Hua Xiang

Novel mixed-valent CoII2CoIII4LnIII4 aggregates with ligands derived from tris-(hydroxymethyl)aminomethane (Tris)

Isostructural Co(II)₂Co(III)₄Ln(III)₄ (Ln = Y (1), Gd (2) and Dy (3)) coordination clusters formed using the ligand Tris are the first examples of 3d-4f complexes involving this ligand and show weak ferromagnetic coupling between the Co(II) ions and slow relaxation (SMM) behaviour for 3.

[NiL]3[BTC]2·14H2O [L=3,10-bis(2-ethyl)-1,3,5,8,10,12-hexaazacyclotetradecane, BTC=1,3,5-benzenetricarboxylate]: synthesis, structure and unique selective guest molecule absorption properties

Reaction of 1,3,5-benzenetricarboxylate with a macrocyclic Ni(II) complex leads to a porous metal-organic framework, which displays a high selectivity for ethanol sorption.

Variations of Structures and Gas Sorption Properties of Three Coordination Polymers Induced by Fluorine Atom Positions in Azamacrocyclic Ligands

Three coordination polymers of [(NiL(1))(3)(TCBA)(2)] (1), [(NiL(2))(3)(TCBA)(2)] (2), and [(NiL(3))(3)(TCBA)(2)] (3) have been constructed using azamacrocyclic Ni(II) complexes [NiL(1)](ClO(4))(2)/[NiL(2)](ClO(4))(2)/[NiL(3)](ClO(4))(2) and TCBA(3-) as building blocks (L(1) = 3,10-bis(2-fluorobenzyl)-1,3,5,8,10,12-hexaazacyclotetradecane; L(2) = 3,10-bis(3-fluorobenzyl)-1,3,5,8,10,12-hexaazacyclotetradecane; L(3) = 3,10-bis(4-fluorobenzyl)-1,3,5,8,10,12- hexaazacyclotetradecane; TCBA(3-) = tri(4-carboxy-benzyl)amine). The results of X-ray diffraction analyses reveal that 1 shows a 2D Borromean structure, while 2 and 3 form 2D layer structures, and the 2D layers are further connected by the interlayer F···F interactions in 2 and C-H···F interactions in 3 to generate two 3D porous structures with 1D fluorine atoms interspersed channels. Gas sorption measurements illustrate that the desolvated 2 and 3can adsorb N(2), H(2), and CO(2) molecules. The different structures and gas sorption properties of 1 and 2/3 are mainly induced by the different positions of F atoms in azamacrocycle ligands.

[NiL]2[Fe(CN)6]·4H2O [L = 3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclotetradecane]: a novel three-dimensional iron(II)–nickel(II) cyanide-bridged bimetallic assembly with a vat-like structure

Reaction of either [Fe(CN)6]3− or [Fe(CN)6]4− with a macrocyclic Ni(II) complex leads to the same product with a new type of 3-D structure, which shows a weak ferromagnetic interaction between the nearest Ni(II) ions through the diamagnetic Fe(II) ion.

Construction of two 3D homochiral frameworks with 1D chiral pores via chiral recognition.

The reactions of a pair of enantiomers of macrocyclic nickel(II) complexes with racemic penicillamine generated two 3D hydrogen-bonded homochiral frameworks of {[Ni(f-(SS)-L)](2)(l-pends)(ClO(4))(2)}(n) (Λ-1) and {[Ni(f-(RR)-L)](2)(d-pends) (ClO(4))(2)}(n) (Δ-1). The frameworks possess 1D tubular pores and opposite right/left-handed helical porous surfaces (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane; pends(2-) = penicillaminedisulfide anion).

Molecular architecture via coordination and multi-intermolecular interactions: Synthesis, structures and magnetic properties of one-dimensional coordination polymers of macrocyclic nickel(II) complexes with terephthalate and trans-butene dicarboxylate

Reactions of terephthalate (TP 2 - ) and trans-butene dicarboxylate (BDC 2 - ) with macrocyclic complexes [NiL 1 ](ClO 4 ) 2 , [NiL 2 ](ClO 4 ) 2 , [NiL 3 (ClO 4 ) 2 and [NiL 4 ](ClO 4 ) 2 which contain different pendant groups gave five new one-dimensional coordination polymers with the formula [NiL 1 (TP)] n (1), [NiL 2 (TP)] n (2), [NiL 1 (BDC)] n (3), [NiL 3 (BDC)] n (4) and [NiL 4 (BDC)] n (5), respectively (L 1 = 3,10-bis(2-phenethyl)-1,3,5,8,10,12-hexaazacyclo-tetradecane, L 2 = 3,10-bis(2-benzyl)-1,3,5,8,10,12-hexaazacyclo-tetradecane, L 3 = 3,10-bis(2-ethyl)-1,3,5,8,10,12-hexaazacyclo-tetradecane, L 4 = 3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclo-tetradecane). These compounds were characterized by single-crystal X-ray analyses. All structures are made up of one-dimensional chains of [NiL 1 , 2 , 3 , 4 ] 2 + units with TP 2 - /BDC 2 - anions. Each Ni(II) ion in the chain is six-coordinated with four nitrogen atoms from the macrocyclic ligand in the equatorial plane, and two carboxylate oxygen atoms from the TP 2 - or BDC 2 - group in axial position. In the structures, different intermolecular interactions and packing modes between the 1D chains are found depending on the nature of the pendant groups and the bridging ligands. The ID chains tend to interact via π...π (compound 1) or C-H...π (compounds 2 and 3) interactions when the compounds contain benzene rings as pendant groups or as bridging ligands, otherwise the ID chains tend to interact via hydrogen bonding interactions (4 and 5). In 1-4, the ID chains are aligned in a parallel mode. In 5, the 1D chains are arranged in a crossover mode. Magnetic susceptibility measurements indicate that these compounds show weak ferromagnetic interactions between the nearest Ni(II) ions through the TP 2 - or BCD 2 - bridges.

Direct observation of the role of lanthanides in stabilizing a ferromagnetic spin orientation in a weak FeIII–FeIII antiferromagnet

[Fe(III)2Ln(III)2(OH)2(L(1))2(HL(2))2(NO3)4(H2O)1½(MeOH)½]·6MeCN (Ln = Y (1), Dy (2); H2L(1) = 2,3-dihydroxybenzaldehyde and H2L(2) is the Schiff base of this aldehyde with furfurylamine) have unusually weak antiferromagnetic interactions between the Fe(III) centres in comparison with other (μ-dihydroxo)diiron(III) complexes. For 1, it was established that modulation of the hydroxo bridges by coordination to the Y(III) ions results in long Fe-O bonds and small Fe-O-Fe angles, leading to J = -0.4 cm(-1). Analysis of the Mössbauer spectra reveals that the intramolecular magnetic field generated by the anisotropic Dy(III) ions in 2 is sufficient to overcome the Fe-Fe antiferromagnetic coupling and reorientate the Fe(III) moments into a ferromagnetic spin orientation.

The diverse structures of Cd(ii) coordination polymers with 1,3,5-benzenetribenzoate tuned by organic bases

The reaction of CdCl2·1.5H2O with 1,3,5-benzenetribenzoic acid (H3BTB) in DMF gave {[Cd3(BTB)2(DMF)4]·3DMF}n (1), while the reactions of Cd(Ac)2·2H2O with H3BTB in DMF/H2O (1 : 10) in the presence of py, bpy, and bib generated {(Hpy)[Cd(BTB)(py)]·0.5DMF·3H2O}n (2), {Cd[Cd2(BTB)2(bpy)]·2bpy·DMF·19H2O}n (3), and {[Cd3(BTB)2(bib)3(H2O)2]·4H2O}n (4), respectively (DMF = N,N′-dimethylformamide, py = pyridine, bpy = 4,4′-bipyridine, bib = 1,4-bis(imidazol-1-yl)butane). X-Ray single-crystal analyses reveal that 1 contains a two-dimensional bilayer structure based on a carboxylate and DMF bridged Cd3 cluster. In 2, two honeycomb-like [Cd(BTB)]nn− sheets are interpenetrated with each other to form a 2D network. In 3, the 2D [Cd(BTB)]nn− honeycomb-like sheets are pillared by bpy to form a 3D framework, and the 3D frameworks are three-fold interpenetrated to generate the framework of 3 with 1D open channels, which are occupied by disordered Cd ions, bpy, DMF and water molecules. Compound 4 consists of a 3D self-penetrated framework constructed by μ2-bib bridging five-fold interpenetrated 2D bilayers. The results of gas sorption measurements indicate that the desolvated 3 can selectively adsorb CO2 and H2 over N2, with a rare large hydrogen sorption hysteresis. The luminescent properties of 1–4 were also investigated.

A two-dimensional coordination polymer with a brick wall structure and hydrophobic channels: synthesis and structure of a macrocyclic nickel(II) complex with 1,3,5-benzenetricarboxylate

The reaction of 1,3,5-benzenetricarboxylate, BTC3−, with a macrocyclic complex [NiL](ClO4)2 (L⊕=⊕ 3,10-bis((2-phenethyl)-1,3,5,8,10,12-hexaazacyclotetradecane) containing hydrophobic pendant groups results in a two-dimensional coordination polymer with a brick wall structure and hydrophobic channels.

Molecular architecture via hydrophobic interaction. Synthesis and structure of [NiL](ClO4)2 ( L=3,10-bis(2-phenylethyl)-1,3,5,8,10,12-hexaazacyclotetradecane)

Abstract The complex with the formula [NiL](ClO4)2, where L=3,10-bis(2-phenylethyl)-1,3,5,8,10,12-hexaazacyclotetradecane, has been synthesized and characterized by single-crystal X-ray analyses. The complexes combine via hydrophobic interaction of lariats to form hydrophobic wall and hydrophilic cavity. All the ClO4− anions are involved in the cavities.