Isoreticular Metal-Organic Frameworks with Aromatic Pores and Dimethylammonium Cations Enable Separation of Light Hydrocarbons and Xenon/Krypton.

The separation of C2-C3 hydrocarbons from methane in natural gas and xenon/krypton purification are crucial yet challenging industrial processes. Herein, we report two isoreticular metal-organic frameworks, ZJU-89 and ZJU-90, featuring aromatic pore environments and dimethylammonium cations, that synergistically enhance the separation of these industrially relevant gas mixtures. ZJU-90 exhibits an exceptional separation performance, achieving CH/CH and CH/CH ideal adsorbed solution theory (IAST) selectivities of 1065 and 48, respectively, at ambient conditions, outperforming most reported adsorbent materials.

Leveraging Diffusion Kinetics to Reverse Propane/Propylene Adsorption in Zeolitic Imidazolate Framework-8.

The separation challenge posed by propylene/propane mixtures arises from their nearly identical molecular sizes and physicochemical properties. Metal-organic frameworks (MOFs) have demonstrated potential in addressing this challenge through the precision tailoring of pore sizes and surface chemistry. However, introducing modifications at the molecular level remains a considerable hurdle.

Customizing Metal-Organic Frameworks by Lego-Brick Strategy for One-Step Purification of Ethylene from a Quaternary Gas Mixture.

One-step purification of ethylene (C H ) from a quaternary gas mixture of C H /C H /C H /CO by adsorption is a promising separation process, yet developing adsorbents that synergistically capture various gas impurities remains challenging. Herein, a Lego-brick strategy is proposed to customize pore chemistry in a unified framework material. The ethane-selective MOF platform is further modified with customized binding sites to specifically adsorb acetylene and carbon dioxide, thus one-step purification of C H with high productivity of polymer-grade product (134 mol kg ) is achieved on the assembly of porous coordination polymer-2,5-furandicarboxylic acid (PCP-FDCA) and PCP-5-aminoisophthalic acid (IPA-NH ).

Modulating the Structures and Magnetic Properties of Dy(III) Single-Molecule Magnets through Acid-Base Regulation.

Chemical modulation on the structures and physical properties of the coordination complexes is of great interest for the preparation of new functional materials. By changing the acidity or basicity of the reaction medium, the deprotonation degree of a multidentate ligand with multiple active protons, Hdaps (Hdaps = ','″-((1,1')-pyridine-2,6-diylbis(ethan-1-yl-1-ylidene))bis(2-hydroxybenzohydrazide)), can be regulated on purpose. With this ligand of different deprotonation and charges, three new Dy complexes ([Dy(Hdaps)(CHCOO)(EtOH)]·CHCOOH (), [Dy(Hdaps)(EtOH)(HO)(MeOH)](CFSO)·(HO) (), and [Dy(Hdaps)(Hdaps)(μ-OH)(EtOH)(HO)] ()) of different nuclearities (mono-, di-, and trinuclear for to , respectively) have been synthesized and characterized structurally and magnetically.

Macrocycle supported dimetallic lanthanide complexes with slow magnetic relaxation in Dy analogues.

Six dimetallic lanthanide complexes, [Ln2(L')(acac)4] (1Dy-3Gd) (Ln = Dy (1Dy), Tb (2Tb) and Gd (3Gd)) and [Ln2(L')(tfac)4] (4Dy-6Gd) (Ln = Dy (4Dy), Tb (5Tb) and Gd (6Gd)) (H2L' = 1,9-dichloro-3,7,11,15-tetraaza-1,9(1,3)-dibenzenacyclohexadecaphane-2,10-diene-1,9-diol), have been synthesized by the reaction of lanthanide nitrates with the HL ligand in the presence of acetylacetonate (acac) (or trifluoroacetylacetonate (tfac) and triethylamine (HL = 4-chloro-2,6-bis(-((3-((3-(dimethylamino)propyl)amino)propyl)imino)methyl)phenol). Ln-Assisted modification of the Schiff base HL occurred and led to the formation of a new macrocyclic ligand (H2L'). X-ray crystallographic analysis revealed that the LnIII ions of complexes 1Dy-6Gd are all eight-coordinated in a square antiprismatic geometry with D4d local symmetry.

Reversible On-Off Switching of the Hysteretic Spin Crossover in a Cobalt(II) Complex via Crystal to Crystal Transformation.

Reversible controlling and switching of magnetic bistability remains relatively difficult. Here, reversible on-off switching of a hysteretic spin transition in a Co complex via a single-crystal to single-crystal (SC-SC) transformation during dehydration and rehydration was reported. Upon dehydration, a switching from a basically low spin state to an abrupt and hysteretic spin crossover (SCO) with broad hysteresis loops was achieved.

A family of lanthanide complexes with a bis-tridentate nitronyl nitroxide radical: syntheses, structures and magnetic properties.

Eleven new lanthanide complexes based on a bis-tridentate nitronyl nitroxide radical NIT-Pm2Py (2-(4,6-di(pyridin-2-yl)pyrimidin-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxy-3-oxide), namely (NIT-Pm2Py)Ln(hfac) (Ln = Gd (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6)), [(NIT-Pm2Py)Ln(hfac)]·xHO (Ln = Gd (7), Tb (8), Ho (10), x = 0.5 for 7 and 1 for 8 and 10) and (NIT-Pm2Py)Ln(hfac) (Ln = Dy (9), Er (11)) were prepared and characterized. These complexes can be selectively prepared by controlling the reaction ratio of Ln(hfac)·2HO to the radical ligand NIT-Pm2Py.

Two three-dimensional [Mo(CN)]-based magnets showing new topologies and ferrimagnetic ordering below 80 K.

The rational design and synthesis of heptacyanomolybdate-based magnets remain a challenge due to the complexity of this system. Here, we reported the crystal structures and magnetic properties of two three-dimensional (3D) frameworks prepared from the self-assembly of the [Mo(CN)] unit with Mn ions in the presence of different amide ligands, namely Mn(DMF)(HO)[Mo(CN)]·HO·CHOH (1) and Mn(DEF)(HO)[Mo(CN)] (2) (DMF = N,N'-dimethylformamide and DEF = N,N'-diethylformamide). Single-crystal structure determinations showed that compound 1 crystallizes in the triclinic space group Pī, while 2 crystallizes in the monoclinic space group P2/n.

Spin crossover in hydrogen-bonded frameworks of Fe complexes with organodisulfonate anions.

We present here the syntheses, crystal structures, and thermal and magnetic properties of a series of mononuclear Fe spin crossover (SCO) complexes of the formula [Fe(bamp)]·Anion·Solv (Anion = NDS, Solv = 2HO, 1; Anion = BPDS, Solv = 4.4HO, 2; Anion = ABDS, Solv = EtO and HO, 3; Anion = DNDS, Solv = MeCN, 4; bamp = 2,6-pyridinedimethanamine, HNDS = 1,5-naphthalenedisulphonic acid, HBPDS = 4,4'-biphenyldisulphonic acid, HABDS = 4,4'-azobenzenedisulfonic acid, HDNDS = 4,4'-dinitrostilbene-2,2'-disulfonic acid). The structures and SCO properties of these complexes can be finely modified by organodisulfonate couteranions.

Syntheses and magnetic properties of a bis-tridentate nitronyl nitroxide radical and its metal complexes.

The first bis-tridentate nitronyl nitroxide mono-radical was synthesized. From this ligand and a bis-bidentate nitronyl nitroxide ligand, metal complexes of MnII and CoII ions were also synthesized and characterized. Field-induced slow magnetic relaxation was observed in the radical-bridged CoII complex.

Heterometallic MLn (M = Co/Zn; Ln = Dy/Y) Complexes with Pentagonal Bipyramidal 3d Centers: Syntheses, Structures, and Magnetic Properties.

We herein reported the syntheses, structures, and magnetic properties of three dinuclear heterometallic MLn complexes, namely, [MLn(HL)(CHOH)(NO)](NO)·S (M = Co, Ln = Dy, S = MeOH (1); M = Zn, Ln = Dy, S = MeOH (2); M = Co, Ln = Y, S = MeNO (3), HL = 2,6-diacetylpyridine bis[2-(semicarbazono) propionylhydrazone]. Synthesized from the predesigned multidentate ligand HL, which has two different coordination pockets (smaller NO and larger NO pockets) suitable for either a 3d or a 4f metal center, all these complexes have very similar structures, where the M centers possess a pentagonal bipyramidal (PBP) geometry and the Ln sites have a tetradecahedron geometry. Magnetic measurements on these compounds revealed the existence of weak ferromagnetic coupling between the Co and Dy centers and the field-induced slow magnetic relaxation of all three complexes.

Syntheses, structures, and magnetic properties of three new Mn-[Mo(CN)] molecular magnets.

By reaction of K4[MoIII(CN)7]·2H2O, Mn(ClO4)2·6H2O and bidentate chelating ligands, three new cyano-bridged compounds, namely Mn2(3-pypz)(H2O)(CH3CN)[Mo(CN)7] (1), Mn2(1-pypz)(H2O)(CH3CN)[Mo(CN)7] (2) and Mn2(pyim)(H2O)(CH3CN)[Mo(CN)7] (3) (3-pypz = 2-(1H-pyrazol-3-yl)pyridine, 1-pypz = 2-(1H-pyrazol-1-yl)pyridine, pyim = 2-(1H-imidazol-2-yl)pyridine), have been synthesized and characterized structurally and magnetically. Single crystal X-ray analyses revealed that although the chelating ligands are different, compounds 1 to 3 are isomorphous and crystallize in the same monoclinic space group C2/m. Connected by the bridging cyano groups, one crystallographically unique [Mo(CN)7]4- unit and three crystallographically unique MnII ions of different coordination environments form similar three-dimensional frameworks, which have a four-nodal 3,4,4,7-connecting topological net with a vertex symbol of {43}{44·62}2{410·611}.

Single-ion magnetism in seven-coordinate Yb complexes with distorted D coordination geometry.

Two seven-coordinate compounds with pentagonal bipyramidal Yb centers, namely, [Yb(HBmshp)(DMF)Cl]·DMF·1.5HO (1) and [Yb(HBmshp)(DMF)Cl]·HBmshp (2) (HBmshp = (2,6-bis[(3-methoxysalicylidene)hydrazinecarbonyl]-pyridine)) were synthesized by changing the molar ratio of reactants in DMF. The structures of compounds 1 and 2 are very similar, except for the existence of different lattice molecules: one DMF and one and a half water molecules in 1, and one neutral uncoordinated ligand in 2.

Reversible On-Off Switching of a Single-Molecule Magnet via a Crystal-to-Crystal Chemical Transformation.

Dynamic molecular crystals are of high interest due to their potential applications. Herein we report the reversible on-off switching of single-molecule magnet (SMM) behavior in a [Mo(CN)] based molecular compound. Upon dehydration and rehydration, the trinuclear MnMo molecule [Mn(L)(HO)][Mo(CN)]·2HO (1) undergoes reversible crystal-to-crystal transformation to a hexanuclear MnMo compound [Mn(L)(HO)][Mn(L)][Mo(CN)] (2).

Two-dimensional frameworks formed by pentagonal bipyramidal cobalt(ii) ions and hexacyanometallates: antiferromagnetic ordering, metamagnetism and slow magnetic relaxation.

We herein report the syntheses, structures, and magnetic properties of two isostructural two-dimensional (2D) coordination polymers based on a pentagonal bipyramidal Co unit [Co(TODA)] and two hexacyanometallates, namely [M(CN)][Co(TODA)]·9HO (M = Cr (1), Co (2), TODA = 1,4,10-trioxa-7,13-diazacyclopentadecane). Structure analyses show that both complexes have 2D honeycomb structures where the [Co(TODA)] units are bridged by the [M(CN)] groups through three cyano groups in the facial positions. Magnetic investigation reveals ferromagnetic coupling between the Cr and Co centres through cyanides in 1.

Room-temperature switching of magnetic hysteresis by reversible single-crystal-to-single-crystal solvent exchange in imidazole-inspired Fe(ii) complexes.

The recent upsurge in molecular magnetism reflects its application in the areas of sensors and molecular switches. Thermal hysteresis is crucial to the molecular bistability and information storage, a wide hysteresis near room temperature is expected to be of practical sense for the molecular compound. In this work, spin crossover iron(ii) complexes [Fe(Liq)2](BF4)2·(CH3CH2)2O (1-Et2O) and [Fe(Liq)2](BF4)2·3H2O (1-3H2O) were prepared and structurally and magnetically analysed.

Metallogrid Single-Molecule Magnet: Solvent-Induced Nuclearity Transformation and Magnetic Hysteresis at 16 K.

Structural assembly and reversible transformation between a metallogrid Dy4 SMM (2) and its fragment Dy2 (1) were established in the different solvent media. The zero-field magnetization relaxation was slowed for dysprosium metallogrid (2) with relaxation barrier of Ueff = 61.3 K when compared to Dy2 (1).

Redox Modulation of Spin Crossover within a Cobalt Metallogrid.

A self-assembled cobalt molecular grid of a pyrazine-bridged bis-tridentate ligand (L(R)), where R = H (1), CH3 (2), and Br (3), was prepared and structurally characterized. Depending on the electronic effects of the substituents on the ligand, the redox of the metal center was systematically modulated, and the magnetic behavior from essentially high-spin Co(II) in 3 versus completely diamagnetic Co(III) in 1 to Co(II) spin-crossover in 2 can be achieved.