Qian Shi

Crystal structures and magnetic properties of three cobalt(II)–organic frameworks with nanoscale channels

Three cobalt(II) coordination polymers, {[Co(nip)(4,4′-bpy)] · 3H2O} n (1), [Co(nip)(bpe)] n (2), and [Co(nip)(bpp)(H2O)] n (3), were hydrothermally synthesized by the reaction of cobalt nitrate hexahydrate and nip with 4,4′-bpy, bpe, and bpp [nip = 5-nitro-1,3-benzenedicarboxylato, 4,4′-bpy = 4,4′-bipyridine, bpe = 1,2-bis(4-pyridyl)ethane, bpp = 1,3-bis(4-pyridyl)propane], respectively. Co(II) displays different coordination in the three complexes, resulting in different structures with nanoscale channels. Compounds 1 and 2 form 2-D layer structures, but 3 has a two-fold interpenetrated 3-D framework. The magnetic properties associated with their crystal structures were investigated.

Hydrothermal synthesis and characterization of LaIII and CuII coordination polymers with 5-nitroisophthalic acid (H2Nip), [La2(μ-Nip)(μ-SO4)2(H2O)5] n and {[Cu3(μ-OH)2(μ-Nip)2(μ-H2O)2] · 2H2O} n

3D LaIII and 2D CuII coordination polymers with 5-nitroisophthalate anions, [La2(μ-Nip)(μ-SO4)2(H2O)5] n (1) and {[Cu3(μ-OH)2(μ-Nip)2(μ-H2O)2]  · 2H2O} n (2), have been synthesized, characterized and studied by X-ray crystallography. The La atoms have eight–coordinate geometries in distorted square antiprism environments and the Cu atoms have five- and six–coordinate geometries with distorted square pyramidal and octahedral environments. Self-assembly of these compounds in the solid state occurs through coordination and hydrogen bonding.

Supramolecular approach to metal–organic gels using excess organic ligand as building units

Abstract A metal–organic gels containing Ag(4,4′-bipyridine)NO3 metal–organic framework and 4,4′-bipyridine units were hydrothermally synthesized using excess 4,4′-bipyridine ligand as building units. The metal–organic gels structure was characterized by various spectroscopic methods and a mechanism of assembly was discussed on the basis of the obtained data. The metal–organic gels retained the characteristics of both the metal–organic framework and gels; furthermore, the reversible hydration/dehydration, reversible anion exchange, and responsive properties were also investigated.

Design, synthesis and magnetic properties of a ladderlike complex constructed by secondary building units

A secondary building unit (SBU), [Ni(2,2′-bipy)(5-npa)(H2O)] n [where 2,2′-bipy = 2,2′-bipyridine, 5-npa = 5-nitroisophthalic dianion], was synthesized as starting material of a polystep reaction. A ladderlike complex (LLC) Ni(II) coordination polymer, {[Ni(2,2′-bipy)(5-npa)(4,4′bipy)0.5]·(H2O)} n , was constructed by polystep reaction using this SBU. In LLC, two SBUs were cross-linked by 4,4′-bipy [where 4,4′-bipy = 4,4′-bipyridine] forming a 1-D ladderlike structure. The magnetic properties of the LLC and SBU are discussed.

Syntheses, structure and magnetism of a new linear-chain coordination polymer [[Co(TMA)2(4,4′-bipyridine)2] · H2O] n [TMA=Trimesate]

A linear-chain one-dimension polymeric complex of Co(II), [[Co(TMA)2(4,4′-bipyridine)2] · H2O] n has been synthesized and characterized. The complex crystallizes in the monoclinic system, space group P2(1)/c with a = 11.344(3) Å, b = 15.880(4) Å, c = 23.436(5) Å, β = 117.831(10)°, V = 3733.5(16) Å3 and D c = 1.437 g cm−3. The effective magnetic moment for this complex indicates that there is almost no ferromagnetic coupling between the Co(II) ions and the magnetic behavior is due to the isolated Co(II).