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The SO32−-templated 3d–4f cluster Gd22Ni21 was synthesized, and has provided insight into the assembly of giant metal clusters. Of 3d–4f clusters reported to date, Gd22Ni21 exhibited the largest low-field magnetic entropy change value of 26.1 J kg−1 K−1 at 2 K and ΔH = 2 T.

The design of assembling high-nuclearity transition-lanthanide (3d-4f) clusters along with excellent magnetocaloric effect (MCE) is one of the most prominent fields but is extremely challenging. Herein, two heterometallic metal coordination polymers are constructed via the “carbonate-template” method, formulated as {[Gd18Ni24(IDA)22(CO3)7(μ3-OH)32(μ2-OH)3(H2O)5Cl]·Cl8·(H2O)14}n and {[Eu18Ni23.5(IDA)22(CO3)7(μ3-OH)32(H2O)5(IN)(CH3COO)2 (NH2CH2COO)Cl]·Cl6·(H2O)17}n [abbreviated as 1-(Gd18Ni24)n and 2-(Eu18Ni23.5)n respectively; H2IDA = iminodiacetic acid; HIN = isonicotinic acid]. Concerning the structures, compounds 1-(Gd18Ni24)n and 2-(Eu18Ni23.5)n both feature the one-dimensional (1D) chain-like structure which is rarely reported in high-nuclearity metal complexes. Meanwhile, the large presences of Gd3+ ions in compound 1-(Gd18Ni24)n are conducive to the fantastic MCE, and the value of −∆Sm is 35.30 J kg−1 K−1 at 3.0 K and ∆H = 7.0 T. And more significantly, compound 1-(Gd18Ni24)n shows the large low-field magnetic entropy change (−∆Sm = 20.95 J kg−1 K−1 at 2.0 K and ∆H = 2.0 T) among the published 3d-4f mixed metal clusters.

Two captivating {P4Mo6}-based compounds, formulated as (H2bbi)2{[Co2(bbi)][Co2.33(H2O)4][H9.33CoP8Mo12O62]}·4H2O (1) and (H2bbi){[Zn(Hbbi)]2[Zn0.75(bbi)][K2Zn(H2O)4][H8.5ZnP8Mo12O62]} (2) [bbi = 1,1′-(1,4-butanediyl)bis(imidazole)], were successfully synthesized under hydrothermal conditions. Structural analysis demonstrates that compounds 1 and 2 are constructed from hourglass-shaped structures [M(P4Mo6O31)2]n− (M = Co, Zn), which are all made up of molybdophosphates and one transition metal ion as the central connecting node. Compounds 1 and 2 feature three-dimensional (3D) frameworks, which are all connected to form a 3D structure by metal ions and bbi ligands. More interestingly, compound 1 exhibits higher catalytic activity than 2 in CO2 photoreduction due to the suitable energy band structure of Co species in {P4Mo6} clusters. The CO yield was 3261 μmol g−1 with high selectivity in 8 h for compound 1 in photocatalytic CO2 reduction, which is highly promising in the photocatalytic field. Additionally, the photoluminescence properties of 2 were investigated.

The distinct nanosized cluster Gd

Two hourglass-type molybdophosphate hybrids with the formulas [Cd(H2O)2DABT]4[Cd(H7P4Mo6O31)2]·19H2O (1) and (C2H5OH)(C3H5N2)6[Co3(H6P4Mo6O31)2]·H2O (2) (DABT= 3,3′-diamino-5,5′-bis(1H-1,2,4-triazo...

Two isomorphic heterometallic 3d–4f cluster-based materials, formulated [Gd8Cr4(IN)18(μ3-O)2(μ3-OH)6(μ4-O)4(H2O)10]·13H2O (1) and [Tb8Cr4(IN)18(μ3-O)2(μ3-OH)6(μ4-O)4(H2O)10]·13H2O (2) (abbreviation: {Ln8Cr4}: Ln = Gd3+ (1); Tb3+ (2); HIN = isonicotinic acid), were achieved by hydro-/solvothermal method through using the ligand HIN. X-ray diffraction analysis illustrates eight lanthanide ions (Ln = Gd3+, Tb3+) and four transition-metal ions (Cr3+) of {Ln8Cr4} were constructed from two classical “drum-like” {Ln4Cr2} structures associated by organic ligands HIN, displaying a one-dimensional wave chain structure, which is rare. The magnetic properties of {Gd8Cr4} were inspected and showed the existence of antiferromagnetic coupling interactions between contiguous metal ions. On top of this, the magnetic entropy change of ΔSm can attain 23.40 J kg−1 K−1 (44.90 mJ cm−3 K−1) at about 3 K and ΔH = 7 T. Besides, fluorescence measurements of {Tb8Cr4} display typical characteristic Tb-based luminescence.

Two captivating {P4Mo6}-based compounds, formulated as (H2bbi)2{[Co2(bbi)][Co2.33(H2O)4][H9.33CoP8Mo12O62]}·4H2O (1) and (H2bbi){[Zn(Hbbi)]2[Zn0.75(bbi)][K2Zn(H2O)4][H8.5ZnP8Mo12O62]} (2) [bbi = 1,1'-(1,4-butanediyl)bis(imidazole)], were successfully synthesized under hydrothermal conditions. Structural analysis demonstrates that compounds 1 and 2 are constructed from hourglass-shaped structures [M(P4Mo6O31)2]n- (M = Co, Zn), which are all made up of molybdophosphates and one transition metal ion as the central connecting node. Compounds 1 and 2 feature three-dimensional (3D) frameworks, which are all connected to form a 3D structure by metal ions and bbi ligands. More interestingly, compound 1 exhibits higher catalytic activity than 2 in CO2 photoreduction due to the suitable energy band structure of Co species in {P4Mo6} clusters. The CO yield was 3261 μmol g-1 with high selectivity in 8 h for compound 1 in photocatalytic CO2 reduction, which is highly promising in the photocatalytic field. Additionally, the photoluminescence properties of 2 were investigated.

Two hourglass-type molybdophosphate hybrids with the formulas [Cd(H

Two three-dimensional (3D) coordination polymers, namely MnII6(CH3COO)2(HCOO)2(IN)8(C4H8O)2(H2O) and MnIII6MnII12(μ3-O)6(CH3COO)12(IN)18(H2O)7.5 (abbreviated as MnII6 and MnII12MnIII6 respectively; HIN = isonicotinic acid), were synthesized by the reaction of Mn(CH3COO)2·4H2O and isonicotinic acid under solvothermal conditions. Magnetic studies revealed that antiferromagnetic interactions may be present in compounds MnII6 and MnII12MnIII6. Moreover, the values of −ΔSm (26.27 (MnII6) and 37.69 (MnII12MnIII6) J kg−1 K−1 at ΔH = 7 T) are relatively larger than those of the reported Mn-based coordination polymers. This work provides a great scope in the magnetocaloric effect (MCE) of pure 3d-type systems.

Temperature usually occupies a crucial position in the construction of chiral compounds. By controlling the temperature of the reaction system, chiral and non-chiral compounds can be designed and synthesized. Given the above, three new chiral and non-chiral compounds based on copper(II) monosubstituted polyoxoanions and Cu(en) complexes (en = ethylenediamine), D/L-[Cu(H2O)(en)2]2{[Cu(H2O)2(en)][SiCuW11O39]}·5H2O (1, D-1 and L-1) and [Cu(H2O)(en)2]{[Cu(en)2]2[SiCuW11O39]}·2.5H2O (2), were successfully synthesized under hydrothermal conditions. The main synthesis conditions of compound 1 (D-1 and L-1) and compound 2 are the same, however, the only difference is that the reaction temperatures are 80 °C and 140 °C, respectively. What's more, compounds 1 and 2 can form a 1D chiral chain by Cu–O and W/Cu–O–W/Cu bonds, respectively, and further obtain a 3D-supramolecular framework through hydrogen bonding interaction. Meanwhile, due to the asymmetry of chiral compound 1, optical second-harmonic generation (SHG) was used to investigate the second-order nonlinear optical effect and it was found that the observed SHG efficiency of compound 1 is 0.3 times that of urea. To further investigate the chiral properties, D-1 and L-1 were used in the electrochemical enantioselective sensing of D-/L-tartaric acid (D-/L-tart) molecules, respectively, which demonstrates that D-1 and L-1 have a good application prospect in sensing chiral substances.

Two isomorphic heterometallic 3d-4f cluster-based materials, formulated [Gd

An eight-membered ring petal-shaped cluster [V8ⅣO8(CH3O)16(C2O4)](C6NH16)2(CH3OH)2 (V8) has been successfully designed and synthesized via hydrothermal method. Structure analysis revealed that each vanadium atom was in an octahedral geometrical configuration six-coordinated, two adjacent vanadium atoms were linked by oxygen atoms on oxalic acid to form a ring. The selective sulfur oxidation experiments reveal that V8 had good catalytic activity under mild conditions, and the removal rate of phenyl sulfide was >99% within 4 h at 40 °C. In addition, the open aperture Z-scan test of V8 was carried out and found that V8 also has latent application value as nonlinear optical (NLO) material.

Three novel metal-organic hosts with POM guests coordination polymers, [Co(bim)4][HPMoVI10VIV4O42] (1), {[Co(bim)2(H2O)]2 [PMoVI8VIVVV3O40(VIVO)2]}·2H2O (2), and {[Ni(bim)2(H2O)]2 [PMoVI8VIVVV3O40(VIVO)2]}□8H2O (3) (bim = bis (1-imidazolyl) methane) have been successfully prepared under hydrothermal conditions. Compound 1 shows one dimensional chain with bi-capping Keggin anion [HPMoVI10VIV4O42]2- (abbreviated as PMo10V4) as guest molecule, which forms a three dimensional array by hydrogen bonds. Considering that there are a large number of free coordinating N present on the organic ligand in 1, we increased the ratio of Co2+/bim and got a new polyoxometalate-based complex 2. Compound 2 mainly consists of host two dimensional rigid MOF sheets and guest bi-capping Keggin anion [PMoVI8 VIVVV3O40(VIVO)2]4- (denoted as PMo8V6) cluster, which are covalently-linked together to form a three dimensional array. Compound 3 and 2 are isomorphic, but contains the metal ions Ni2+ instead of Co2+ and the number of free water is different. Magnetothermal studies indicate that compound 1 and 2 all have antiferromagnetic interactions. Interestingly, compound 2 represents the novel 3D host-guest coordination polymer network with a gradual and partial spin-crossover phenomenon.

Based on {e-PMoV8MoVI4O40Zn4} POM units, two novel organic–inorganic hybrids, [TBA]2[H3PMoV8MoVI4O40Zn4]2[4-pyim]6·7H2O (1) (4-pyim = 4-(imidazol-2-yl)pyridine) and [H3PMoV8MoVI4O40Zn4][2-pyim]4·3H2O (2) (2-pyim = 2-(imidazol-2-yl)pyridine), have been triumphantly gained under the hydrothermal conditions via self-assembly method. Compound 1 is made up of two Zn-e-Keggin units jointed by two Zn O bonds, which modified by three 4-pyim ligands, respectively, to form a dimer, while compound 2 consists of a Zn-e-Keggin unit coordinated with four 2-pyim ligands. The coordination mode of the different ligands causes a change in the number of ligands coordinated on each Zn-e-Keggin unit, resulting in the formation of dimers and monomers. What’s more, the third-order non-linear optical (NLO) properties of the two compounds were detected in detail due to the existence of a large number of conjugated organic ligands. Compound 1 has a superiority over compound 2 in NLO performance and the two-photon absorption (TPA) cross section (σ) are 7320 GM for 1 and 1573 GM for 2, which is attributed to the fact that 1 own more conjugated organic ligands. The NLO testing results of compound 1 and 2 show that Zn-e-Keggin unit can provide a good NLO response through combining with conjugated organic ligands, indicating that it is a wally choice for NLO materials. Furthermore, the electrochemistry properties of two compounds were also amply explored.