Wen-Long Liu

Hydrothermal syntheses, structures and luminescent properties of d10 metal–organic frameworks based on rigid 3,3′,5,5′-azobenzenetetracarboxylic acid

Four novel d10 metal–organic frameworks based on rigid 3,3′,5,5′- azobenzenetetracarboxylic acid (H4abtc) in the presence of auxiliary 2,2′-biimidazole (biim), 1,10-phenanthroline (phen) and pyridine (py) have been synthesized under hydrothermal conditions and structurally characterized. Their formulae are [Cd2(abtc)(biim)2]n (1), {[Cd(abtc)0.5(phen)]4·4H2O}n (2), {[Zn(abtc)0.5(phen)]4·2H2O}n (3) and [Zn3(abtc)(py)4(OH)2]n (4). Complex 1 possesses a one-dimensional (1D) infinite tubular structure by using biim as auxiliary ligand. The structures of complexes 2 and 3 exhibit three-dimensional (3D) (4,4)-connected frameworks with (4284) topologys by employing phen as auxiliary ligands. By utilizing py as auxiliary ligand, complex 4 is a (2,3,4)-connected framework with a (10)(83)2(8,105) topology in which there exists -{Zn-O-Zn}- zigzag chains and 46-member macrocycles which are linked by multicarboxylate ligands to form a 3D supramolecular structure. The structural differences among 1–4 indicate the importance of the auxiliary ligands for the framework formation of the coordination polymers. In addition, the thermal stabilities and photoluminescence properties of 1–4 are also investigated.

Novel 48-membered hexadecanuclear and 60-membered icosanuclear manganese metallamacrocycles.

Either an S 8 symmetrical 48-membered hexadecanuclear or an S 10 symmetrical 60-membered icosanuclear manganese metallamacrocycle was self-assembled using a manganese ion and a ditopic pentadentate ligand. This was either N-4-phenylbenzoylsalicylhydrazide (H 3pbshz) containing a rigid rod-shaped, bulky biphenyl residue as a terminal N-acyl group or N-3,3-diphenylpropionylsalicylhydrazide (H 3dppshz) containing a flexible beta-branched N-acyl group, but with two sterically bulky phenyl residues at the Cbeta position. The backbone of these metal-organic assemblies is a repeating unit consisting of a -[Mn-N-N-] link that extends to complete either the 48-membered cyclic structure involving 16 manganese(III) centers and 16 ditopic linker ligands or the 60-membered cyclic structure involving 20 manganese(III) centers and 20 ditopic linker ligands (depending on the ligand used). Even though the nuclearity of the metallamacrocycles was different, the successive manganese centers were in the same chiral sequence, ...(LambdaLambdaDeltaDelta)(LambdaLambdaDeltaDelta)....

A nitro-decorated NbO-type metal–organic framework with a highly selective CO2 uptake and CH4 storage capacity

A nitro-decorated NbO-type metal–organic framework, Cu2NTPTB (NJU-Bai 14; H4NTPTB = 2′-nitro-[1,1′:4′,1′′-terphenyl]-3,3′′,5,5′′-tetracarboxylic acid), was synthesized and structurally characterized. It exhibited high permanent porosity with a BET surface area of 2384 m2 g−1, improved adsorption selectivity of CO2/CH4 (6.5) and CO2/N2 (20.8) at 298 K and 1 bar, high excess unsaturation CO2 uptake (94.0 wt%) at 273 K and 20 bar, and high methane total uptake of 184 cm3 cm−3 at 290 K and 35 bar.

Hydrothermal syntheses, structures and luminescent properties of Zn(II) coordination polymers assembled with benzene-1,2,3-tricarboxylic acid involving in situ ligand reactions

Five Zn(II) coordination polymers, [Zn(1,2,3-Hbtc)(1,4-bix)]·0.5(1,4-bix)·H2O (1), [Zn(mocip)(1,4-bix)] (2), [Zn3(1,2,3-btc)2(4,4′-bpy)2(H2O)2]2·7H2O (3), [Zn3(1,2,3-btc)2(bbi)3]2·3H2O (4) and [Zn(dmcaip)(1,3-bix)]·DMF (5), were prepared by hydro(solvo)thermal reactions of ZnO with 1,2,3-H3btc (1,2,3-H3btc = 1,2,3-benzenetricarboxylic acid) in the presence of different N-donor ligands (1,4-bix = 1,4-bis(imidazol-1-ylmethyl)benzene, 4,4′-bpy = 4,4′- bipyridine, bbi = 1,1′-(1,4-butanediyl)bis(imidazole), 1,3-bix = 1,3-bis(imidazol-1-ylmethyl)benzene, H2mocip = 2-(methoxycabonyl)isophthalic acid and H2dmcaip = 2-(dimethylcarbamoyl)isophthalic acid). Their crystal structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses and IR spectra. Complex 1 has a one-dimensional (1D) infinite tubular structure, whereas 2 exhibits two-dimensional (2D) supramolecular networks assembled from 1D chains and 1,4-bix. The three-dimensional (3D) framework of 3 can be described as a trinodal 4-connected (42·64)2(65·8)(42·64)2 topology, which consists of 2D [Zn3(1,2,3-btc)2] layers and 4,4′-bpy pillars. Complex 4 features a 5-nodal (3,4)-connected 3D coordination net with a (6·74·8)2(62·72·82)(6·72)2 topology. Complex 5 has a rare 1D double meso-helical supramolecular structure. Interestingly, in the complexes 2 and 5, the starting 1,2,3-H3btc reagents are converted into new ligands (mocip2− in 2 and dmcaip2− in 5) under solvothermal conditions via in situ ligand reactions. Moreover, thermal stabilities, X-ray powder diffraction and the fluorescent properties of complexes 1–5 have been investigated.

Metallic macrocycle with a 1,3-alternate calix[4]arene salicylideneamine ligand

The calix[4]arene-based podand which incorporates two salicylideneamine units in 1,3-alternate positions of the lower rim has been prepared and subjected to complexation studies with transition metal ions. The nickel and copper complexes form a 2 : 2 stoichiometric metallic macrocyclic framework.

A novel molecular ladder structure of Cu(II)–Ba(II) coordination polymer exhibiting ferromagnetic coupling

A novel one-dimensional ladder-like Cu-Ba compound ([Ba(H2O)3(CuL)2] x 2H2O)n (H3L = Glycylglycine, N-[1-(2-hydroxyphenyl)propylidene]), has been synthesized and structurally characterized; it exhibits ferromagnetic interaction.

Heterometallic coordination polymers based on dipeptide schiff base Cu(II) metalloligand: synthesis, structures, and magnetic properties

Three new heterometallic coordination polymers formulated as {[Ca(CuL)(H2O)5]·H2O}n (1), [Sr(CuL)(H2O)2]n (2), and [Ba(CuL)(H2O)4]n (3) have been obtained by reaction of a rigid metalloligand [CuL]2− (H4L = N-5-sulfosalicylideneglycylglycine) with the corresponding alkaline earth metal cations M2+ (M = Ca, Sr or Ba). Their crystal structures are determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses and IR spectra. The coordination preferences of the alkaline earth metal cations are found to have pronounced effects on the structural topologies. Complex 1 has a distorted ladder-like one-dimensional (1D) structure. In complex 2, Sr(II) ions link metalloligands [CuL]2−via the sulfonate and carbonyl oxygen atoms to generate a three-dimensional (3D) framework. Complex 3 is arranged in a 3D framework formed by the linkage of copper(II) and barium(II) via carboxylate and sulfonate bridges. Variable-temperature magnetic susceptibility studies indicate that all the complexes exhibit weak antiferromagnetic interactions between the Cu(II) paramagnetic centers.

A New 2D Network Constructed from the Extension of Transition-Metal-Grafted e-Keggin Polyoxoanion by a Bridging Organic Carboxylate

By introducing a bridging ligand of 5-methylisophthalic acid (shortened as 5-mip) into the tetrahedral Zn4-ε-Keggin system, a new 2D network of [TBA]3[H4PMo8VMo4VIO40Zn4][C7H6(COO)2]2 (1) was synthesized under hydrothermal condition. It was characterized by FT-IR, BET, TGA/DSC-MASS analysis, powder X-ray diffraction and single-crystal X-ray diffraction, respectively. Besides, compound 1 shows remarkable electrocatalytic activity towards bromate reduction.

Synthesis and crystal structure of metal complexes of Schiff bases derived from Glycylglycine and Salicylaldehyde [Ni(H2O)6(Ml)2]·nH2O (M = Cu, Ni; L = C11H9N2O4)

Complexes [Ni(H2O)6(ML)2]·nH2O (M = Cu, Ni; L = Schiff base derived from glycylglycine and salicylaldehyde, C11H9N2O4) were synthesized and characterized. The [Ni(H2O)6(CuL)2]·10H2O complex 1 crystallized in the space group , with a = 7.217(1), b = 11.674(1), c = 12.678(1) Å, α = 66.56(1), β = 76.60(1), γ = 80.46(1)°, and Z = 1. The [Ni(H2O)6(NiL)2]·2H2O complex 2 crystallized in the group P2(1)/c, with a = 10.564(2), b = 20.246(4), c = 6.965(2) Å, β = 103.14(1)°, and Z = 2. Hydrogen bonding involving [ML]−, Ni(H2O)6 2+ and molecular water forms a three-dimensional (3D) supermolecule. The determination of variable-temperature magnetic susceptibilities indicates an antiferromagnetic interaction between the metallic atoms of 1, and a corresponding ferromagnetic interaction for 2.

Intramolecular photo-substitution in the inclusion compound of mono[6-deoxy-6-(2-aminoethyl thio-1,2-dicyane ethylenylthio)]-β-cyclodextrin with cyclopentadienyl manganese tricarbonyl in DMF solution

Abstract A novel host of β-cyclodextrin (β-CD) derivative, mono[6-deoxy-6-(2-aminoethyl thio-1,2-dicyane ethylenylthio)]-β-CD ( 3 ), and its inclusion compound 4 with cyclopentadienyl manganese tricarbonyl (CpMn I (CO) 3 ) have been prepared and characterized by spectroscopic methods. It is experimentally evident that the inclusion complexation stabilized the guest extremely when complex 4 was heated. Upon irradiation of inclusion compound 4 in DMF solution, an interesting intramolecular photo-substitution resulting in the formation of a self-stabilized compound mono[6-deoxy-6-(2-aminoethyl thio-1,2-dicyane ethylenylthio)]-β-CDMn II Cp(DMF) 2 ( 7 ) was observed. Based upon a double-recognition between the host and the organometallic guest, compound 7 became very stable in DMF solution.