Bis[tris­(1H-pyrazol-1-yl-κN 2)methane]­nickel(II) bis­{[tris­(1H-pyrazol-1-yl-κN 2)methane]­tris­(thio­cyanato-κN)nickelate(II)} methanol disolvate

Ganna Lyubartseva; Sean Parkin; Uma Prasad Mallik

doi:10.1107/S1600536811045144

. 2011 Nov 5;67(Pt 12):m1656–m1657. doi: 10.1107/S1600536811045144

Bis[tris(1H-pyrazol-1-yl-κN ²)methane]nickel(II) bis{[tris(1H-pyrazol-1-yl-κN ²)methane]tris(thiocyanato-κN)nickelate(II)} methanol disolvate

Ganna Lyubartseva ^a,^*, Sean Parkin ^b, Uma Prasad Mallik ^a

PMCID: PMC3238592 PMID: 22199483

Abstract

Attempts to prepare the mononuclear [(tpm)Ni^II L ₃]⁻¹ [tpm = tris(1H-pyrazol-1-yl)methane and L = thiocyanate] anion yielded the methanol-solvated salt, [(tpm)₂Ni^II][(tpm)Ni^II(NCS)₃]₂·2CH₃OH or [Ni(C₁₀H₁₀N₆)₂][Ni(NCS)₃(C₁₀H₁₀N₆)]₂·2CH₃OH. The asymmetric unit consists of half a centrosymmetric bis[tris(1H-pyrazol-1-yl)methane]nickel(II) cation and an octahedral nickelate(II) anion bound to one tpm and three L ligands, and a methanol solvent molecule. One of the L ligands is disordered over two positions with occupancy factors of 0.650 (3) and 0.350 (3). There are O—H⋯S interactions between the methanol and the disordered thiocyanate anion, and a weak C—H⋯O hydrogen bond between the cation and the methanol O atom.

Related literature

For the ligand synthesis, see: Reger et al. (2000 ▶). For structural, spectroscopic and angular overlap studies of tris(1H-pyrazol-1-yl)methane complexes, see: Astley et al. (1993 ▶). For background information on the modelling of metallo-enzyme sites by small molecules, see: Kitajima et al. (1992 ▶); Trofimenko et al. (1992 ▶); Looney et al. (1992 ▶); Looney & Parkin (1994 ▶). A previous attempt to make similar building blocks with nickel(II) and a cyanide ligand is given in Lyubartseva & Parkin (2009 ▶).

Experimental

Crystal data

[Ni(C₁₀H₁₀N₆)₂][Ni(NCS)₃(C₁₀H₁₀N₆)]₂·2CH₄O
M _r = 1445.65
Monoclinic,
a = 33.4463 (8) Å
b = 7.3287 (2) Å
c = 27.2689 (7) Å
β = 112.590 (1)°
V = 6171.3 (3) Å³
Z = 4
Cu Kα radiation
μ = 3.52 mm⁻¹
T = 90 K
0.20 × 0.06 × 0.02 mm

Data collection

Bruker X8 Proteum diffractometer
Absorption correction: multi-scan (SADABS in APEX2; Bruker, 2006 ▶) T _min = 0.740, T _max = 0.933
41685 measured reflections
5605 independent reflections
4932 reflections with I > 2σ(I)
R _int = 0.061

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.128
S = 1.11
5605 reflections
418 parameters
6 restraints
H-atom parameters constrained
Δρ_max = 1.34 e Å⁻³
Δρ_min = −0.44 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97 and local procedures.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811045144/ng5255sup1.cif

e-67-m1656-sup1.cif^{(39.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811045144/ng5255Isup2.hkl

e-67-m1656-Isup2.hkl^{(274.5KB, 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
O1S—H1S⋯S3ⁱ	0.84	2.43	3.267 (4)	175
O1S—H1S⋯S3′ⁱ	0.84	2.88	3.459 (6)	128
C23—H23⋯O1S	1.00	2.15	3.118 (4)	162

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Symmetry code: (i) Inline graphic .

Acknowledgments

GL gratefully acknowledges Southern Arkansas University for the financial support.

supplementary crystallographic information

Comment

Tripodal ligands with three pyrazolyl groups are increasingly being used in small-molecule modeling of the active sites of metallo-enzymes in which the metal is coordinated to two or three imidazole groups from histidine (Kitajima et al. 1992, Trofimenko et al. 1992, Looney et al. 1992, Looney & Parkin 1994). One of the goals of this research is to explore the chemistry of the neutral ligand tris(pyrazol-1-yl)methane compared to the more extensively studied isoelectronic but anionic ligand tris(pyrazol-1-yl)borate. In attempts to prepare mononuclear [(tpm)Ni^IIL₃]^-1 , where tpm is tris(pyrazol-1-yl)methane, a symmetrical tripodal neutral nitrogen donor ligand, and L is NCS^-, a uninegative N-donor pseudohalide anion, we obtained [(tpm)₂Ni^II][(tpm)Ni^II(NCS)₃]₂.2CH₃OH as blue monoclinic crystals in 57% isolated yield. The structure consists of centrosymmetric [bis[tris(1-pyrazolyl)methane-κ³]-nickel(II) cations, with Ni^II—N distances ranging from 2.077 (2) to 2.082 (2) Å. The intraligand N—Ni—N angles in the cation range from 85.81 (10) to 95.27 (10)°, which introduces a slight trigonal distortion from perfect octahedral geometry. The anion consists of nickellate (II) atom surrounded octahedrally by one tripodal tris(pyrazol-1-yl)methane ligand and three isothiocyanate ligands. The tpm ligand N—Ni distances range from 2.080 (3) to 2.119 (3) Å, and the isothiocyanate N—Ni distances range from 2.046 (3) to 2.070 (3) Å.

Experimental

The tris(pyrazolyl)methane ligand was synthesized according to the previously published procedure by Reger et al. (2000). Tetrabutylammonium thiocyanate was purchased from Aldrich and used as received. NiCl₂.6H₂0 (475 mg, 2 mmol) was dissolved in 15 ml methanol. Tris(pyrazolyl) methane (428 mg, 2 mmol) was dissolved in 15 ml methanol. The ligand solution was added dropwise to metal solution and with moderate stirring. Once the addition was complete, tetrabutylammonium thiocyanate (1.81 g, 6 mmol) was added. The solution was filtered and methanol was evaporated slowly. Blue crystals were obtained after 3 days (549 mg, 57% yield). Elemental analysis, calculated for Ni₃C₄₈H₄₈N₃₀S₆O₂ : C 39.88, H 3.35, N 29.07; found C 39.21, H 2.99, N 29.27%. IR (cm^-1): 3361, 3133, 2977, 2071, 1516, 1440, 1400, 1284, 1247, 1220, 1088, 1050, 980, 905, 858, 788, 766, 660, 608, 475.