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Z.-H. Zhang et al. / Journal of Solid State Chemistry 238 (2016) 217–222
amyl; X¼Clꢀ, Iꢀ) were refluxed with the distilled 1-methylimi-
dazole to give the two kinds of eight ILs. The ILs were washed with
ethyl acetate, and then dried under a vacuum at least for 10 h
([EMI]Cl: white solid, [PMI]Cl: colorless oil, [BMI]Cl: white solid,
[AMI]Cl: colorless oil, [EMI]I: yellow solid, [PMI]I: yellow oil, [BMI]
I: yellow oil, [PMI]I: yellow oil). Elemental analysis of C, H and N
was carried out on a Vario EL III elemental analyzer. FT-IR spectra
were collected from KBr pellets (Aldrich,499%, FT-IR grade) with
a Bruker Tensor 27 FT-IR spectrometer in the range of 4000–
400 cm–1. TGA were carried out in N2 atmosphere on a SDT Q600
V8.3 Build 101 instrument with a heating rate of 10 °C ꢁ minꢀ1 and
a N2 flow rate of 20 cm3 ꢁ minꢀ1. PXRD data for the materials were
collected at ambient temperature with a Rigaku D/Max–3c (Japan)
diffractometer (Cu-Kα1,2 X-radiation, λ1¼1.540598 Å and
λ2¼1.544426 Å), equipped with an X'Celerator detector and a
flatplate sample holder in a Bragg–Brentano para-focusing optics
configuration (40 kV, 50 mA). Intensity data were collected by the
step counting method (step being 0.02°) in continuous mode in
(calcd): C, 38.95(38.90); H, 3.41(3.26); N, 4.85(4.77).
[BMI]2[Co3(BDC)3I2] (7). 1.0 mmol, 0.2911 g Co(NO3)2 ꢁ 6H2O and
0.50 mmol, 0.0836 g H2BDC mixed with 1.0 mL (ca. 1.52 g) [BMI]I.
IR data (in KBr, cmꢀ1) for 7: 3581(w), 3384(w), 3141(m), 3102(m),
1592(s), 1492(m), 1387(s), 1302(s), 1167(m), 1014(m), 890(w), 819
(s), 740(s), 554(s). Elemental analysis (%), Found (calcd): C, 39.93
(40.06); H, 3.40(3.36); N, 4.74(4.67).
[AMI]2[Co3(BDC)3I2] (8). 1.0 mmol, 0.2915 g Co(NO3)2 ꢁ 6H2O and
0.50 mmol, 0.0834 g H2BDC mixed with 1.2 mL (ca. 1.83 g) [AMI]I.
IR data (in KBr, cmꢀ1) for 8: 3591(w), 3149(m), 3102(m), 2952(m),
1600(s), 1500(m), 1388(s), 1301(s), 1166(m), 1007(m), 871(w), 831
(s), 740(s), 628(w), 540(s). Elemental analysis (%), Found (calcd): C,
41.28(41.03); H, 3.87(3.77); N, 4.63(4.56).
2.3. Single crystal X-ray diffraction
Single crystals of compounds 1–8 were manually harvested
from crystallisation vials and mounted on Hampton Research
CryoLoops using FOMBLIN Y perfluoropolyether vacuum oil (LVAC
25/6, purchased from Aldrich) [23] with the help of a Stemi 2000
stereomicroscope equipped with Carl Zeiss lenses. Data were col-
lected on a Rigaku Mercury CCD diffractometer equipped with a
the range of 5r2θr60°. Fluorescence spectra were acquired on a
Hitachi F-4600 fluorescence spectrophotometer with the excita-
tion and emission slits setted to 5 nm.
2.2. Synthesis of the compounds
graphite-monochromated Mo-K
(2) Kolpotocheirodon the intensity data were collected by the
α
radiation (
λ¼0.71073 Å) at 293
ω
Synthesis of [EMI]2[Co3(BDC)3Cl2] (1). 2.0 mmol, 0.5825 g Co
(NO3)2 ꢁ 6H2O and 0.50 mmol, 0.0831 gH2BDC were placed in a
crystallisation vial placed in a 25 mL teflon-lined stainless-steel
autoclave mixed with 1.005 g [EMI]Cl. The mixture was kept inside
the furnace at 160 °C for 5 days, and then naturally cooled to
ambient temperature. The blue crystals of 1 suitable for single
crystal X-ray diffraction were collected after soak clearing with
acetone. IR data (in KBr, cm–1) for 1: 3703(w), 3325(w), 3145(m),
3097(s), 2989(m), 1583(s), 1383(s), 1306(m), 1167(s), 1018(w), 825
(m), 740(s), 624(w), 557(m). Elemental analysis (%), Found (calcd):
C, 45.05(44.93); H, 3.31(3.56); N, 5.75(5.82).
Synthesis of compounds 2–8. Compounds 2–8 were synthesized
from the similar preparation process as described in compound 1.
[PMI]2[Co3(BDC)3Cl2] (2): 2.5 mmol, 0.7275 g Co(NO3)2 ꢁ 6H2O
and 0.50 mmol, 0.0833 g H2BDC mixed with 0.8 mL (ca. 0.93 g)
[PMI]Cl. IR data (in KBr, cmꢀ1) for 2: 3660(w), 3138(w), 3082(w),
2966(w), 1601(s), 1389(s), 1308(s), 1166(m), 1014(w), 825(m), 744
(s), 557(m). Elemental analysis (%), Found (calcd): C, 46.05(46.08);
H, 3.91(3.87); N, 5.69(5.66).
scan technique and were reduced using CrystalClear program. [24]
The crystal structures of compounds 1–8 were solved by direct
method using SHELXTL™ package of crystallographic software
[25] and refined by fullmatrix least-squares technique on F2. All
non-hydrogen atoms were refined anisotropically. Hydrogen
atoms were located at geometrically calculated positions to their
carrier atoms and refined with isotropic thermal parameters in-
cluded in the final stage of the refinement. The summaries of the
structural determination and refinement for 1-8 are listed in
Supporting Information (Tables 1 and 2). The selected bond dis-
tance and angles are listed in Supporting Information (Table S1).
Crystallographic data (excluding structure factors) for the
structures reported in this paper have been deposited with the
Cambridge Crystallographic Data Center (the deposition CCDC
numbers 1452374-1452381 for compounds 1–8 respectively).
These data can be obtained free of charge from The Cambridge
[BMI]2[Co3(BDC)3Cl2] (3): 1.5 mmol, 0.4365 g Co(NO3)2 ꢁ 6H2O
and 0.50 mmol, 0.0834 g H2BDC mixed with 1.0026 g [BMI]Cl. IR
data (in KBr, cmꢀ1) for 3: 3666 (w), 3298(w), 3142(m), 3088(m),
2963(m), 1963(w), 1841(w), 1593(s), 1385(s), 1307(s), 1160(m),
1010(w), 825(s), 742(s), 625(w), 543(s). Elemental analysis (%),
Found (calcd): C, 47.02(47.17); H, 3.97(4.16); N, 5.61(5.50).
[AMI]2[Co3(BDC)3Cl2] (4). 1.5 mmol, 0.4359 g Co(NO3)2 ꢁ 6H2O
and 0.50 mmol, 0.0832 g H2BDC mixed with 0.9 mL (ca. 0.99 g)
[AMI]Cl. IR data (in KBr, cm–1) for 4: 3718(w), 3282(w), 3133(m),
3087(m), 2961(m), 1944(w), 1682(m), 1597(s), 1392(s), 1296(s),
1164(m), 1010(w), 740(s), 625(w), 555(s). Elemental analysis (%),
Found (calcd): C, 48.15(48.20); H, 4.40(4.43); N, 5.42(5.35).
[EMI]2[Co3(BDC)3I2] (5). 1.0 mmol, 0.2914 g Co(NO3)2 ꢁ 6H2O and
0.50 mmol, 0.0833 g H2BDC mixed with 1.0031 g [EMI]I. IR data (in
KBr, cmꢀ1) for 5: 3722(w), 3408(w), 3151(m), 3103(m), 2974(w),
1591(s), 1156(m), 1385(s), 1302(m), 1164(m), 1018(w), 825(s), 746
(s), 555(s). Elemental analysis (%), Found (calcd): C, 38.15(37.75);
H, 3.11(2.99); N, 4.78(4.89).
3. Results and discussion
3.1. Crystal structures of compounds 1–8
With the corresponding RMIþ cations anchoring in the inter-
layer spaces and Xꢀ anions as the terminal ligand, similar 2D
layered compounds 1–8, [RMI]2[Co(BDC)3X2] (X¼Cl, RMI ¼ EMI
(1), PMI (2), BMI (3), AMI (4); X¼I, RMI ¼ EMI (5), PMI (6), BMI
(7), AMI (8)), were obtained. These structures possess the same
[Co3(BDC)3X2]2ꢀ skeleton framework (Fig. 1), including the same
coordination spheres of the Co(II) centers (Fig. 2 and Fig. S1) and
the coordination fashions of the BDC2ꢀ ligands. Therefore, only the
structure of compound 1 will be discussed in detail. The asym-
metric unit of compound 1 comprises of one and a half Co(II)
centers, one and a half BDC2ꢀ ligands, one Clꢀ and one EMIþ
(Fig. 2). The total four positive charges on one and a half Co(II)
centers and EMIþ cation are neutralized by one and half BDC2ꢀ
ligands and one Clꢀ to keep charge balance. BDC2ꢀ ligands in
compound 1 exhibit two kinds of μ4 coordination fashions: bis-
bidentate and bis-bridging monodentate coordination fashions
(Scheme 1). Two independent Co1 and Co2 centers show different
coordination geometries: a distorted tetrahedron coordination
[PMI]2[Co3(BDC)3I2] (6). 1.0 mmol, 0.2915 g Co(NO3)2 ꢁ 6H2O and
0.50 mmol, 0.0830 g H2BDC mixed with 1.0 mL (ca. 1.51 g) [PMI]I.
IR data (in KBr, cmꢀ1) for 6: 3830(w), 3737(w), 3415(w), 3133(m),
3101(m), 2962(w), 1631(s), 1592(s), 1383(s), 1302(s), 1160(m), 1018
(m), 902(w), 825(s), 746(s), 555(s). Elemental analysis (%), Found