Bis[bis­(3,5-diamino-1H-1,2,4-triazol-4-ium)copper(I)] tris­(hexa­fluoridosilicate)

Marian Mys’kiv; Evgeny Goreshnik

doi:10.1107/S160053681004225X

. 2010 Oct 23;66(Pt 11):m1453–m1454. doi: 10.1107/S160053681004225X

Bis[bis(3,5-diamino-1H-1,2,4-triazol-4-ium)copper(I)] tris(hexafluoridosilicate)

Marian Mys’kiv ^a,^*, Evgeny Goreshnik ^b

PMCID: PMC3009260 PMID: 21588872

Abstract

In the title compound, [Cu(C₂H₆N₅)₂]₂(SiF₆)₃, the asymmetric unit is composed of one [Cu(HL)₂]³⁺ cation (where L is 3,5-diamino-1,2,4-triazole) and one and a half SiF₆ ²⁻ anions. The rather large positively charged guanazole ligand moiety promotes the low metal coordination number of 2 for the Cu^I atom. The compound was obtained using the electrochemical alternating-current technique starting from an ethanol–methanol solution of CuSiF₆·4H₂O and guanazole. In the crystal, N—H⋯F hydrogen bonds play an important role in the formation of a three-dimensional network. As a result of these hydrogen bonds, there are also π–π interactions [centroid–centroid distance = 3.3024 (14) Å] involving one of the triazole groups in molecules related by an inversion center, and short Cu⋯N interactions [2.909 (3) Å] involving an –NH₂ group, leading to the formation of a dimer-like arrangement.

Related literature

For 1,2,4-triazole and its functionalized derivatives, see: Potts (1984 ▶). For complexes of the same ligand and copper(I) complexes of similar voluminous ligands, see: Aznar et al. (2006 ▶); Fabretti (1992 ▶); Goreshnik et al. (2004 ▶).

Experimental

Crystal data

[Cu(C₂H₆N₅)₂]₂(SiF₆)₃
M _r = 953.84
Triclinic,
a = 7.482 (2) Å
b = 8.366 (1) Å
c = 12.131 (3) Å
α = 87.98 (2)°
β = 89.11 (2)°
γ = 67.89 (2)°
V = 703.1 (3) Å³
Z = 1
Mo Kα radiation
μ = 1.81 mm⁻¹
T = 293 K
0.24 × 0.20 × 0.04 mm

Data collection

Siemens AED2 diffractometer
Absorption correction: numerical (de Meulanaer & Tompa, 1965) ▶ T _min = 0.649, T _max = 0.935
4089 measured reflections
4089 independent reflections
3367 reflections with I > 2σ(I)
3 standard reflections every 60 min intensity decay: 2%

Refinement

R[F ² > 2σ(F ²)] = 0.053
wR(F ²) = 0.155
S = 1.06
4089 reflections
244 parameters
4 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 1.23 e Å⁻³
Δρ_min = −1.01 e Å⁻³

Data collection: STADI4 (Stoe & Cie, 1998 ▶); cell refinement: STADI4; data reduction: X-RED (Stoe & Cie, 1998 ▶); program(s) used to solve structure: SHELXS86 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Crystal Impact, 2010 ▶), ORTEPIII (Burnett & Johnson, 1996 ▶) and ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: enCIFer (Allen et al., 2004 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053681004225X/su2214sup1.cif

e-66-m1453-sup1.cif^{(19.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053681004225X/su2214Isup2.hkl

e-66-m1453-Isup2.hkl^{(196.3KB, 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
N2—H2⋯F2ⁱ	0.86 (2)	1.86 (2)	2.694 (3)	166 (4)
N3—H3⋯F8	0.88 (2)	2.02 (3)	2.798 (3)	146 (4)
N4—H4B⋯F1ⁱⁱ	0.86	1.95	2.742 (4)	153
N4—H4A⋯F9ⁱⁱ	0.86	1.95	2.801 (3)	171
N5—H5A⋯F6ⁱⁱⁱ	0.86	1.95	2.803 (3)	174
N5—H5B⋯F9^iv	0.86	2.07	2.898 (3)	162
N7—H7⋯F4ⁱ	0.86 (2)	1.85 (2)	2.686 (3)	162 (4)
N8—H8⋯F7^v	0.86 (2)	2.04 (3)	2.812 (3)	148 (4)
N8—H8⋯F3^v	0.86 (2)	2.22 (3)	2.813 (3)	126 (3)
N9—H9B⋯F8^vi	0.86	2.05	2.892 (3)	166
N9—H9A⋯F5^vii	0.86	2.02	2.841 (4)	159
N10—H10B⋯F5^v	0.86	2.22	2.909 (3)	137
N10—H10A⋯F6ⁱⁱⁱ	0.86	2.02	2.845 (3)	160

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

Acknowledgments

The authors thank the Slovenian Research Agency (ARRS) and the Ukrainian Ministry for Science and Higher Education for financial support (bilateral project BI—UA/09–10–015, M/55–2009)

supplementary crystallographic information

Comment

1,2,4-triazole and its functionalized derivatives, particularly 3,5-diamino-1,2,4-triazole (L), have attracted great interest and are actively studied as ligands in the synthesis of coordination compounds, biologically active compounds with a wide range efficiency, and as components of high-energy compositions [Potts, 1984]. On the other hand only a few X-ray crystal structures of complexes of this triazole have been reported (Aznar et al., 2006). The formation of low soluble polynuclear metal derivatives is one of the hindrances for structural studies of such compounds. It may be expected that the protonated form of the ligand (LH) will possess lower affinity to metal centers. Herein, we report on the synthesis and crystal structure of the title copper(I) hexafluorosilicate complex of LH.

Beside the positively charged state, the LH moiety demonstrates ability of metal coordination. In the structure of [Cu(LH)₂]₂(SiF₆)₃ each metal atom is bound to two nitrogen atoms from two LH moieties (Fig. 1). A similar linear copper(I) surrounding comprising of two nitrogen atoms from two voluminous ligand molecules was observed, for example, in the structure of bis(2-methylbenzimidazole)copper(I) dichlorocuprate(I) (Goreshnik et al., 2004). Because of the low copper(I) ion coordination number both Cu–N distances appear to be rather short, 1.8747 (18) and 1.8749 (17) Å. Despite the cationic status of the ligand moiety the Cu - N bond length is practically the same [1.874 (2) Å] as in the above mentioned bis(2-methylbenzimidazole)copper(I) cation.

In the crystal each NH and NH₂hydrogen atom participates in the formation of strong N—H···F hydrogen bonds (Table 1). The closest NH₂ group to the coordinated copper ion [Cu1···N10ⁱ = 2.9092 (29) Å, symmetry code (i) = -x + 1, -y, -z + 1], forms noticeably shorter hydrogen bonds than all the others. Each of the two crystallographically independent SiF₆^2- anions is bound to six LH units (Fig. 2). The [Cu(LH)]³⁺ and SiF₆^2- units are interconnected by N—H···F bonds to form a three dimensional network (Fig. 3). In the crystal there are also π–π interactions involving triazole rings (N1—N3,C3,C4 = Cg2) related by an inversion center, with a centroid-to-centroid distance of 3.3024 (14)Å for Cg2···Cg2ⁱⁱ [symmetry code (ii) = -x, -y, 1 - z].

As was already mentioned, the guanazolium moiety in this structure acts as a ligand despite its cationic status. Such behaviour was observed previously in the structure of platinum(II) dibromo bis(3,5-diamino-1(2)-triazolium) dibromide (Fabretti, 1992). It emphasizes the high affinity of this triazole derivative towards metal ions. The relatively large size of the LH units and their positive charge lead to the low coordination number of the copper ion.

Experimental

The title compound was prepared using electrochemical synthesis. An ethanol solution of (LH)₂SiF₆ (where L = 3,5-diamino-1,2,4-triazole) was added to a solution of Cu₂SiF₆^.4H₂O (prepared by dissolving [(CuOH)₂CO₃] in H₂SiF₆) in CH₃OH. This solution was then placed in a small test-tube and copper-wire electrodes were inserted. By usage of the alternating-current electrochemical technique at 0.5 V of tension during some days colourless crystals of the title compound appeared on the electrodes.