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The cation-templated self-assembly of 1,4-bis­(2-methyl-1H-imidazol-1-yl)butane (bmimb) with CuSCN gives rise to a novel two-dimensional network, namely catena-poly[2,2′-dimethyl-1,1′-(butane-1,4-di­yl)bis­(1H-imidazol-3-ium) [tetra-μ2-thio­cyanato-κ4S:S4S:N-dicopper(I)]], {(C12H20N4)[Cu2(NCS)4]}n. The CuI cation is four-coordinated by one N and three S atoms, giving a tetra­hedral geometry. One of the two crystallographically independent SCN anions acts as a μ2-S:S bridge, binding a pair of CuI cations into a centrosymmetric [Cu2(NCS)2] subunit, which is further extended into a two-dimensional 44-sql net by another kind of SCN anion with an end-to-end μ2-S:N coordination mode. Inter­estingly, each H2bmimb dication, lying on an inversion centre, threads through one of the windows of the two-dimensional 44-sql net, giving a pseudorotaxane-like structure. The two-dimensional 44-sql networks are packed into the resultant three-dimensional supra­molecular framework through bmimb–SCN N—H...N hydrogen bonds.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270113011992/bg3158sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270113011992/bg3158Isup2.hkl
Contains datablock I

mol

MDL mol file https://doi.org/10.1107/S0108270113011992/bg3158Isup3.mol
Supplementary material

CCDC reference: 950431

Comment top

Inorganic supramolecular networks and coordination polymers have attracted considerable interest because of their fascinating crystal structures and potential applications in fields such as gas adsorption or separation, catalysis, optical materials and so on (Zhou et al., 2012; Yoon et al., 2012; Cui et al., 2012; Li et al., 2009). Of the supramolecular compound types reported, subgroups based on copper(I)–halide/pseudohalide aggregates are particularly interesting, due to their versatile motifs and luminescent properties (Peng et al., 2010; Hao et al., 2010; Xu et al., 2006). In contrast with the well studied coordination architectures of copper(I) halides, copper(I) pseudohalides are relatively unexplored. As a pseudohalide anion (Moss et al., 1995), thiocyanate (SCN-) possesses various bonding modes, such as a terminal mode, an end-on µ2-bridging mode, an end-to-end µ2-bridging mode and a 1,1,3-µ3-bridging mode (Niu et al., 2008), which diversifies the structures and makes structure prediction difficult. The most common strategy for achieving copper(I)–halide/pseudohalide networks is the reaction between CuI (or Cu powder) and halide/pseudohalide salts of the appropriate cation (Babich et al., 1996; Helgesson & Jagner, 1991; Domasevitch et al., 1999; Rusanova et al., 2000). Heterocyclic cation-templated synthesis, on the other hand, provides a new way of constructing polymeric CuSCN networks with target motifs (Raston et al., 1979; Song et al., 2012). However, the use of a cationic biimidazole-based template in the construction of polymeric Cu–SCN networks has not been reported. Based on the considerations above, we chose CuSCN and 1,4-bis(2-methyl-1H-imidazol-1-yl)butane (bmimb) to carry out the reaction under solvothermal conditions, which eventually gave rise to catena-poly[2,2'-dimethyl-1,1'-(butane-1,4-diyl)bis(1H-imidazol-3-ium) [tetra-µ2-thiocyanato-κ4S:S;κ4S:N-dicopper(I)], (I), with an anionic {[Cu2(NCS)4]2-}n network and H2bmimb cations accommodated in the network cavities.

As shown in Fig. 1, the asymmetric unit of (I) contains one CuI cation and two crystallographically independent SCN- anions, and a 2,2'-dimethyl-1,1'-(butane-1,4-diyl)bis(1H-imidazol-3-ium) (H2bmimb) dication lying on an inversion centre. The coordination environment of the CuI cation can be described as a slightly distorted tetrahedron defined by one N and three S atoms from SCN- anions [Cu—S = 2.3165 (9)–2.4222 (9) Å and Cu—N = 1.952 (3) Å]. The Cu—S and Cu—N bond lengths fall within the range previously reported for CuSCN complexes (Lv et al., 2009; Deluzet et al., 2002; Rahal et al., 1997). The distortion of the tetrahedron can be indicated by the calculated value of the τ4 parameter (Yang et al., 2007) to describe the geometry of a four-coordinate metal system, which is 0.92 for Cu1 (for an ideal tetrahedron, τ4 = 1).

In (I), the SCN- anions show two kinds of binding modes, µ2-S:S and µ2-N:S. The µ2-S:S SCN- anions bind a pair of inversion-centre related CuI cations to form a [Cu2(NCS)2] subunit, in which the distance between the two CuI cations is 2.8676 (8) Å, close to the sum of the ionic radii (2.80 Å; Bondi, 1964), indicating a weak CuI···CuI interaction. As shown in Fig. 2, each [Cu2(NCS)2] subunit is connected to four others by four µ2-N:S SCN- anions, forming an infinite two-dimensional 44-sql network along the bc plane (Wells, 1997). The distance between the [Cu2(NCS)2] subunits is 7.859 (5) Å, which is comparable with the values observed in other reported {[Cu2(NCS)4]2-}n networks, for example in {(bpe)[Cu2(NCS)4]}n [9.55 Å; bpe = ?,?'-(ethane-1,2-diyl)dipyridinium [Please complete ligand name]; Niu et al., 2008] and {(biqpp)[Cu2(NCS)4]}n [7.28 Å; biqpp = ?,?'-(propane-1,3-diyl)diisoquinolinium [Please complete ligand name]; Song et al., 2012].

The H2bmimb cations, with an antiantianti configuration, are trapped in the network cavities. They thus act only for charge neutralization and do not coordinate to any metal centres. The two-dimensional 44-sql networks are packed into the resultant three-dimensional supramolecular framework through bmimb–SCN N—H···N hydrogen bonds.

The most outstanding feature of (I) is the rare polypseudorotaxane structure, consisting of the two-dimensional inorganic {[Cu2(NCS)4]2-}n network penetrated by the H2bmimb template cations. Along the a direction, each rhombus ring of the two-dimensional network is penetrated by H2bmimb cations (Fig. 3), leaving no space for solvent molecules. Heterocyclic cation-templated synthesis has been employed previously to construct Cu–SCN networks, but such rotaxane-like interlocking is rare because a rotaxanate interaction needs an ideal distance between the [Cu2(NCS)2] units in each rhombus molecular ring, neither too long nor too short [More details and a reference?].

In summary, polyrotaxane architectures consisting of a two-dimensional inorganic network perforated with organic molecules have rarely been reported, and thus (I) can be regarded as an unprecedented example of a polypseudorotaxane derived from the H2bmimb cation.

Related literature top

For related literature, see: Babich (1996); Bondi (1964); Cui et al. (2012); Deluzet et al. (2002); Domasevitch et al. (1999); Hao et al. (2010); Helgesson & Jagner (1991); Li et al. (2009); Lv et al. (2009); Moss et al. (1995); Niu et al. (2008); Peng et al. (2010); Rahal et al. (1997); Raston et al. (1979); Rusanova et al. (2000); Song et al. (2012); Wells (1997); Xu et al. (2006); Yang et al. (2007); Yoon et al. (2012); Zhou et al. (2012).

Experimental top

A mixture of CuSCN (12.1 mg, 0.1 mmol), bmimp (4.4 mg, 0.02 mmol) and N,N-dimethylformamide–acetonitrile (1:1 v:v, 1.5 ml) mixed solvent was sealed in a glass tube and heated to 413 K over a period of 10 h, kept at 413 K for 50 h and then cooled slowly to 303 K over a period of 13 h. Pale-yellow crystals of (I) were collected, washed with ethanol and dried in air (yield 75%).

Refinement top

All H atoms were generated geometrically and allowed to ride on their parent atoms in the riding-model approximation, with N—H = 0.86 Å, aromatic C—H = 0.93Å, methyl C—H = 0.97 Å and methylene C—H = 0.96 Å, and with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: APEX2 (Bruker,2005); cell refinement: APEX2 (Bruker,2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The structure of (I), showing the atom-numbering scheme and the coordination environment around the CuI centre. Displacement ellipsoids are drawn at the 50% probability level. The dashed line indicates hydrogen bonding. [Symmetry codes: (i) -x + 2, y - 1/2, -z + 1/2; (ii) -x + 2, -y + 1, -z + 1; (iii) -x, -y, -z + 1; (iv) x, -y + 3/2, z + 1/2.]
[Figure 2] Fig. 2. The two-dimensional network with 44-sql topology of (I), viewed along the a direction. (Colour key for the electronic version of the journal: Cu purple, C grey, S yellow and N blue.)
[Figure 3] Fig. 3. A schematic representation of the H2bmimb cation (highlighted in space-filling mode) penetrating the window of the two-dimensional 44-sql network. (Colour scheme as in Fig. 2.)
catena-Poly[2,2'-dimethyl-1,1'-(butane-1,4-diyl)bis(1H-imidazol-3-ium) [tetra-µ2-thiocyanato-κ4S:S;κ4S:N-dicopper(I)]] top
Crystal data top
(C12H20N4)[Cu2(NCS)4]F(000) = 588
Mr = 579.72Dx = 1.685 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3077 reflections
a = 9.6679 (8) Åθ = 2.7–27.5°
b = 9.7024 (8) ŵ = 2.25 mm1
c = 12.3648 (10) ÅT = 298 K
β = 99.969 (1)°Block, pale-yellow
V = 1142.33 (16) Å30.24 × 0.13 × 0.10 mm
Z = 4
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
2004 independent reflections
Radiation source: fine-focus sealed tube1752 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.028
ϕ and ω scansθmax = 25.0°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
h = 1111
Tmin = 0.615, Tmax = 0.806k = 611
5275 measured reflectionsl = 1214
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.123H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.084P)2 + 0.4244P]
where P = (Fo2 + 2Fc2)/3
2004 reflections(Δ/σ)max = 0.001
137 parametersΔρmax = 0.74 e Å3
0 restraintsΔρmin = 0.63 e Å3
Crystal data top
(C12H20N4)[Cu2(NCS)4]V = 1142.33 (16) Å3
Mr = 579.72Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.6679 (8) ŵ = 2.25 mm1
b = 9.7024 (8) ÅT = 298 K
c = 12.3648 (10) Å0.24 × 0.13 × 0.10 mm
β = 99.969 (1)°
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
2004 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
1752 reflections with I > 2σ(I)
Tmin = 0.615, Tmax = 0.806Rint = 0.028
5275 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.123H-atom parameters constrained
S = 1.06Δρmax = 0.74 e Å3
2004 reflectionsΔρmin = 0.63 e Å3
137 parameters
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 (Å2) top
xyzUiso*/Ueq
Cu11.03138 (5)0.47548 (5)0.39248 (3)0.0416 (2)
S10.83468 (8)0.60220 (8)0.43440 (6)0.0329 (2)
S21.19361 (9)0.61379 (10)0.32662 (7)0.0443 (3)
C10.7063 (4)0.4857 (4)0.4123 (3)0.0394 (8)
C21.1036 (3)0.7332 (4)0.2505 (2)0.0331 (7)
C30.3087 (4)0.1792 (5)0.3477 (3)0.0538 (10)
H3A0.27210.09470.31380.065*
H3B0.38100.21370.31060.065*
H3C0.23450.24590.34290.065*
C40.3680 (3)0.1536 (3)0.4644 (2)0.0324 (7)
C50.5005 (4)0.1670 (4)0.6280 (3)0.0414 (8)
H50.57090.19450.68500.050*
C60.4025 (3)0.0721 (4)0.6323 (2)0.0366 (7)
H60.39120.02100.69380.044*
C70.1967 (4)0.0274 (4)0.5013 (3)0.0421 (8)
H7A0.20930.10940.54680.051*
H7B0.18790.05600.42530.051*
C80.0634 (3)0.0459 (3)0.5178 (3)0.0354 (7)
H8A0.05290.13040.47520.042*
H8B0.06950.07000.59460.042*
N10.6152 (4)0.4078 (4)0.3963 (3)0.0623 (11)
N21.0444 (3)0.8189 (3)0.1978 (3)0.0479 (8)
N30.4766 (3)0.2169 (3)0.5216 (2)0.0366 (6)
H30.52550.27970.49670.044*
N40.3210 (3)0.0627 (3)0.5299 (2)0.0300 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0425 (3)0.0401 (3)0.0418 (3)0.00673 (19)0.0058 (2)0.00521 (17)
S10.0323 (5)0.0315 (4)0.0339 (4)0.0004 (3)0.0028 (3)0.0014 (3)
S20.0331 (5)0.0501 (5)0.0492 (5)0.0024 (4)0.0059 (4)0.0200 (4)
C10.036 (2)0.054 (2)0.0261 (15)0.0010 (18)0.0005 (14)0.0070 (14)
C20.0314 (16)0.0392 (18)0.0280 (14)0.0063 (15)0.0034 (12)0.0016 (14)
C30.050 (2)0.077 (3)0.0339 (17)0.014 (2)0.0056 (16)0.0059 (18)
C40.0291 (16)0.0363 (17)0.0336 (15)0.0034 (14)0.0100 (13)0.0006 (14)
C50.0333 (17)0.053 (2)0.0365 (16)0.0022 (17)0.0037 (14)0.0101 (16)
C60.0333 (17)0.047 (2)0.0300 (15)0.0014 (16)0.0065 (13)0.0016 (14)
C70.0331 (18)0.039 (2)0.053 (2)0.0068 (15)0.0057 (15)0.0095 (16)
C80.0307 (17)0.0331 (16)0.0420 (17)0.0040 (14)0.0053 (14)0.0027 (14)
N10.048 (2)0.090 (3)0.0446 (17)0.034 (2)0.0041 (14)0.0094 (18)
N20.0467 (18)0.0448 (18)0.0504 (17)0.0015 (15)0.0030 (14)0.0135 (15)
N30.0291 (14)0.0387 (15)0.0446 (15)0.0042 (13)0.0130 (12)0.0014 (13)
N40.0216 (12)0.0329 (13)0.0352 (13)0.0034 (11)0.0043 (10)0.0056 (11)
Geometric parameters (Å, º) top
Cu1—N2i1.952 (3)C4—N41.330 (4)
Cu1—S22.3165 (9)C5—C61.329 (5)
Cu1—S12.3954 (9)C5—N31.383 (4)
Cu1—S1ii2.4222 (9)C5—H50.9300
Cu1—Cu1ii2.8676 (8)C6—N41.374 (4)
S1—C11.666 (4)C6—H60.9300
S1—Cu1ii2.4222 (9)C7—N41.479 (4)
S2—C21.643 (3)C7—C81.516 (5)
C1—N11.151 (5)C7—H7A0.9700
C2—N21.146 (4)C7—H7B0.9700
C3—C41.478 (4)C8—C8iii1.517 (6)
C3—H3A0.9600C8—H8A0.9700
C3—H3B0.9600C8—H8B0.9700
C3—H3C0.9600N3—H30.8600
C4—N31.313 (4)
N2i—Cu1—S2117.38 (10)C6—C5—N3106.1 (3)
N2i—Cu1—S1106.85 (10)C6—C5—H5126.9
S2—Cu1—S1112.95 (4)N3—C5—H5126.9
N2i—Cu1—S1ii110.71 (10)C5—C6—N4107.9 (3)
S2—Cu1—S1ii101.54 (3)C5—C6—H6126.0
S1—Cu1—S1ii106.94 (3)N4—C6—H6126.0
N2i—Cu1—Cu1ii122.74 (10)N4—C7—C8111.4 (3)
S2—Cu1—Cu1ii119.65 (3)N4—C7—H7A109.3
S1—Cu1—Cu1ii53.90 (2)C8—C7—H7A109.3
S1ii—Cu1—Cu1ii53.04 (2)N4—C7—H7B109.3
C1—S1—Cu1102.29 (13)C8—C7—H7B109.3
C1—S1—Cu1ii101.70 (12)H7A—C7—H7B108.0
Cu1—S1—Cu1ii73.06 (3)C7—C8—C8iii110.4 (3)
C2—S2—Cu1106.60 (11)C7—C8—H8A109.6
N1—C1—S1178.3 (4)C8iii—C8—H8A109.6
N2—C2—S2177.9 (3)C7—C8—H8B109.6
C4—C3—H3A109.5C8iii—C8—H8B109.6
C4—C3—H3B109.5H8A—C8—H8B108.1
H3A—C3—H3B109.5C2—N2—Cu1iv172.3 (3)
C4—C3—H3C109.5C4—N3—C5109.6 (3)
H3A—C3—H3C109.5C4—N3—H3125.2
H3B—C3—H3C109.5C5—N3—H3125.2
N3—C4—N4107.9 (3)C4—N4—C6108.4 (3)
N3—C4—C3125.9 (3)C4—N4—C7126.6 (3)
N4—C4—C3126.2 (3)C6—N4—C7124.9 (3)
Symmetry codes: (i) x+2, y1/2, z+1/2; (ii) x+2, y+1, z+1; (iii) x, y, z+1; (iv) x+2, y+1/2, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3···N10.862.052.889 (4)164

Experimental details

Crystal data
Chemical formula(C12H20N4)[Cu2(NCS)4]
Mr579.72
Crystal system, space groupMonoclinic, P21/c
Temperature (K)298
a, b, c (Å)9.6679 (8), 9.7024 (8), 12.3648 (10)
β (°) 99.969 (1)
V3)1142.33 (16)
Z4
Radiation typeMo Kα
µ (mm1)2.25
Crystal size (mm)0.24 × 0.13 × 0.10
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2005)
Tmin, Tmax0.615, 0.806
No. of measured, independent and
observed [I > 2σ(I)] reflections
5275, 2004, 1752
Rint0.028
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.123, 1.06
No. of reflections2004
No. of parameters137
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.74, 0.63

Computer programs: APEX2 (Bruker,2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2008), publCIF (Westrip, 2010).

Selected geometric parameters (Å, º) top
Cu1—N2i1.952 (3)Cu1—S1ii2.4222 (9)
Cu1—S22.3165 (9)Cu1—Cu1ii2.8676 (8)
Cu1—S12.3954 (9)
N2i—Cu1—S2117.38 (10)N2i—Cu1—S1ii110.71 (10)
N2i—Cu1—S1106.85 (10)S2—Cu1—S1ii101.54 (3)
S2—Cu1—S1112.95 (4)S1—Cu1—S1ii106.94 (3)
Symmetry codes: (i) x+2, y1/2, z+1/2; (ii) x+2, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3···N10.862.052.889 (4)164.0
 

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