Absolute helicity of 1D chains influenced by enantiopure ligands

Two novel coordination polymers, [Cd(D-1-Hcam)(nta)(H₂O)₂]₂[Cd(D-3-Hcam)(nta)(H₂O)₂]₂·4H₂O (1) and [Cd(DL-Hcam)(nta)(H₂O)₂]·H₂O (2) (D-1-Hcam/D-3-Hcam = monodehydrated d-camphoric acid, Hnta = nicotinic acid and DL-Hcam = monodehydrated dl-camphoric acid), have been synthesized under hydrothermal conditions. Complex 1 is a three-dimensional hydrogen bonding framework composed of two kinds of 1D helical chains which exhibit the same right-handed helix, whereas complex 2 is constructed with one kind of 1D racemic chains. Interestingly, both two chiral molecules in the structures play important roles in the absolute helicity although they are not in the backbones of the helix which are made of rigid achiral ligands. Furthermore, different coordination modes of chiral ligands regulated the fluorescent emission.     

A pair of nonporous homochiral cobalt-based coordination polymers for enantioselective recognition and electrocatalysis

A pair of nonporous enantiomers [Co(H₂O)(bpy)(L-Mand)]•H₂O•Cl (L-1) and [Co(H₂O)(bpy)(L-Mand)]•H₂O•Cl (D-1) (L-Mand = L-Mandelic acid, D-Mand = D-Mandelic acid, bpy = 4,4′-bipyridine) with 3D supermolecule framework possess excellent enantioselective recognition and electrocatalysis ability towards L- and/or D-tart.     

Synthesis,crystal structure and luminescence of novel two-dimensional interpenetrating frameworks

Two novel metal coordination polymers, [Zn(nic)(isonic)]_n (1) and [Cu(nic)(isonic)]_n (2) (H₂nic = nicotinic acid, H₂isonic = isonicotinic acid), have been hydrothermally synthesized and characterized by elemental analysis, IR, and single crystal X-ray diffraction. X-ray single-crystal structural analyses reveal that 1 and 2 are isomorphous, two-dimensional interpenetrating (4, 4) frameworks bridged by nic and isonic ligands, and further assembled into a three-dimensional supramolecular structure via π–π stacking interaction. Moreover, 1 displayed photoluminescent properties in the blue range at room temperature.     

Synthesis,structure, stability and DNA cleavage activities of three Cr(III) complexes with salicylate and ammonium ligands

Complexes [Cr(III)(SA)(en)₂]⁺ (1), [Cr(III)(SA)(DETA)(H₂O)]⁺ (2) and [Cr(III)(SA)(TETA)]⁺ (3) were synthesized (H₂SA = salicylic acid, en = ethylenediamine, DETA = diethylenetriamine, TETA = triethylenetetramine). Kinetics studies show that 2 is the most instable one among these complexes. In addition, only 2 is found to be a very efficient catalyst of the cleavage of PBR322 DNA in the absence of any added cofactor. The degradation rate from supercoiled form to nicked form was 1.05 ± 0.081 h^− 1 (10^− 5 M) at pH 7.4 and 37 °C. Thiobarbituric acid-reactive substances assay shows 2 fail to produce OH causing any degradation of deoxyribose ring even in the presence of ascorbic acid. Ethidium bromide displacement assay suggests that only 2 can kick out EB from the groove of DNA. The interaction with DNA causes a blue shift of the d → d transition spectra of 2.     

Diverse architectures of hybrid materials induced by different mixed-ligands and applications in luminescence

For investigating the effects of different azacyclo-assisting ligands and O-donor bridging ligands on the structural construction, three different structural complexes, namely, {Zn(DBTA)(phen)(H₂O)}_n (1) (DBTA = 2, 5-Dibromo-terephthalic acid, phen = 1,10-Phenanthroline), [Zn(DBTA)(bimb)]_n (2) (bimb (1,4-bis(imidazole-1-ylmethyl)benzene) and {[Zn₂(bmimb)(PO₄)₂]·(H₂O)₂}_n (3) (bmimb = 1,2-bis(methylimidazole-1-ylmethyl) benzene) have been constructed by different mixed-ligands and Zn atoms. Their structures have been characterized by single-crystal X-ray diffraction analysis, elemental analysis, and Infrared spectroscopy. Complex 1 exhibits a common 2D layer with 4,4-connected topology. Complex 2 features an interesting 2-fold interpenetrating net with the aid of long-chain flexible azacyclo-assisting ligands. Complex 3 shows 3D supramolecular architecture with tetranuclear water cluster filling in the pores. Their fluorescence properties were also measured.     

Hydrothermal syntheses and crystal structures of four novel lanthanide(III) complexes based on two mixed N,O-donor ligands

Four novel polymeric lanthanide(III) complexes [Pr(NCP)(2,5-pydc)]_n·1.5nH₂O (1), [La(NCP)(2,5-pydc)]_n (2), [Nd(NCP)(2,5-pydc)]_n (3) and [Sm(NCP)(2,5-pydc)]_n (4) (HNCP = 2-(4-carboxyphenyl)imidazo(4,5-f)(1,10)phenanthroline, 2,5-H₂pydc = pyridine-2,5-dicarboxylic acid) have been hydrothermally synthesized and characterized via elemental analysis and single crystal X-ray diffraction. Structural analyses revealed that all of these four complexes possess similar two-dimensional sheet structures, which are further linked by the hydrogen bonds to furnish three-dimensional supramolecular structures. Meanwhile, the thermogravimetric analysis and photoluminescent property of complexes 1–4 have also been investigated.     

Novel heterobimetallic Cu/Mn coordination polymers prepared by “direct permanganate” synthesis

Two heterometallic Cu/Mn complexes [Cu(Me₂en)₂][Mn₂(ox)₃] · 2H₂O (1) (Me₂en = N,N-dimethylethylenediamine, H₂ox – oxalic acid) and [Cu(1,3-pn)(ox)(H₂O)][Mn(ox)(H₂O)₂] · H₂O (2) (1,3-pn = 1,3-diaminopropane) are prepared by the one-pot reaction of copper powder, tetrabutylammonium permanganate, oxalic acid and N-chelating ligands. Their structures are investigated by single-crystal X-ray analysis that reveals interesting variation in bridging motives of the oxalate groups composing the Mn-polymeric fragments.     

Assembly of one 2D layer and two 3D pillared-layer structures derived from metal ions and 5-(pyridin-4-yl)isophthalic acid with or without pillars

Three new coordination polymers, [Mn(L)(H₂O)₂]₂·5H₂O (1), [Cu(L)(4,4′-bipy)]₂·H₂O (2) and [Pb(L)(4,4′-bipy)_0.5] (3) (H₂L = 5-(pyridin-4-yl)isophthalic acid; 4,4′-bipy = 4,4′-bipyridine) have been synthesized and characterized by IR, thermogravimetric analysis, X-ray powder diffraction and X-ray single crystal diffraction. Complex 1 shows a 2D layer structure which stacks with the other ones to form 1D channels to hold 1D water chains. Complex 2 displays a 3D + 3D → 3D polycatenation network. 3 shows a unique 2D + 2D → 3D polycatenation net in which each Pb center has a hemidirected coordination geometry due to the existence of “inert pair effect”. The thermal and luminescent properties of 1–3 were also examined.     

Two helical one-dimensional copper(II) coordination polymers based on N-(2-hydroxylbenzyl)glycine and N-(2-hydroxylbenzyl)-l-alanine: Syntheses,crystal structures and magnetic studies

Two new helical Cu(II) coordination polymers, [Cu(2,2′-bpy)(Hsgly)]Cl · 2H₂O(H₂sgly = N-(2-hydroxylbenzyl)glycine) (1) and [Cu(2,2′-bpy)(Hsala)](NO₃) · 2H₂O(H₂sala = N-(2-hydroxylbenzyl)-l-alanine) (2) were synthesized. Single crystal X-ray diffraction analysis indicated that both complexes showed helical chains arrangement of Cu(II) centers bridged by carboxyl groups. The magnetic measurements showed complex 1 exhibited ferromagnetic interaction while there was no interaction between the Cu(II) centers in complex 2.     

Two novel 2D organic–inorganic hybrid silicotungstates assembled by {Cu2Ln2(ox)(SiW11)2} dimers and [Cu(en)(ox)]/[Cu(en)2] linkers

Two novel 2-D organic–inorganic hybrid silicotungstates [H₂en][Cu(en)₂(H₂O)]₂{[Cu(en)₂]₃[Cu(en)(ox)]₂[Ln₂(ox)(α-SiW₁₁O₃₉)₂]}·nH₂O (Ln = Er^III, n = 10 for 1, Ln = Sm^III, n = 8 for 2) with mixed organic ligands of ox and en (ox = oxalate, en = ethylenediamine) have been hydrothermally synthesized and characterized by IR spectrum, thermogravimetric analysis (TGA), power X-ray diffraction (PXRD) and X-ray single-crystal diffraction, respectively. Notably, 1 and 2 are isomorphic and exhibit the first novel 2D organic–inorganic hybrid silicotungstates assembled by {Cu₂Ln₂(ox)(SiW₁₁)₂} dimers and [Cu(en)(ox)]/[Cu(en)₂] linkers. Furthermore, the TG curve of 1 and 2 display three steps of weight loss in the range of 25–1000 °C.     

Novel silver(I) compounds assembled from hybrid ligands based on linear or T-shaped coordination environment

Two novel 1D compounds {[Ag₃(Hbptc)(bpa)₂]·H₂O}_n (1) and [Ag₂(H₂bptc)(bpp)₂]_n (2) (H₄bptc = 3,3′,4,4′-benzophenonetetracarboxylic acid, bpa = 1,2-bis(4-pyridyl)ethane and bpp = 1,3-bis(4-pyridyl)propane) were synthesized and structurally characterized. The crystal structures of compounds exhibit two kinds of ladder-like chains based on linear or T-shaped coordination environment of Ag(I). Fluorescence spectra of compounds 1 and 2 indicate the unusual intensity of fluorescent emission upon photoexcitation which may be attributed to ligand-to-metal charge transfer and Ag–Ag interactions.     

Synthesis,characterization and crystal structure of one Mn(II) complex with 4,4′-bisimidazolylbiphenyl and 4,4′-sulfonyldibenzoic acid

One new title compound [Mn₃(BIBP)(sdb)(NO₂⁻)₂(H₂O)₂]_n·2DMF (1) (BIBP = 4,4′-bisimidazolylbiphenyl, sdb = 4,4′-sulfonyldibenzoic acid) has been synthesized under hydrothermal condition. The title compound was characterized by IR spectra, thermal analysis, single crystal and powder X-ray diffraction. Magnetic susceptibility measurements indicate that compound 1 exhibits antiferromagnetic coupling interaction.     

Solvent-free synthesis of new open-framework metal oxalates with different 4-connected topologies

Three open-framework metal oxalates, formulated as (Hdbu)[In₂(OH)(ox)₃] (1), (Hthfa)[Eu₂(Hthfa)(H₂O)(ox)₄]⋅ 3H₂O (2), and (Hepc)[Bi(ox)₂] (3), were prepared under solvent-free conditions, where dbu = 1,8-diazabicyclo[5.4.0]undec-7-ene, ox = oxalate, thfa = tetrahydrofurfurylamine, and epc = 4-ethylpiperazine-1-carbaldehyde. Topological analyses reveal that these compounds have different 4-connected networks with sra (for 1), lon (for 2), and dia (for 3) topologies. Compound 2 displays a bright red luminescence as a result of excitation at 397 nm.     

Blue-green photoluminescent 5- and 10-connected metal 5-(4′-carboxy-phenyl)tetrazolate coordination polymers

Hydrothermal reaction of Zn/Cd salts, NaN₃ and 4-cyanobenzoic acid via in situ [2 + 3] cycloaddition generated two blue-green photoluminescent coordination polymers [Zn(cptta)(H₂O)] (1) and [Cd(cptta)(H₂O)] (2) (H₂cptta = 5-(4′-carboxy-phenyl)tetrazole). When only metal ions are considered as nodes, 1 shows rare 5-connected Shubnikov plane topological type and 2 has unprecedented 10-connected {3¹².4²⁴.5⁹} topological type.     

Metal ions directed self-assembly based on rigid polycarboxylate ligand 5-tert-butyl isophthalic acid and flexible N-heterocyclic ligand 1,4-bis(2-methylimidazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene

Two new complexes {[Cd(bmimx)_0.5(tbip)(H₂O)] · H₂O}_n (1) and [Zn(bmimx)(tbip)]_n (2) (bmimx = 1,4-bis(2-methylimidazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene, H₂tbip = 5-tert-butyl isophthalic acid) based on mixed ligands have been hydrothermally synthesized by varying the metal ions. Structural analysis reveals that complex 1 displays a 2D layer structure with a 4⁴-sql topology; complex 2 exhibits a 3D 4-fold interpenetrated framework with sra topology. The structural differences between 1 and 2 indicate that metal ions have significant effects on the formation of the final architectures. In addition, the thermal stabilities and photoluminescent properties of the two complexes were also investigated.     

Synthesis,structure, and properties of two novel copper(II) complexes, [Cu(phen)(L)2]·6H2O and [Cu(phen)3]·(ClO4)2

Two novel copper(II) complexes, namely [Cu(phen)(L)₂]·6H₂O (1) and [Cu(phen)₃]·(ClO₄)₂ (2) have been synthesized under mild condition (HL = 5-methyl-1H-pyrazole-3-carboxylic acid, phen = 1,10-phenanthroline). We report the structural evidence of discrete water decamer conformation in the solid state. These units are found to act as supramolecular glue in the aggregation of mononuclear copper(II) complex to give a three-dimensional network through hydrogen-bonding. The preliminary investigation on the thermal behavior and the anion exchange property of the complexes are presented.     

Solvothermal syntheses,crystal structures and luminescent properties of two new aromatic dicarboxylate indium coordination polymers

Two new indium coordination polymers formulated as [In(BPDA)(phen)Cl]_n (1) and [In(BDC)(HBDC)·2DMF]_n (2) (H₂BPDA = 2,2′-biphenyldicarboxylic acid, C₁₄H₁₀O₄; phen = 1,10-phenanthroline, C₁₂H₈N₂; H₂BDC = 1,3-benzenedicarboxylic acid, C₈H₆O₄; DMF = N,N-dimethylformamide, C₃H₇NO) have been synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction, infrared (IR), thermal gravimetric analyses (TG) and luminescent studies. Molecular structural analyses reveal that complex 1 exhibits an indium-2,2′-biphenyldicarboxylate helical chained structure decorated with 1,10-phenanthroline, and complex 2 possesses a two-dimensional (2D) layered structure constructed by 1,3-benzenedicarboxylate ligands and InO₆ octahedra, which has a (4,4) topological structure. Blue-green emission at 480 nm (λ_ex = 340 nm) for 1, intense blue-green emission at 492 nm, green emission at 535 nm, and yellow-green emission at 576 nm (λ_ex = 340 nm) for 2 are observed in the solid state at room temperature.     

Novel two-dimensional Co(II) and Cd(II) coordination polymers with intriguing net topologies

Three new two-dimensional coordination polymers were constructed from 2,6-bis(imidazole-1-yl)pyridine (2.6-bip), terephthalic acid (1,4-bdcH₂), and M(NO₃)∙nH₂O (M = Co, Cd). [M(2,6-bip)(1,4-bdc)] (1: M = Co; 2: M = Cd) were prepared under hydrothermal condition, whereas [Cd(2,6-bip)(1,4-bdc)∙xDMF] (3) was obtained under solvothermal condition in DMF solvent. Single-crystal X-ray analyses revealed the first example of a 2D 4-connected net of 6⁶ topology in 1 and 2 and a rare 2D 4,5-connected net of 4,5 L20 topology in 3. All these complexes were thermally robust and emissive in solid-states. This work confirmed the versatility of using hingelike 2,6-bip as a linker and the importance of solvent effect in the process of framework formation.     

Syntheses,characterizations, and redox behaviors of new self-assembled metal complexes with bridging ligands incorporating chalcogen sites

Three new complexes, [Zn(dbsf)₂(dmf)₂] · 5.5dmf (dbsf = 4,4′-sulfonyldibenzoate) (1β), [Cu(tdsa)(phen)₂] · 1.5EtOH (tdsa = 5,5′-thiodisalicylate, phen = 1,10-phenanthroline) (2), and [Cu(sdp)(phen) · Cu(Hsdp)(phen)(CH₃COO)] · 3EtOH (sdp = 4,4′-sulfonyldiphenolate) (3) were prepared and structurally characterized. Complex 1β shows a one-dimensional coordination framework constructed from bridges between Zn(II) centers with two ligands. Complex 2 is a monomeric complex, which assembles by π–π interactions. Complex 3 shows a unique two-dimensional coordination framework that is constructed from two Cu(II) centers, sdp, and Hsdp. The redox properties of these three complexes were characterized by solid-state cyclic voltammetry. Complexes 1β and 3 show irreversible reduction waves because of the reduction of their sulfone sites. Complex 2 shows an irreversible oxidation wave because of oxidation of the sulfide site.     

Microporous metal–organic frameworks constructed by Cu(I)/Zn(II), Tpt and 1,4-benzenedicarboxylate

Two novel metal–organic frameworks, [Cu(tpt)(bdc)_1/2]_n · nH₂O (1) and [Zn(tpt)(bdc)_1/2I]_n (2) (tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine, H₂bdc = 1,4-benzenedicarboxylic acid), have been prepared by hydrothermal reactions. In complex 1, Cu(I) center is in a trigonal coordination environment with bidentate tpt coordinating Cu(I) atoms to form 1D zigzag chains, and bdc ligand links the zigzag chains to form a 2D layered structure. In complex 2, Zn(II) center is in a trigonal–pyramidal environment with bidentate tpt coordinating Zn(II) atoms to form zigzag chains, and bdc links the zigzag chains to form metal–organic framework which contains interesting hexagonal nano-channels.