Interpenetrated MetalâOrganic Frameworks of ... - ACS Publications

Subscriber access provided by Fudan University

Article

Interpenetrated Metal-Organic Frameworks (MOFs) of Cobalt (II): Structural Diversity, Selective Capture and Conversion of CO2 Bharat Ugale, Sandeep Singh Dhankhar, and C. Mallaiah Nagaraja Cryst. Growth Des., Just Accepted Manuscript • Publication Date (Web): 24 Apr 2017 Downloaded from http://pubs.acs.org on April 27, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Crystal Growth & Design is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Crystal Growth & Design

Interpenetrated Metal-Organic Frameworks (MOFs) of Cobalt (II): Structural Diversity, Selective Capture and Conversion of CO2 Bharat Ugale, Sandeep Singh Dhankhar and C. M. Nagaraja* Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India.Tel: 91- 1881-242229. Email: [email protected] Abstract Three new metal-organic frameworks (MOFs) of Co(II), [{Co(muco)(bpa)(2H2O)}.2H2O]n (1), [{Co(muco)(azopy)}.H2O]n (2) and [{Co(muco)(4bpdp)}.2DMF.H2O]n (3) (where, muco = trans, trans-muconate dianion, bpa = 1,2-bis(4-pyridyl)ethane, azopy = 4,4′-bisazobipyridine and 4bpdb = 1,4- bis(4-pyridyl)-2,3-diaza-1,3-butadiene) have been synthesized and structurally characterized by single-crystal X-ray diffraction analysis. Structural analysis revealed that MOF1 exhibits an interesting 3-fold interpenetrated 3D pillar-layered framework structure with 4-c, {66} topology. While 2 and 3 possess 2-fold interpenetrated 3D pillar-layered framework structure with 7-c, {3^3.4^13.5^4.6} net topology. Gas adsorption study of the compounds show that 1 exhibits selective adsorption of CO2 over other (H2, N2 and Ar) gases with uptake higher than those of 2 and 3. Further, the metal coordinated water molecules in MOF1 can be reversibly removed by high temperature treatment to generate dehydrated framework of 1 composed of highly unsaturated, Lewis acidic Co(II) ions projected in the 1D pore channels. Interestingly, the activated framework of 1 acts as an efficient recyclable catalyst for heterogeneous cycloaddition of carbon dioxide with epoxides to generate cyclic carbonates with high yield and selectivity even at mild conditions (1 atm of CO2). Furthermore, the catalyst can be easily recycled and reused for four successive cycles without significant loss of catalytic activity and structural rigidity. Thus, the influence of N, N'-donor spacers on the structure, topology and the functionality of MOFs has been presented. 1

ACS Paragon Plus Environment

Crystal Growth & Design 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1. Introduction Metal-organic frameworks (MOFs) are a new class of crystalline materials which have attracted tremendous attention over the last few decades due to their intriguing network topologies and novel properties.1-5 Possessing the merits of both inorganic and organic building blocks, MOFs show useful applications for hydrogen storage,6-10 carbon dioxide capture,11-18 gas separation,19-23 catalysis,24-33 sensing,34-39 magnetism,40-43 drug delivery

44-46

and so on.47-50 The crystal engineering51

of MOFs depends on several factors such as, coordination behavior of the metal ion, solvent, pH, concentration of the reaction, the counter ion, temperature and time of reaction.52-55 It has been observed that use of rigid ligand, trans, trans-muconic acid (H2muco) in combination with pyridyl linkers resulted MOFs with interpenetration/entanglement due to its moderately longer spacer length.56-58 The origin of interpenetration in a framework is due to the availability of large voids and MOFs with various degree of interpenetration have been reported. However, the factors governing the degree of interpenetration are still unknown.59-61 Thus systematic investigation on the influence of bipyridyl spacers on the framework structure, dimensionality, topology and functionality has gained considerable interest. Being a greenhouse gas, carbon dioxide (CO2) has attracted a growing interest as an abundant C1 building block for organic transformations owing to its free availability, nontoxicity, renewability.62 CO2 can be converted into value-added chemicals using various strategies which are being investigated worldwide.63-66 However, the thermodynamic stability and kinetic inertness of CO2 pose great challenge for its conversion, so efficient catalytic systems needs to be developed for selective capture and conversion of CO2 into value added organic compounds at mild conditions. Being 100% atom-economic reaction, cycloaddition of CO2 to epoxides represent one of the most promising method for generation of either cyclic carbonates or polycarbonates.67 Various homogeneous catalysts including alkali metal salts,68,69 ionic liquids,70 organocatalysts,71,72 and 2


Page 2 of 33

Page 3 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


quaternary ammonium73,74 or quaternary phosphonium salts,75,76 transition-metal complexes,77-79 salenmetal compounds,80-82 etc., have been employed for catalytic cycloaddition of CO2 and epoxides to cyclic carbonates. However, their widespread application is prevented due to limitations of catalyst recycling and separation of products. Keeping the above points in mind, we were interested to synthesize MOFs based on rigid organic ligand and various bipyridine donors for selective capture and conversion of CO2. Herein, we report the syntheses of

three new metal-organic frameworks (MOFs)

[{Co(muco)(bpa)(2H2O)}.2H2O]n

(1),

[{Co(muco)(azopy)}.H2O]n

of

Co(II),

(2)

and

[{Co(muco)(4bpdp)}.2DMF.H2O]n (3) (where, muco = trans, trans-muconate dianion, bpa = 1,2-bis(4pyridyl)ethane, azopy = 4,4′-bisazobipyridine and 4bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) and structurally characterized by single-crystal X-ray diffraction analysis. Structural analysis revealed that MOF1 exhibits an interesting 3-fold inter penetrated 3D pillar-layered framework structure with 4-c, {66} topology. While 2 and 3 possess 2-fold interpenetrated 3D pillar-layered framework structure with 7-c, {3^3.4^13.5^4.6} net topology. Gas adsorption study revealed selective adsorption property of MOF1 for CO2 over other (H2, N2 and Ar) gases with uptake higher than those of 2 and 3. The metal coordinated water molecules in 1 can be reversibly removed by high temperature treatment to generate dehydrated framework composed of highly unsaturated, Lewis acidic Co(II) ions projected in the 1D pore channels. The activated framework of 1 acts as an efficient recyclable catalyst for heterogeneous cycloaddition of carbon dioxide with epoxides to generate cyclic carbonates with high yield and selectivity even at mild conditions (1 atm of CO2). Furthermore, the catalyst can be easily recycled and reused for four successive cycles without significant loss of catalytic activity and structural rigidity. Thus, the influence of N, N'-donor spacers on the structure, topology and the functionality of MOFs has been presented.

3



2. Experimental Section 2.1. Materials Commercially available reagents were used in all reactions as provided without any further purification. Co(OAc)2.4H2O, Co(NO3)2.6H2O, trans, trans-muconic acid (muco), 1,2-bis(4pyridyl)ethane (bpa), were purchased from Sigma Aldrich chemical Co. and 1,4-bis(4-pyridyl)-2,3diaza-1,3-butadiene) (4bpdb) and

4,4'-bisazobipyridine (azopy) have been synthesized following

previously reported procedure.83,84 All the reagents and the internal standard used for catalytic reactions were purchased from TCI chemicals and used without further purification. 2.2. Physical Measurements Thermo Fischer Flash 2000 Elemental Analyzer was used for elemental analysis of C, H and N. FTIR (Fourier transform infrared) spectra were recorded on a Bruker IFS 66v/S spectrophotometer using KBr pellets in the region 4000-400 cm-1. Thermogravimetric analysis (TGA) was done using Metler Toledo Thermogravimetric analyzer in N2 atmosphere with a flow rate of 30 mL/min in the 50 – 600 °C temperature range at a heating rate of 10 °C/min. PANalytical’s X’PERT PRO diffractometer with Cu Kα radiation (k = 1.542 Å; 40 kV, 20 mA) was used for Powder XRD measurements. The products of catalytic reactions were identified and the catalytic conversions were determined using 1HNMR spectra recorded in CDCl3 on JEOL JNM-ECS-400 spectrometer operating at frequency of 400 MHz. 2.3. Gas adsorption measurements N2 adsorption-desorption isotherms were carried out at 77 and 273 K, whereas CO2 adsorption isotherms were conducted at 273 and 298 K using Quadrasorb SI (QUANTACHROME) automatic volumetric instrument. Ar and H2 adsorption isotherms were recorded at 273K. Ultrapure (99.995%) N2, He, H2, Ar and CO2 gases were used for the adsorption measurements. Prior to adsorption

4


Page 4 of 33

Page 5 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


measurements the samples (~ 80 mg) were evacuated at 393 K under vacuum (20 mTorr) for 15 hours using Flovac degasser (QUANTACHROME) and purged with ultrapure nitrogen gas on cooling. Then the evacuated sample was introduced to the Quadrasorb SI (QUANTACHROME) automatic volumetric instrument and further all operations were computer controlled. 77 K was achieved using liquid nitrogen and 273 and 298K was achieved for CO2 uptake measurements by using a Julabo chiller with an ethylene glycol-water mixture (1:1) as a coolant. All selectivity experiments were carried out at 273K. Dead volume of sample cell was measured using Helium gas (99.995%). 2.4. Synthesis 2.4.1. Synthesis of [{Co(muco)(bpa)(2H2O)}.2H2O ]n (1) Pre-mixed stock solutions of H2muco (0.036 g, 0.25 mmol) neutralized with NaOH (0.020 g, 0.5 mmol) in 12.5 ml of H2O and bpa (0.047 g, 0.25 mmol) in 12.5ml of EtOH were prepared and stirred for 30 min. Also, separately a solution of Co(OAc)2·4H2O (0.062 g, 0.25 mmol) in 25ml H2O was prepared. Then 2ml of pre-mixed solution was slowly and carefully layered over 2 ml of metal solution using 1 ml of 2:1 (v/v) buffer solution of H2O and EtOH. The light pink colored rectangular crystals of [{Co(muco)(bpa)(2H2O)}.2H2O] (1) were obtained after twelve weeks. Yield; 81%. The phase purity of as-synthesized MOF1 was confirmed from powder X-ray diffraction pattern. (Figure S1) Anal. calcd. For C18H24N2O8Co: C, 47.48; H, 5.33; N, 6.15. Found: C, 47.73; H, 5.44; N, 6.08. IR (cm-1): 3420(bw), 3044(w), 1656(s), 1608(s), 1550-1435(s), 1340-1210(s), 810-744(s). The above prepared MOF1 was used for catalysis reaction with prior activation at 120oC under vaccum for 15h. Its structural and thermal stability was also checked before using for catalytic reactions. Yield: 85% (after activation). Anal. calcd. For C18H16N2O4Co: C, 56.41; H, 4.21; N, 7.31. Found: C, 57.01; H, 4.90; N, 7.42.

5



2.4.2. Synthesis of [{Co(muco)(azopy)}.H2O]n (2) MOF2 was prepared solvothermally at temperature of 115°C. To aqueous solution (4 ml) of Co(NO3)2.6H2O (0.073g, 0.25 mmol), DMF solution (2ml) of H2muco (0.036g, 0.25mmol) was added dropwise with constant stirring. To the above pre-mixed solution, 2 ml of ethanolic solution of azopy (0.046g, 0.25 mmol) was dropwise added and stirred vigorously for 15 min and then taken in a 30 mL screw cap glass vial, sealed and heated at 115 °C for 48 hrs. Room temperature cooling gave dark reddish-pink colored needle shaped crystals of MOF2. Yield (82%). The phase purity of assynthesized MOF2 was confirmed by powder X-ray diffraction pattern (Figure S2) Anal. calcd. For C32H26N8O9Co2: C, 48.99; H, 3.35; N, 14.29. Found: C, 49.34; H, 3.31; N, 14.46. IR (cm-1): 3345(b), 3011(w), 1655(s), 1611(s), 1570(s), 1520-1390(s), 1331-1207(s). 2.4.3. Synthesis of [{Co(muco)(4bpdb)}.2DMF.H2O]n (3) MOF3 was prepared by employing similar conditions to that of 2 except in place of azopy, here 4bpdb (0.053g, 0.25 mmol) was used. After heating at 115°C for 48 hrs and subsequent cooling to room temperature, dark pink crystals of 3 were obtained. Yield (77%). The phase purity of assynthesized MOF3 was confirmed from powder X-ray diffraction pattern (Figure S3). Anal. calcd. For C24H30N6O7Co: C, 52.46; H, 5.51; N, 15.40. Found: C, 52.31; H, 5.37; N, 15.43. IR (cm-1): 3240 (b), 3022 (w), 1648(s), 1602(s), 1570(s), 1511-1365(s), 1311-1230(s). 2.5. Catalytic Cycloaddition Reactions The catalytic cycloaddition reactions with CO2 at 1 atm pressure were carried out by introducing carbon dioxide in a balloon to a 50ml round bottom flask containing the catalyst and the epoxide and the flask is sealed with septa and parafilm. Whereas, the cycloaddition reactions with CO2 pressure of 0.8 Mpa were carried out in a 50 ml stainless steel high-pressure reactor. Prior to catalytic reactions, the catalysts were activated at 393 K for 15 h under vacuum to remove the guest

6


Page 6 of 33

Page 7 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


and metal-coordinated water molecules and then transferred to the reactor. All the reactants/reagents including internal standard were added at room temperature and the reactor was pressurized with CO2 (up to 0.5 Mpa), flushed twice and then the required pressure was attained (0.8 MPa) for 12 h. The reagent, 1,2-epoxy propane was handled at low temperature due to its low boiling point. The reaction mixture was stirred at 750 rpm under pressurized conditions for 12h. After catalytic reactions, the pressure was released slowly and catalyst was separated by filtration and the catalytic conversion was determined by 1H NMR spectroscopy. The recovered catalyst after catalytic reaction was washed with water and methanol three times, dried at 393 K for 15 h under vacuum and then reused for successive cycles. 2.6. X-ray Crystallography Single crystal X-ray structural data of MOFs 1˗3 were collected on a CMOS based Bruker D8 Venture PHOTON 100 diffractometer equipped with a INCOATEC micro-focus source with graphite monochromated Mo Kα radiation (λ = 0.71073 Å) operating at 50 kV and 30 mA. The SAINT85 program was used for integration of diffraction profiles and absorption correction was made with SADABS program.86 The structures were initially solved by SIR 9287 and refined by full matrix least square method using SHELXL-201388 and WinGX system, Ver 2013.3.89 The non hydrogen atoms in all the structures were located from the difference Fourier map and refined anisotropically. All the hydrogen atoms were fixed by HFIX and placed in ideal positions and included in the refinement process using riding model with isotropic thermal parameters. The disordered guest solvent molecules in MOFs 1 and 3 were treated with SQUEEZE option of PLATON90 multipurpose crystallographic software. The molecular formula of 1 and 3 was determined based on the elemental analyses and TGA. The potential solvent accessible area or void space was calculated using the PLATON90 software. All the crystallographic and structure refinement data of the MOFs 1-3 is summarized in

7



Page 8 of 33

Table 1. Selected bond lengths, angles and hydrogen bond details of 1 - 3 are summarized in Tables S1-S6 respectively. The crystallographic information file is deposited with the CCDC numbers 1511816, 1518366 and 1511819 for MOFs 1-3 respectively. Table 1. Crystal data and structure refinement parameters for 1-3. Parameters

1

2

3

Empirical formula C18H24N2O8Co C32H26N8O9Co2 C24H30N6O7Co 455.33 Formula mass 784.47 549.48 Monoclinic Crystal system Orthorhombic Monoclinic C2/c(No.15) Space group Pca21(No.29) C2/c(No.15) 35.522(5) a /Å 14.595(5) 15.5845(7) 13.846(5) b /Å 13.344(5) 15.0522(6) 9.548(5) c /Å 21.324(5) 20.9475(9) 90.00 α (°) 90.00 90.00 103.20(5) β (°) 90.00 110.286(2) 90.00 γ(°) 90.00 90.00 3 4572(3) V(Å ) 4153(2) 4609.1(3) 8 4 8 Z -3 1.220 1.250 1.180 ρ(g cm ) -1 0.781 0.853 0.770 µ(mm ) 1736 1592 1672 F(000) 298 298 298 T(K) 0.71073 0.71073 0.71073 λ(Mo Kα)(Å) 2.4 2.3 2.4 Θmin(°) 28.4 28.6 26.6 Θmax(°) 61400 111092 61965 Total data 5741 10508 4813 Unique data 0.058 0.194 0.039 Rint 4688 6207 4220 Data[I>2σ(I)] a 0.0623 0.0922 0.0415 R1 b 0.1887 0.3148 0.1062 wR2 1.05 1.07 1.15 S a

R1 = ∑║F0│-│Fc║/∑│Fo│, bwR2 = [∑w(Fo2-Fc2)2/∑w(Fo2)2]1/2

8


Page 9 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Results and discussion 3.1. Synthesis Scheme MOF1 was prepared at room temperature by layering of aqueous solutions of Co(OAc)2·4H2O and trans, trans-muconic acid with ethanolic solution of bpa (Scheme 1). Whereas, MOFs 2 and 3 were synthesized by solvothermal reaction of Co(NO3)2·6H2O, trans, trans-muconic acid along with azopy and 4bpdb linkers, respectively in H2O-DMF-EtOH mixed solvent system (Scheme 1).

Scheme 1. Schematic representation for preparation of MOFs 1-3. 3.2 Structural features of 1-3 3.2.1. Structural description of [{Co(muco)(bpa)(2H2O)}.2H2O]n (1) MOF1 crystallizes in monoclinic crystal system with centrosymmetric, C2/c space group. Single crystal X-ray diffraction study revealed a three-dimensional (3D) framework structure comprising of muco dianion and the bpa spacer. The asymmetric unit contains one Co(II) ion, one muconate dianion, one bpa spacer and two coordinated water molecules along with two solvent water molecules of crystallization. The Co1 center is in a distorted octahedral geometry with CoO4N2 chromophore satisfied by two carboxylate oxygen atoms (O1 and O3) from two bridging muconate

9



dianions, two nitrogen atoms (N1 and N2) from the bpa spacer and two oxygens (O1W and O2W) from two coordinated water molecules (Figure 1a). The Co1-O and Co1-N bond lengths are in the range of 2.150(3)-2.060(3) and 2.147(3)-2.131(3) Å, respectively. The degree of distortion from an ideal octahedral geometry at Co1 can be seen from the cisoid and transoid angles which are in the range of 88.11(10)-92.75(10)º and 175.91(10)-178.96(11)º, respectively. The Co(II) centers are connected by muconate dianion and bpa spacer in an alternate fashion forming a 2D [Co(muco)Co(bpa)]n hexagonal network (Figure. 1b).

Figure 1. (a) The coordination environment around Co(II) in 1. (the hydrogen atoms and solvent molecules are omitted for clarity) (b) View of a single 2D network [Co(muco)(bpa)]n along the crystallographic ab-plane. (c) View of 3D single pillar-layered framework excluding the 3-fold interpenetration.

10


Page 10 of 33

Page 11 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


These 2D layers are further pillared by bpa spacers forming a 3D pillar-layered framework which houses a large 1D channels of dimension ~8.60 X 20.01 Å2 (Figure 1b and 1c). Each Co(II) metal acts as a 4-connecting node and the overall structure has neb-net topology with Schläfli point symbol {66}, analyzed by TOPOS. As shown in Figure 1c, the 3D framework possess a large void which assists the nucleation of two other independent nets to produce a 3-fold interpenetrated, 3D framework (Figure 2a). TOPOS analysis on 3-fold interpenetrated framework gives Schläfli vertex symbol of [6.6.6.6(2).6(2).6(2)] (Figure 2b). In spite of 3-fold interpenetration the framework possesses 1D channels of dimension of ~8.11 X 5.31 Å2 containing four Co(II) centers projected in the pore (Figure 2 c and d) with void volume of ~ 23.5 % (4572.0 Å3) per unit cell calculated using PLATON after removal of guest water molecules. The distance between the two adjacent Co….Co centers along Co…muco…Co and along Co…bpa…Co are 11.037 and 13.560 Å, respectively. Selected bond lengths and angles are given in Table S1, and the selected C-O…H hydrogen bonding interactions between the carboxylate oxygens and the guest water molecules are summarized in Table S2.

11



Figure 2. (a) View of 3-fold interpenetrated 3D pillar-layered framework in 1 (three different interpenetrating nets are shown in three different colors). (b) Topological representation of the 3-fold interpenetrated 3D framework in 1. (c) and (d) shows the view of 3D framework with 1D channels decorated with four Co(II) ions along the crystallographic c-axis.

3.2.2. Structural description of [{Co(muco)(azopy)}.H2O]n (2) MOF2 crystallizes in the Orthorhombic crystal system with the non-centrosymmetric, Pca21 space group. Single crystal X-ray diffraction study revealed a 3D framework structure composed of a muco dianion and the azopy spacer. The asymmetric unit contains two Co(II) ions, two muconate dianions, two azopy spacers and one solvent water molecule of crystallization. The geometry around Co1 is a distorted octahedron with CoO4N2 chromophore satisfied by four carboxylate oxygen atoms

12


Page 12 of 33

Page 13 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(O2, O3, O5 and O6) from two bridging muconate dianions and two nitrogen atoms (N1 and N2) from the azopy spacer. The geometry around Co2 center is also in distorted octahedron satisfied by four carboxylate oxygens (O1, O4, O7 and O8) from two different muconate dianions and two nitrogen (N3 and N4) atoms from two different azopy spacers (Figure 3a). The Co-O and Co-N bond lengths are in the range 2.256(11)-1.995(10) and 2.208(11)-2.121(9) Å, respectively. The degree of distortion from an ideal octahedral geometry is reflected in the octahedral angles around Co(II) centers, which are in the range of 86.3(5) – 121.4(5)º and 151.0(5) – 176.8(5)º, respectively. Co1 and Co2 are connected by two different muconate dianions through monodentate bridging µ1 µ1-OO and chelating bidented, µ2-O fashion forming a 2D [Co1Co2(muco)2]n sheet (Figure 3b). The void space present in the 2D sheet promotes interpenetration of another 2D net to form 2-fold interpenetrated net (Figure. 3c). These 2D nets are further pillared by azopy linkers to generate 3D pillar-layered framework which possess 1D channels along the b-axis (Figure 3d). These 1D channels are blocked due to 2-fold interpenetration as shown in Figure 3d and 3e. TOPOS analysis suggest presence of two types of 7-c Co(II) nodes and the structure has a Schläfli point symbol {3^3.4^13.5^4.6} (Figure 3b) . The interpenetration analysis by TOPOS

suggests

the

presence

of

2-fold

interpenetration

with

vertex

symbol

[3.3.3.4.4.4.4.4.4.4.4.4.4.4.4.4.5.5.5.5.6(5)] (Figure 3e and 3f). The distance between the two adjacent Co….Co centers along Co…muco…Co and along Co…azopy…Co are 11.567 Å and 13.344 Å, respectively. Interestingly, in spite of 2-fold interpenetration, the framework possess solvent accessible void volume of ~ 29.8 % (4153.0 Å3) per unit cell volume calculated using PLATON after removal of guest water molecule. Selected bond lengths and angles are given in Table S3, and the selected CO…H hydrogen bonding interactions between the carboxylate oxygens and the guest water molecules are summarized in Tables S4.

13



Figure 3. (a) The asymmetric unit showing coordination environment around Co(II) in MOF2 (the hydrogen atoms are omitted for clarity). (b) View of [Co2(muco)2]n 2D network formed by bridging of Co(II) ions by muco in ac-plane. (c) View of 2-fold interpenetrated [Co2(muco)2]n 2D networks in the crystallographic ac-plane in MOF2 (d) View of single 3D pillar-layered framework and (e) 2-fold interpenetrated 3D pillar-layered framework (two different colors are used to represent two nets) (f) topological representation of the 2-fold interpenetrated 3D framework.

3.2.3. Crystal structure of [{Co(muco)(4bpdb)}.2DMF.H2O]n (3) MOF3 crystallizes in the monoclinic crystal system with the centrosymmetric, C2/c space group. Single crystal X-ray diffraction study a 3D framework constituted by muco dianion and the 4bpdb spacer and isostructural to MOF2. The asymmetric unit is composed of a Co(II), muco, 4bpdb spacer and two guest DMFs and a water molecule of crystallization. The geometry at Co1 center is a distorted octahedron with CoO4N2 chromophore satisfied by four carboxylate oxygen atoms (O1, O2, O3, and O4) from two bridging muconate dianions and two nitrogen atoms (N1 and N2) from 4bpdb 14


Page 14 of 33

Page 15 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


spacer (Figure 4a). The Co-O and Co-N bond lengths are in the range 2.1993(18) - 2.0068(17) and 2.146(2) -2.146(2) Å, respectively. The degree of distortion from an ideal octahedral geometry at Co center is reflected in the cisoid and transoid angles which are in the range of 60.20(6) – 119.28(7)º and 149.63(7) – 178.42(8)º, respectively. As shown in Figure 3b, the Co(II) ions are connected by muco ligand to form the 2D [Co2(muco)2]n sheets which are further pillared by 4bpdb linkers to form the 3D pillar-layered framework which possess 1D channels along the b-axis (Figure 4b). Due to 2-fold interpenetration, the void space in 1D channels is reduced as shown in Figure 4c. TOPOS analysis unveil the presence of two types of 7-c Co(II) nodes and the structure has a Schläfli point and vertex symbol as {3^3.4^13.5^4.6} and [3.3.3.4.4.4.4.4.4.4.4.4.4.4.4.4.5.5.5.5.6(5)] respectively (Figure 4d). The distance between the two adjacent Co….Co centers along Co…muco…Co and along Co…4bpdb…Co are 11.467 and 15.585 Å, respectively. Interestingly, in spite of 2-fold interpenetration, the structure exhibit solvent accessible void volume of ~ 28.7 % (4609.0 Å3) per unit cell volume calculated using PLATON after removal of guest solvent molecules. The bond lengths and bond angles are given in Table S5 and the selected hydrogen bonding interactions are summarized in Tables S6.

15



Figure 4. (a) The asymmetric unit showing coordination environment around Co(II) in MOF3. (the hydrogen atoms are omitted for clarity). (b) 3D pillar-layered framework view without the 2-fold interpenetration in 3 formed by pillaring of 4bpdb spacer. (c) 3D pillar-layered framework view with 2-fold interpenetration in MOF3 (two different colors represent the different folds of interpenetration). (d) View of a single unit of showing 2-fold interpenetration in MOF3. 3.3. Thermal stability of MOFs 1-3 MOF1 shows a weight loss of ~ 15.2 % around 180-230 ºC corresponding to the loss of two guest water molecules and two coordinated water molecules (calc. wt% 15.83) and the dehydrated framework is stable upto 300°C. In the temperature range of 300-450°C a second weight loss of ~60.31 % was observed which corresponds to the loss of a bpa linker and muconic acid (Figure 5). MOF2 shows a weight loss of ~ 4.69 % in the temperature range 100-170 ºC corresponding to loss of two guest water molecules (calc. wt% 4.58). The dehydrated framework is stable upto 230ºC, second 16


Page 16 of 33

Page 17 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


weight loss of ~ 67.16% in temperature range 170-425 ºC corresponds to the loss of azopy linker and muconate ligand (Figure 5). MOF3 shows a weight loss of ~ 13.1 % in the temperature range 100-180 ºC which corresponds to loss of one guest water molecule and one guest DMF molecule (calc. wt% 13.32). The dehydrated framework is stable upto 250ºC, second weight loss of ~ 60.1% in temperature range 200-425 ºC corresponds to the loss of 4bpdb linker and muconate ligand (Figure 5). MOF1 degassed does not show a weight loss around 180-230 ºC corresponding to the loss of two guest water molecules and two coordinated water molecules as in 1 and the dehydrated framework is stable upto 290°C. In the temperature range of 280-500°C a continuous weight loss of ~68.3 % was observed which corresponds to the loss of a bpa linker and muconic acid (Figure 5).

Figure 5. Thermal stability curves.

17



3.4. Gas adsorption studies Single crystal structural analysis of MOFs 1-3 revealed that the compounds posses solvent accessible voids. Therefore, the N2 adsorption isotherms of 1-3 was carried out to elucidate the basic sorption behavior. Prior to adsorption measurements, the samples (~100 mg) were activated by degassing at an elevated temperature of 393K under vacuum conditions (20 mTorr) for 15 hours to generate the dehydrated framework. PXRD patterns of the activated samples revealed that the original framework structure is retained even after activation (Figure S4-S6). For confirmation of permanent porosity in MOFs 1-3, N2 adsorption isotherms were carried out at 77K which show type-II profile suggesting mainly surface adsorption (Figure S7). This behaviour can be attributed due to 1D nature of the channels (Figure S8) and at low temperatures (77K), probably N2 molecules (kinetic diameter = 3.6 Å) interact strongly with the pore aperture blocking other molecules to pass through resulting in mainly surface adsorption. On the other hand, CO2 adsorption isotherms of MOFs 1-3 show a typical type-I behaviour supporting their microporous nature and the corresponding BET surface area values are respectively 127.7, 20.3 and 4.7 m2/g estimated from CO2 isotherms carried out at 273 K (Figure 6). Furthermore, CO2 adsorption isotherms of MOFs 1-3 at 273 K revealed higher uptake of 1 over others (Figure 6). The higher CO2 uptake of MOF1 can be attributed due to its stronger interaction with the four unsaturated Co(II) centers decorated in the 1D channels (Figure 2d) owing to significant quadruple moment (−1.4 × 10−39 Cm2) of CO2. Therefore, CO2 adsorption measurements of MOF 1 at 273 K follow a typical type-I profile with volumetric uptake of 1.57 and 1.08 mmol/g at 273 and 298 K, respectively as the pressure approaches to 1 atm (Figure 7a). The adsorption branches of isotherms measured at 273 and 298K were fitted to Freundlich-Langmuir equation91 (shown in Figures S9 and S10) to obtain a precise prediction over the quantity of CO2 adsorbed at saturation point. The estimated

18


Page 18 of 33

Page 19 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


value of isosteric heat of adsorption (Qst) for CO2 gas was found to be 37.3 kJ/mol for 1 at lower coverage (Figure S11). The continuous decrement in isosteric heat of adsorption value (Qst) also reveals the dependency of Qst as a function of CO2 loading, this can be explained by considering the blocking of the unsaturated Co(II) centers by incoming CO2 molecules leading to consequent reduction in Qst values on higher loading.

Figure 6. CO2 adsorption isotherms of MOFs 1-3 carried out at 273K. Further, the adsorption studies of 1 for other gases (H2, N2 and Ar) carried out at 273 K showed negligible uptake with 1.37 cc/g of H2; 2.88 cc/g of N2 and 4.09 cc/g of Ar, respectively (Figure 7b). Thus, MOF1 exhibits a highly selective adsorption property for CO2 over other (N2, H2 and Ar) gases which can be ascribed due to the polarizability and significant quadrupole moment of CO2 (-1.4 X 1039 cm2) leading to its stronger interaction with the unsaturated Co(II) ions decorated in the 1D channels of 1 with isosteric heat of adsorption (Qst) value of 37.3 kJ/mol. 19



Figure 7. (a) CO2 adsorption-desorption isotherms carried out at 273 and 298K for MOF1 (closed circles represent adsorption and open circles for desorption). (b) Adsorption-desorption isotherms of 1 for different adsorbates (CO2, H2, Ar, N2) at 273K showing selective adsorption for CO2. 3.5. Catalytic Cycloaddition of CO2 with Epoxides As discussed before, MOF1 is microporous with 1D channels decorated with octahedral Co(II) ions having two coordinated water molecules. Upon removal of the coordinated water molecules by thermal treatment under vacuum resulted dehydrated sample of 1 with the 1D channels decorated with four Lewis acidic Co(II) ions (Figure 2d).The formation of 4-coordinate tetrahedral Co(II) ions is supported by the color change from pink to dark purple after activation (Figure S12). The high thermal stability of the dehydrated sample (Figure S4) along with its Lewis acidity motivated us to investigate its catalytic properties for heterogeneous cycloaddition of CO2 with epoxides to generate cyclic carbonates (Scheme 2).

20


Page 20 of 33

Page 21 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Scheme 2. Cycloaddition of CO2 with epoxides catalyzed by MOF1 The optimum conditions required for the cycloaddition reaction was investigated from the controlled experiments carried out at different temperatures and loadings of TBAB (Tetra-n-butyl ammonium bromide). Controlled experiments revealed that temperature of 80oC with catalyst:TBAB loading (0.5:0.5 mol%) and CO2 pressure of 0.8 MPa are optimum conditions for >95% conversion of the styrene oxide to the corresponding cyclic carbonate in 12h (Table 2). It was observed that both catalyst (1) and TBAB are essential for the catalytic reaction (Table 2).92-95 Further, we were interested to test the catalytic reaction at milder conditions i.e. 1 atm of CO2 pressure. Therefore, controlled experiments carried out at 1 atm pressure, temperature of 100°C with time period of 15h resulted similar catalytic conversions observed at 0.8 MPa of CO2 (Table 2, entries 12-15). Furthermore, the progress of the catalytic reactions were easily monitored by recording the 1H NMR spectra of the aliquots taken at regular intervals of time with reference to an internal standard (1,1',2,2'tetrachloroethane). Remarkably, no additional byproducts were observed in the catalytic reaction and the cyclic carbonates were formed with 100% selectivity (Figure S13-S14). The mechanism of cycloaddition reaction of CO2 with the epoxides catalyzed by MOFs generally require binary catalytic system with Lewis acid catalytic site (Co2+ ions in MOF1) and the nucleophilic co-catalyst (TBAB)

21



Page 22 of 33

which is essential for ring opening of the epoxides (Figure S15). In the absence of nucleophilic cocatalyst, high reaction temperatures are required to achieve ring opening of the epoxides.96 Table 2. Optimization of reaction parameters for cycloaddition of CO2 with styrene oxide catalyzed by MOF1. Entry

Catalyst

Co-catalyst

Pressure

Time

Temperature

Conversion

No.

[mol%]

[mol%]

[MPa]

[h]

[°C]

[%][a]

1

None

None

0.8

12

r.t.

0

2

None

None

0.8

12

60

0

3

None

None

0.8

12

80

0

4

MOF1

None

0.8

12

r.t.

0

5

MOF1

None

0.8

12

60

0

6

MOF1

None

0.8

12

80

0

7

None

TBAB

0.8

12

r.t.

95

11

Co(OAc)2.4H2O TBAB

0.8

12

80

64.4

12

MOF1

TBAB

1 atm

12

80

59

13

MOF1

TBAB

1 atm

12

100

85.2

14

MOF1

TBAB

1 atm

15

100

94.6

15

Co(OAc)2.4H2O TBAB

1 atm

15

100

62.1

Reaction conditions: Styrene oxide (20 mmol), Catalyst : TBAB (0.5:0.5 mol%).

[a]

The catalytic

conversion was determined by 1H NMR analysis using 1,1', 2,2'-tetrachloroethane as internal standard.

22


Page 23 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Having confirmed the catalytic activity of MOF1, the scope of the reaction was extended to other epoxides having larger chain length. The results show that the catalytic activity decreases with increase in the alkyl chain length of epoxide (Table 3 entries 1 - 4) which can be attributed due to the electronic and steric effects. The reduced catalytic activity can be attributed due to the confinement of the pore size of 1, resulting in restricted diffusion of the bigger substrates into the pore and the observed catalytic activity could be mostly due to surface catalysis by Co(II) ions exposed to the surface of the MOF. Interestingly, the lower catalytic conversion of the epoxides, (Entry 3 and 4, Table 3) can be correlated well to their larger size (8.198 X 3.39 and 13.321 X 3.39 Å2) respectively, compared to the pore size (~8.11 X 5.31 Å2) of the MOF (Table S7). Thus the high efficiency and size-dependent selectivity observed for smaller epoxides suggest the utility of MOF1 as a promising heterogeneous catalyst for cycloaddition of carbon dioxide. Furthermore, the catalyst can be easily separated by simple filtration and washed with diethyl ether followed by methanol/water and reused for four consecutive cycles without significant loss in catalytic activity (Figure 8). PXRD patterns of the recycled catalyst after four catalytic cycles matches well with the parent compound suggesting retention of the original framework structure (Figure S4). The reaction conditions followed here are relatively milder as compared to previous reports of MOFs which use either higher pressure/temperature or high loading of co-catalyst. Hence, MOF1 represent a rare example of interpenetrated MOF exhibiting selective capture and conversion of CO2 at mild conditions.

23



Page 24 of 33

Table 3. Cycloaddition reaction of various substituted epoxides catalyzed by MOF1. Entry

Substrate

Pressure

No.

Time

Temp.

Conversion

[h]

[°C]

[%][a]

TON[b]

1

0.8 MPa

12

80

100

200

2

0.8 MPa

12

80

>99

198

3

0.8 MPa

12

80

85.1

166

4

0.8 MPa

12

80

68.2

136

5

0.8 MPa

12

80

>95

190

6

1 atm

12

100

85.6

171

7

1 atm

15

100

94.2

188

8

1 atm

12

100

76.1

152

9

1 atm

12

100

63.3

126

Reaction conditions: epoxide (20 mmol), Catalyst : TBAB (0.5:0.5 mol%).

[a]

The catalytic

conversions were determined by 1H NMR analysis using 1,1',2,2'-tetrachloroethane as the internal standard. [b]TON: moles of cyclic carbonate /moles of catalyst used.

24


Page 25 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 8. Recycling test of MOF1 4. CONCLUSIONS Herein, we report synthesis of a series of three new Co(II) metal-organic frameworks using mixed ligand systems and characterized them structurally. MOF1 exhibits an interesting 3-fold interpenetrated 3D pillar-layered framework structure with 4-c, {66} topology. While 2 and 3 possess 2-fold interpenetrated 3D pillar-layered framework structure with 7-c, {3^3.4^13.5^4.6} net topology. Owing to the generation of Lewis acidic Co(II) ions in the 1D pore channels, the activated sample of 1 exhibits selective adsorption of CO2 over other (H2, N2 and Ar) gases and act as efficient recyclable catalyst for heterogeneous cycloaddition of CO2 to epoxides resulting cyclic carbonates with high yield and selectivity even at 1 atm pressure of CO2. The catalyst can be facilely separated and reused

25



for successive cycles without significant loss of activity and structural rigidity. The present study demonstrates the influence of auxiliary ligands on the structure, topology and the functionality of the resulting MOFs. Acknowledgements Authors gratefully acknowledge the financial support from Department of Science and Technology (DST), Government of India. Supporting Information Crystallographic data of MOFs 1-3, PXRD plots for the MOFs, structural data, gas adsorptiondesorption isotherms, 1H NMR spectra, optimized geometries of epoxides. This material is available free of charge via the Internet at http://pubs.acs.org. AUTHOR INFORMATION

Corresponding Author *[email protected] Notes The authors declare no competing financial interest.

References : (1) Themed Issue: Introduction to Metal-Organic Frameworks, Chem. Rev. 2012, 112, 673-1268. (2) Themed Issue: Metal-Organic Frameworks, Chem. Soc. Rev. 2014, 43, 5415-6172. (3) Virtual Issue: Emerging Applications of Metal–Organic Frameworks and Covalent Organic Frameworks, Chem. Mater. 2016, 28, 8079–8081. (4) Moulton, B.; Zaworotko, M. J. Chem. Rev. 2001, 101, 1629–1658. (5) Yaghi, O. M.; O'Keeffe, M.; Ockwig, N. W.; Chae, H. K.; Eddaoudi, M.; Kim, J. Nature 2003, 423, 705–714. 26


Page 26 of 33

Page 27 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(6) Murray, L. J.; Dincǎ, M.; Long, J. R. Chem. Soc. Rev. 2009, 38, 1294−1314. (7) Collins, D. J.; Zhou, H. C. J. Mater. Chem. 2007, 17, 3154−3160. (8) Kubota, Y.; Takata, M.; Matsuda, R.; Kitaura, R.; Kitagawa, S.; Kato, K.; Sakata, M.; Kobayashi, T. C. Angew. Chem., Int. Ed. 2005, 44, 920−923. (9) Suh, M. P.; Park, H. J.; Prasad, T. K.; Lim, D. W. Chem. Rev. 2012, 112, 782−835. (10) Dhankhar, S. S.; Kaur, M.; Nagaraja, C. M. Eur. J. Inorg. Chem. 2015, 2015, 5669−5776. (11) Wu, Y. L.; Qian, J.; Yang, G. P.; Yang, F.; Liang, Y.; T.; Zhang, W. Y.; Wang, Y. Y. Inorg. Chem. 2017, 56, 908−913. (12) Kim, H. R.; Yoon, T. U.; Kim, S. I. An, J.; Bae, Y. S.; Lee, C. Y. RSC Adv. 2017, 7, 1266-1270. (13) An, L.; Wang, H.; Xu, F.; Wang, X. L.; Wang, F.; Li, J. Inorg. Chem. 2016, 55, 12923−12929. (14) Zhao, J.; Dong, W. W.; Wu, Y. P.; Wang, Y. N.; Wang, C.; Li, D. S.; Zhang, Q. C. J. Mater. Chem. A 2015, 3, 6962−6969. (15) Sabouni, R.; Kazemian, H.; Rohani, S. Environ. Sci. Pollut. Res. 2014, 21, 5427-5449. (16) Sumida, K.; Rogow, D. L.; Mason, J. A.; McDonald, T. M.; Bloch, E. D.; Herm, Z. R.; Bae, T. H.; Long, J. R. Chem. Rev. 2012, 112, 724−781. (17) Nagaraja, C. M.; Haldar, R.; Maji, T. K.; Rao, C. N. R. Cryst. Growth Des. 2012, 12, 975−981. (18) Janabi, N. A.; Deng, H.; Borges, J.; Liu, X.; Garforth, A.; Siperstein, F. R.; Fan, X. Ind. Eng. Chem. Res. 2016, 55, 7941–7949. (19) Li, J. R.; Sculley, J.; Zhou, H. C. Chem. Rev. 2012, 112, 869-932. (20) Foo, M. L.; Horike, S.; Inubushi, Y.; Kitagawa, S. Angew. Chem. Int. Ed. 2012, 51, 6107–6111. (21) Basdogan, Y.; Sezginel, K. B.; Keskin, S. Ind. Eng. Chem. Res. 2015, 54, 8479–8491. (22) Wen, H. M.; Wang, H.; Li, B. Cui, Y.; Wang, H.; Qian, G.; Chen, B. Inorg, Chem. 2016, 55, 7214 –7218.

27



(23) Chen, B.; Xiang, S.; Qian, G. Acc. Chem. Res. 2010, 43, 1115–1124. (24) Horike, S.; Dincǎ, M.; Tamaki, K.; Long, J. R. J. Am. Chem. Soc. 2008, 130, 5854−5855. (25) Yoon, M.; Srirambalaji, R.; Kim, K. Chem. Rev. 2012, 112, 1196−1231. (26) Corma, A.; García, H.; Llabrés i Xamena, F. X. Chem. Rev. 2010, 110, 4606−4655. (27) Liu, J.; Chen, L.; Cui, H.; Zhang, J.; Zhang, L.; Su, C. Y. Chem. Soc. Rev. 2014, 43, 6011−6061. (28) Fisac, D. R.; Aguirre-Díaz, L. M.; Iglesias, M.; Snejko, N.; Puebla, E. G.; Monge, M. A.; Gándara, F.; J. Am. Chem. Soc. 2016, 138, 9089–9092. (29) Zhang, W. Q.; Li, Q. Y.; Zhang, Q.; Lu, Y.; Lu, H.; Wang, W.; Zhao, X.; Wang, X. J. Inorg. Chem. 2016, 55, 1005–1007. (30) Kutzscher, C.; Nickerl, G.; Senkovska, I.; Bon, V.; Kaskel, S.; Chem. Mater. 2016, 28, 2573– 2580. (31) Ugale, B.; Nagaraja, C. M. RSC Adv. 2016, 6, 28854− 28864. (32) Ugale, B.; Dhankhar, S. S.; Nagaraja, C. M. Inorg. Chem. Front. 2017, 4, 348-359. (33) Chen, Y. F.; Ma, Y. C.; Chen, S. M. Cryst. Growth Des. 2013, 13, 4154-4157. (34) Li, P.; Moon, S. Y.; Guelta, M. A.; Harvey, S. P.; Hupp, J. T.; Farha. O. K. J. Am. Chem. Soc. 2016, 138, 8052–8055. (35) Wang, B.; Lv, X. L.; Feng, D.; Xie, L. H., Zhang, J.; Li, M.; Xie, Y.; Li, J. R.; Zhou, H. C. J. Am. Chem. Soc. 2016, 138, 6204–6216. (36) Pal, T. K.; Chatterjee, N.; Bharadwaj, P. K. Inorg. Chem. 2016, 55, 1741–1747. (37) Gole, B.; Bar, A. K.; Mukherjee, P. S. Chem. Commun. 2011, 47, 12137−12139. (38) Allendorf, M. D.; Bauer, C. A.; Bhakta, R. K.; Houk, R. J. T. Chem. Soc. Rev. 2009, 38, 1330−1352. (39) Singh, D.; Nagaraja, C. M. Dalton Trans. 2014, 43, 17912−17915.

28


Page 28 of 33

Page 29 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(40) Kurmoo, M. Chem. Soc. Rev. 2009, 38, 1353−1379. (41) Zeng, Y. F.; Hu, X.; Liu, F. C.; Bu, X. H. Chem. Soc. Rev. 2009, 38, 469−480. (42) Li, H.; Sadiq, M. M.; Suzuki, K.; Ricco, R.; Doblin, C.; Hill, A. J.; Lim, S.; Falcaro, P.; Hill, M. R. Adv. Mater. 2016, 28, 1839–1844. (43) Nagaraja, C. M.; Kumar, N.; Maji, T. K.; Rao, C. N. R. Eur. J. Inorg. Chem. 2011, 2011, 2057−2063. (44) Liu, J.; Zhang, L.; Lei, J.; Shen, H.; Ju, H. ACS Appl. Mater. Interfaces 2017, 9, 2150–2158. (45) Horcajada, P.; Gref, R.; Baati, T.; Allan, P. K.; Maurin, G.; Couvreur, P.; Ferey, G.; Morris, R. E.; Serre, C. Chem. Rev. 2012, 112, 1232-1268. (46) Kundu, T.; Mitra, S.; Patra, P.; Goswami, A.; Díaz, D. D.; Banerjee, R. Chem. Eur. J. 2014, 20, 10514–10518. (47) Lee, K.; Howe, J. D.; Lin, L. C.; Smit, B.; Neaton, J. B. Chem. Mater. 2015, 27, 668−678. (48) Nagaraja, C. M.; Ugale, B.; Chanthapally, A. CrystEngComm 2014, 16, 4805−4815. (49) Zhou, H. C.; Long, J. R.; Yaghi, O. M. Chem. Rev. 2012, 112, 673–674. (50) Li, D. S.; Wu, Y. P.; Zhao, J.; Zhang, J.; Lu, J. Y. Coord. Chem. Rev. 2014, 261, 1−27. (51) Desiraju, G. R.; Vittal, J. J.; Ramanan, A. Crystal engineering: a textbook; World Scientific, 2011. (52) Batten, S. R.; Robson, R. Angew. Chem., Int. Ed. 1998, 37, 1460–1494. (53) Carlucci, L.; Ciani, G.; Proserpio, D. M. Coord. Chem. Rev. 2003, 246, 247–289. (54) Nagarkar, S. S.; Chaudhari, A. K.; Ghosh, S. K. Cryst. Growth Des. 2012, 12, 572–576. (55) Ugale, B.; Singh, D.; Nagaraja, C. M. J. Solid State Chem. 2015, 226, 273–278. (56) Mir, M. H.; Kitagawa, S.; Vittal, J. J. Inorg. Chem. 2008, 47, 7728-7733. (57) Mir, M. H.; Vittal, J. J. Inorg. Chim. Acta 2013, 403, 97-101. (58) Mir, M. H.; Koh, L. L.; Tan, G. K.; Vittal, J. J. Angew. Chem. 2010, 122, 400-403.

29



(59) Batten, S. R. CrystEngComm 2001, 3, 67-72. (60) Friedrichs, O. D.; O'Keeffe, M.; Yaghi, O. M. Solid State Sci. 2003, 5, 73-78. (61) Jiang, H. L.; Makal, T. A.; Zhou, H. C. Coord. Chem. Rev. 2013, 257, 2232-2249. (62) Sakakura, T.; Choi, J. C.; Yasuda, H. Chem. Rev. 2007, 107, 2365-2387. (63) Omae, I. Coord. Chem. Rev. 2012, 256, 1384-1405. (64) North, M.; Pasquale, R.; Young, C. Green Chem. 2010, 12, 1514-1539. (65) Li, Y. N.; Ma, R.; He, L. N.; Diao, Z. F. Catal. Sci. Technol. 2014, 4, 1498-1512. (66) Yu, B.; He, L. N. ChemSusChem. 2015, 8, 52-62. (67) Zhou, Z.; He, C.; Xui, J.; Yang, L.; Duan,C. J. Am. Chem. Soc. 2015, 137, 15066-15069. (68) Qu, J.; Cao, C. Y.; Dou, Z. F.; Liu, H.; Yu, Y.; Li, P.; Song, W. G. ChemSusChem. 2012, 5, 652655. (69) Wu, Z.; Xie, H.; Yu, X.; Liu, E. ChemCatChem. 2013, 5, 1328-1333. (70) Yang, Z. Z.; Zhao, Y. N.; He, L. N.; Gao, J.; Yin, Z. S. Green Chem. 2012, 14, 519-527. (71) Whiteoak, C. J.; Nova, A.; Maseras, F.; Kleij, A. W. ChemSusChem. 2012, 5, 2032-2038. 104. (72) Wilhelm, M. E., Anthofer, M. H.; Cokoja, M.; Markovits, I. I. E.; Herrmann, W. A.; Kuhn, F. E. ChemSusChem. 2014, 7, 1357-1360. (73) Monassier, A.; D’Elia, V.; Cokoja, M.; Dong, H.; Pelletier, J. D. A.; Basset, J. M.; Kühn, F. E. ChemCatChem. 2013, 5, 1321-1324. (74) Langanke, J.; Greiner, L.; Leitner, W. Green Chem. 2013, 15, 1173-1182. (75) Ren, Y.; Shim, J. J. ChemCatChem. 2013, 5, 1344-1349. (76) Song, Q. W.; He, L. N.; Wang, J. Q.; Yasuda, H.; Sakakura, T. Green Chem. 2013, 15, 110-115. (77) Man, M. L.; Lam, K. C.; Sit, W. N.; Ng, S. M.; Zhou, Z.; Lin, Z.; Lau, C. P. Chem. Eur. J. 2006, 12, 1004-1015.

30


Page 30 of 33

Page 31 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(78) Ma, R.; He, L. N.; Zhou, Y. B. Green Chem. 2016, 18, 226-231. (79) Ema, T.; Miyazaki, Y.; Shimonishi, J.; Maeda C.; Hasegawa, J. Y. J. Am. Chem. Soc. 2014, 136, 15270-15279. (80) Clegg, W.; Harrington, R. W.; North M.; Pasquale, R. Chem. Eur. J. 2010, 16, 6828-6843. (81) Escárcega-Bobadilla, M. V.; Martínez Belmonte, M.; Martin, E.; Escudero Adán, E. C.; Kleij, A. W. Chem. Eur. J. 2013, 19, 2641-2648. (82) Lu, X. B.; Zhang, Y. J.; Liang, B.; Li, X.; Wang, H. J. Mol. Catal. A: Chem. 2004, 210, 31-34. (83) Brown, E. V.; Granneman, G. R. J. Am. Chem. Soc. 1975, 97, 621-627. (84) Gao, E. Q.; Cheng, A. L.; Xu, Y. X.; Yan, C. H.; He, M. Y. Cryst. Growth Des. 2005, 5, 1005– 1011. (85) SMART (V 5.628), SAINT (V 6.45a), XPREP, SHELXTL; Bruker AXS Inc., Madison, Wisconsin, USA, 2004. (86) Sheldrick, G. M.; Siemens Area Detector Absorption Correction Program, University of Göttingen, Göttingen, Germany, 2004. (87) Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A. J. Appl. Crystallogr. 1993, 26, 343350. (88) Sheldrick, G. M.; SHELXL-2014, Program for Crystal Structure Solution and Refinement; University of Göttingen, Göttingen,Germany, 2014. (89) Farrugia, L. J. WinGX-A Windows Program for Crystal Structure AnalysisJ. Appl. Crystallogr. 2012, 45, 849-854. (90) Spek, A. L. J. Appl. Crystallogr.2003, 36, 7-13. (91) Dhankhar S. S.; Nagaraja, C. M. RSC. Adv. 2016, 6, 86468–86476. (92) Song, J.; Zhang, Z.; Hu, S.; Wu, T.; Jiang, T.; Han, B. Green Chem. 2009, 11, 1031-1036.

31



(93) Gao, W. Y.; Chen, Y.; Niu, Y.; Williams, K.; Cash, L.; Perez, P. J.; Wojtas, L.; Cai, J.; Chen, Y. S.; Ma, S. Angew. Chem., Int. Ed. 2014, 53, 2615–2619. (94) Beyzavi, M. H.; Stephenson, C. J.; Liu, Y.; Karagiaridi, O.; Hupp, J. T.; Farha, O. K. Front. Energy Res. 2015, 2, 63–72. (95) Kurmoo, M.; Kumagai, H.; Chapman, K. W.; Kepert, C. J. Chem. Commun., 2005, 3012–3014. (96) Ugale, B.; Dhankhar, S. S.; Nagaraja, C. M. Inorg. Chem. 2016, 55, 9757−9766.

32


Page 32 of 33

Page 33 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


For table of contents use only Interpenetrated Metal-Organic Frameworks (MOFs) of Cobalt (II): Structural Diversity, Selective Capture and Conversion of CO2 Bharat Ugale, Sandeep Singh Dhankhar and C. M. Nagaraja*

Three new metal-organic frameworks (MOFs) of Co(II) [{Co(muco)(bpa)(2H2O)}.2H2O]n (1), [{Co(muco)(azopy)}.H2O]n (2) and [{Co(muco)(4bpdp)}.2DMF.H2O]n (3) have been synthesized and structurally characterized. MOF1 exhibits an interesting 3-fold interpenetrated 3D pillar-layered framework structure with 4-c, {66} topology. While 2 and 3 possess 2-fold interpenetrated 3D pillarlayered framework structure with 7-c, {3^3.4^13.5^4.6} net topology. Interestingly, the activated framework of MOF1 shows selective adsorption of CO2 and acts as an efficient recyclable catalyst for heterogeneous cycloaddition of carbon dioxide with epoxides to generate cyclic carbonates with high yield and selectivity even at mild conditions (1 atm of CO2). Thus, the influence of N, N'-donor spacers on the structure, topology and the functionality of MOFs has been presented.

33


Interpenetrated MetalâOrganic Frameworks of ... - ACS Publications

Recommend Documents

Interpenetrated MetalâOrganic Frameworks of ... - ACS Publications