Effect of Coordinated Solvent Molecules on Metal Coordination

Subscriber access provided by UNIV OF CALIFORNIA SAN DIEGO LIBRARIES

Article

Effect of Coordinated-Solvent Molecules on Metal Coordination Sphere and Solvent-Induced Transformations Wen-Qian Zhang, Wen-Yan Zhang, Rui-Dong Wang, Chun-Yan Ren, Quan-Quan Li, Yan-Ping Fan, Bin Liu, Ping Liu, and Yao-Yu Wang Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.6b01366 • Publication Date (Web): 28 Dec 2016 Downloaded from http://pubs.acs.org on December 31, 2016

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 47

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

Effect of Coordinated-Solvent Molecules on Metal Coordination Sphere and Solvent-Induced Transformations Wen-Qian Zhang,§ Wen-Yan Zhang,§ Rui-Dong Wang, Chun-Yan Ren, Quan-Quan Li, Yan-Ping Fan, Bin Liu, Ping Liu,* and Yao-Yu Wang Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, P. R. China KEYWORDS: Mn(II) MOFs, solvent effect, single crystal coordinated solvent exchange, magnetic property

ABSTRACT:

Four

similar

Mn(II)

Metal-Organic

Frameworks

(MOFs),

{[Mn2(nbtc)(H2O)2(S)]·S·0.5H2O}n [S = DMF (1), DMA (2), NMP (3), DEF (4)] (DMF = N,N'-dimethylformamide,

DMA

N-methyl-2-pyrrolidinone, solvothermally

from

DEF

the

6,6'-dinitro-2,2',4,4'-biphenyl

=

nitro

=

N,N'-dimethylacetamide,

N,N'-diethylformamide), and

tetracarboxylic

carboxyl acid

doubly (H4nbtc),

have

NMP been

assembled

functionalized and

=

ligand

characterized

by

single-crystal X-ray diffraction, elemental analyses (EA), infrared spectroscopy (IR), thermogravimetric analyses (TGA) and powder X-ray diffraction (PXRD). All MOFs exhibit unique 3D double-walled open-frameworks with 1D parallelogram channels and have 1 ACS Paragon Plus Environment


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

Page 2 of 47

guest/coordinated water and carbonyl solvent molecules, reasonably providing a good example of the competitive behavior of water and carbonyl solvent molecules and an excellent candidate for studying the single crystal coordinated solvent exchange (SCCSE) transformations. Interestingly, due to the different steric hindrance of the series of coordinated carbonyl solvent molecules, MOFs’ structural differences primarily display on the coordination mode of O1W and coordination sphere of Mn1/Mn2 between MOFs 1(4) and 2(3). And it is also found that a small variation on the lattice parameters, unit cell volume and

density

occurs.

Furthermore,

MOFs

1-3

show

solvent-induced

single-crystal-to-single-crystal (SCSC) transformations, which only exchange coordinated and guest carbonyl solvent molecules (DMF, DMA, NMP). And fortunately, the available single crystal data of 2' and 2'' have been collected, which were obtained by soaking 1 and 3 in DMA solution for 5 days and 7 days respectively and they have the same molecular formula as 2 but slightly different structures from 2. In such transformations, the complete solvent exchanging time discrimination of 2 to 3 (10 days), 3 to 2 (7 days), 3 to 1 (5 days), 1 to 2 (5 days) and 2 to 1 (3 days) is susceptible to the size of carbonyl solvent molecules (NMP > DMA > DMF); and the metal coordination sphere of SCSC regenerated samples is influenced not only by the character of coordinated carbonyl solvents but also the nature of mother crystals. In addition, MOFs 1-4 exhibit antiferromagnetic coupling, confirmed through magnetic susceptibility measurements.

INTRODUCTION Metal-Organic Frameworks (MOFs) have gained considerable attention for their attractive structures and potential applications,1-5 but the assembly processes of MOFs are still undetermined due to numerous effect factors.6-9 Typically solvent molecules are away from the crystal lattice and just affect the cultivation of crystals, yet sometimes the solvent 2 ACS Paragon Plus Environment

Page 3 of 47

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


molecules can act as weakly coordinated ligands to influence the constructions of MOFs. In this case, the size, coordinating ability, electron-pair donating and accepting ability, and steric hindrance of solvents are all significant factors to affect the metal coordination sphere, the coordination connectivity and network.10-13 Up to now, the effect of solvents on MOFs’ formation remains a challenge to not only provide the probability of a given solvent coordinating or not to a metal atom, but also reasonably predict the coordination behavior of solvents with metal centers. Additionally, when the solvent molecules as guests or terminal ligands participate in the crystal lattice, the pseudo-polymorphous structural isomers and their conversions by solvent exchanges may bring out.14-16 Indeed, recently some solvent molecules induced transformations, especially the single crystal coordinated solvent exchange (SCCSE) transformations of crystalline MOFs, have been reported as a new method for the post-synthesis modification.17 Such SCCSE transformations are important to understand the effect of solvents on the structural construction and evolvement, the solid-state chemistry in general, and the relationship between structure and function of MOFs. However, most of the reported solvent-induced transformations only involve guest solvent molecules exchange,18-22 and it is still rare that coordinated solvent molecules are exchanged,23-25 for they refer to the coordination bonds breakage and the new ones formation, which usually damage the crystallinity and long-range structural sequence of the original crystals. Hence, it should be a suitable strategy for calibrating a given solvent’s effect through the analysis and comparison of a series of structures, especially including SCCSE transformations, in which a series of coordinated solvents bond to one transition metal.23-25 However, such available series of structures, which can be compared, are limited. MOFs with aromatic multicarboxylate ligands could be preeminent candidates for researching single crystal to single crystal (SCSC) transformations, because a part of them possess good stability in air and/or in solvent.23,26-28 Some aromatic multicarboxylate ligands, 3 ACS Paragon Plus Environment


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

Page 4 of 47

such as 1,4-benzenedicarboxylic acid (H2BDC), 1,3,5-benzenetricarboxylic acid (H3BTC), biphenyl-3,5,3',5'-tetracarboxylate

acid

biphenyl-3,4,3',4'-tetracarboxylate

acid

(3,5-H4bptc, (3,4-H4bptc,

Scheme

1a)

Scheme

and 1b),

biphenyl-2,2',4,4'-tetracarboxylic acid (2,4-H4bptc, Scheme 1c), have been extensively studied,26,29-32 and their MOFs’ SCSC transformations have also been studied.26,33 While compared with these pure carboxylate ligands, our particular interest focus on the ligand 6,6'-dinitro-2,2',4,4'-biphenyltetracarboxylic acid (H4nbtc, Scheme 1e) because of the nitro and carboxyl doubly functionalized groups, the rotated hindrance of two phenyl rings, suitable size of the phenyl tether, and inadequate exploration in the domain of MOFs. After its several examples reported by us recently,34,35 here as an extension study, a series of similar Mn(II) MOFs {[Mn2(nbtc)(H2O)2(S)]·S·0.5H2O}n [S = DMF (1), DMA (2), NMP (3), DEF (4)] (DMF = N,N'-dimethylformamide, DMA = N,N'-dimethylacetamide, NMP = N-methyl-2-pyrrolidinone,

DEF

=

N,N'-diethylformamide),

exhibiting

unique

3D

double-walled open-frameworks, have been successfully obtained. And they possess two different types of guest and coordinated solvent molecules: one is water molecules, and the other is a series of carbonyl solvent molecules. Therefore, the series of MOFs are good candidates for performing the solvent-induced SCSC transformations, studying the coordination capacity of water and carbonyl solvent molecules with the same Mn(II) atom simultaneously, and calibrating the effect of solvents on metal coordination sphere through the analysis and comparison of their structures. The results show that coordinated solvent molecules play important roles in the structural variation of both as-synthesized and SCSC regenerated samples. In 1-4, accompany with larger steric hindrance of carbonyl solvent molecules in 2 and 3 than that in 1 and 4, the coordination mode of O1W change from bridging in 1 and 4 to terminal in 2 and 3, and the coordination sphere of Mn1 turn from hexa-coordinated distorted octahedron in 1 and 4 into penta-coordinated distorted tetragonal 4 ACS Paragon Plus Environment

Page 5 of 47

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


pyramid geometries in 2 and 3. Furthermore, in the state-liquid guest/coordinated carbonyl solvent molecules exchange transformations of MOFs 1-3, the good quality single crystal of 2' and 2'' were fortunately obtained by soaking 1 and 3 in DMA solution for 5 days and 7 days, respectively, and it is shown that 2, 2' and 2'' have the same molecular formula {[Mn2(nbtc)(H2O)2(DMA)]·DMA·0.5H2O}n but somewhat structural difference. And there exist not only the time-exchanged discrimination based on the size of soaked solvent molecules, but the coordination mode of O1W and the metal coordination sphere difference of SCSC regenerated crystals influenced by the joint contributions of coordinated carbonyl solvents and the nature of mother crystals. In addition, the magnetic properties of 1-4 have also been investigated.

Scheme 1

EXPERIMENTAL SECTION Materials and General Methods. All solvents and raw materials were commercially purchased, and the H4nbtc ligand was purchased from Jinan Henghua Sci. & Tec. Co., Ltd., which were used without further purification. Elemental analyses (C, H, and N) were carried out on a Perkin-Elmer 2400C Elemental Analyzer. The FT-IR spectra (4000-400 cm-1) were recorded with KBr pellets on a Nicolet Avatar 360 FTIR spectrometer. Thermogravimetric analyses (TGA) were performed in N2 stream using a Netzsch TG209F3 equipment at a heating rate of 10 °C/min. Powder X-ray diffraction (PXRD) data were measured by the use of a Bruker D8 ADVANCE X-ray powder diffractometer (Cu-Kα, 1.5418 Å). Variable-temperature magnetic susceptibilities were obtained on a Quantum Design MPMS-XL-7 SQUID magnetometer. Diamagnetic correction was implemented using Pascal’s constant.36 5 ACS Paragon Plus Environment


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

Page 6 of 47

Synthesis of {[Mn2(nbtc)(H2O)2(DMF)]·DMF·0.5H2O}n (1). The First Method. H4nbtc (0.05 mmol, 21 mg) and Mn(OAc)2·4H2O (0.05 mmol, 12 mg) were added in solvents DMF/H2O/CH3CN (2:5:3, 10 mL) with additional two drops of NaOH (0.5 M) aqueous solution. The mixture was put in a 23 mL Teflon-lined stainless steel vessel and heated at 105 °C for 72 hours, and then cooled to room temperature at a rate of 0.1 °C/min. The resulting yellow acicular crystals of 1 were dried in air. Yield: 60% based on H4nbtc. Elemental analysis (%): Calcd for C22H23N4O16.5Mn2: C, 36.84; H, 3.23; N, 7.81. Found: C, 36.88; H, 3.21; N, 7.75. IR (KBr, cm-1): 3432 (m), 3093(w), 2928(s), 1660(s), 1616(s), 1593(s), 1534(m), 1454(m), 1389(s), 1356(s), 1290(s), 1191(w), 1112(w), 930(w), 799(w), 723(m). The Second Method. Freshly prepared 2 or 3 (0.100 g) were soaked in DMF solution (10 mL) in a screw-cap vial container at room temperature for 3 days or 5 days, respectively. The yellow acicular crystals of 1 were isolated by washing with DMF. Synthesis of {[Mn2(nbtc)(H2O)2(DMA)]·DMA·0.5H2O}n (2). The First Method. A similar procedure to above preparation of 1 was used except that the DMF was replaced by DMA (2 ml), and the reaction temperature increased into 120 °C. After slowly cooling to room temperature, the yellow acerate crystals of 2 were acquired. Yield: 58% based on H4nbtc. Elemental analysis (%): Calcd for C24H27N4O16.5Mn2: C, 38.67; H, 3.65; N, 7.52. Found: C, 38.70; H, 3.52; N, 7.60. IR (KBr, cm-1): 3400 (m), 3085(w), 2930(w), 1661(s), 1619(s), 1589(s), 1535(m), 1452(m), 1422(m), 1383(s), 1351(s), 1291(w), 1190(w), 1109(w), 933(w), 790(w), 724(m). The Second Method. Freshly prepared 1 or 3 (0.100 g) were soaked in DMA solution (10 mL) in a screw-cap vial container at room temperature for 5 days or 7 days, respectively. The 6 ACS Paragon Plus Environment

Page 7 of 47

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


yellow acerate crystals of 2' or 2'' were isolated by washing with DMA. Synthesis of {[Mn2(nbtc)(H2O)2(NMP)]·NMP·0.5H2O}n (3). The First Method. A similar procedure to above preparation of 1 was used except that the DMF was replaced by NMP (2 ml), and the reaction temperature increased into 145 °C. After slowly cooling to room temperature, the yellow needle-like crystals of 3 were obtained. Yield: 64% based on H4nbtc. Elemental analysis (%): Calcd for C26H27N4O16.5Mn2: C, 40.59; H, 3.53; N, 7.28. Found: C, 40.82; H, 3.42; N, 7.39. IR (KBr, cm-1): 3407(m), 3085(w), 1664(s), 1620(s), 1591(s), 1537(s), 1453(m), 1382(s), 1345(s), 1304(w), 1188(w), 1115(w), 930(w), 791(w), 720(m). The Second Method. Freshly prepared 2 (0.100 g) were soaked in NMP solution (10 mL) in a screw-cap vial container at room temperature for 10 days. The yellow needle-like crystals of 3 were isolated by washing with NMP. Synthesis of {[Mn2(nbtc)(H2O)2(DEF)]·DEF·0.5H2O}n (4). A similar procedure to above preparation of 1 was used except that the DMF was replaced by DEF (2 ml), and the reaction temperature increased into 145 °C. After the mixture was slowly cooled to room temperature, the yellow needle-shaped crystals of 4 were filtered out. Yield: 50% based on H4nbtc. Elemental analysis (%): Calcd for C26H31N4O16.5Mn2: C, 40.37; H, 4.04; N, 7.24. Found: C, 40.82; H, 4.12; N, 7.29. IR (KBr, cm-1): 3392(m), 3091(w), 1660(s), 1620(s), 1591(s), 1537(s), 1454(m), 1386(s), 1352(s), 1304(w), 1200(w), 1115(w), 930(w), 791(w), 722(m). X-ray Crystallography. Single-crystal diffraction data of these MOFs were collected on a Bruker SMART APEX II 7 ACS Paragon Plus Environment


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

Page 8 of 47

CCD diffractometer equipped with a graphite-monochromated Mo-Kα radiation (λ = 0.71073 Å) by using φ/ω scan technique for 1-4, 2' and 2''. Absorption corrections were implemented by SADABS. All the structures were worked out by the direct methods and refined by full-matrix least-squares refinements based on F2.37 Non-H atoms were placed from Fourier maps and refined anisotropically. The H atoms attached to C atoms were located in calculated positions with a riding model and refined isotropically. The H atoms of water molecules were located from diverse Fourier maps, and then constrained at fixed positions and refined with isotropic displacement parameters. The nitro O4 in 4, the nitro O3, O4, O5, O6 in 2' and 2'', and the carboxyl O7, O8, O9, O10, the coordinated and free DMA molecules in 2'' were treated by dividing into two parts automatically with different occupancy ratio; The coordinated DMA molecules in 2'' were divided into three parts automatically with different occupancy ratio. The highly disordered guest molecules in MOFs 2-4, and 2'', which lead to high R and wR values, were removed by the SQUEEZE routine in PLATON.38 And the final chemical formulas of MOFs 2-4 were estimated from the SQUEEZE results in alliance with the TGA and EA results. Single crystal data as well as details of data collection and refinements for these MOFs are epitomized in Table S1. Selected bond lengths and angles for MOFs 1-4, 2' and 2'' are given in Table S2. CCDC: 1451365-1451370 for 1-4, 2' and 2''.

Scheme 2

RESULTS AND DISCUSSION Syntheses Analysis and Preliminary Characterization. Syntheses of these four Mn(II) MOFs were commodiously implemented under solvothermal conditions, which have been proven to be an efficient technique for the assemblies of MOFs.39,40 As depicted in Scheme 2, the suitable crystals of 1-4 were successfully obtained 8 ACS Paragon Plus Environment

Page 9 of 47

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


by selecting the different carbonyl solvents (DMF/DMA/NMP/DEF) into the synthetic system. Attempts had been made to prepare new MOFs with methanol or alcohol instead of the carbonyl solvents under the same synthetic conditions and solvent ratio at different temperatures, but there is no crystal was synthesized. The IR spectra of 1-4 show strong bands for the deprotonated carboxylate groups in the range of 1620-1616 cm-1 for the asymmetric stretching and in the range of 1356-1345 cm-1 for symmetric stretching, and no typical absorptions of the -COOH group in the 1700-1750 cm-1 range, implying the complete deprotonation of the H4nbtc in 1-4. They also show strong absorptions in the 1537-1534 cm-1 and 1389-1382 cm-1 regions, characteristic of the asymmetric and symmetric vibrations of the nitro groups. In addition, the presence of carbonyl molecules (DMF, DMA, NMP and DEF for 1-4, respectively) are provided by strong and sharp bands at about 1660 cm-1, which correspond to the C=O stretching vibrations. The broad bands at region of 3440-3400 cm-1 agree with the asymmetric vibrations of hydroxyl groups, indicating the existence of water molecules. Various features at region of 3093-2920 cm-1 can be considered as the C-H stretching vibrations. PXRD patterns for 1-4 were measured on bulk crystalline powders to identify the phase purity of the four MOFs. The experimental powder X-ray diffraction patterns match well with simulated patterns (Figure S1-S4), demonstrating the consistency of as-synthesized bulk samples and the testing single crystals. The discrimination of intensity might be owing to the powder samples’ preferred orientation. To study the thermal stabilities of these MOFs, they were subjected to TGA experiments from 30 °C to 700 °C under the nitrogen atmosphere (Figure 1). TG curve of 1 reveals a weight loss of 11.54% from the beginning to 122 °C, corresponding to the releases of lattice water and DMF molecules (calcd. 11.44%), and then a weight reduction of 15.48% in the 122-279 °C range, showing great resemblance to the loss 9 ACS Paragon Plus Environment


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

Page 10 of 47

of two coordinated water molecules and one coordinated DMF (calcd. 15.21%). Upon further heating, a gradual weight decrease of 30.53% appears from 279 to 547 °C, which agrees with the removal of a half nbtc4- ligand (calcd. 29.05%), and then the ligand successively begins to decompose. For 2, the first weight loss is 12.20% which appears from the room temperature to 118 °C, quite consistent with the removal of lattice water and DMA molecules (calcd. 12.86%), after that, a weight loss of 17.22% appears in the 118-295 °C, which is assigned to the loss of coordinated water and DMA molecules (calcd. 16.58%). With the temperature increasing, a half of nbtc4- ligand begins to collapse in the 295-539 °C range (obsd. 27.67%, calcd. 27.90%), and followed by the decomposition of the rest organic networks. For 3, the curve exhibits a weight decrease of 13.87% before 222 °C, which is in agreement with the loss of lattice water and NMP molecules (calcd. 14.05%), and followed by a weight loss of 17.77% in the 222-346 °C range due to the loss of coordinated water and NMP molecules (calcd. 17.57%). Upon further heating, gradual decomposition is observed. For 4, a placid weight loss of 31.40% shows up at 300 °C, corresponding to the whole water and DEF molecules (calcd. 31.97%), and then the framework begins to collapse on further heating.

Figure 1

Crystal

Structures

of

{[Mn2(nbtc)(µ2-H2O)(H2O)(DMF)]·DMF·0.5H2O}n

{[Mn2(nbtc)(H2O)2(DMA)]·DMA·0.5H2O}n {[Mn2(nbtc)(H2O)2(NMP)]·NMP·0.5H2O}n

(1), (2),

(3),

and

{[Mn2(nbtc)(µ2-H2O)(H2O)(DEF)]·DEF·0.5H2O}n (4). The X-ray crystallographic studies reveal that all 1-4 crystallize in monoclinic space group C2/c, and display 3D architectures with different carbonyl solvent molecules (DMF for 1, DMA for 2, NMP for 3 and DEF for 4). The asymmetric unit consists of two Mn(II) ions, one nbtc4- ligand, one coordinated carbonyl solvent molecule, two coordinated H2O molecules, 10 ACS Paragon Plus Environment

Page 11 of 47

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


one lattice carbonyl solvent molecule and half of lattice H2O molecule. All Mn-O lengths in 1-4 fall in the normal ranges (2.092(4)-2.371(3) Å for 1, 2.113(5)-2.329(5) Å for 2, 2.101(6)-2.273(7) Å for 3, 2.084(4)-2.447(4) Å for 4).41-44 In 1 and 4, as shown in Figure 2a and S5a, both Mn1 and Mn2 centers are hexa-coordinated, showing slightly distorted octahedron geometries. Mn1 is completed by four carboxylic oxygen atoms from four nbtc4- ligands which occupy the equatorial plane and two axial oxygen atoms from one µ2-H2O bridge (O1W) and one terminal water molecule (O2W). While Mn2 is coordinated with four carboxylic oxygen atoms belonging to three nbtc4ligands, one µ2-H2O oxygen atom (O1W) and one terminal DMF/DEF oxygen atom (O13). Each nbtc4- ligand acts as a µ7-bridge to link seven Mn(II) ions (four Mn1 and three Mn2 ions), and its dihedral angles between two benzene rings are ca. 89° for 1 and 88° for 4, which are almost perpendicular with each other, showing R- and S-conformations (Figure 2b). In nbtc4-, 4,4'-carboxylate groups take the µ2-η1:η1 bridging mode, and 2,2'-carboxylate groups are the µ2-η2:η0 chelating mode. Therefore, as shown in Figure 2c and 2d, 2,2',4-carboxylate groups bridge four Mn(II) atoms to give rise to an infinite 1D double chain that includes two Mn-O rod-shaped chains, in which the separations of the neighbouring Mn···Mn is 3.424 Å and 3.843 Å for 1 and 3.473 Å and 3.825 Å for 4. Then, through the 4'-carboxyl groups of nbtc4- ligand, each double chain can connect four adjacent chains forming unique 3D double-walled rod-packing MOFs with 1D rhombic channel along the c axis (Figure 4a).

Figure 2

In general, the crystal structures of 2 and 3 are similar to 1 and 4, which have also formed the infinite 1D double chains and the double-walled 3D rod-packing constructions, however, there exist some differences getting noticed. As shown in Figure 3 and S5b, the coordinated carbonyl solvent molecules change into DMA and NMP molecules, respectively, in 2 and 3, 11 ACS Paragon Plus Environment


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

Page 12 of 47

and the bridging water in 1 and 4 turn into terminal ligand with Mn1⋅⋅⋅O1W distance in 2 and 3 beyond the regular ranges of Mn-O bond lengths (2.796 Å for 2, and 2.515 Å for 3).41-44 Therefore, the coordination numbers of Mn1 decrease from 6 to 5, so that the configuration of Mn1 centers change from distorted octahedron in 1 and 4 into distorted tetragonal pyramid in 2 and 3. Meanwhile, the Mn⋅⋅⋅Mn distances in the Mn-O rod-shaped chain for 2 (3.655 Å and 3.884 Å), 3 (3.528 Å and 3.810 Å) are also different from that of 1 and 4. PLATON analyses45 reveal that MOFs 1-4 possess large voids of 2218.9 Å3, 2423.7 Å3, 2380.8 Å3 and 2284.8 Å3, which represent 39.9%, 42.4%, 42.6% and 41.1% per unit cell volume, respectively, after omitting all solvent molecules. Gas adsorption experiments (N2 at 77K and CO2, CH4 at 195K) have been conducted, while they just show surface adsorption probably due to the framework deformation and/or partial collapse stemming from the guest/coordinated solvent molecules releases (Figure S6).

Figure 3

Intriguingly, such double-walled 3D MOFs also can be viewed as the cross-linking of two single-walled 3D structures. MOF 1 as an example has been represented in detail here. The 4,4'-carboxylate groups of nbtc4- firstly join Mn(II) ions to form a single-walled 3D MOF, serving nbtc4- ligands as pillars (Figure 4b). Then, through the 2,2'-carboxyl groups further coordinating with Mn(II) atoms of the adjacent single-walled 3D MOF, the more complicated 3D MOF with double walls is generated (Figure 4c). Even though 3D MOFs based on Mn-O rod-shaped chains and long multicarboxylate ligands have been familiar,46-49 as far as we know, such double-walled 3D MOFs has been rarely reported so far.50-52 In addition, it should be mentioned that because the coordinated DMF molecules are locked inside the short narrow necks of the pore, there is the discrete 1D rhombic channel in this MOF (Figure 5a). Whereas, if these DMF molecules are eliminated, the interconnected 3D channels will be found due to 12 ACS Paragon Plus Environment

Page 13 of 47

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


adjacent 1D channels interlinked together through the opening necks (Figure 5b). Significantly, the coordinated DMF molecules affect the resultant 1D channel.

Figure 4

Figure 5

The Effect of 2,2'-Dicarboxyl Group and Nitro Groups. Strategically designing or selecting featured organic ligands on the basis of their functional groups/substituent, coordination modes, length, and rigidity is an efficient route to achieve expected MOFs.53 In this regard, no matter whether some substituent, such as nitro groups, participate or not in the coordination, it may further exert a profound effect on the assembling process, structures and physical properties of the complexes.54-56 However, the effect of such functional groups/substituent on the structural construction is not explicit. To gain an insight into that function and make expected MOFs, it is significantly important to compare these four structures with other Mn(II) MOFs constructed by similar ligands. By

referring

to

the

literature,

we

have

noticed

other

two

similar

ligands

2,2'-dinitrobiphenyl-4,4'-dicarboxylic acid (H2nbpdc, Scheme 1d) and 2,4-H4bptc (Scheme 1c), and their reported different 3D rod-packing Mn(II) MOFs, [Mn2(nbpdc)2(bpp)]n (1a) (Figure 6b) and [Mn(H2bptc)]n (1b) (Figure 6c), respectively.57,58 Compared with H4nbtc (Scheme 1e), H2nbpdc is short of two carboxyl groups while 2,4-H4bptc of two nitro groups. Structural comparisons of these MOFs show that: in 1, the unique 3D double-walled open-framework with 1D rhombic channel is composed of two single-walled 3D structures constructed by the 4,4'-carboxylate groups and connected by the 2,2'-carboxylate groups (Figure 6a); whereas in 1a, only the 4,4'-carboxyl groups of nbpdc2- link adjacent Mn(II) 13 ACS Paragon Plus Environment


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

Page 14 of 47

atoms forming an infinite rod-shaped 1D Mn-O chain, which connect other four adjacent Mn-O chains through the biphenyl parts of nbpdc2- to form a 3D single-walled MOF; quite different from 1 and 1a, in 1b, four carboxyl groups at 2,2',4,4'-position of H2bptc2- link the Mn(II) atoms and generate a 3D closed-framework through the biphenyl parts of H2bptc2-. As described above, in MOFs 1 and 1a, all nitro groups are uncoordinated and the 4,4'-carboxyl groups similarly run through the adjacent Mn-O chains to support the 3D structures in common. While in 1, the 2,2'-carboxyl groups in the single-walled 3D structure further coordinate with Mn ions of the adjacent single-walled 3D MOF to expand the structure to a complicated double wall. 1a cannot join together further to afford such double-walled framework due to the absence of the 2,2'-carboxyl groups. But, in 1b, due to the lack of nitro groups, the 2,2'-carboxyl groups are in parallel arrangement and the H2bptc2ligands could be arranged back to back, which leads to a close-packed framework different from 1 and 1a. In addition, in 1, all nitro groups of nbtc4- are towards into the channel, which crowd the pores of 1 in some degree, while in 1a, the nitro groups of nbpdc2- are in stagger arrangement. Therefore, because of the steric hindrance of the 2,2'-carboxyl and nitro groups in 1, the angle of its parallelogram channel (63°) is larger than that of 1a (44°), that is, the parallelogram channel in 1a is more flat but lager. The nbtc4- ligands employ a highly twisted conformation wherein the two benzene rings are almost perpendicular with a 89° dihedral angle for 1 (Figure 6d), corresponding to that of 87° and 75° for 1a (Figure 6e) and 1b (Figure 6f), respectively. Thus, the 2,2'-carboxyl groups and nitro groups exert important effects on the final structures, even though the nitro groups are not involved in the coordination, which cause that 1 generate a 3D double-walled framework, 1a form a 3D single-walled structure, and 1b display a 3D close-packed construction.

Figure 6 14 ACS Paragon Plus Environment

Page 15 of 47

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


The Effect of Solvents on the Metal Coordination Sphere in 1-4. Single-crystal X-ray diffraction analyses show that, there exist four different coordinated carbonyl solvents (DMF, DMA, NMP, DEF) in 1-4, and although all these carbonyl solvents as terminal ligands coordinate to the Mn ion through the carbonyl O atoms and Mn2 are hexa-coordinated distorted octahedron geometries, Mn1 centers turn from hexa-coordinated distorted octahedron in 1 and 4 into penta-coordinated distorted tetragonal pyramid geometries in 2 and 3 due to the water molecule O1W as terminal ligand instead of bridging one in 1 and 4. As a result of such changes, a small variation on the lattice parameters and unit cell volume (Table S1) occurs whilst the C2/c space group maintaining. To shed more light on what caused the changes above, further structural analyses have been investigated. According to the analysis results, as shown in Figure 7, it is found that, accompany with the changed coordinated carbonyl solvent molecules, the locations of coordinated atoms, the coordination mode of water molecules, the Mn1⋅⋅⋅Mn2 distances, and the distances between the coordinated solvent molecules are changed. First, for Mn2, the O13-Mn2-O11 and O13-Mn2-O7 of 2 and 3 are smaller than that of 1 and 4 (90.5° and 86.6° for 2, 90.5° and 87.3° for 3, 96.2° and 89.4° for 1, 94.9° and 88.9° for 4), while the angles of O13-Mn2-O1W and O13-Mn2-O9 are larger than that of 1 and 4 (97.8° and 86.5° for 2, 99.3° and 85.0° for 3, 95.9° and 83.6° for 1, 95.7° and 83.0° for 4); And then, the Mn1⋅⋅⋅Mn2 distances and the angles of Mn2-O9-Mn1 and O13-Mn2-Mn1 in 2 and 3 are getting larger than that of 1 and 4 (3.655 Å for 2, 3.528 Å for 3, 3.424 Å for 1, 3.473 Å for 4; 108.1° and 109.4° for 2, 104.7° and 108.1° for 3, 101.3° and 102.8° for 1, 102.9° and 103.3° for 4, respectively), which directly result in the Mn1⋅⋅⋅O1W distance of 2 and 3 beyond the normal range of Mn-O lengths (2.796 Å for 2, 2.515 Å for 3, 2.371 Å for 1, 2.447 Å for 4).41-44 And thus, the coordinated bridging water molecule O1W in 1 and 4 change into terminal one in 2 15 ACS Paragon Plus Environment


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

Page 16 of 47

and 3, and the distances between the coordinated solvent molecules are larger than that of 1 and 4 (O1W⋅⋅⋅O13 and O1W⋅⋅⋅O2W are 3.367 Å and 4.891 Å for 2, 3.326 Å and 4.586 Å for 3, 3.264 Å and 4.435 Å for 1, 3.252 Å and 4.523 Å for 4). Besides, for Mn1, the angles of O9-Mn1-O11 and O1-Mn1-O8 in 2 and 3 become smaller than that of 1 and 4 (141.6° and 167.0° for 2, 146.8° and 167.0° for 3, 151.5° and 173.4° for 1, 149.3° and 170.3° for 4). The results indicate that the fine distinctions of these coordinated carbonyl solvents may play important roles in the metal coordination sphere and the different coordination ways of the coordinated water molecules, despite that the carbonyl solvents all coordinate to the Mn(II) atom through the carbonyl O atoms, and their electron-donating abilities are semblable.59 In general, the electron-donating and accepting abilities of coordinated solvents are broadly accepted to play an important part in the metal coordination sphere, as well as the steric interaction also operates when the solvents bound to the metal centers, however, the steric hindrance work markedly for solvent molecules with a bulky functional group.59 Except for the same carbonyl oxygen atoms O13, the C17 links one group of -N(CH3)2 in DMF, one -N(CH3)2 and one -CH3 in DMA, one -(CH2)3N(CH3) in NMP and one group of -N(CH2CH3)2 in DEF. Notably, the local conformation in the shadow of the C17 for DMF is similar to that for DEF, and for NMP is analogous to that for DMA. Hence, the steric hindrance of NMP and DMA is bulkier than that of DMF and DEF, and further, the steric effect of NMP is slightly larger than that of DMA, and that of DMF is slightly smaller than that of DEF, due to the different substitutional group, that is, the steric hindrance among these four solvents is NMP > DMA > DEF > DMF. So as shown in Figure 7, ascribed to the different steric effect of these four carbonyl solvent molecules, the carbonyl carbon atom C17 of DMF and DEF in their asymmetric unit direct to the orientation of Mn2-O11, while that of DMA and NMP to the Mn2-O1W. Therefore, the larger steric hindrance of DMA and NMP affect the coordination sphere configuration of Mn2, and lead to the angles of O13-Mn2-Mn1 16 ACS Paragon Plus Environment

Page 17 of 47

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 Mn2-O9-Mn1 as well as the distances of Mn1⋅⋅⋅Mn2 and Mn1⋅⋅⋅O1W getting larger, and then influence the coordination sphere configuration of Mn1. Thus, it turns out that the local bulkiness, especially around the coordinated carbonyl O atoms rather than the whole bulkiness of solvent molecules, plays a significant part in the steric effect of solvents in the structural variation of metal coordination sphere and then the coordination ways of the coordinated water molecule.

Figure 7

The Single-Crystal Solvents Exchange Transformations and the Effect of Coordinated Solvents. Furthermore, for 1-4, the presence of guest/coordinated carbonyl solvents and water molecules, as well as the good stability in air (for several months), all prompt us to perform solvent exchange studies on them. Solvents exchanging with water, methanol or alcohol, and the series of carbonyl solvents have been studied, but just the results of carbonyl solvent exchange were obtained. As shown in Scheme 3, when the crystalline samples of 1-4 were selected and immersed in the corresponding carbonyl solvents, studies show that, the guest/coordinated carbonyl solvent molecules in MOFs 1-3 were completely exchanged except 3 to 1 within one month. The crystalline samples of 1 were selected and immersed in DMA for 5 days at room temperature, leading to complete replacement of DMF with DMA affording 2' with retention of crystallinity. In return, the crystalline samples of 2 can be completely reverted to 1 by exposing in DMF for 3 days. Similarly, crystals of 3 can completely transform into 1 and 2'' by dipping crystals of 3 in DMF and DMA for 5 days and 7 days, respectively. And likewise, crystals of 2 can completely convert to 3 in NMP solvent for 10 days, while crystals of 1 cannot probably because the NMP is too larger to enter the 17 ACS Paragon Plus Environment


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

channel supported by DMF. In contrast, no desirable results were found between 1-3 and 4 within one month even though similar attempts had been made, which may be explained by that the DEF with largest size cannot access the channels freely. Moreover, it can be found that the complete transformation from 2 to 1 was observed in a short period (3 days), while that from 1 to 2 required more time (5 days) for the smaller size of DMF made it faster to enter the channels of the open framework supported by DMA. Likewise, in the DMA/NMP solvents system, similar phenomenon was also observed. Thus, among the transformations of 1-4, the situation of solvent-exchange and the time-exchange discrimination are all susceptible to the size of solvents: DEF > NMP > DMA > DMF.11

Scheme 3

All regenerated products of above transformations have been performed through single-crystal X-ray diffraction, PXRD patterns and TGA. Although X-ray diffraction studies on regenerated 1 and 3 just show that the rough single crystal skeleton frameworks remain unchanged due to the highly disordered solvent molecules, both TGA curves and the PXRD patterns of regenerated 1 and 3 are identical to that of the corresponding as-synthesized 1 and 3 respectively and significant different to that of the pristine materials (Figure S1, S3, S7a and S7c), which further demonstrates that the solvent exchange transformations have been thoroughly realized. For regenerated 2' and 2'', though TGA curves are identical to that of the corresponding as-synthesized 2 (Figure S7b), which demonstrates the solvent exchange transformations, their observed PXRD patterns are not completely consistent with that of 2 or the pristine materials (Figure S8), while match well with their simulated patterns (Figure 8). And as shown in Figure 9, further single crystal structural observations for 2' and 2'' indicate that, the carbonyl solvent molecules of DMF and NMP transform into DMA, while compared to 2, 18 ACS Paragon Plus Environment

Page 18 of 47

Page 19 of 47

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


differences are observed on the coordination mode of O1W and coordination sphere of Mn1/Mn2 between these MOFs. In 2', though DMF is replaced by the larger steric hindrance of DMA, the coordination configuration of Mn1 is still hexa-coordinated, holding distorted octahedron geometry like 1, instead of the penta-coordinated Mn1 of 2, attributed to the nature of mother crystal 1. Given that replacement, the distance of Mn1···Mn2 ions increase from 3.424 Å into 3.503 Å and the separation of Mn1-O1W increase from 2.371 Å into 2.453 Å. Consequently, the separation of Mn1-O1W is larger than that of 1, but smaller than that of 2, which is within the normal range of Mn-O bond lengths,41-44 that is, 2' would like to be 2, but it cannot achieve that aspiration due to the restriction of 1 and has to stay at the “middle” position between 1 and 2. So, when the solvent molecule DMF is replaced by lager steric hindrance DMA, 2' was obtained, different from 1 or 2. On the other hand, when NMP is replaced by DMA, 2'' is gained. In 2'', the Mn1-O1W bond is still fractured like that of 2 and 3, while the O1W atom is more far away from Mn1 centers (2.515 Å for 3, 2.848 Å for 2'') and the separation of the Mn1···Mn2 ions increases from 3.528 Å into 3.621 Å. More strikingly, the configuration of Mn1 is hexa-coordinated, rather than the penta-coordinated Mn1 of 2 or 3, because the O10 atom is pushed closely to coordinate with Mn1 center (Mn1-O10, 2.400 Å within the normal ranges of Mn-O bond lengths41-44). So, when the solvent molecule NMP is replaced by DMA, 2'' is obtained, which is distinct from 2 or 3, but maintain the rough structure of mother crystal 3. Besides, during the transformation processes, the guest and coordinated water molecules are always impregnable to the soaked solvents, which reasonably provides an excellent example of the competitive behavior of two coordinated solvents. Notably, such example that guest and coordinated carbonyl solvent molecules could be exchanged simultaneously, to the best of our knowledge, still remains scarce, which plays a key role to probe the structural variation of metal coordination sphere, the coordination connectivity and network. 19 ACS Paragon Plus Environment


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

Page 20 of 47

Figure 8

Figure 9

Magnetic Measurements. For 1, though the 3D network, it could be regarded as 1D Mn-carboxylate chain linked by mixed bridges in the magnetism perspective. In an applied magnetic field of H = 1000 Oe, magnetic properties have been measured on crystalline samples of these MOFs in the 2-300 K temperature regions. As displayed in Figure 10, the χMT value per Mn for 1 at 300 K is 4.240 cm3 K mol-1, slightly lower than the spin-only value of 4.375 cm3 K mol-1 expected from high-spin d5 (S = 5/2) configuration and g = 2.60 Upon cooling, the χMT value displays a gradual decrease to 3.429 cm3 K mol-1 at 50 K, and followed by a sharp decline to 0.255 cm3 K mol-1 at 2 K. This curve is the type of the presence of antiferromagnetic interactions between Mn(II) centers. In the structure of 1, the minimum distance between neighbouring 1D chains is 6.852 Å. It is indicated that the nbtc4- ligands play insignificant parts in propagating magnetic exchanges which mainly appear in the 1D chains. Interestingly, there are two kinds of predominant super-exchange ways within the chains. One connects Mn(II) ions in µ2-η2:η0 and syn-syn bridging modes via two carboxylate groups with the Mn-O-Mn bond angle of 118° ( > 110°), which usually induce weak antiferromagnetic coupling in Mn(II)-MOFs.61 The other links Mn(II) ions through one µ2-aqua, one µ-syn-syn and µ2-η2:η0 bridging carboxylate groups with the value of Mn-OCOOH-Mn and Mn-Owater-Mn of being 101° and 96°, respectively. To evaluate the intrachain coupling, we applied the modified theoretical expression proposed by Rojo for an alternating chain model,62 in which J1 and J2 stand for the alternating exchange constants, S is a classical spin operator, N, g, β and k have their usual meanings. 20 ACS Paragon Plus Environment

Page 21 of 47

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


Ng2 β2 1 + u1 + u2 + u1 u2 χ = S (S + 1) 3kT 1 – u1u2 Where u1 = coth [J1S (S + 1) / kT] – kT / J1S (S + 1), u2 = coth [J2S (S + 1) / kT] – kT / J2S (S + 1) and S = 5/2 For 1, the least-squares fitting reveals that g = 2.03, J1 = – 1.02 cm-1, J2 = – 1.02 cm-1, zJ' = – 2

0.07 cm-1, R = 0.0025 (R = [∑ (χobs T – χcalc T) ∑ (χobs T)2 ]). The negative J1 and J2 further indicate the antiferromagnetic between the Mn(II) centers through the mixed carboxylate groups and the µ2-aqua bridge.63-66 Magnetic data for 2-4 are similar to those of 1 and fit to the model to yield coupling constants, J1 = – 2.12 cm-1, J2 = – 1.08 cm-1, zJ' = – 0.365 cm-1, with g = 2.02, R = 0.0003 (2), J1 = – 1.57 cm-1, J2 = – 1.68 cm-1, zJ' = –0.05 cm-1, with g = 2.01, R = 0.00099 (3) and J1 = – 2.80 cm-1, J2 = – 0.91 cm-1, zJ' = – 0.06 cm-1, with g = 1.98, R = 0.00099 (4) indicative of weak antiferromagnetic coupling as well (Figure S9).

Figure 10

CONCLUSION In summary, a new series of Mn(II) MOFs based on H4nbtc have been constructed successfully under solvothermal conditions with the same reactants but in different carbonyl solvent molecules DMF, DMA, NMP and DEF, respectively. MOFs 1-4 reveal rarely 3D double-walled open-frameworks with 1D parallelogram channels and have guest/coordinated carbonyl solvent molecules and water molecules. And it is indicated that the local bulkiness of carbonyl solvent molecules, especially around the coordinated carbonyl O atoms rather than the whole bulkiness, plays a crucial part in the steric effect of solvents in the structural variation of metal coordination sphere, and the coordinated water molecules showing different coordination modes: as a bridging linker in 1 and 4, but terminal solvent in 2 and 3. 21 ACS Paragon Plus Environment


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

Page 22 of 47

Furthermore, the solvent exchange transformations have been realized between MOFs 1-3. It is noted that, during the transformation processes, only guest/coordinated carbonyl solvent molecules (DMF, DMA, NMP) could be exchanged, while the water molecules cannot be, providing a good example of the competitive behavior of these two kinds of solvents. Meanwhile, it is indicated that the exchanging time is susceptible to the size of carbonyl solvent molecules and the metal coordination sphere of SCSC regenerated samples is influenced by the joint contributions of coordinated carbonyl solvents and the nature of mother crystals. In addition, the magnetic property analyses on 1-4 reveal that these MOFs show antiferromagnetic exchange interactions between the metal centers. ASSOCIATED CONTENT Supporting Information Crystallographic data, PXRD patterns, sorption isotherms, TGA curves, as well as additional tables, structural figures and magnetic susceptibilities. This material is available free of charge via the Internet at http://pubs.acs.org. AUTHOR INFORMATION Corresponding Author *(P. Liu): [email protected]. Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. §Wen-Qian Zhang and Wen-Yan Zhang contributed equally. ACKNOWLEDGMENT 22 ACS Paragon Plus Environment

Page 23 of 47

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


This work was supported by the NSF of China (No. 21673173, 21272184, 21572177, 21371142, 21531007, 21103137 and J1210057), the NSF of Shaanxi Province of China (No. 2016JZ004 and 2015JZ003), the Xi'an City Science and Technology Project (No. CXY1511(3)), the Northwest University Science Foundation for Postgraduate Students (No. YZZ14052 and YZZ15040) and the Chinese National Innovation Experiment Program for University Students (No. 201510697004) for financial support. REFERENCES (1) Bai, Y.; Dou, Y. B.; Xie, L. H.; Rutledge, W.; Li, J. R.; Zhou, H. C. Chem. Soc. Rev. 2016, 45, 2327-2367. (2) Burtch, N. C.; Jasuja, H.; Walton, K. S. Chem. Rev., 2014, 114, 10575-10612. (3) Xu, X. B.; Nosheen, F.; Wang, X. Chem. Mater. 2016, 28, 6313-6320. (4) Cui, Y. J.; Li, B.; He, H. J.; Zhou, W.; Chen, B. L; Qian, G. D. Acc. Chem. Res. 2016, 49, 483-493. (5) Wang, Y. L.; Liu, Z. Y.; Li, Y. X.; Bai, Z. L.; Liu, W.; Wang, Y. X.; Xu X. M.; Xiao C. L.; Sheng, D. P.; Diwu, J.; Su, J.; Chai, Z. F.; Albrecht-Schmitt, T. E.; Wang, S. A. J. Am. Chem. Soc. 2015, 137, 6144-6147. (6) Stock, N.; Biswas, S. Chem. Rev. 2012, 112, 933-969. (7) Rosa, I. M. L.; Costa, M. C. S.; Vitto, B. S.; Amorim, L.; Correa, C. C.; Pinheiro, C. B.; Doriguetto, A. C. Cryst. Growth Des. 2016, 16, 1606-1616. (8) Chen, D. M.; Ma, X. Z.; Zhang, X. J.; Xu, N.; Cheng, P. Inorg. Chem. 2015, 54, 2976-2982. (9) Sun, J. W.; Yan, P. F.; An, G. H.; Sha, J. Q.; Wang, C.; Li, G. M. Dalton Trans. 2016, 45, 1657-1667. (10) Li, L. N.; Wang, S. Y.; Chen, T. L.; Sun, Z. H.; Luo, J. H.; Hong, M. C. Cryst. Growth Des. 2012, 12, 4109-4115. (11) Zhang, M. W; Bosch, M.; Zhou, H. C. CrystEngComm 2015, 17, 996-1000. (12) Huang, W. H.; Luan, X. J.; Zhou, X.; Chen, J.; Wang, Y. Y.; Shi, Q. Z. CrystEngComm 2013, 15, 10389-10398. (13) Diaz-Torres, R.; Alvarez, S. Dalton Trans. 2011, 40, 10742-10750. (14) Li, Y. T.; Li, L.; Zhu, Y. P.; Meng, X. G.; Wu, A. X. Cryst. Growth Des. 2009, 9, 4255-4257. 23 ACS Paragon Plus Environment


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

Page 24 of 47

(15) Tedesco, C.; Erra, L.; Immediata, I.; Gaeta, C.; Brunelli, M.; Merlini, M.; Meneghini, C.; Pattison, P.; Neri, P. Cryst. Growth Des. 2010, 10, 1527-1533. (16) Kang, G.; Jeon, Y.; Lee, K. Y.; Kim, J.; Kim, T. H. Cryst. Growth Des. 2015, 15, 5183-5187. (17) Manos, M. J.; Kyprianidou, E. J.; Papaefstathiou, G. S.; Tasiopoulos, A. J. Inorg. Chem. 2012, 51, 6308-6314. (18) Zhang, X. J; Vieru, V.; Feng, X. W.; Liu, J. L.; Zhang, Z. J.; Na, B.; Shi, W.; Wang, B. W.; Powell, A. K.; Chibotaru, L. F.; Gao, S.; Cheng, P.; Long, J. R. Angew. Chem. Int. Ed. 2015, 54, 9861-9865. (19) Marti-Rujas, J. ; Bonafede, S.; Tushi, D.; Cametti, M. Chem. Commun. 2015, 51, 12357-12360. (20) Ganguly, S.; Mukherjee, S.; Dastidar, P. Cryst. Growth Des. 2016, 16, 5247-5259. (21) Ho, T. Y.; Huang, S. M.; Wu, J. Y.; Hsu, K. C.; Lu, K. L. Cryst. Growth Des. 2015, 15, 4266-4271. (22) Xiao, W. C; Hu, C. H; Ward, M. D. J. Am. Chem. Soc. 2014, 136, 14200-14206. (23) Lan, Y. Q.; Jiang, H. L.; Li, S. L.; Xu, Q. Inorg. Chem. 2012, 51, 7484-7491. (24) Liu, Z. Y.; Yang, E. C.; Li, L. L.; Zhao, X. J. Dalton Trans. 2012, 41, 6827-6832. (25) Kyprianidou, E. J.; Lazarides, T.; Kaziannis, S.; Kosmidis, C.; Itskos, G.; Manos, M. J.; Tasiopoulos, A. J. J. Mater. Chem. A 2014, 2, 5258-5266. (26) Chen, Y. F.; Feng, X.; Huang, X. Q.; Lin, Z. G.; Pei, X. K.; Li, S. Q.; Li, J. K.; Wang, S.; Li, R.; Wang, B. Chem. Eur. J. 2015, 21, 13894-13899. (27) Zhou, X. P.; Xu, Z. T.; Zeller, M.; Hunter, A. D.; Chui, S. S.; Che, C. M. Inorg. Chem. 2011, 50, 7142-7149. (28) Zhao, N.; Sun, F. X.; He, H. M.; Jia, J. T.; Zhu, G. S. Cryst. Growth Des. 2014, 14, 1738-1743. (29) Hu, Z. G.; Nalaparaju, A.; Peng, Y. W.; Jiang, J. W.; Zhao, D. Inorg. Chem. 2016, 55, 1134-1141. (30) Li, X. J.; Sun, X. F.; Li, X. X.; Fu, Z. H.; Su, Y. Q.; Xu, G. Cryst.Growth Des. 2015, 15, 4543-4548. (31) Sun, L. X.; Qi, Y.; Che, Y. X.; Batten, S. R.; Zheng, J. M. Cryst. Growth Des. 2009, 9, 2995-2998. (32) Su, F.; Lu, L. P.; Feng, S. S. J. Mol. Struct. 2015, 1096, 38-42. (33) Li, Q. Q.; Ren, C. Y.; Huang, Y. Y.; Li, J. L.; Liu, P.; Liu, B.; Liu, Y.; Wang, Y. Y. 24 ACS Paragon Plus Environment

Page 25 of 47

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


Chem. Eur. J. 2015, 21, 4703-4711. (34) Ren, C. Y.; Liu, B.; Wu, W. P.; Liu, P.; Yang, G. P.; Kang, Y. F.; Wang, Y. Y. Inorg. Chem. Commun. 2015, 53, 46-49. (35) Li, Q. Q.; Zhang, W. Q.; Ren, C. Y.; Fan, Y. P.; Li, J. L.; Liu, P.; Wang, Y. Y. CrystEngComm 2016, 18, 3358-3371. (36) Carlin, R. L., Magnetochemistry. Spring-Verlag: Berlin, 1986. (37) Sheldrick, G. M., SHELXL-97, Program for the Refinement of the Crystal Structures. University of Göttingen: Germany, 1997. (38) Van Der Sluis, P.; Spek, A. L. Acta Crystallogr. Sect. A 1990, 46, 194-201. (39) Catarineu, N. R.; Schoedel, A.; Urban, P.; Morla, M. B.; Trickett, C. A.; Yaghi, O. M. J. Am. Chem. Soc. 2016, 138, 10826-10829. (40) Wu, Y.; Moorhouse, S. J.; O'Hare, D. Chem. Mater. 2015, 27, 7236-7239. (41) Agarwal, R. A.; Mukherjee, S.; Sañudo, E. C.; Ghosh, S. K.; Bharadwaj, P. K. Cryst. Growth Des. 2014, 14, 5585-5592. (42) Bhattacharya, S.; Bhattacharyya, A. J.; Natarajan, S. Inorg. Chem. 2015, 54, 1254-1271. (43) Yi, F. Y.; Sun, Z. M. Cryst. Growth Des. 2012, 12, 5693-5700. (44) Perea-Buceta, J. E.; Mota, A. J.; Costes, J. P.; Sillanpaa, R.; Krzystek, J.; Colacio, E. Dalton Trans. 2010, 39, 10286-10292. (45) Spek, A. L. J. Appl. Cryst. 2003, 36, 7-13. (46) Sun, M. L.; Zhang, J.; Lin, Q. P.; Yin, P. X.; Yao, Y. G. Inorg. Chem. 2010, 49, 9257-9264. (47) Lin, Z. J.; Zou, R. Q.; Xia, W.; Chen, L. J.; Wang, X. D.; Liao, F. H.; Wang, Y. X.; Lin, J. H.; Burrell, A. K. J. Mater. Chem. 2012, 22, 21076-21084. (48) Zhang, H. B.; Li, N.; Tian, C. B.; Liu, T. F.; Du, F. L.; Lin, P.; Li, Z. H.; Du, S. W. Cryst. Growth Des. 2012, 12, 670-678. (49) He, Y. P.; Tan, Y. X.; Zhang, J. Cryst. Growth Des. 2013, 13, 6-9. (50) Gao, W. Y.; Yan, W. M.; Cai, R.; Meng, L.; Salas, A.; Wang, X. S.; Wojtas, L.; Shi, X. D.; Ma, S. Q. Inorg. Chem. 2012, 51, 4423-4425. (51) Hong, K.; Bak, W.; Chun, H. Inorg. Chem. 2013, 52, 5645-5647. (52) Su, S. Q.; Chen, W.; Song, X. Z.; Zhu, M.; Qin, C.; Song, S. Y.; Guo, Z. Y.; Wang, S.; Hao, Z. M.; Li, G. H.; Zhang, H. J. CrystEngComm 2012, 14, 1681-1686. (53) Lu, W. G.; Wei, Z. W.; Gu, Z. Y.; Liu, T. F.; Park, J.; Park, J.; Tian, J.; Zhang, M. W.; Zhang, Q.; Gentle III, T.; Bosch, M.; Zhou, H. C. Chem. Soc. Rev. 2014, 43, 5561-5593. 25 ACS Paragon Plus Environment


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

Page 26 of 47

(54) Zhang, J. Y.; Jing, X. H.; Ma, Y.; Cheng, A. L.; Gao, E. Q. Cryst. Growth Des. 2011, 11, 3681-3685. (55) Joarder, B.; Desai, A. V.; Samanta, P.; Mukherjee, S.; Ghosh, S. K. Chem. Eur J. 2015, 21, 965-969. (56) Qin, T.; Gong, J.; Ma, J. H.; Wang, X.; Wang, Y. H.; Xu, Y.; Shen, X.; Zhu, D. R. Chem. Commun. 2014, 50, 15886-15889. (57) Li, B. Y.; Li, G. H.; Liu, D.; Peng, Y.; Zhou, X. J.; Hua, J.; Shi, Z.; Feng, S. H. CrystEngComm 2011, 13, 1291-1298. (58) Pan, Z. R.; Xu, J.; Yao, X. Q.; Li, Y. Z.; Guo, Z. J.; Zheng, H. G. CrystEngComm 2011, 13, 1617-1624. (59) Zhang, Y.; Watanabe, N.; Umebayashi, Y.; Ishiguro, S. i. J. Mol. Liq. 2005, 119, 167-170. (60) Kar, P.; Biswas, R.; Ida, Y.; Ishida, T.; Ghosh, A. Cryst. Growth Des. 2011, 11, 5305-5315. (61) Wang, Z. M.; Zhang, B.; Fujiwara, H.; Kobayashi, H.; Kurmooc, M. Chem. Commun. 2004, 416-417. (62) Cortés, R.; Drillon, M.; Solans, X.; Lezama, L.; Rojo, T. Inorg. Chem. 1997, 36, 677-683. (63) Yang, F. L.; Yuan, A. H.; Zhou, H.; Zhou, H. B.; Yang, D.; Song, Y.; Li, Y. Z. Cryst. Growth Des. 2015, 15, 176-184. (64) Chakraborty, P.; Majumder, I.; Banu, K. S.; Ghosh, B.; Kara, H.; Zangrando, E.; Das, D. Dalton Trans. 2016, 45, 742-752. (65) Wang, H. H.; Yuan, H. Q.; Mahmood, M. H. R.; Jiang, Y. Y.; Cheng, F.; Shi, L.; Liu, H. Y. RSC Adv. 2015, 5, 97391-97399. (66) Zhang, M. D.; Zheng, B. H.; Wang, Z.; Jiao, Y.; Chen, M. D. J. Mol. Struct. 2014, 1076, 496-500.

26 ACS Paragon Plus Environment

Page 27 of 47

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 1. The Chemical Drawings of (a) 3,5-H4bptc; (b) 3,4-H4bptc; (c) 2,4-H4bptc; (d) H2nbpdc; (e) H4nbtc

Scheme 2. Synthetic Conditions of MOFs 1-4

Figure 1. TGA curves for MOFs 1-4. 27 ACS Paragon Plus Environment


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

Page 28 of 47

Figure 2. (a) Coordination environment of Mn(II) ions in 1 (the hydrogen atoms of DMF molecule and benzene rings are omitted for clarity). Symmetry mode: A = x – 1/2, y + 1/2, z; B = – x + 1, – y + 2, – z; C = – x + 1, y, – z + 1/2; D = x – 1/2, – y + 3/2, z – 1/2; (b) the equally racemic and mesomeric mixture of crystal with enantiomorphism in 1 (green: Mn, rose: R-conformation nbtc4- ligand, yellow: S-conformation nbtc4- ligand, hydrogen atoms are omitted for clarity); (c) the infinite 1D double chain formed by R- and S-conformation nbtc4ligands and the Mn(II) cations in 1 (nitro groups of nbtc4- ligands and hydrogen atoms are omitted for clarity); (d) the Mn-O rod-shaped chains in 1.

Figure 3. Coordination environment of Mn(II) ions in 2 (the hydrogen atoms of DMA molecule and benzene rings are omitted for clarity). Symmetry mode: A = x, – y + 1, z – 1/2; B = – x + 3/2, y – 1/2, – z + 1/2; C = – x + 3/2, – y + 3/2, – z; D = x + 1/2, y – 1/2, z. 28 ACS Paragon Plus Environment

Page 29 of 47

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 4. (a) The 3D open-framework of 1 with DMF guests filling in the 1D nitro-decorated channel (other nitro groups of nbtc4- ligands and DMF molecules are killed for clarity, the hydrogen atoms are omitted for clarity); (b) The 3D single-walled structure formed by nbtc4ligands linking Mn(II) ions through the 4,4'-carboxyl groups in 1 (nitro groups and solvent molecules are killed for clarity, the hydrogen atoms are omitted for clarity); (c) The 3D double-walled open-framework formed by two single-walled structures which are connected by the 2,2'-carboxyl groups in 1 (nitro groups and solvent molecules are killed for clarity, the hydrogen atoms are omitted for clarity).

Figure 5. Network channels are modeled using the program Mercury with (a) and without (b) coordinated DMF molecules in 1 (the hydrogen atoms have been omitted for clarity).



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

Page 30 of 47

Figure 6. (a) The 3D double-walled open-framework of 1 with 1D channels based on H4nbtc; (b) The 3D single-walled open-framework of 1a with 1D channels based on H2nbpdc (bpp molecules are omitted for clearly comparison); (c) The 3D closed-packed framework of 1b based on 2,4-H4bptc; The coordination modes of 1 (d), 1a (e) and 1b (f). Hydrogen atoms and solvent molecules have been omitted for clarity.

Figure 7. The metal coordination sphere of Mn1 and Mn2 in MOFs 1-4.


Page 31 of 47

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 3. Schematic Representation of Solvents Exchange between MOFs 1-3

Figure 8. PXRD patterns for 2' (a) and 2'' (b).

Figure 9. The metal coordination sphere of Mn1 and Mn2 in MOFs 2' and 2''.



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

Page 32 of 47

Figure 10. Temperature dependence of magnetic susceptibilities in the form of χMT and χM vs. T plots for 1 at 1000 Oe. The solid lines denote the theoretical curves with the best-fit parameters.


Page 33 of 47

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


SYNOPSIS TOC. Series of Mn(II) Metal-Organic Frameworks have been assembled solvothermally, in which 1-3 exhibit state-liquid guest/coordinated carbonyl molecules exchange. The steric hindrance of coordinated carbonyl molecules affects the coordination ways of water molecules and the metal coordination configuration, and that of SCSC regenerated samples is influenced by joint contributions of carbonyl solvents and the nature of mother crystals.



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

The Chemical Drawings of (a) 3,5-H4bptc; (b) 3,4-H4bptc; (c) 2,4-H4bptc; (d) H2nbpdc; (e) H4nbtc Scheme 1

ACS Paragon Plus Environment

Page 34 of 47

Page 35 of 47

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


Synthetic Conditions of MOFs 1-4 Scheme 2



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

TGA curves for MOFs 1-4. Figure 1


Page 36 of 47

Page 37 of 47

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


(a) Coordination environment of Mn(II) ions in 1 (the hydrogen atoms of DMF molecule and benzene rings are omitted for clarity). Symmetry mode: A = x – 1/2, y + 1/2, z; B = – x + 1, – y + 2, – z; C = – x + 1, y, – z + 1/2; D = x – 1/2, – y + 3/2, z – 1/2; (b) the equally racemic and mesomeric mixture of crystal with enantiomorphism in 1 (green: Mn, rose: R-conformation nbtc4- ligand, yellow: S-conformation nbtc4ligand, hydrogen atoms are omitted for clarity); (c) the infinite 1D double chain formed by R- and Sconformation nbtc4- ligands and the Mn(II) cations in 1 (nitro groups of nbtc4- ligands and hydrogen atoms are omitted for clarity); (d) the Mn-O rod-shaped chains in 1. Figure 2



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

Coordination environment of Mn(II) ions in 2 (the hydrogen atoms of DMA molecule and benzene rings are omitted for clarity). Symmetry mode: A = x, – y + 1, z – 1/2; B = – x + 3/2, y – 1/2, – z + 1/2; C = – x + 3/2, – y + 3/2, – z; D = x + 1/2, y – 1/2, z. Figure 3


Page 38 of 47

Page 39 of 47

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


(a) The 3D open-framework of 1 with DMF guests filling in the 1D nitro-decorated channel (other nitro groups of nbtc4- ligands and DMF molecules are killed for clarity, the hydrogen atoms are omitted for clarity); (b) The 3D single-walled structure formed by nbtc4- ligands linking Mn(II) ions through the 4,4'carboxyl groups in 1 (nitro groups and solvent molecules are killed for clarity, the hydrogen atoms are omitted for clarity); (c) The 3D double-walled open-framework formed by two single-walled structures which are connected by the 2,2'-carboxyl groups in 1 (nitro groups and solvent molecules are killed for clarity, the hydrogen atoms are omitted for clarity). Figure 4



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

Network channels are modeled using the program Mercury with (a) and without (b) coordinated DMF molecules in 1 (the hydrogen atoms have been omitted for clarity). Figure 5


Page 40 of 47

Page 41 of 47

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


(a) The 3D double-walled open-framework of 1 with 1D channels based on H4nbtc; (b) The 3D single-walled open-framework of 1a with 1D channels based on H2nbpdc (bpp molecules are omitted for clearly comparison); (c) The 3D closed-packed framework of 1b based on 2,4-H4bptc; The coordination modes of 1 (d), 1a (e) and 1b (f). Hydrogen atoms and solvent molecules have been omitted for clarity. Figure 6



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

The metal coordination sphere of Mn1 and Mn2 in MOFs 1-4. Figure 7


Page 42 of 47

Page 43 of 47

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


Schematic Representation of Solvents Exchange between MOFs 1-3 Scheme 3



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

PXRD patterns for 2' (a) and 2'' (b). Figure 8


Page 44 of 47

Page 45 of 47

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


The metal coordination sphere of Mn1 and Mn2 in MOFs 2' and 2''. Figure 9



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

Temperature dependence of magnetic susceptibilities in the form of χMT and χM vs. T plots for 1 at 1000 Oe. The solid lines denote the theoretical curves with the best-fit parameters. Figure 10


Page 46 of 47

Page 47 of 47

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


SYNOPSIS TOC


Effect of Coordinated Solvent Molecules on Metal Coordination

Recommend Documents