Achieving tailorable gated adsorption by tuning the dynamic behavior of a host porous material is of great interest because of its practical application in gas adsorption and separation. Here we devise a unique cation-exchange approach to tune the dynamic behavior of a flexible anionic framework, [Zn2(bptc)(datrz)]− (denoted as MAC-6, where H4bptc = [1,1′-biphenyl]-3,3′,5,5′-tetracarboxylic acid and Hdatrz = 3,5-diamine-1H-1,2,4-triazole), so as to realize the tailorable gated adsorption. The CO2 adsorption amount at 273 K can be enhanced by exchanging the counterion of protonated dimethylamine (HDMA+) with tetraethylammonium (TEA+), tetrabutylammonium (TBA+), and tetramethylammonium (TMA+), where the adsorption behavior is transferred from nongated to gated adsorption. Interestingly, the Pgo for gate-opening adsorption can be further tuned from 442 to 331 mmHg by simply adjusting the ratio of HDMA+ and TMA+. The origin of this unique tunable property, as revealed by X-ray diffraction experiments and structure models, is rooted at the cation-responsive characteristic of this flexible framework.

Magnetic Fe3O4 nanospheres coated with Mg-MOF-74 have been facilely prepared via epitaxial growth. Owing to the intrinsic hydrophilic pore surface and size-exclusive properties of Mg-MOF-74, the Fe3O4@Mg-MOF-74 core–shell nanoparticles show effective and selective enrichment of 441 N-glycosylation sites of 418 glycopeptides from 125 glycoproteins in 1 μL of human serum.

There is great interest in integration of paramagnetic gadolinium compounds and superparamagnetic iron oxide-based nanoparticles into ordered mesoporous carbon spheres (OMCSs) as a combined platform for T1- and T2-weighted magnetic resonance (MR) imaging and drug carrying. In this work, highly dispersed γ-Fe2O3 and GdPO4 nanoparticle co-functionalized mesoporous carbon spheres were successfully prepared using a 3d–4f heterometallic cluster of [Fe6Gd6(μ3-O)2(CO3)(O3PPh)6(O2CtBu)18] as the precursor. The study reveals that multi-scale confinement effects play a role in concurrent generation of Fe and Gd nanoparticles in the carbon matrix. In addition, dual-mode MR imaging and drug carrying properties were evaluated by in vitro experiments, showing satisfactory r1 and r2 relaxivity values of 8.2 and 94.3 mM−1 s−1, respectively, and doxorubicin hydrochloride (DOX) carrying amount of 132 mg g−1, suggesting potential as a combined system for diagnosis and therapy.

There is great interest in integration of paramagnetic gadolinium compounds and superparamagnetic iron oxide-based nanoparticles into ordered mesoporous carbon spheres (OMCSs) as a combined platform for T1- and T2-weighted magnetic resonance (MR) imaging and drug carrying. In this work, highly dispersed γ-Fe2O3 and GdPO4 nanoparticle co-functionalized mesoporous carbon spheres were successfully prepared using a 3d–4f heterometallic cluster of [Fe6Gd6(μ3-O)2(CO3)(O3PPh)6(O2CtBu)18] as the precursor. The study reveals that multi-scale confinement effects play a role in concurrent generation of Fe and Gd nanoparticles in the carbon matrix. In addition, dual-mode MR imaging and drug carrying properties were evaluated by in vitro experiments, showing satisfactory r1 and r2 relaxivity values of 8.2 and 94.3 mM−1 s−1, respectively, and doxorubicin hydrochloride (DOX) carrying amount of 132 mg g−1, suggesting potential as a combined system for diagnosis and therapy.

Exploring the adsorption and separation of water, methanol, and ethanol is important concerning the use of a sustainable energy source from biofuel. In this paper, the effects of the flexibility of substituted groups have been studied based on three iso-reticular metal–organic frameworks (MOFs), in which the pore surface is decorated with propargyl (–CH2–CCH), allyl (–CH2–CHCH2), and propyl (–CH2–CH2–CH3) groups respectively. These substituted groups stretch into the channel, acting as gates, and the gate-opening for guests is controlled by the flexibility as well as host–guest interactions. Our study results indicate that (i) the adsorption capacity of water, methanol and ethanol enhances accordingly with the increase of the flexibility of substituted groups; (ii) the adsorptive discrimination of water, methanol, and ethanol on this porous sorbent could be tuned by varying the substituted groups.

The reaction of X-H2BDC (X = H, Br, NO2 and CH3) and methyl-functionalized dmbpy ligands with metal salts under different solvent media conditions generates nine structurally diverse zinc(II)/cadmium(II)-based coordination polymers (CPs), {[Zn2(BDC)2(DMF)3]·DMF}n (1), [Zn(BDC)2(dmbpy)]n (2), {[(Me2NH2)2Zn3(Br-BDC)4]·3DMF·3H2O}n (3), [Zn2(Br-BDC)2(dmbpy)]n (4), {[Zn13(NO2-BDC)8(μ3-OH)2(μ2-OH)6(H2O)4]·12H2O·2NO3}n (5), [Zn2(NO2-BDC)2(dmbpy)(H2O)2]n (6), {[Cd(NO2-BDC)(dmbpy)0.5(H2O)]·(ACN)·H2O}n (7), [Zn(CH3-BDC)(dmbpy)0.5(H2O)]n (8), and [Zn(CH3-BDC)(dmbpy)0.5]n (9) (H2BDC = isophthalic acid, Br-H2BDC = 5-bromoisophthalic acid, NO2-H2BDC = 5-nitroisophthalic acid, CH3-H2BDC = 5-methylisophthalic acid, dmbpy = 2,2′-dimethyl-4,4′-bipyridine, DMF = N,N-dimethylformamide, ACN = acetonitrile). All the compounds are synthesized using dual linkers (X-H2BDC and dmbpy). 1 and 7–8 show a 2D (4,4) network when dinuclear metal ions and ligands are regarded as nodes and linkers, respectively. 2 is a wave-like chain with BDC ligands alternately pointing up and down. CPs 3–6 and 9 all exhibit 3D networks with 5-connected sqp, 6-connected jsm, 6-connected pcu, (3,4)-connected dmc and 6-connected jsm topologies, respectively. Furthermore, luminescence, thermogravimetric and chemical stability properties of these CPs were investigated. The results suggest that both organic ligands and solvent media influence the final resulting CPs.

Metal–organic frameworks with tunable functional groups like solid-solution have received considerable interest. In this paper, a crs-type structure built of [Zn3(OH)(dmtrz)3] triazolate-trinuclear and [Zn2(COO)4] paddlewheel units, linked by 3,5-dimethyl-1,2,4-triazolate (dmtrz) and isophthalate (ipa) ligands (named as MAC-4-A), has been used as a prototype framework. Four types of functional groups (B: 5-hydroxyisophthalate, C: 5-aminoisophthalate, D: 5-ethoxyisophthalate, and E: 5-acetamidoisophthalate) have been integrated into the framework, giving isostructures of MAC-4-B to E, respectively. Then, by the solid-solution framework approach, four group samples are prepared, which are MAC-4-AB-x, MAC-4-AC-x, MAC-4-AD-x, and MAC-4-AE-x (x denoted as the ratio of functional ligands in the framework, x = 0.3, 0.5, 0.7), and their CO2 and N2 adsorptions have been studied. Our results revealed that the CO2 capacity is enhanced with the increase of functional groups and then decreases, showing a maximum uptake amount on MAC-4-AB-0.5, MAC-4-AC-0.5, MAC-4-AD-0.7, and MAC-4-AE-0.5 at 298 K and 1 bar, respectively. On the other hand, the calculated selectivity of CO2 over N2 gradually increases, giving the highest selectivity after the pore surface is completely functionalized.

A flexible structure of {[Zn2(dmtrz)2(L1)]·6H2O}n (MAC-11) (Hdmtrz = 3,5-dimethyl-1H,1,2,4-triazole, H2L1 = (E)-4,4′-stilbenedicarboxylic acid), which is a self-catenated rob-type net built of two-dimensional [Zn(dmtrz)] layers pillared by L1 ligands, has been solvothermally synthesized. It shows an interesting thermo/water-induced reversible phase transformation accompanied by a photoluminescence response from 418 nm to 453 nm. Based on an iso-framework of {[Zn2(dmtrz)2(L2)]·4H2O}n (MAC-13, H2L2 = (E)-azobenzene-4,4′-dicarboxylic acid), a pcu-type framework of {[Zn2(trz)2(L1)]·4H2O}n (MAC-14, Htrz = 1H, 1,2,4-triazole), and a layered structure of [Zn(dmtrz)(HCOO)], a possible mechanism for the photoluminescence response to the reversible phase transformation for MAC-11 was also proposed.

Two metal–organic frameworks containing a geometrically spin-frustrated trinuclear-triangular copper cluster ([Cu3O]) have been successfully isolated, which are {[Cu4.5(μ3-OH)(dmtrz)3(m-bdc)2.5(H2O)2(CH3OH)(DMF)]·DMF·5H2O}n (MAC-8) and {[Cu5(μ3-OH)(dmtrz)3(bdc)3(H2O)4]·3H2O}n (MAC-9) (Hdmtrz = 3,5-dimethyl-1H-1,2,4-triazole, H2m-bdc = 1,3-benzenedicarboxylic acid, H2bdc = 1,4-benzenedicarboxylic acid, DMF = N′,N-dimethylformamide). Magnetic and gas adsorption studies revealed the successful combination of strong antiferromagnetic properties (Jav = −106.6 and −113.7 cm–1 for [Cu3O] in MAC-8 and MAC-9, respectively) and high surface areas (1058 m2/g for MAC-8 and 1242 m2/g for MAC-9) in both of the structures. Further structural studies revealed that the high surface areas could be ascribed to the unique two-dimensional hexagonal pattern of [Cu3(O)] clusters, in which the [Cu3(O)] clusters are connected to each other in an end-end fashion via mononuclear copper ions/paddle-wheel units.

A three-dimensional porous structure of [Zn7O2(bpdc)4(dmpp)2]·6DEF·10H2O (MAC-7, H2bpdc = 4,4′-biphenyldicarboxylic acid, Hdmpp = 3,5-dimethyl-4-(4′-pyridyl)pyrazole), built of 12-bridged carboxylate-pyrazolate shared Zn7O2 clusters, has been synthesized. Because of the presence of 12-bridged carboxylate-pyrazolate shared building block, MAC-7 is a double-linked pcu-type framework and shows reversible phase transformation. Photoluminescent property studies indicate that MAC-7 could sense nitrobenzene over toluene, p-xylene, and mesitylene by luminescent quenching.

A three-dimensional (3D) porous structure of [Cu3(μ3-OH)(μ2-O)(dmtrz)2(HCOO)(μ2-H2O)(H2O)3]·H2O (1) has been in situ solvothermally synthesized. In 1, the trinuclear triangular [Cu3(μ3-OH)(μ2-O)(dmtrz)2] cluster connects itself infinitely, resulting in the type-II channel structure, which is different from that of the rigid type-I channel structure reported previously. Reversible dehydration and rehydration induced crystal-to-amorphous-like phase transformation for structure 1 has been observed and confirmed by PXRD patterns and gas adsorption. Furthermore, as a response to the structural transformation, the stimuli-induced modulation of magnetic properties have been observed.

Solvothermal reaction of [1,1′-biphenyl]-3,3′,5,5′-tetracarboxylic acid (H4bptc), 3,5-diamine-1H-1,2,4-triazole (Hdatrz) and zinc acetate affords a three-dimensional structure of [Zn2(bptc)(datrz)](CH3)2NH2·2H2O (MAC-6). It is a (3,6)-connected framework built of paddle-wheel and triazolate-dinuclear metal clusters together with bptc ligands, and shows a novel (42.6)2(44.66.85) topology. Heating crystal samples of MAC-6 leads to the structure transformation to [Zn2(bptc)(datrz)(H2O)0.5](CH3)2NH2·H2O (MAC-6′), in which the paddle-wheel unit deforms to a dinuclear unit. Remarkably, MAC-6′ can reversibly recover to MAC-6 when the samples of MAC-6′ were immersed into DMF. The deformation and reformation of the paddle-wheel unit were studied by single-crystal-to-single-crystal (SCSC) transformation. In addition, their photoluminescent properties were also studied.

Magnetic Fe3O4 nanospheres coated with Mg-MOF-74 have been facilely prepared via epitaxial growth. Owing to the intrinsic hydrophilic pore surface and size-exclusive properties of Mg-MOF-74, the Fe3O4@Mg-MOF-74 core–shell nanoparticles show effective and selective enrichment of 441 N-glycosylation sites of 418 glycopeptides from 125 glycoproteins in 1 μL of human serum.

Exploring the adsorption and separation of water, methanol, and ethanol is important concerning the use of a sustainable energy source from biofuel. In this paper, the effects of the flexibility of substituted groups have been studied based on three iso-reticular metal–organic frameworks (MOFs), in which the pore surface is decorated with propargyl (–CH2–CCH), allyl (–CH2–CHCH2), and propyl (–CH2–CH2–CH3) groups respectively. These substituted groups stretch into the channel, acting as gates, and the gate-opening for guests is controlled by the flexibility as well as host–guest interactions. Our study results indicate that (i) the adsorption capacity of water, methanol and ethanol enhances accordingly with the increase of the flexibility of substituted groups; (ii) the adsorptive discrimination of water, methanol, and ethanol on this porous sorbent could be tuned by varying the substituted groups.

There is great interest in integration of paramagnetic gadolinium compounds and superparamagnetic iron oxide-based nanoparticles into ordered mesoporous carbon spheres (OMCSs) as a combined platform for T1- and T2-weighted magnetic resonance (MR) imaging and drug carrying. In this work, highly dispersed γ-Fe2O3 and GdPO4 nanoparticle co-functionalized mesoporous carbon spheres were successfully prepared using a 3d–4f heterometallic cluster of [Fe6Gd6(μ3-O)2(CO3)(O3PPh)6(O2CtBu)18] as the precursor. The study reveals that multi-scale confinement effects play a role in concurrent generation of Fe and Gd nanoparticles in the carbon matrix. In addition, dual-mode MR imaging and drug carrying properties were evaluated by in vitro experiments, showing satisfactory r1 and r2 relaxivity values of 8.2 and 94.3 mM−1 s−1, respectively, and doxorubicin hydrochloride (DOX) carrying amount of 132 mg g−1, suggesting potential as a combined system for diagnosis and therapy.

There is great interest in integration of paramagnetic gadolinium compounds and superparamagnetic iron oxide-based nanoparticles into ordered mesoporous carbon spheres (OMCSs) as a combined platform for T1- and T2-weighted magnetic resonance (MR) imaging and drug carrying. In this work, highly dispersed γ-Fe2O3 and GdPO4 nanoparticle co-functionalized mesoporous carbon spheres were successfully prepared using a 3d–4f heterometallic cluster of [Fe6Gd6(μ3-O)2(CO3)(O3PPh)6(O2CtBu)18] as the precursor. The study reveals that multi-scale confinement effects play a role in concurrent generation of Fe and Gd nanoparticles in the carbon matrix. In addition, dual-mode MR imaging and drug carrying properties were evaluated by in vitro experiments, showing satisfactory r1 and r2 relaxivity values of 8.2 and 94.3 mM−1 s−1, respectively, and doxorubicin hydrochloride (DOX) carrying amount of 132 mg g−1, suggesting potential as a combined system for diagnosis and therapy.