Microporous Manganese Formate: A Simple Metal-Organic Porous Material with High Framework Stability and Highly Selective Gas Sorption Properties

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1 Supporting Information Microporous Manganese Formate: A Simple Metal-Organic Porous Material with High Framework Stability and Highly Selective Gas Sorption Properties Danil N. Dybtsev, Hyungphil Chun, Sun Hong Yoon, Dongwoo Kim, and Kimoon Kim* Contribution from the National Creative Research Initiative Center for Smart Supramolecules, and Department of Chemistry, Division of Molecular and Life Sciences, Pohang University of Science and Technology, San 31 Hyojadong, Pohang , Republic of Korea Materials and methods. All the reagents and solvents employed were commercially available and used as supplied without further purification. FT-IR spectra were recorded from KBr pellets on a Perkin-Elmer Spectrum GX instrument. TGA data were obtained on a Perkin-Elmer Pyris 1 TGA instrument with a heating rate of 10 ºC/min under N 2 atmosphere. The power XRD diffractograms were obtained on a Bruker D8 Advance system equipped with Cu sealed tube (λ = Å). Following conditions were used: 40 kv, 40 ma, increment = 0.01º, scan speed = 1 s/step. The FT-IR spectra (Fig. S1) of 1 ⅓G before and after the guest removal, the TGA data (Fig. S2) of 1 ⅓G and the powder XRD patterns (Fig. S3) of 1 ⅓G before and after the guest removal are shown below. BET gas sorption experiments. A glass vacuum manifold equipped with an oil pump and a diffusion pump was used. Standard volumetric technique was used to obtain the BET sorption data in the pressure range from 10-2 Torr to 1 atmosphere. The porous manganese formate sample was activated by heating at 150ºC and 10-2 Torr for 18 h. Highly pure gases were used for the measurements. The BET surface area was calculated from the line regression plot of 1/(w((P 0 /P) 1)) vs. P/P 0 (where w is the total volume absorbed at particular P/P 0 point and P 0 is 1 atm pressure) in the range bar. The BET plots for the H 2 and CO 2 sorption/desorption data of 1 is shown in Fig. S4. Single cryatal X-ray diffraction study. Crystals of 1 ⅓G (G = dioxane, THF, furan, or cyclohexane) and 1 which was prepared by heating single crystals of 1 ⅓dioxane at 150 ºC under vacuum for 24 h, were picked up with paraton oil on the tip of a glass capillary tube and mounted on a Siemens SMART CCD diffractometer equipped with a graphite-monochromated Mo-K α (λ = Å) radiation source in a cold nitrogen stream ( 50 ºC). All crystallographic data were corrected for Lorentz and polarization effects (SAINT), and semi-empirical absorption corrections based on equivalent reflections were applied (SADABS). The structures were solved by direct methods and refined by full-matrix least-squares method implemented in SHELXTL program package. All the non-hydrogen atoms were refined anisotropically. Hydrogen atoms were added to their geometrically ideal positions. Thermal ellipsoid plots of the crystallographic asymmetric units of 1 ⅓dioxane and 1 are shown in Fig. S5 and S6, respectively. The connectivity around the four independent Mn(II) ions is shown in Fig. S7. Among the four independent Mn(II) centers, Mn(1) is connected to four neighboring Mn(1) centers via two Mn(2) and a Mn(3) and a Mn(4) linkages. Therefore, the simplification of the 3D net in 1 ⅓dioxane by connecting all the Mn(II) S1

2 centers results in a distorted diamond-related net where Mn(1) centers behave as tetrahedral four-connecting nodes and Mn(2), Mn(3) and Mn(4) as node-to-node connectors (Fig. S8). Synthesis of non-porous manganese formates. The same reaction as that for 1 G in the absence of organic templates produced crystalline products which are a mixture of densely packed manganese formates having the same formula Mn(CHO 2 ) 2. The unit cell dimensions and the X-ray crystal structure of one of the two phases (large, block-shaped colorless crystals; hereafter α-form) match those already reported by A. K. Powell et al. (Eur. J. Inorg. Chem. 2003, ). According to the report, the α-form decomposes to Mn 3 O 4 in the range C, nearly 100 degrees lower than the present porous polymorph, 1 ⅓dioxane. The other phase (colorless thin plates) having the same formula unit was found to be a previously unknown phase (hereafter β-form). Prolonged heating during the synthesis increases the formation of the α-form over β-form. Crystal data of β-manganese formate: MnC 2 H 2 O 4, fw = , orthorhombic, Pna2 1, a = (1), b = 8.389(1), c = (1) Å, V = (2) Å 3, Z = 12, T = 223 K, d calc = g/cm 3, R 1 (I > 2σ(I)) = 0.044, wr 2 (all data) = 0.112, GOF = In the structure, the crystallographic asymmetric unit contains three independent Mn(II) and six formate anions. Each metal cation is coordinated by six formate ligands in an octahedral geometry and each formate anion connects three Mn(II) ions. Contrary to the structures of α-mn(cho 2 ) 2 and 1, where all formate ligands have a syn-syn-anti binding mode, β-mn(cho 2 ) 2 has two formates in a syn-syn-anti mode and four in an anti-syn-anti mode (Fig. S9). The Mn(II)- centered octahedra share edges and form 1D zigzag chains along the b axis. The chains are connected by formate linkers to form a densely packed structure without any notable opening (Fig. S10). S2

3 1 Wavenumber, (cm -1 ) Fig. S1. FT-IR spectra of 1 ⅓dioxane and 1. Fig. S2. TGA plot for 1 ⅓dioxane. Two clear weight loss steps were observed at ºC (16.9 %, liberation of dioxane) and ºC (41.8 %, decomposition of 1). The residual weight (41.3 %) corresponds to Mn(II) oxide. S3

4 Mn(CHO 2 ) 2 ⅓dioxane (as-synthesized) Mn(CHO 2 ) 2 (evacuated) Mn(CHO 2 ) 2 (simulated) Mn(CHO 2 ) 2 ⅓dioxane (simulated) Fig. S3. X-ray powder diffraction patterns (normal diffractograms) and simulated ones (inverted) based on the single-crystal structures of 1 ⅓dioxane and 1. S4

5 Absorption Linear(Absorption) Desorption Linear(D esorption) B.E.T. Equation y = x y = x P/P Absorption Linear(Absorption) Desorption Linear(D esorption) B.E.T. Equation y = x y = x P/P0 Fig. S4. BET plots (squares) and linear fits (lines) for the H 2 (top) and CO 2 (bottom) sorption/desorption data. S5

6 C(4D) O(1D) C(1D) C(3D) O(2D) C(2D) C(6) O(8) Mn(2) O(6) O(3) O(5) O(9) C(4) C(2) O(7) Mn(4) Mn(1) O(10) C(1) O(11) O(2) Mn(3) O(4) O(1) C(5) C(3) O(12) Fig. S5. An ORTEP drawing of the crystallographic asymmetric unit in 1 ⅓dioxane. Hydrogen atoms are not labeled. O(9) O(2) C(5) Mn(2) O(6) C(3) O(5) O(10) O(3) O(1) C(1) C(4) Mn(1) O(7) O(12) O(8) Mn(3) O(4) C(2) O(11) C(6) Mn(4) Fig. S6. An ORTEP drawing of the crystallographic asymmetric unit in 1. Hydrogen atoms are not labeled. S6

7 Fig. S7. Ball-and-stick view of 1 showing the connectivity between Mn(II) ions. Mn(1) acts as a tetrahedral node while Mn(2), Mn(3) and Mn(4) play bridging roles between two nearest Mn(1) centers. Fig. S8. Simplified view of the distorted diamond net of 1 obtained by connecting all the Mn(II) ions. The Mn(1) centers are shown as green spheres with a larger diameter in order to emphasize their role as 4-connecting nodes. S7

8 C(6) O(6) O(4) C(4) O(11) Mn(3) C(2) C(5) O(9) Mn(2) O(1) O(10) O(2) Mn(1) O(7) O(3) O(12) C(1) O(5) C(3) O(8) Fig. S9. The thermal ellipsoid drawing (50% probability) of the crystallographic asymmetric unit in β-mn(hco 2 ) 2. Hydrogen atoms are not labeled. Fig. S10. Top: the structure of zigzag chain in β-mn(hco 2 ) 2. Bottom: the crystal packing in β-mn(hco 2 ) 2. Hydrogen atoms are omitted. S8