Hua-Hong Zou

A unique 2D framework containing linear trimeric cobalt(II) of mixed Td-Oh-Td geometries linked by two different single-carboxylate-aromatic amine ligands: structure and magnetic properties.

A new 2D coordination polymer Co3(OH)2(pa)2(ina)2 (1, pa = 3-(1H-benzimidazol-2-yl) propanoic carboxylate, ina = isonicotinate) contained uncommon, linear Co(ii) trimers of mixed Td-Oh-Td geometries, exhibits spin canting below 20 K. Such magnetic behavior mainly arises from the Dzyaloshinski-Moriya interaction from the anisotropic, mixed geometries trimeric Co(II) ions to the crimpled 2D network based on the nature of the binding modes of Co(II)-carboxylate trimer and the effect of the intertrimers arrangement of 1. The mixed single-carboxylate-aromatic amine ligands bridged metal systems display a new structurally authenticated example of a thick 2D layer, and also indicate homometallic Co(II) clusters with Td-Oh-Td mixed-geometries can result in relatively obvious noncompensation moments, according to different efficient spins of Co(II) at very low temperature, in spite of antiferromagnetic intracluster interactions.

Second ligands-assisted structural variation of entangled coordination polymers with polycatenated or polythreaded features

The self-assembly of transition metal salts with dicarboxylate ligands and second ligands afford a series of entangled coordination frameworks based on different metal clusters, namely, [Ni2(oba)2(bpy)2(H2O)2]·(DMF)(H2O)2 (1), [Ni2(oba)2(bpy)2(sa)(H2O)2]·(H2O)4 (2), [Cu5(oba)4(bpy)5(pca)2(H2O)4]·(H2O)9 (3), [Co3(oba)2(bpy)2(dbca)2]·(H2O)6 (4), [Co3(oba)2(dbca)2(H2O)] (5) and [Co3(oba)2(bph)2(SO4)]·(H2O)4 (6) [oba = 4,4′-oxydibenzoic acid; bpy = 4,4′-bipyridine; dbca = [1,1′-biphenyl]-2,2′-dicarboxylic acid; sa = 2-hydroxybenzoic acid; pca = picolinic acid; bph = (1E,2E)-1,2-bis(pyridin-4-ylmethylene)hydrazine]. Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra and TG analyses. The auxiliary ligands play important roles in the formation of various entangled networks. 1 shows a box-like structure and is interlocked in a parallel fashion. Compound 2 represents the first example of a 3D polycatenated framework with different size arms. 3 displays 2D → 3D entangled polymers with polycatenated and polythreaded features based on 4,4-sql layers, which are formed by short/long alternate pillars. 4 shows an interesting framework of 2D → 3D polythreading feature with a Co3 cluster occupying the corner of the grid. However, 5 displays 3D polycatenation with a 1D zigzag metal chain. An unusual [Co3SO4] unit, which is linked by four bph ligands and four oba ligands, exhibiting an anionic three-dimensional (3D) framework is observed in 6. Compounds 4–6 display antiferromagnetic properties.

Nanospheric [M20(OH)12(maleate)12(Me2NH)12]4+ Clusters (M = Co, Ni) with Oh Symmetry

Nanospheric hydroxo-bridged clusters of [M(20)(OH)(12)(maleate)(12)(Me(2)NH)(12)](BF(4))(3)(OH)·nH(2)O (M = Co (1), Ni (2)) with O(h) symmetry were afforded under hydrothermal condition with Co(BF(4))(2)·6H(2)O/Ni(BF(4))(2)·6H(2)O and fumaric acid in a DMF/EtOH mixed solvent. They are characterized by elemental analysis, IR, and X-ray diffraction. X-ray single crystal diffraction analyses show that these two complexes are isostructural containing an ideally cubic M(8) core in that each two M atoms are doubly bridged at the edges by one OH(-) and one maleate, while these OH(-) and maleate groups are coordinated further by exterior identical 12 M atoms which construct a perfect M(12) icosahedron to encapsulate the cubic core. To our knowledge, such large clusters with O(h) symmetry are seldom. The variable-temperature magnetic susceptibility studies reveal that these two isostructures exhibit antiferromagnetic interactions.

One novel 3-D vanadoborate with unusual 3-D Na–O–Na network

A new 3-D vanadoborate {Na2B18V12O54(OH)6(H2O)[Na8(H2O)16]}·2H2O (1) has been hydrothermally synthesized and structurally characterized. The crystal of 1 is built up from an unusual 3-D Na–O–Na network and entrapped [V12B18O54(OH)6(H2O)]10− clusters (denoted [V12B18]). Such a Na–O–Na network is constructed by the linkage of rare 1-D helical [Na4(H2O)84+]n chains and [NaO6] octahedra. 1 represents the rare example of extended POMs with 3-D inorganic metal–oxygen networks. Magnetic measurements illustrate that 1 has antiferromagnetic exchange interactions between metal centers.

A series of new lanthanoid thioarsenates: insights into the influence of lanthanide contraction on the formation of new lanthanoid thioarsenates.

A series of new lanthanoid thioarsenates [Ln(teta)(μ-η(1):η(2):η(1)-As(III)S3)]n {Ln = Ce (Ia), Pr (Ib), Nd (Ic), and Sm (Id); teta = triethylenetetramine} and [Ln(teta)(en)(μ-η(1):η(1):η(1)-As(V)S4)]n {Ln = La (IIa), Ce (IIb), Pr (IIc), and Nd (IId); en = ethylenediamine} were prepared by the solvothermal reaction of K3AsO3, S, LnCl3 and organic amines and structurally characterized. Compounds Ia–d crystallise in the orthorhombic space group Aba2 and display 1-D neutral chains [Ln(teta)(μ-η(1):η(2):η(1)-As(III)S3)]n, which represent the first examples of 1-D organic hybrid lanthanoid sulfides built up from trigonal-pyramidal [As(III)S3](3-) acting as tetradentate bridging ligands to interlink [Ln(teta)](3+) ions, while compounds IIa–d crystallise in the orthorhombic space group P2(1)2(1)2(1) and consist of other 1-D neutral chains [Ln(teta)(en)(μ-η(1):η(1):η(1)-As(V)S4)]n, which are built up from the linkages of the tetrahedral [As(V)S4](3-) ion and the [Ln(teta)(en)](3+) ion. To learn more about the influence of lanthanide contraction on the formation of lanthanoid thioarsenates, three organic hybrid lanthanoid thioarsenates [Ln(teta)(en)As(V)S4] [Ln = Dy (IIIa), Ho (IIIb), and Tm (IIIc)] with the neutral molecular structure type in the monoclinic centrosymmetric space group P2(1)/c are also presented. Their optical and magnetic properties have been investigated, and density functional theory calculations of Ia and IIa have also been performed.

New 3-D polyoxovanadoborate architectures based on [V12B18O60]16− clusters

Three new 3-D polyoxovanadoborates {[Cu(dien)(H2O)]3V12B18O54(OH)6(H2O)}·4H3O·5.5H2O (1, dien = diethylenetriamine), {[Cd(H2O)2]3V12B18O54(OH)6(H2O)}·4H3O·9.5H2O (2) and {[Na(H2O)3]4Na2V12B18O56(OH)4(H2O)}(H3dien)2 (3) have been hydrothermally synthesized and structurally characterized. Compounds 1–3 contain vanadoborate cluster [V12B18O60] constructed by two hexameric oxovanadate units [V6O9] and one puckered [B18O42] ring via sharing O atoms. The vanadoborate cage [V12B18O60] can present different degrees of protonation, namely [V12B18O60H6]10− for 1 and 2, [V12B18O60H4]12− for 3. The clusters [V12B18O60H6]10− in 1 are connected by complex cations [Cu(dien)(H2O)]2+ into a new 3-D framework via all terminal O atoms of square-pyramidal [VO5] groups, while the clusters [V12B18O60H6]10−/[V12B18O60H4]12− in 2 and 3 are linked with [Cd(H2O)2]2+ groups/the combination of [Na(H2O)3]+ and Na+ ions to give another two types of new 3-D frameworks via O atoms of [BOx] (x = 3, 4) polyhedra, respectively. Magnetic measurements illustrate that compounds 1 and 2 have antiferromagnetic exchange interactions between metal centers. The theoretical band structure of 2 has been also studied.

Two new 3-D boratopolyoxovanadate architectures based on the [V12B16O50(OH)8]12− cluster with different metal linkers

Two new 3-D boratopolyoxovanadates {[Zn2NaV12B16O50(OH)8(H2O)7]}·7(H3O)·4H2O (1) and [Cd3Na3.5V12B16O50(OH)8(H2O)8]·2.5(H3O)·11H2O (2) were synthesized employing hydrothermal reactions and structurally characterized. Both 1 and 2 contain the boratopolyoxovanadate cluster [V12B16O50(OH)8]12− built up from one continuous contorted [V12O36] ring and two [B8O17(OH)4] clusters. The clusters [V12B16O50(OH)8]12− in both 1 and 2 are linked by Zn2+/Cd2+ ions into the sql layer and self-penetrating sql layer, respectively, which are further connected by Na+ ions to form the 3-D boratopolyoxovanadate architectures. The most interesting feature is that each [V12B16O50(OH)8]12− unit in 2 acts as a multidentate ligand coordinated with six Cd2+ ions and eight Na+ ions, which represents the highest coordination number of [V12B16O50(OH)8]12− with metal cations to date. Magnetic measurements illustrate that both 1 and 2 have antiferromagnetic exchange interactions between metal centers.

A novel 3-D chiral polyoxovanadate architecture based on breaking high symmetry of spherical [V15O36Cl]8− cluster

A novel 3-D chiral polyoxovanadate {[Zn(en)2]2V15O36Cl}[Zn(en)2(H2O)]2·3H2O (1, en = ethylenediamine) has been hydrothermally synthesized under spontaneous resolution without any chiral source. The unique 3-D chiral architecture of 1 is built up from destroying high symmetry of the spherical [V15O36Cl]8− cluster. Magnetic measurements illustrate that 1 has antiferromagnetic exchange interactions between metal centers.

A series of new 3-D boratopolyoxovanadates containing five types of [KxOy]n building units

A series of new 3-D boratopolyoxovanadates {K2V12B18O54(OH)6(H2O)[K8(H2O)16]}·3H2O (1), {K10V12B18O54(OH)6(H2O)}·14H2O (2), {V12B18O54(OH)6(H2O)[K6(H2O)12]}·2(H2dien)·3H2O (3, dien = diethylenetriamine), {V6B20O44(OH)8(H2O)[K8(H2O)6]} (4), and {V6B20O44(OH)8(H2O)[K(H2O)]2}·2(H3dien)·6H2O (5) have been hydrothermally synthesized and structurally characterized. These compounds contain five types of [KxOy]n building units, namely, a dimeric [K2O16] unit for 5, a 1-D [K3O12]n chain for 3, a 3-D [K5O10]n sub-network for 1, a 3-D [K5O12]n sub-network for 2, and a 3-D [K4O7]n sub-network for 4. The 3-D frameworks of both 1 and 2 are built up from a different 3-D inorganic [KxOy]n sub-network and entrapped [V12B18O54(OH)6(H2O)]10− (denoted as [V12B18]) clusters, respectively. 3 contains [V12B18] clusters and 1-D [K3O12]n chains, which are interconnected to form a 3-D {V12B18O54(OH)6(H2O)[K6(H2O)12]}n architecture with 1-D tunnels filled with protonated H2dien2+ ions. The 3-D architecture of 4 is constructed by another rare 3-D inorganic [K4O7]n sub-network and entrapped [V6B20O44(OH)8(H2O)] (denoted as V6B20) clusters. Compounds 1, 2 and 4 represent rare examples of extended POVs with the 3-D inorganic [KxOy]n sub-networks. 5 contains [V6B20] clusters and dimeric [K2O16] units, which are interconnected to give a 3-D {B20V6O44(OH)8(H2O)[K(H2O)]2}n architecture with 1-D tunnels filled with protonated H3dien3+ ions. Although a few boratopolyoxovanadates contain the [V6B20] cluster, they display either a discrete [V6B20] cluster or a low-dimensional extended structure. Therefore, both 4 and 5 are rare examples of 3-D boratopolyoxovanadate architectures based on the [V6B20] clusters. The magnetic susceptibilities of both 4 and 5 show the antiferromagnetic interaction between VIV cations. Their spectroscopic properties were also investigated.

A series of lanthanide glutarates: lanthanide contraction effect on crystal frameworks of lanthanide glutarates

A series of lanthanide glutarates [Ln(phen)(glu)Cl]n {Ln = Y (1a), Tm (1b); phen = 1,10-phenanthroline; glu = glutarate}, [Ln2(phen)2(glu)3]n {Ln = Ce (2a), Tb (2b), Ho (2c)} and [La2(glu)3(H2O)3]n·5nH2O (3) have been hydrothermally synthesized and characterized structurally. Compounds 1a–b are isostructural and consist of 1-D neutral [Ln(phen)(glu)Cl]n chains, which are built up from the linkages of [Ln(phen)Cl]3+ ions and glutarate ligands. Compounds 2a–c are isostructural and contain 2-D [Ln2(phen)2(glu)3]n layers, where Ln3+ ions are connected by three kinds of glutarate ligands. The 3-D framework of compound 3 is constructed by the linkages of La3+ ions and glutarate ligands. Although some 3-D lanthanide glutarates have been reported, they exhibit a very robust structural type, whose structure is not changed by different Ln3+ ions, but compound 3 shows a new structural type. A systematic investigation of six lanthanide glutarates and some reported compounds revealed that the well-known lanthanide contraction has a significant influence on the formation of lanthanide glutarates. The photoluminescent properties of 1b and 2b, and magnetic properties of 1b, 2b and 2c have been studied.