Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270113011153/wq3033sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270113011153/wq3033Isup2.hkl |
CCDC reference: 845880
To a solution of Co(NO3)2.6H2O (58.2 mg, 0.2 mmol) and BTB (38.5 mg, 0.2 mmol) in CH3CN (5 ml) was added dropwise a solution of KSCN (38.9 mg, 0.4 mmol) in water (10 ml) with gentle stirring. After several weeks, red blocks suitable for X-ray analysis were obtained (yield 52.7%, based on BTB). Analysis, calculated for C18H28CoN14O2S2: C 36.30, H 4.74, N 32.93%; found: C 36.41, H 4.76, N 33.01%. IR (KBr, ν, cm-1): 1278 (m), 1576 (s), 2108 (s), 2073 (s), 3329 (m).
C-bound H atoms were placed in calculated positions and treated using a riding-model approximation, with C—H = 0.93 (triazole) or 0.97 Å (methylene) and with Uiso(H) = 1.2Ueq(C). Water H atoms were located in a difference Fourier map and refined with a restraint of O—H = 0.83(s.u.?) Å and with Uiso(H) = 1.5Ueq(O).
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
[Co(NCS)2(C8H12N6)2]·2H2O | Z = 1 |
Mr = 595.61 | F(000) = 309 |
Triclinic, P1 | Dx = 1.485 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.7131 (11) Å | Cell parameters from 2719 reflections |
b = 9.2600 (13) Å | θ = 2.2–22.8° |
c = 10.2716 (15) Å | µ = 0.85 mm−1 |
α = 113.988 (2)° | T = 293 K |
β = 91.893 (3)° | Block, red |
γ = 94.895 (2)° | 0.21 × 0.20 × 0.19 mm |
V = 665.97 (17) Å3 |
Bruker SMART CCD area-detector diffractometer | 2440 independent reflections |
Radiation source: fine-focus sealed tube | 2197 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.103 |
ϕ and ω scans | θmax = 25.4°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | h = −9→9 |
Tmin = 0.837, Tmax = 0.851 | k = −11→10 |
3422 measured reflections | l = −9→12 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.048 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.123 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | w = 1/[σ2(Fo2) + (0.070P)2 + 0.2P] where P = (Fo2 + 2Fc2)/3 |
2440 reflections | (Δ/σ)max < 0.001 |
175 parameters | Δρmax = 0.63 e Å−3 |
3 restraints | Δρmin = −0.62 e Å−3 |
[Co(NCS)2(C8H12N6)2]·2H2O | γ = 94.895 (2)° |
Mr = 595.61 | V = 665.97 (17) Å3 |
Triclinic, P1 | Z = 1 |
a = 7.7131 (11) Å | Mo Kα radiation |
b = 9.2600 (13) Å | µ = 0.85 mm−1 |
c = 10.2716 (15) Å | T = 293 K |
α = 113.988 (2)° | 0.21 × 0.20 × 0.19 mm |
β = 91.893 (3)° |
Bruker SMART CCD area-detector diffractometer | 2440 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | 2197 reflections with I > 2σ(I) |
Tmin = 0.837, Tmax = 0.851 | Rint = 0.103 |
3422 measured reflections |
R[F2 > 2σ(F2)] = 0.048 | 3 restraints |
wR(F2) = 0.123 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | Δρmax = 0.63 e Å−3 |
2440 reflections | Δρmin = −0.62 e Å−3 |
175 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Co1 | 0.5000 | 0.5000 | 0.0000 | 0.02759 (19) | |
S1 | 0.79068 (14) | 0.08862 (13) | 0.04577 (12) | 0.0701 (3) | |
N1 | 0.4094 (3) | 0.5355 (3) | 0.2037 (2) | 0.0352 (5) | |
N2 | 0.3565 (3) | 0.6538 (3) | 0.4339 (3) | 0.0435 (6) | |
N3 | 0.3079 (3) | 0.4953 (3) | 0.3821 (3) | 0.0407 (5) | |
N4 | 0.7507 (3) | 0.6156 (3) | 0.1056 (2) | 0.0329 (5) | |
N5 | 1.0118 (3) | 0.6616 (3) | 0.2241 (3) | 0.0514 (7) | |
N6 | 0.9583 (3) | 0.7986 (3) | 0.2286 (2) | 0.0364 (5) | |
N7 | 0.5748 (3) | 0.2793 (3) | −0.0191 (3) | 0.0402 (5) | |
C1 | 0.4167 (4) | 0.6720 (3) | 0.3229 (3) | 0.0395 (6) | |
H1 | 0.4605 | 0.7702 | 0.3260 | 0.047* | |
C2 | 0.3399 (4) | 0.4279 (3) | 0.2462 (3) | 0.0406 (6) | |
H2 | 0.3168 | 0.3198 | 0.1884 | 0.049* | |
C3 | 0.2280 (4) | 0.4210 (4) | 0.4700 (4) | 0.0523 (8) | |
H3A | 0.2762 | 0.4781 | 0.5680 | 0.063* | |
H3B | 0.2575 | 0.3126 | 0.4368 | 0.063* | |
C4 | 0.0317 (4) | 0.4190 (4) | 0.4660 (3) | 0.0473 (7) | |
H4A | −0.0151 | 0.3680 | 0.3672 | 0.057* | |
H4B | −0.0143 | 0.3549 | 0.5144 | 0.057* | |
C5 | 1.0851 (4) | 0.9910 (3) | 0.4650 (3) | 0.0411 (6) | |
H5A | 1.1411 | 0.9079 | 0.4790 | 0.049* | |
H5B | 1.1613 | 1.0894 | 0.5117 | 0.049* | |
C6 | 1.0645 (4) | 0.9504 (4) | 0.3058 (3) | 0.0467 (7) | |
H6A | 1.0102 | 1.0337 | 0.2909 | 0.056* | |
H6B | 1.1788 | 0.9452 | 0.2684 | 0.056* | |
C7 | 0.8834 (4) | 0.5563 (3) | 0.1485 (3) | 0.0465 (7) | |
H7 | 0.8836 | 0.4484 | 0.1261 | 0.056* | |
C8 | 0.8043 (4) | 0.7683 (3) | 0.1582 (3) | 0.0399 (6) | |
H8 | 0.7419 | 0.8447 | 0.1473 | 0.048* | |
C9 | 0.6606 (4) | 0.1986 (3) | 0.0080 (3) | 0.0375 (6) | |
O1 | 0.5035 (6) | 0.9225 (5) | 0.6903 (4) | 0.1209 (15) | |
H1A | 0.430 (8) | 0.859 (8) | 0.629 (6) | 0.181* | |
H1B | 0.479 (10) | 0.934 (9) | 0.771 (3) | 0.181* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Co1 | 0.0293 (3) | 0.0259 (3) | 0.0267 (3) | 0.00047 (18) | −0.00347 (18) | 0.01083 (19) |
S1 | 0.0788 (7) | 0.0725 (6) | 0.0840 (7) | 0.0313 (5) | 0.0058 (5) | 0.0531 (6) |
N1 | 0.0339 (11) | 0.0381 (12) | 0.0328 (12) | 0.0025 (9) | 0.0023 (9) | 0.0142 (9) |
N2 | 0.0400 (13) | 0.0503 (14) | 0.0346 (12) | −0.0009 (11) | −0.0010 (10) | 0.0130 (10) |
N3 | 0.0367 (12) | 0.0496 (14) | 0.0406 (13) | 0.0031 (11) | 0.0036 (10) | 0.0238 (11) |
N4 | 0.0316 (11) | 0.0325 (11) | 0.0319 (11) | −0.0006 (9) | −0.0052 (9) | 0.0118 (9) |
N5 | 0.0422 (14) | 0.0414 (14) | 0.0583 (16) | 0.0014 (11) | −0.0170 (12) | 0.0102 (12) |
N6 | 0.0380 (12) | 0.0360 (12) | 0.0298 (11) | −0.0068 (10) | −0.0048 (9) | 0.0105 (9) |
N7 | 0.0423 (13) | 0.0315 (12) | 0.0464 (13) | 0.0043 (10) | −0.0034 (10) | 0.0162 (10) |
C1 | 0.0365 (14) | 0.0410 (15) | 0.0369 (14) | −0.0005 (12) | 0.0001 (11) | 0.0131 (12) |
C2 | 0.0409 (15) | 0.0383 (15) | 0.0412 (15) | 0.0029 (12) | 0.0040 (12) | 0.0152 (12) |
C3 | 0.0497 (18) | 0.068 (2) | 0.0590 (19) | 0.0121 (16) | 0.0142 (14) | 0.0450 (17) |
C4 | 0.0470 (17) | 0.0527 (18) | 0.0503 (17) | 0.0040 (14) | 0.0104 (13) | 0.0291 (14) |
C5 | 0.0415 (15) | 0.0366 (15) | 0.0372 (14) | −0.0085 (12) | −0.0097 (12) | 0.0103 (11) |
C6 | 0.0502 (17) | 0.0410 (16) | 0.0397 (16) | −0.0181 (13) | −0.0075 (13) | 0.0126 (12) |
C7 | 0.0449 (16) | 0.0319 (14) | 0.0520 (18) | 0.0035 (12) | −0.0141 (13) | 0.0080 (12) |
C8 | 0.0440 (15) | 0.0336 (14) | 0.0420 (15) | −0.0023 (12) | −0.0093 (12) | 0.0178 (12) |
C9 | 0.0425 (15) | 0.0325 (14) | 0.0372 (14) | 0.0000 (12) | 0.0012 (11) | 0.0148 (11) |
O1 | 0.117 (3) | 0.126 (3) | 0.062 (2) | −0.040 (2) | 0.005 (2) | −0.010 (2) |
Co1—N7i | 2.105 (2) | N7—C9 | 1.147 (3) |
Co1—N7 | 2.105 (2) | C1—H1 | 0.9300 |
Co1—N1 | 2.134 (2) | C2—H2 | 0.9300 |
Co1—N1i | 2.134 (2) | C3—C4 | 1.511 (4) |
Co1—N4 | 2.151 (2) | C3—H3A | 0.9700 |
Co1—N4i | 2.151 (2) | C3—H3B | 0.9700 |
S1—C9 | 1.632 (3) | C4—C4ii | 1.508 (6) |
N1—C2 | 1.323 (4) | C4—H4A | 0.9700 |
N1—C1 | 1.350 (4) | C4—H4B | 0.9700 |
N2—C1 | 1.312 (4) | C5—C5iii | 1.508 (6) |
N2—N3 | 1.355 (4) | C5—C6 | 1.521 (4) |
N3—C2 | 1.319 (4) | C5—H5A | 0.9700 |
N3—C3 | 1.463 (4) | C5—H5B | 0.9700 |
N4—C8 | 1.314 (3) | C6—H6A | 0.9700 |
N4—C7 | 1.345 (3) | C6—H6B | 0.9700 |
N5—C7 | 1.305 (4) | C7—H7 | 0.9300 |
N5—N6 | 1.351 (3) | C8—H8 | 0.9300 |
N6—C8 | 1.316 (3) | O1—H1A | 0.826 (10) |
N6—C6 | 1.460 (3) | O1—H1B | 0.827 (10) |
N7i—Co1—N7 | 180.0 | N3—C2—H2 | 124.8 |
N7i—Co1—N1 | 91.24 (9) | N1—C2—H2 | 124.8 |
N7—Co1—N1 | 88.76 (9) | N3—C3—C4 | 112.9 (2) |
N7i—Co1—N1i | 88.76 (9) | N3—C3—H3A | 109.0 |
N7—Co1—N1i | 91.24 (9) | C4—C3—H3A | 109.0 |
N1—Co1—N1i | 180.00 | N3—C3—H3B | 109.0 |
N7i—Co1—N4 | 89.71 (9) | C4—C3—H3B | 109.0 |
N7—Co1—N4 | 90.29 (9) | H3A—C3—H3B | 107.8 |
N1—Co1—N4 | 88.55 (8) | C4ii—C4—C3 | 114.4 (3) |
N1i—Co1—N4 | 91.45 (8) | C4ii—C4—H4A | 108.7 |
N7i—Co1—N4i | 90.29 (9) | C3—C4—H4A | 108.7 |
N7—Co1—N4i | 89.71 (9) | C4ii—C4—H4B | 108.7 |
N1—Co1—N4i | 91.45 (8) | C3—C4—H4B | 108.7 |
N1i—Co1—N4i | 88.55 (8) | H4A—C4—H4B | 107.6 |
N4—Co1—N4i | 180.0 | C5iii—C5—C6 | 113.6 (3) |
C2—N1—C1 | 103.0 (2) | C5iii—C5—H5A | 108.9 |
C2—N1—Co1 | 128.38 (19) | C6—C5—H5A | 108.9 |
C1—N1—Co1 | 128.58 (19) | C5iii—C5—H5B | 108.9 |
C1—N2—N3 | 103.0 (2) | C6—C5—H5B | 108.9 |
C2—N3—N2 | 109.5 (2) | H5A—C5—H5B | 107.7 |
C2—N3—C3 | 128.4 (3) | N6—C6—C5 | 111.3 (2) |
N2—N3—C3 | 122.1 (3) | N6—C6—H6A | 109.4 |
C8—N4—C7 | 102.3 (2) | C5—C6—H6A | 109.4 |
C8—N4—Co1 | 127.55 (18) | N6—C6—H6B | 109.4 |
C7—N4—Co1 | 129.82 (18) | C5—C6—H6B | 109.4 |
C7—N5—N6 | 102.5 (2) | H6A—C6—H6B | 108.0 |
C8—N6—N5 | 109.3 (2) | N5—C7—N4 | 114.9 (3) |
C8—N6—C6 | 129.6 (2) | N5—C7—H7 | 122.5 |
N5—N6—C6 | 121.0 (2) | N4—C7—H7 | 122.5 |
C9—N7—Co1 | 154.4 (2) | N4—C8—N6 | 110.9 (2) |
N2—C1—N1 | 114.0 (3) | N4—C8—H8 | 124.5 |
N2—C1—H1 | 123.0 | N6—C8—H8 | 124.5 |
N1—C1—H1 | 123.0 | N7—C9—S1 | 177.3 (3) |
N3—C2—N1 | 110.4 (3) | H1A—O1—H1B | 111 (3) |
N7i—Co1—N1—C2 | 147.1 (2) | N4—Co1—N7—C9 | 16.3 (5) |
N7—Co1—N1—C2 | −32.9 (2) | N4i—Co1—N7—C9 | −163.7 (5) |
N4—Co1—N1—C2 | −123.2 (2) | N3—N2—C1—N1 | 0.1 (3) |
N4i—Co1—N1—C2 | 56.8 (2) | C2—N1—C1—N2 | 0.0 (3) |
N7i—Co1—N1—C1 | −36.5 (2) | Co1—N1—C1—N2 | −177.09 (18) |
N7—Co1—N1—C1 | 143.5 (2) | N2—N3—C2—N1 | 0.2 (3) |
N4—Co1—N1—C1 | 53.2 (2) | C3—N3—C2—N1 | 178.3 (3) |
N4i—Co1—N1—C1 | −126.8 (2) | C1—N1—C2—N3 | −0.1 (3) |
C1—N2—N3—C2 | −0.2 (3) | Co1—N1—C2—N3 | 176.99 (17) |
C1—N2—N3—C3 | −178.4 (3) | C2—N3—C3—C4 | −89.8 (4) |
N7i—Co1—N4—C8 | 2.4 (2) | N2—N3—C3—C4 | 88.1 (4) |
N7—Co1—N4—C8 | −177.6 (2) | N3—C3—C4—C4ii | −66.7 (4) |
N1—Co1—N4—C8 | −88.8 (2) | C8—N6—C6—C5 | 114.9 (3) |
N1i—Co1—N4—C8 | 91.2 (2) | N5—N6—C6—C5 | −63.6 (4) |
N7i—Co1—N4—C7 | 174.3 (3) | C5iii—C5—C6—N6 | −61.6 (4) |
N7—Co1—N4—C7 | −5.7 (3) | N6—N5—C7—N4 | −0.7 (4) |
N1—Co1—N4—C7 | 83.0 (3) | C8—N4—C7—N5 | 0.6 (4) |
N1i—Co1—N4—C7 | −97.0 (3) | Co1—N4—C7—N5 | −172.8 (2) |
C7—N5—N6—C8 | 0.5 (3) | C7—N4—C8—N6 | −0.3 (3) |
C7—N5—N6—C6 | 179.2 (3) | Co1—N4—C8—N6 | 173.32 (18) |
N1—Co1—N7—C9 | −72.2 (5) | N5—N6—C8—N4 | −0.1 (3) |
N1i—Co1—N7—C9 | 107.8 (5) | C6—N6—C8—N4 | −178.7 (3) |
Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x, −y+1, −z+1; (iii) −x+2, −y+2, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1A···N2 | 0.83 (1) | 2.14 (4) | 2.899 (4) | 152 (7) |
O1—H1B···S1iv | 0.83 (1) | 2.90 (4) | 3.620 (4) | 147 (7) |
C6—H6B···O1iii | 0.97 | 2.58 | 3.430 (5) | 146 |
C8—H8···S1v | 0.93 | 2.85 | 3.602 (3) | 139 |
Symmetry codes: (iii) −x+2, −y+2, −z+1; (iv) −x+1, −y+1, −z+1; (v) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | [Co(NCS)2(C8H12N6)2]·2H2O |
Mr | 595.61 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 7.7131 (11), 9.2600 (13), 10.2716 (15) |
α, β, γ (°) | 113.988 (2), 91.893 (3), 94.895 (2) |
V (Å3) | 665.97 (17) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 0.85 |
Crystal size (mm) | 0.21 × 0.20 × 0.19 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2000) |
Tmin, Tmax | 0.837, 0.851 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3422, 2440, 2197 |
Rint | 0.103 |
(sin θ/λ)max (Å−1) | 0.602 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.048, 0.123, 1.01 |
No. of reflections | 2440 |
No. of parameters | 175 |
No. of restraints | 3 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.63, −0.62 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXTL (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 1999).
Co1—N7 | 2.105 (2) | Co1—N4 | 2.151 (2) |
Co1—N1 | 2.134 (2) | ||
N7—Co1—N1 | 88.76 (9) | N1—Co1—N4 | 88.55 (8) |
N7—Co1—N4 | 90.29 (9) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1A···N2 | 0.826 (10) | 2.14 (4) | 2.899 (4) | 152 (7) |
O1—H1B···S1i | 0.827 (10) | 2.90 (4) | 3.620 (4) | 147 (7) |
C6—H6B···O1ii | 0.97 | 2.58 | 3.430 (5) | 145.8 |
C8—H8···S1iii | 0.93 | 2.85 | 3.602 (3) | 138.7 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+2, −y+2, −z+1; (iii) x, y+1, z. |
Considerable attention has been paid to the design, synthesis and characterization of metal–organic framework (MOF) materials over the past decade, not only because of their intriguing structures but also for their potential utility in nonlinear optics, magnetism, gas storage, ion exchange, catalysis etc. (Allendorf et al., 2009; Li et al., 2009; Murray et al., 2009). The most effective and facile approach to MOFs is to utilize multipyridine ligands to link metal ions (Liu, Kravtsov & Eddaoudi, 2008 or Liu, Liu et al., 2008 ?; Su et al., 2010). The 1,2,4-triazole ligand has been widely used to build MOFs, due to its excellent coordinating ability and large conjugated system (Megger et al., 2010; Cheng et al., 2011). On the basis of the relative orientation of its –CH2– groups, 1,4-bis(1,2,4-triazol-1-yl)butane (BTB) can adopt different conformations compared with the corresponding 1,2,4-triazole ligand (Liu, Kravtsov & Eddaoudi, 2008 or Liu, Liu et al., 2008 ?; Wang et al., 2008, 2011; Zhu et al., 2009). Here, we have used a combination of BTB and thiocyanate (SCN-) to generate a new two-dimensional CoII coordination complex, {[Co(NCS)2(BTB)2].2H2O}n, (I).
Complex (I) (Fig. 1) crystallizes in the triclinic space group P1, with an asymmetric unit consisting of a divalent CoII cation, two halves of two crystallographically distinct BTB ligands (BTB-A contains atoms N1–N3/C1–C4 and BTB-B contains atoms N4–N6/C5–C8), one N-bound thiocyanate ligand and one aolvent water molecule. Atom Co1 possesses a distorted {CoN6} octahedral geometry, with the equatorial positions taken up by triazole N atoms from four different BTB ligands. The axial positions are occupied by thiocyanate N atoms. The Co—N bond lengths [2.105 (2)–2.151 (2) Å] are comparable with the corresponding values found in other CoII complexes (Tian et al., 2011; Zhang et al., 2012). The key bond lengths and angles are listed in Table 2. The thiocyanate ligands are almost perfectly linear [S1—C9—N7 = 177.3 (3)°], but adopt a significantly bent coordination at the CoII cation [C9—N7—Co1 = 154.4 (2)°].
Each CoII cation is linked covalently to four others through the distal donors of the tethering BTB ligands, forming neutral (4,4)-topology two-dimensional rhomboid grid layer motifs, which are coincident with the (121) crystal planes (Fig. 2). The Co···Co distances through the crystallographically distinct ligands BTB-A and BTB-B are 13.0473 (14) and 12.4894 (11) Å, respectively. These differences reflect small conformational variances within the distinct BTB ligands. BTB-A shows a gauche–trans–gauche conformation (torsion angles = 67.0, 180.0 and 67.0°), while BTB-B adopts a gauche–trans–gauche conformation (torsion angles = 61.4, 180.0 and 61.4°). These rhomboid subunits are noticeably pinched, with Co—Co—Co angles of ~94.7 and ~85.3°, respectively. As determined by through-space Co···Co distances, the apertures within the grid measure 17.30 × 18.79 Å.
The trans-disposed thiocyanate ligands project into the interlamellar regions (Fig. 2). Interlayer interaction is fostered by weak C—H···S and O—H···S interactions [C8···S1 = 3.602 (3) Å and O1···S1 = 3.620 (4) Å]. The molecules of (I) are linked through O1—H1A···N2 and C6—H6B···O1 hydrogen-bonding interactions, constructing a three-dimensional supramolecular architecture (Fig. 3). More interestingly, atom O1 acts as a donor in two hydrogen-bond interactions involving atom S1 and triazole atom N2. Approximately 7.5% of the crystal volume is occupied by solvent molecules, with a volume of ~49.9 Å3 in each unit cell (660.0 Å3) (PLATON; Spek, 2009). However, there are no significant difference electron-density features in these regions.
Variable-temperature magnetic measurements were performed on polycrystalline samples of complex (I) in the range of 1.8–300 K in a field of 2 kOe in the form of χMT versus T (Fig. 4). At room temperature, the χMT value is 2.54 cm3 K mol-1, which is much larger than the spin-only value of 1.88 cm3 K mol-1 for isolated CoII systems assuming g = 2, which can be attributed to the significant orbital contribution of the octahedral CoII cations. As the temperature decreases, the χMT value gradually decreases and reaches a minimum of 1.66 cm3 K mol-1 at 1.8 K, which is mainly ascribed to the spin-orbit coupling effects (Plater et al., 1999).
To investigate the magnetic couple nature between CoII cations, the simple phenomenological equation and the fitting method which, can be written as
χMT = Aexp(-E1/kT) + Bexp(-E2/kT)
could be used for roughly estimating the spin-orbit coupling and the magnetic exchange of complex (I) (Rabu et al., 2001; Rueff et al., 2001, 2002). The best-fitting results (for the solid) are: A + B = 2.73 cm3 K mol-1, E1/k = 53.2 K, corresponding to one CoII cation, and -E2/k = -0.15 K (R = 2.4 × 10-4) (Fig. 4), indicating the weak antiferromagnetic coupling between CoII cations (J = -0.3 K). Compared with the spin-orbit coupling, the J value is very small and can be neglected.
In summary, using BTB and KSCN, we isolated {[Co(NCS)2(BTB)2].2H2O}n, (I), which was characterized by single-crystal X-ray diffraction, elemental analysis and IR spectroscopy. Magnetic investigations show that weak antiferromagnetic coupling exists between CoII cations in complex (I).