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Two thermally stable single-ion magnets containing a dysprosium ion with the ligand fod (1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octadione) and bpy (2,2′-bipyridine) or phen (1,10-phenathroline) were synthesized, named 1Dy (Dyfod3bpy) and 2Dy (Dyfod3phen). They both have 6 oxygen atoms and 2 nitrogen atoms around the lanthanide metal ion in the center, forming a pseudo-D4d coordination structure. Dynamic magnetic studies show that they both exhibit temperature dependent processes and quantum tunneling relaxation under zero applied dc field. Interestingly, 1Dy melts at 90 °C and evaporates at 269 °C to form the amorphous compound 3Dy. The XRD data show that there is little change of the local structure between 1Dy and the evaporated sample 3Dy. Magnetic measurements show that 3Dy retains the SMM properties, but the relaxation barrier shifts from 87 K to 122 K and the quantum tunneling becomes slower.

With the help of ascorbic acid as reductant, an exceedingly rare example of a visible single-crystal-to-single-crystal transformation from a CuII-framework to a CuI-chain under mild conditions has been observed, which involves the metal valence tautomerism and restructuring of bonds. The two compounds exhibit the properties of solvatochromism and luminescence aggregation-induced-emission towards CH3OH, respectively.

Single crystals of three polymorphous compounds were synthesized started from two building blocks, [Fe(CN)(6)](3-) and [Co(L-N3O2)](2+) (L is a Schiff-base macrocyclic ligand derived from the condensation of 2,6-diacetylpyridine with 3,6-dioxaoctane-1,8-diamine) using a crystallization condition control. All three compounds consist of electroneutral skeletons made up of Fe6Co6 twelve-metal ring units, which is the smallest enclosed circle in their structures: 1 is comprised of 1D nanometer-diameter tubes possessing nanometer-sized tunnels (0.58 nm x 0.74 nm); 2 and 3 are based on piled-up 2D lamellar layers in the (6, 3) and (4, 4) networks, respectively. Magnetic studies indicate ferromagnetic interactions between cyanide-bridged cobalt(II) and iron(III) in each compound.

A new 1D Dy3+ complex based on β-diketone, namely, [Dy(L)3(H2O)]·0.5CH3OH·0.5H2O (1) (HL = 1-phenyl-3-(4′-pyridyl-N-oxide)-propane-1,3-dione) has been designed and synthesized by the combination of β-diketone and pyridine-N-oxide group. The magnetic study indicates the compound's slow magnetic relaxation originating from the single-ion behavior of Dy3+ with strong anisotropy, which is further supported by theoretical calculations.

In this work, we present the synthesis of three novel 3D Cd(II) coordination polymers, {[Cd(IN)2]·H2O}n (1), [Cd2(IN)2(SO4)(DMF)2]n (2) and {[Cd3(IN)5.5]·0.5OH−}n (3) (HIN = isonicotinic acid). Coordination polymers 1 and 2 were obtained via solvothermal reactions. The synthesis of coordination polymer 3 was realized by a simple temperature induced single crystal to single crystal transition from 1. Single-crystal X-ray diffraction analyses revealed that 1–3 exhibit three different structural types: 1 displays a (6,3)-connected rtl net with the Schlafli symbol (4·62)2 (42·610·83) constructed from mononuclear [CdO4N2] clusters with the help of HIN. 2 is defined as a 6-connected pcu net with the Schlafli symbol {412·63} which is built from binuclear [Cd2(SO2)2] clusters and HIN linkers. 3 can be regarded as a 9-connected ncd net with the Schlafli symbol {36·422·58}, which consists of paddlewheel trinuclear [Cd3(O2C)5] clusters and a bridging HIN. Coordination polymers 1–3 display luminescence with emission maxima containing deep blue, blue, light blue and green at 298 K or 77 K both in solvents (polarity: DMF > CH3OH > CH2Cl2) and in the solid state. The lifetime of all the molecules is in microsecond scale.

Hydro(solvo)thermal reactions between 1,1′-biphenyl-2,2′,3,3′-tetracarboxyl acid (H4bptc) and Cd(NO3)2·4H2O at the presence of the ‘second’ ligands of bpydo, bpe, bpp and bix (bpydo = 4,4′-bipyridine-N,N′-dioxide; bpe = 1,2-bis-(4-pyridyl)ethane; bpp = 1,3-Bis-(4-pyridyl)propane; bix = 1,4-bis(imidazol-1-yl-methyl)benzene) yield four new 2D metal–organic coordination polymers [Cd9(bptc)4(μ3-OH)2(H2O)14]·(bpydo)·2H2O (2), [Cd2(bptc)(bpe)(H2O)2]·H2O (3), [Cd4(bptc)(Hbptc)(bpp)(μ3-OH)(H2O)4] (4), [Cd2(bptc)(bix)(H2O)] (5). Compound 2 presents a 2D grid structure with heptanuclear cadmium cluster and two kinds of discrete Cd atoms secondary building units (SUBs), 3 has a 2D structure with the novel Schlafli symbol of (4.62)(43.63)(44.610.8), 4 gives a 2D grid structure with a pentanuclear cadmium cluster, binuclear cadmium cluster and discrete Cd atom SUBs, and 5 has a 2D distorted CdI2-type topology structure with the Schlafli symbol of (43)2(46.66.83). The novel achiral crown-ether-like cycles in 2, 4 and 5 are found and occupied by the single Cd atom or binuclear cadmium cluster. All compounds give strong luminescent emission and have potential application as optical materials.

The complexes of formulae M(dca)2(bpeado) (M = Mn (1), Fe (2), Co (3), Ni (4), Cu (5); dca = dicyanamide; bpeado = 1,2-bis(4-pyridyl)ethane-N,N′-dioxide) have been synthesized and characterized by X-ray single crystal diffraction. Compounds 1–5 contain 3D self-penetrating networks, in which bidentate dca ligands bridge the octahedral metal ions to form square-grid like M(dca)2 sheets and these sheets are further connected by criss-crossing bpeado to give a 3D self-penetrating network. Variable temperature magnetic susceptibility studies have shown that these compounds generally display very weak antiferromagnetic coupling because of the long bpeado and μ1,5-dca pathways. Consequently, no magnetic ordering was found.

Two mononuclear compounds, [Fe(H2O)5(dpdo)]SO4·4H2O 1 and [Cd(dpdo)(H2O)3I2]·0.5dpdo 2 (dpdo⊕=⊕4,4′-bipyridine dioxide) have been obtained from the reactions of (NH4)2SO4·FeSO4 or CdI2 with dpdo. The mononuclear units in compound 1 are juxtaposed in head-to-tail mode along the [010] direction and connected through π–π stacking and hydrogen bonding to give a ladder-like motif. These ladders are further linked into a 3D network through hydrogen bonding between SO42− anions and water molecules. Compound 2 forms a dimer unit [Cd(dpdo)(H2O)3I2]2 through π–π stacking and hydrogen bonding. These dimer subunits and solvated dpdo molecules are alternately arrayed in the [011] plane through π–π stacking and hydrogen bonding, leading to a two-dimensional sheet. Intermolecular O⋯I interactions link these sheets, also giving a 3D network.

Two novel 3D compounds based on Keggin heteropoly blue anion-chains, [Na(H2O)2{MI(btp)}4(PWVI8WV4O39)] (M = Cu (1), Ag (2), btp = 1,3-bis(1,2,4-triazol-1-yl)propane), have been hydrothermally synthesized and characterized by elemental analysis, IR, TG, PXRD and single crystal X-ray diffraction. In compounds 1 and 2, the neighboring Keggin clusters are connected via sharing terminal oxygen atoms to form unusual Keggin anion chains by W–O–W covalent interactions, which are further reinforced by two copper(I) or silver(I) bridging fragments. Such saturated Keggin anion chains have been observed for the first time. The (Mbtp)4 40-membered cation-macrocycles and {Na(H2O)2} units serve as linkers to bond two adjacent anion chains resulting in infinite 2-D layers. The layers are further fused by interactions between the 40-membered macrocycles and {Na(H2O)2} units leading to intricate 3-D frameworks, which exhibit a novel 4, 6, 8-connected topology. In addition, compounds 1 and 2 exhibit good electrocatalytic activity for reduction of nitrite and fluorescence properties in the solid state at room temperature.

The organic–inorganic hybrid charge-transfer salt of BETS and a two-dimensional oxalate–metalate: BETS3[Cu2(C2O4)3](CH3OH)2 (1) was obtained by the electrochemical oxidation of neutral BETS in the presence of [(C2H5)3NH]2Cu(C2O4)2 in a C6H5Cl–CH3OH solution. 1 crystallizes in a triclinic crystal system with cell parameters: a = 8.7716(3) A, b = 16.9903(6) A, c = 20.5716(7) A, α = 104.794(2)°, β = 102.209(2)°, γ = 92.243(2)°, V = 2883.1(2) A3 and P1 in 293 K. Donor layers and Jahn–Teller distorted honeycomb anions stack alternatively along the c axis in 1. The crystal structure of 1 is similar to the reported compound [BEDT–TTF]3[Cu2(C2O4)3](CH3OH)2 (BEDT–TTF = bis(ethylene-dithio)tetrathiafulvalene, ET). Compared with the BEDT–TTF salt, the c axis expands by 2.3% at room temperature, the shorter interaction between the donor molecules increases, the room temperature conductivity increases from 4 S cm−1 to 140 S cm−1 and the antiferromagnetic interaction between the metal atoms with Jahn–Teller distortion through the oxalato-bridge enhances.

FePt concave nanocubes enclosed by highly active high-index atom steps were synthesized by a facile process. The oleic acid was demonstrated to be the key point for the formation of FePt concave nanocubes. Due to the concave structure, the FePt concave nanocubes exhibit higher electrocatalytic activity than either FePt nanocubes or commercial Pt catalysts in methanol oxidation.

Four new poly(oxomolybdophosphates), Na[FeIII(2,2′-bpy)3]2[FeII2Sr2MoV12O24(OH)6(H2O)8(H2PO4)2(HPO4)2(PO4)4]·[PO4]·9H2O 1, [H2(bpp)]2[MnII2Sr2Mo12O24(OH)6(H2O)8(H2PO4)2(HPO4)2(PO4)4]·8H2O 2, [H2(4,4′-bpy)]2[CdII2Sr2Mo12O24(OH)6(H2O)6(H2PO4)2(HPO4)2(PO4)4]·5H2O 3 and [H2(4,4′-bpy)][MnII2Sr4Mo12O24(OH)6(H2O)12(HPO4)4(PO4)4]·8H2O 4 (2,2′-bpy = 2,2′-bipyridine, bpp = 1,3-bi(4-pyridyl)-propane, 4,4′-bpy = 4,4′-bipyridine), have been hydrothermally synthesized and structurally characterized by elemental analysis, TG, IR, UV-vis and single-crystal X-ray diffraction. All the compounds are based on the [P4Mo6O31]12− (abbreviated as [P4Mo6]) polyoxometalate units, which are further connected into sandwich-type dimeric units by various transition metal (TM) ions. In compounds 1–3, the dimeric {(TM)[P4Mo6]2} units are linked by new {Sr2TM} trinuclear fragments into one-dimensional (1-D) chains. These 1-D chains are further packed into various three-dimensional (3-D) supramolecular assemblies due to the use of different bipyridine-based structure-directing agents. In compound 4, the dimeric {(TM)[P4Mo6]2} units are linkered by an unprecedented {Sr4Mn} pentanuclear unit into new 3-D open framework, exhibiting a 64.82-nbo (niobium-oxide-like) topology. The electrochemical properties of these compounds were investigated.

Two polymorphs of (H2mela)2[CuCl5]Cl (mela = melamine) prepared by solution diffusion methods have been characterized structurally and magnetically. The kinetic phase in the monoclinic space groupP2/c was first crystallized. When kept in the mother solution, the kinetic phase gradually dissolved, while the thermodynamically stable phase in the monoclinic space groupP21/m appeared and became the final product. This transformation process was monitored by powder X-ray diffraction. Structural analysis revealed that the two polymorphs consist of alternatively arranged negative layers of [CuCl53−]n chains and discrete non-coordination Cl− anions and positive layers of H-bonded dimers of [H2mela2+]2, assembled though H-bonds in the lattices. The difference between the two structures lies in the packing and H-bonding patterns in the solids. The transformation associated changes in structures mainly referred to H-bonding are discussed. Both compounds are antiferromagnetic chains. Thermal stability and IR spectroscopic properties were also studied.

The assembly of three simple achiral but acentric building blocks, protonated monoamine AH+, formate HCOO− and Er3+, resulted in a series of chiral crystals of ammonium-templated erbium–formate frameworks with formula [AH+][Er(HCOO)4−], indicating that the increased opportunity to obtain chiral crystalline solids could be achieved by incorporating multiple acentric centers within the lattice.

Two mixed azide-hmt bridged compounds were obtained with neutral 3D networks, Co2(N3)4(hmt)(H2O) (1) and Ni2(N3)4(hmt)(H2O) (2), hmt = hexamethylenetetramine. In 1, the azide ions present three kinds of coordination modes in the connection of two unique Co2+ ions. Each Co1 is connected by trans-EE-azide ions and hmt into extended (4,4) layers, and each Co2 is connected by EO-azide ions into dimers which are located between the neighboring (4,4) layers. The cis-EE-azide ions connect the dimers to the neighboring layers to form rare 3D networks. The Co12+ and Co22+ ions have four and three connections through azide bridges to the neighboring Co2+ ions, respectively. Twisted torsion angles of cis/trans-EE azide bridges are observed in 1, with a value of 83.39 and 117.43°, respectively. The Ni analogue 2 is isostructural with 1 revealed by IR, elemental analysis and Powder X-ray diffraction. Magnetic investigation shows that 1 is a weak ferromagnet below Tc = 15.0 K, with a large coercivity of 1 T at 2 K, while 2 is a soft ferromagnet below Tc = 10.0 K.

Two new metal–organic complexes [Cd1.5(btrc)(bix)]n (1) and [Zn2(btrc)(Hbtrc)0.5(bix)2]n(2) (H3btrc = 1,2,4-benzenetricarboxylate; bix = 1,4-bis(imidazol-1-ylmethyl)-benzene) have been hydrothermally synthesized and characterized by single crystal X-ray diffraction. Complex 1 represents a three-dimensional (3D) structure based on the 2D sheets and bix pillars. Complex 2 exhibits unique architecture. The two complexes exhibit strong fluorescent emissions in their solid states at room temperature.

The reaction of 1,2-bis(4-pyridyl)ethane-N,N′-dioxide (bpeado) with metal perchlorate or tertraphenylborate yields coordination frameworks with different structurse, [Mn(bpeado)3][ClO4]2 (1), [Cu(bpeado)2(H2O)2][ClO4]2·bpeado (2) and [M(bpeado)3][B(Ph)4]2 [M = Mn3 and Co4]. Compound 1 is based-on octahedrally coordinated MnO6 centers bound through six oxygen atoms from six separate anti-bpeado ligands with 3-fold interpenetrated α-Po-type structure. 2 has two-dimensional (4,4) layers bridged by four separate anti-bpeado molecules and the layers were further connected by hydrogen bonding between the coordination water molecules and the intercalated bpeado, forming a 2-fold interpenetrated α-Po-type network. Compounds 3 and 4 are isostructural and comprised of non-interpenetrating rectangular (4,4) layers bridged by both anti- and gauche-bpeado.

The change of the alkyl chain length in N,N-bis(coordinating group)-substituted oxamides was observed to be able to tune the structures of two new radical complexes[Cu2(oxen)(4-NITPhPy)2](ClO4)2 (1) [oxen = N,N-bis(2-aminoethyl)oxamide] and [Cu2(oxpn)(4-NITPhPy)2](ClO4)2·H2O (2) [oxpn = N,N-bis(2-aminopropyl)oxamide], which constructed from trans-oxamido-bridged Cu(II)–Cu(II) dinuclear building blocks and a new nitronyl nitroxide, 2-[4-(4-pyridyl)phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (4-NITPhPy): 1 possesses a dinuclear structure while 2 shows a 1D chain structure. The magnetic data of 1 could be analyzed using a model derived from the Cu(II)–Cu(II) dinuclear building block with two nitroxide terminal ligands, giving J1 = −286 cm−1, J2 = −6 cm−1 and θ = −3.95 K. The magnetic interactions in 2 were simulated by an appropriate uniform chain model composed of the tetraspin [Cu2-(NIT)2] units. The best fitting gives J1 = −213.5 cm−1, J2 = 19.13 cm−1 and Jc = −2.11 cm−1.