057 (3)	0.045 (2)	0.049 (3)	0.009 (2)	0.018 (2)	0.000 (2)
C7	0.066 (3)	0.050 (3)	0.049 (3)	−0.003 (2)	0.019 (3)	−0.005 (2)
C8	0.109 (5)	0.058 (3)	0.039 (3)	0.004 (3)	0.006 (3)	−0.006 (2)
C9	0.101 (4)	0.045 (3)	0.042 (3)	−0.006 (3)	0.014 (3)	0.000 (2)
C10	0.094 (5)	0.063 (3)	0.059 (3)	0.005 (3)	0.019 (3)	0.017 (3)
C11	0.184 (9)	0.133 (7)	0.120 (7)	0.061 (6)	0.119 (7)	0.062 (5)
C12	0.208 (11)	0.096 (5)	0.054 (4)	−0.008 (6)	−0.017 (5)	−0.006 (4)
C13	0.071 (4)	0.080 (4)	0.120 (6)	−0.030 (3)	0.051 (4)	−0.026 (4)
C14	0.197 (10)	0.120 (7)	0.098 (6)	−0.069 (7)	0.035 (6)	−0.043 (5)
C15	0.135 (8)	0.071 (5)	0.239 (12)	−0.054 (5)	0.043 (8)	0.024 (6)

Geometric parameters (Å, º)

Ni1—N3^i	2.108 (4)	N3—C7	1.301 (6)
Ni1—N3	2.108 (4)	N3—C9	1.375 (6)
Ni1—N5^i	2.126 (3)	N4—C8	1.342 (7)
Ni1—N5	2.126 (3)	N4—C7	1.344 (6)
Ni1—N1	2.140 (3)	N5—C4	1.305 (5)
Ni1—N1^i	2.140 (3)	N5—C6	1.357 (6)
P1—O2	1.568 (3)	N6—C5	1.334 (7)
P1—O1	1.603 (4)	N6—C4	1.337 (6)
P1—S2	1.9626 (18)	C1—C2	1.357 (6)
P1—S1	1.9690 (19)	C5—C6	1.342 (6)
O1—C10	1.407 (6)	C8—C9	1.333 (8)
O2—C13	1.441 (6)	C10—C12	1.479 (10)
N1—C3	1.324 (5)	C10—C11	1.515 (11)
N1—C1	1.358 (6)	C13—C14	1.465 (10)
N2—C3	1.329 (6)	C13—C15	1.520 (10)
N2—C2	1.341 (7)
N3^i—Ni1—N3	180	C1—N1—Ni1	128.5 (3)
N3^i—Ni1—N5^i	88.45 (14)	C3—N2—C2	108.3 (4)
N3—Ni1—N5^i	91.55 (14)	C7—N3—C9	104.8 (4)
N3^i—Ni1—N5	91.55 (14)	C7—N3—Ni1	127.4 (3)
N3—Ni1—N5	88.45 (14)	C9—N3—Ni1	127.5 (3)
N5^i—Ni1—N5	180	C8—N4—C7	106.7 (4)
N3^i—Ni1—N1	90.97 (13)	C4—N5—C6	105.0 (4)
N3—Ni1—N1	89.03 (13)	C4—N5—Ni1	127.4 (3)
N5^i—Ni1—N1	88.74 (13)	C6—N5—Ni1	127.5 (3)
N5—Ni1—N1	91.26 (13)	C5—N6—C4	108.0 (4)
N3^i—Ni1—N1^i	89.03 (13)	C2—C1—N1	110.2 (4)
N3—Ni1—N1^i	90.97 (13)	N2—C2—C1	105.6 (4)
N5^i—Ni1—N1^i	91.26 (13)	N1—C3—N2	111.0 (4)
N5—Ni1—N1^i	88.74 (13)	N5—C4—N6	110.9 (4)
N1—Ni1—N1^i	180	N6—C5—C6	105.8 (4)
O2—P1—O1	109.0 (2)	C5—C6—N5	110.4 (4)
O2—P1—S2	103.90 (15)	N3—C7—N4	111.8 (5)
O1—P1—S2	113.69 (17)	C9—C8—N4	107.1 (5)
O2—P1—S1	113.62 (17)	C8—C9—N3	109.6 (5)
O1—P1—S1	100.77 (16)	O1—C10—C12	113.0 (5)
S2—P1—S1	116.00 (8)	O1—C10—C11	104.8 (5)
C10—O1—P1	123.7 (4)	C12—C10—C11	116.6 (7)
C13—O2—P1	123.8 (4)	O2—C13—C14	112.7 (6)
C3—N1—C1	104.8 (4)	O2—C13—C15	104.6 (6)
C3—N1—Ni1	126.0 (3)	C14—C13—C15	113.6 (7)
O2—P1—O1—C10	−48.9 (5)	N3^i—Ni1—N5—C6	9.9 (4)
S2—P1—O1—C10	66.5 (5)	N3—Ni1—N5—C6	−170.1 (4)
S1—P1—O1—C10	−168.7 (4)	N5^i—Ni1—N5—C6	−94 (91)
O1—P1—O2—C13	−58.4 (5)	N1—Ni1—N5—C6	−81.1 (4)
S2—P1—O2—C13	−179.9 (5)	N1^i—Ni1—N5—C6	98.9 (4)
S1—P1—O2—C13	53.2 (5)	C3—N1—C1—C2	0.6 (5)
N3^i—Ni1—N1—C3	108.3 (3)	Ni1—N1—C1—C2	−170.3 (3)
N3—Ni1—N1—C3	−71.7 (3)	C3—N2—C2—C1	0.0 (5)
N5^i—Ni1—N1—C3	19.9 (3)	N1—C1—C2—N2	−0.4 (5)
N5—Ni1—N1—C3	−160.1 (3)	C1—N1—C3—N2	−0.6 (5)
N1^i—Ni1—N1—C3	161 (53)	Ni1—N1—C3—N2	170.6 (3)
N3^i—Ni1—N1—C1	−82.5 (4)	C2—N2—C3—N1	0.4 (5)
N3—Ni1—N1—C1	97.5 (4)	C6—N5—C4—N6	−0.7 (5)
N5^i—Ni1—N1—C1	−171.0 (4)	Ni1—N5—C4—N6	175.3 (3)
N5—Ni1—N1—C1	9.0 (4)	C5—N6—C4—N5	1.2 (6)
N1^i—Ni1—N1—C1	−30 (53)	C4—N6—C5—C6	−1.1 (6)
N3^i—Ni1—N3—C7	−25 (100)	N6—C5—C6—N5	0.7 (6)
N5^i—Ni1—N3—C7	91.4 (4)	C4—N5—C6—C5	0.0 (5)
N5—Ni1—N3—C7	−88.6 (4)	Ni1—N5—C6—C5	−176.0 (3)
N1—Ni1—N3—C7	−179.9 (4)	C9—N3—C7—N4	2.0 (6)
N1^i—Ni1—N3—C7	0.1 (4)	Ni1—N3—C7—N4	175.6 (3)
N3^i—Ni1—N3—C9	148 (100)	C8—N4—C7—N3	−2.0 (6)
N5^i—Ni1—N3—C9	−96.4 (4)	C7—N4—C8—C9	1.1 (7)
N5—Ni1—N3—C9	83.6 (4)	N4—C8—C9—N3	0.1 (7)
N1—Ni1—N3—C9	−7.7 (4)	C7—N3—C9—C8	−1.3 (7)
N1^i—Ni1—N3—C9	172.3 (4)	Ni1—N3—C9—C8	−174.9 (4)
N3^i—Ni1—N5—C4	−165.2 (4)	P1—O1—C10—C12	−95.3 (7)
N3—Ni1—N5—C4	14.8 (4)	P1—O1—C10—C11	136.7 (5)
N5^i—Ni1—N5—C4	90 (90)	P1—O2—C13—C14	−94.2 (7)
N1—Ni1—N5—C4	103.8 (4)	P1—O2—C13—C15	141.8 (6)
N1^i—Ni1—N5—C4	−76.2 (4)

Symmetry code: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N4—H4A···S1	0.86	2.49	3.288 (5)	155
N2—H2B···S2^ii	0.86	2.59	3.442 (4)	173
N6—H6A···S2^iii	0.86	2.66	3.481 (4)	160

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