Search

The DNA binding and the antibacterial activities of metal organic compounds have great significance for the development of anticancer drugs. In this study, a copper coordination network, [Cu2L(H2O)2]n (CuNet), based on H4L where 2,6-pyridine-dicarboxylic acid moieties are spaced by p-benzyloxy, is prepared hydrothermally. Single crystal X-ray analysis demonstrates that the fully deprotonated ligand L4– with high planarity in CuNet adopts a bis-µ2-η1: η1: η2 coordination mode to bind four Cu(II) to render a graphene-like network, which is further propped up to a 3D supramolecular framework through the hydrogen bonds between coordinated water and uncoordinated carboxyl oxygen. Considering its highly planar structural feature and excellent antibacterial properties of Cu(II), the DNA binding and antibacterial performance were explored. The UV-Visible absorption titration and EB-DNA competition determination exhibited that CuNet bound DNA in an intercalation mode with the higher binding constant Kb of 2.42 × 105 M− 1, and the comparable quenching constant Ksv of 1.62 × 104 M− 1 upon compared with the documented DNA linkers. In addition, the antibacterial activity test demonstrates that CuNet exhibits comparable inhibitory effect on Escherichia coli with that of cefradine at the concertation of 0.70 mg/mL. This work has certain significance for the development of metal drugs.

A new CuII coordination network with high conjugation as well as abundant available active sites as a selective Na2S, (NH4)2S and H2S sensor and adsorbent of methylene blue with excellent recovery was developed.

Two luminescent film sensors constructed from new lanthanide coordination polymers based on a new tetra-monodentated ligand for ratiometric detection of Zn2+ and NH3 in water were developed.

To advance the structural development and fully explore the application potential, it is highly desirable but challenging to elucidate the relationship between the structures and properties of ZnII-LnIII heterometallic species. Herein, three types of ZnII-LnIII heterometallic compounds (LnIII = GdIII, TbIII) formulated as [Zn16Ln4L12(μ3-O)4(NO3)12]·8CH3CN (ZnLn-1), [Zn2Ln2L2(NO3)6(H2O)2]·3CH3CN (ZnLn-2), and [Zn4Ln2L8(OAc)12]·xCH3CN (ZnLn-3: for Ln = Gd, x = 5; for Ln = Tb, x = 4) were dictated by common inorganic anions, NO3- and OAc-, with the aid of the multidentate ligand H2L with propane as the central skeleton and 3-methoxysalicylamide and 3-methoxysalicylaldimine as terminal groups. ZnLn-1 features cubic cages with four {Zn4L3} tetrahedral subunits and four Ln3+ centers positioned at the eight vertices alternately when NO3- was introduced into the reaction system exclusively. An attempt to replace NO3- in ZnLn-1 with OAc- partially led to the formation of {Zn2Ln2L2} heterometallic wheels. Meanwhile, ZnLn-3 featuring double-hairpin-like {Zn4Ln2L4} hemicycles that are orthogonal to each other assisted by intermolecular hydrogen bonds was constructed when NO3- in ZnLn-1 was completely replaced by OAc-. Their structural integrity in solution were ascertained by both emission and 1H NMR spectroscopy. Ascribed to the different Zn2+-containing antenna, ZnTb-2 possesses a relatively strong emission characteristic of Tb3+; ZnTb-1 has moderate Tb3+ luminescence, yet an absence of Tb3+ emission is found in ZnTb-3. Such an emission difference could be mainly attributed to the antenna effect directed by distinct structural characteristics induced by anions. The anion-dictated self-assembly strategy presented herein not only offers a facile approach to regulate the coordination mode of H2L to such an extent to obtain diverse structures of ZnII-LnIII heterometallic species but also provides an understanding of how common inorganic anions tune coordination-driven self-assemblies as well as the subsequent luminescence properties.

It is challenging to develop highly stable lanthanide luminescent sensors for detecting heavy metal ions and nitroaromatics in view of the human health and environmental security. To this end, two water stable Ln-MOFs with the chemical constitution of {[Ln(HL)]·3DMF·3H2O}n (Ln = Eu, LZG-Eu and Ln = Tb, LZG-Tb) have been developed solvothermally using a multidentate ligand (H4L) with the central phenyl backbone bisubstituted by 2,6-pyridine-dicarboxylic acid at the para-position, H4L = 1,4-bis(2',2'',6',6''-tetracarboxy-1,4':4,4''-pyridyl)benzene. Single crystal analysis demonstrates that two novel Ln-MOFs feature 4,4,4-connected nets with an unprecedented topology symbol of {42·6·83}2{42·62·82}{42·84} and contain two kinds of one-dimensional channels. Powder X-ray diffraction as well as the luminescence determination results indicate that they retain their crystallinity and structural integrity in harsh acidic and basic conditions with pH in the range of 4-11. Moreover, they are highly luminescent, which makes them excellent chemical sensors for detecting Cu2+ and 4-NP (4-nitrophenol) with high selectivity and sensitivity in aqueous media such as deionized water, tap water, and river water based on distinct quenching effects. To the best of our knowledge, their detection limits are lower than those documented so far. In addition, the quenching efficiency of 4-NP was retained in the presence of interfering ions even after the compounds were used for five cycles, which makes them attractive, reliable, visual, and recyclable luminescent Ln-MOF sensor materials for 4-NP. The recognition mechanism for Cu2+ could be attributed to the dissociation of the main framework induced by Cu2+ and the subsequent formation of a Cu2+ coordination species and that for 4-NP is considered to be multi-quenching mechanisms dominated by competition absorption.

From the perspective of human health and environmental safety, the development of hydrostable fluorescent sensors for the detection of heavy metal ions and nitroaromatics is an important but a challenging issue. To this end, a water-stable Zn2+ coordination polymer formulated as {[Zn(H2L)]·2DMF·3H2O}n (ZnCP) was prepared elaborately by a solvothermal method using a multidentate ligand (H4L) with 2,6-pyridine-dicarboxylic acid spaced by para-substituted benzene. Single-crystal analysis shows that the new ZnCP exhibits one-dimensional chain structural features, which further promoted to afford a wrinkled two-dimensional network structure via inter-chain hydrogen bonding. Powder X-ray diffraction and fluorescence measurements show that it can maintain crystallinity and structural integrity under harsh acidic and alkaline conditions with the pH ranging from 4 to 11. Notably, the bright blue–emissive ZnCP showed selective fluorescence quenching effects for Fe3+ and picric acid (PA), which makes it an excellent chemical sensor for Fe3+ and picric acid (PA) with low detection limits of 0.41 and 0.26 μM in water. The recognition mechanism of Fe3+ could be attributed to UV absorption competition and resonance energy transfer in the aid of weak electrostatic interactions, while the recognition mechanism of PA is considered to be a multi-quenching mechanism dominated by absorption competition and PET effects with the assistance of hydrogen bonding. In addition, poly(methyl methacrylate) (PMMA) films doped with ZnCP (ZnCP@PMMA) were developed to provide better sensing performance and portability for practical applications.

Recently, by tuning the coordination behavior of a new asymmetric multidentate ligand, H3L, containing two nitrogen and six oxygen donors by both metal centres and anions, H3L = 1-(2-hydroxy-3-methoxy-benzamido)-2-(2-hydroxy-3-methoxy-benzylideneamino)-2-hydroxy propane, three types of heterometallic compounds with the chemical composition of [Zn8Ln2L2(OH)4(OAc)12]·xCH3OH·yCH3CN·zH2O (Zn8Ln2, where Ln = Nd, Tb, Dy and Er), [Ni3Tb2(HL)2(OH)4(OAc)6]·3CH3CN·H2O (Ni3Tb2), and [Ni2Tb2(HL)2(OAc)4(NO3)2(H2O)2]·4CH3CN·3H2O (Ni2Tb2) were developed. Structural analysis revealed that four ellipsoidal decanuclear ZnII–LnIII clusters resulted from the assembly of H3L with Zn(OAc)2·2H2O and Ln(OAc)3·6H2O. Replacement of Zn(OAc)2·2H2O with Ni(OAc)2·4H2O rendered a butterfly pentanuclear NiII–LnIII cluster, and upon further using Tb(NO3)3·6H2O to replace Tb(OAc)3·6H2O, a tetranuclear NiII–LnIII metallocycle was obtained. The luminescence studies on these compounds indicated that the ZnII-containing chromophore is a good antenna for sensitizing the characteristic emission of Ln3+ effectively from the visible to near-infrared region as a result of its energy match, perfect shielding and less concentration quenching compared to its NiII analogues, where the d → d transitions characteristic of Ni2+ were observed in the excitation spectra when irradiated. Notably, weak emission bands characteristic of Tb3+ were observed in the spectrum of Ni2Tb2 but not in that of Ni3Tb2 when excited by the d→d transition, which may be attributed to the difference in crystal field. Furthermore, the magnetic susceptibility studies indicate that the magnetic exchange for the TbIII ions in Zn8Tb2, Ni3Tb2 and Ni2Tb2 is ferromagnetic, whereas that for the DyIII ions in Zn8Dy2 is antiferromagnetic. Our results are of great significance for the rational design and synthesis of novel heterometallic supramolecular structures with interesting luminescence and magnetic properties.

Three LnIII coordination polymers, [LnL(NO3)3]n∙2C4H8O2 (LnL, Ln= Nd, NdL; Eu, EuL; Tb, TbL) based on a asymmetric poly-monodentate ligand L, which has abundant branched end groups for chelating Ln...

To advance the structural development and fully explore the application potential, it is highly desirable but challenging to elucidate the relationship between the structures and properties of Zn

From the perspective of human health and environmental safety, the development of hydrostable fluorescent sensors for the detection of heavy metal ions and nitroaromatics is an important but a challenging issue. To this end, a water-stable Zn

It is common knowledge that the spatial structure of substrates is the major influencing factor in DNA binding. To tune the binding affinity of DNA, a new 4-acylpyrazolone derivative ligand, (2-hydroxy-N′-((5-hydroxy-3-methyl-1-(4-nitrophenyl)-4,5-dihydro-1H-pyrazol-4-yl)(phenyl)methylene)benzohydrazide) (H2L) and its three complexes have been prepared and well characterized. Reaction of H2L with CuCl2 resulted in a mononuclear compound with tetra-coordinated quadrilateral plane, [Cu(HL)Cl] (1). When H2L was coordinated to Cu(OAc)2, a dinuclear Cu(II) compound with chemical formula of [Cu2L2(CH3OH)2]·CH3OH (2) was obtained, and the coordination geometry of Cu(II) is a square pyramid. Upon assembly of H2L with Mn(OAc)2, a quite different dinuclear compound with chemical composition of [Mn2L2(O CH3)2(H2O)2]·CH3OH (3) was afforded, where Mn(III) displayed distorted octahedral configurations. DNA binding studies were performed on H2L and its three complexes by means of electron absorption titration and EB–DNA competition experiments, and the results indicate they all bind DNA in an intercalation mode, and their binding affinity follows the order of 1 > 2 > 3 > H2L. In addition, time-dependent density functional theory (TD-DFT) calculations were performed for H2L and its three complexes to better clarify the electronic transitions in the UV-vis spectra.

Two dinuclear lanthanide complexes, [Er2(HL)2(NO3)4]·2CH3CN∙CH3OH (1) and [Yb2(HL)2(NO3)4]·3CH3CN∙CH3OH (2) based on a salicylamide imine multidentate ligand, H3L = 1-(2-hydroxy-benzamido)-2-(3-hydroxy-naphthaleneamino)-ethane, were prepared and well characterized by elemental analysis, IR spectra, thermogravimetric analysis as well as X-ray diffraction analysis. Single crystal X-ray diffraction shows that the two phenol oxygen atom bridged dinuclear compounds are isomorphous where two deprotoned HL2− ligands possess the same coordination mode with the naphtol and amide oxygen atom coordinating to one Er(III) ion and phenol oxygen atom from salicylamide bridging two Er(III) ions. Photophysical studies indicates that 1 and 2 exhibit near-infrared emissions characteristic of Er(III) and Yb(III) ions and these effective sensitizations are approved by DFT calculation. The results presented herein indicate that the deprotoned HL2− not only offers a good protection for Er(III) and Yb(III) ions but also exhibits a good antennae effect with respect to Er(III) and Yb(III) ions as a result of efficient ligand to metal energy transfer.

A new Mn(III) coordination polymer, [MnL]n, based on a salicylamide imine multidentate ligand, 1-(2-hydroxy-benzamido)-2-(2-hydroxy-5-nitrobenzylideneamino)-ethane (H3L) was prepared. Single crystal analysis revealed that the title compound was a herringbone like Mn(III) coordination polymer where deprotonated ligand L3– acted as a pentadentate ligand with amide group being bridge to connect two Mn(III) centres. Magnetic susceptibilities indicates that [MnL]n exhibits an antiferromagnetic coupling with a long-range canted antiferromagnetic ordering and metamagnetic behavior at low temperatures. And the photophysical determination shows that [MnL]n also displays strong long life red luminescence. The results presented herein indicates [MnL]n appears to be an excellent candidate for multifunctional material as a result of its high thermal stability, interesting magnetic and luminescent properties.

A monocationic ZnII tetrahedral cluster, [Zn4L3(μ3-OH)]·NO3·1.25H2O (Zn4L3) based on a new salicylamide imine ligand H2L, H2L = 1-(2-hydroxy-3-methoxy-benzamido)-3-(2-hydroxy-3-methoxy-benzylideneamino)-propane, has been prepared. Single crystal X-ray analysis reveals that three deprotonated ligands L2– chelate three Zn(II) centres with their salicylamide moiety in such a way that the three salicylimine groups attached to the other side of the three chelates are converged to bind another Zn(II) centre to provide a tetrahedral cluster with two phenyl groups of the same ligand L2– being close enough to present a strong intramolecular π⋯π stacking effect. Fluorescence studies indicate that Zn4L3 is stable in water and exhibits highly sensitive and selective recognition of phosphates against other common anions including CO32–, HCO3–, NO3–, F−, Cl−, Br−, I−, HSO4–, SO42–, OAc−, BF4–, ClO4– and CF3SO3– in HEPES buffer solution (pH = 7.4) + DMSO (V : V = 1 : 9). The excellent sensing capability of Zn4L3 for phosphate against other common anions with a low detection limit of 0.15 μM renders it a candidate probe for phosphate detection. Furthermore, the observed fluorescence quenching responses of Zn4L3 towards phosphates were highly reversible. The possible sensing mechanisms for phosphate detection by Zn4L3 was investigated by means of 1H NMR, UV-Vis spectra and high-resolution ESI-MS spectra and the results indicate that phosphates could exclusively decompose Zn4L3 to release H2L in HEPES buffer solution (pH = 7.4) + DMSO (V : V = 1 : 9).

Three LnIII coordination polymers, [Ln2L3(NO3)3]n·2CH3COOCH2CH3 (Ln = Nd (Nd2L3), Eu (Eu2L3), Tb (Tb2L3)), following coordination-assembly reactions involving a new bi-monodentate salicylamide ligand, L = 1,4-bis[(2΄-thenylaminoformyl)phenoxyl]methyl}-benzene, have been successfully synthesized. Among them, Nd2L3 and Tb2L3 were structurally authenticated by single-crystal X-ray diffraction and the results indicate both Nd2L3 and Tb2L3 are one-dimensional corrugated blockchains with LnIII containing 64-membered block loops filled by ethyl acetate molecules alternating in nearly orthogonal directions. For they are isomorphous, two binary co-doped lanthanide coordination polymers, Tb0.965Eu1.035L3 and Tb0.717Nd1.283L3 are obtained. Luminescent studies indicate that Tb0.965Eu1.035L3 exhibits a temperature recognition property with the significantly high sensitivity of 2.61% per K in the 296–386 K temperature range upon excitation at 345 nm as well as white emission when excited in the range of 370–390 nm. Tb0.717Nd1.283L3 shows enhanced NdIII-centred NIR luminescence and diminished TbIII-centred luminescence as compared to those of Nd2L3 and Tb2L3. The results presented herein show that the energy transfer from TbIII to both EuIII and NdIII has been successfully achieved in Tb0.965Eu1.035L3 and Tb0.717Nd1.283L3. Generally speaking, this work explores the potential applications of lanthanide-based coordination polymers based on multi-monodentate salicylamide ligand in the area of thermal sensing.

Five heterometallic ZnII6-LnIII3 macrocycles based on a salicylamide imine multidentate unsymmetrical ligand H2L [1-(2-hydroxy-3-methoxy-benzamido)-2-(2-hydroxy-3-methoxy-benzylideneamino)-ethane] have been prepared via a coordination-driven self-assembly strategy. Single-crystal X-ray diffraction analysis reveals that the five metallocycles are isomorphic with a formula of [Zn6Ln3L6(OH)2(NO3)4(H2O)]·3NO3· nCH3CN (ZnLn-1, where Ln = Pr, Nd, Eu, Tb, or Yb; for ZnPr-1, n = 4; for ZnNd-1, ZnEu-1, and ZnTb-1, n = 2; for ZnYb-1, n = 3), where six octadentate ligands L2- and two in situ-formed μ2-OH- ions bridged the alternating ZnII-LnIII-ZnII subunits into a macrocycle. Along with the structural novelty, ZnNd-1 shows distinctive enhanced emission in the visible and near-infrared range upon addition of OAc-. On the basis of ultraviolet-visible spectroscopy, 1H nuclear magnetic resonance, single-crystal X-ray diffraction, and high-resolution electrospray ionization mass spectrometry, we deduced that this emission enhancement could be attributed to the synergistic effect of TICT and the absent nonradiative transition of μ2-OH- induced distinctively by OAc- bridging. Our results demonstrate that the NdIII-containing heterometallic macrocycle can act as a host for anion exchanging and provide a nice example of heterometallic macrocycles with interesting properties and potential applications.

For sensing application, a salicylacylhydrazone (H2L) with multiple binding sites which was condensed by salicylhydrazide and 4-acylpyrazolone, H2L = 4-Benzoyl-3-methyl-l-phenyl-5-pyrazolone-benzoic acid hydrazide was prepared. Fluorescence studies indicate that H2L could be used as turn-on sensors to distinguish between Cd2+ and Zn2+ in Hepes buffer solution (pH = 6.8) and the origin of the specificity of the fluorescence recognition was disclosed through 1H NMR spectra, UV–Vis spectra, ESI mass spectra, X-ray single crystal diffraction and DFT calculations. H2L test silica sheets were further prepared to offer easy and real-time detection of Cd2+ and Zn2+ ions. Furthermore, the in situ system generated from the sensing of Zn2+ and Cd2+ (ZnHL and CdHL) showed good relay recognition ability for picric acid (PA) via fluorescence quenching. The recognition mechanism of PA could be attributed to the multi-quenching mechanism dominated by the competitive absorption with PET effect and hydrogen bond being assistance when density functional theory calculations and multiple experimental evidences, including ESI mass spectrum, 1H NMR spectra as well as UV–Vis absorption are combined. To enhance their sensing ability together with the convenience of detection, the hybrid films of ZnHL@PMMA and CdHL@PMMA are prepared by doping them to polymethyl methacrylate (PMMA) matrix to improve their fluorescence performance, chemical stability, sensitivity, cheapness and quickness.

Two new sandwich-type heterometallic ZnII-LnIII clusters based on a methoxy substituted salicylamide Salen-like ligand, [Zn2Er3(HL)2(H2L)2(OH)2(NO3)3](NO3)2·2CH3OH (Zn2Er3), [Zn2Yb3(HL)2(H2L)2(OH)2 (NO3)3](NO3)2·2CH3OH (Zn2Yb3), H3L = 1-(2-hydroxy-4-methoxy-benzamido)-2-(2-hydroxy-3-methoxy-benzylideneamino)-ethane, were prepared and structurally characterized. Single-crystal structure analyses reveal that both compounds are pentanuclear clusters with a hydroxyl bridged trinuclear LnIII3 core swaddled by two ZnII ions, two singly deprotoned H2L− ligands, two doubly deprotoned HL− ligands and three nitrate anions. Photophysical determination indicates that the two ZnII-LnIII compounds display both ligand-centered and near-infrared emission. The magnetic susceptibility measurements reveal that Zn2Er3 displays antiferromagnetic interactions with zero field slow magnetization relaxation diagnostic of single-molecule-magnet (SMM).

A new salicylamide Salen-like multidentate ligand, 1-(2-hydroxy-3-methoxy-benzamido)-2-(2-hydroxy-3-methoxy-benzylideneamino)-ethane (H3L), was synthesised and used to build up heterometallic magnetic clusters. As a result, four new highly thermal stable cyclic tetranuclear heterometallic clusters which were characterized by elemental analysis, X-ray diffraction, IR and TGA measurements, [M2Ln2L2(NO3)4] (M2Ln2, where MII = CuII, NiII and LnIII = TbIII, DyIII), were successfully obtained with high yield under solvothermal conditions. Temperature-dependent magnetic susceptibility measurements exhibit strong ferromagnetic interactions between CuII and LnIII in Cu2Ln2 which were evaluated by comparing their magnetic susceptibilities with those of the isostructural Ni2Ln2 clusters containing diamagnetic NiII ions. Furthermore, alternating-current magnetic susceptibility studies carried out for the four tetranuclear compounds indicate that Cu2Ln2 exhibit interesting slow relaxation of magnetization of the SMM behavior and the effective energy barriers for Cu2Tb2 can be obtained from alternating-current susceptibility measurements by applying an external 2000 Oe direct-current field.

Three 2D lanthanide coordination polymers of in situ formed nitrilotriacetic anion (NTA3−) have been hydrothermally synthesized with N-(2-carbamoylmethyl) iminodiacetic acid (H2ADA) as starting material. The photoluminescence properties as well as the energy-transfer behavior of the resulted coordination polymers are studied in detail and the investigations reveal that both EuIII and TbIII complexes show intense emissions characteristic of EuIII and TbIII ion under irradiation of 399 nm. Considering the blue-emission of compound GdIII and the intense emission of EuIII and TbIII compounds, we afforded EuIII and TbIII doped white light emitting materials by the different combination of the doped EuIII and TbIII concentrations.

Three new sandwich-type hexanuclear ZnII–LnIII clusters based on a methoxy substituted salicylamide Salen-like ligand and o-vanilline, [Zn2Ln4(HL)4(o-vanilline)2(OH)4(CH3OH)2]·2NO3·5CH3OH (Ln = Eu, Tb and Dy, H3L = 1-(2-hydroxy-4-methoxy-benzamido)-2-(2-hydroxy-3-methoxy-benzylideneamino)-ethane) were synthesised. Single-crystal structure analyses reveal that these ZnII–LnIII clusters display a hydroxyl bridged tetranuclear LnIII4 core sandwiched in an environment of two ZnII ions, four doubly deprotonated HL2− and two singly deprotonated o-vanilline. Photophysical determinations indicate that the ZnII–EuIII cluster shows mixed emissions both originating from ligands and EuIII ions, and the other two only display ligand-centered emission in visible region. The magnetic studies reveal that the ZnII–DyIII cluster displays rare ferromagnetic behavior with slow magnetic relaxation behavior at zero field.

To develop a LnIII complex-supported chemsensor, two new phenoxy bridged dinuclear EuIII complexes, [Eu2(H2L)3(NO3)3]·3CH3CN (EuL) and [Eu2(H2L′)2(NO3)4]·3CH3CN (EuL′), constructed by two new structurally related salicylamide salen-like ligands, 1-(2-hydroxy-benzamido)-2-(2-hydroxy-5-nitro-benzylideneamino)-ethane (H3L) and 1-(2-hydroxy-benzamido)-2-(2-hydroxy-4-diethylamino-benzylideneamino)-ethane (H3L′), have been synthesized and structural analysis shows that the different substitution groups on 2-(iminomethyl)phenol moiety have significant effects on their structures. Upon excitation of the ligand-centered absorption band at 375 nm, emissions both originating from ligands and EuIII ions were observed in the two EuIII compounds with the EuIII-centered emission intensity more than three times higher than that of ligand-centered emission. The capability of EuL and EuL′ for selective detection Al3+ ions were evaluated and the results indicate EuL exhibits a turn-on luminescent enhancement as high as 5.7 fold with Kd = 1.53 × 10−4 in CH3CN, but comparable compound EuL′ could not detect Al3+ among various cations. The considerably ‘turn-on’ luminescence response of EuL concomitantly led to the apparent color change from reddish to brilliant red, which could also be identified by naked eyes easily under UV lamp. This luminescence enhanced response can be explained in terms of the decrease of non-radiative transitions in EuL in addition to excited-state intra-molecular proton transfer (ESIPT) and photo-induced electron transfer suppression upon Al3+ coordination which is also rationalized by a theoretical calculation.

Three new TbIII containing complexes of a novel heptadentate amide open crown ether ligand [Tb4L2(NO3)10(CH3COO)2] (TbL), [ZnTbL(NO3)5]2·3CH3CN·CH3COOCH2CH3·H2O (TbZnL) and [CdTbL(NO3)5]·4CH3CN (TbCdL), L = 2,2′-((4-((bis(pyridin-2-ylmethyl)amino)methyl)-1,2-phenylene)bis(oxy))bis(N,N-diisopropylacetamide), were step-by-step prepared and structurally characterized. Photophysical properties of the three emitting TbIII complexes have been investigated in detail. A large increase of the quantum yield and lifetime was observed for TbZnL compared with TbL, whereas a moderate increase of the quantum yield and lifetime was observed for TbCdL.

A Cu(II) complex based on a pyrazolone derivative, 2-hydroxy-N′-((1-(4-methoxyphenyl)-3methyl-5-oxo-4,5-dihydro-1H-pyrazol-4-yl)(phenyl)methylene)benzohydrazide (H2L), has been prepared. IR spectra, UV-vis spectra, elemental analysis and single-crystal X-ray diffraction indicate that the Cu(II) complex was mononuclear with the chemical composition of [Cu(HL)Cl]·CH3OH. The Cu(II) compound presented herein exhibits interesting supramolecular characteristics and a novel 3D supramolecular architecture resulted due to the appropriate synergy of multiple intermolecular hydrogen bonds. The interaction of the Cu(II) complex with calf-thymus DNA was investigated by electronic absorption titration as well as EB-DNA competition experiment, and the results indicate that the Cu(II) compound which has a strong affinity for binding DNA is combined with DNA in an embedded manner. Furthermore, Time-Dependent Density Functional Theory calculations (TD-DFT) have been performed on optimized geometries for a better understanding of the electronic transitions in the UV-vis spectra of H2L and Cu(II) complex.

The employment of a multidentate salicylamide salen-like ligand, 2-hydroxy-N-(2-(2-hydroxybenzylidene)amino)ethyl)benzamide (H3L), in aid of NO3(-) anions under weak basic conditions in Zn(II)-Ln(III) chemistry (Ln = Eu, and Dy, ) led to the isolation of two novel butterfly heterometallic dodecanuclear clusters with six Ln(III) ions occupying the body position and six Zn(II) ions the outer wing-tip sites. All of them are fully characterized by elemental analysis, FT-IR spectroscopy, TG analysis, single-crystal X-ray diffraction, and X-ray powder diffraction (XRPD) techniques. Luminescence studies indicate that exhibits dual emission, while exhibits a bright blue emission under visible light excitation. Furthermore, magnetic susceptibility studies carried out for indicate that the magnetic exchange between Dy(III) ions revealed ferromagnetic interactions with interesting slow relaxation of magnetization of the SMM behavior.

Four new polynuclear complexes based on a versatile asymmetric ligand, [Cu 2 (H 2 L) 2 Cl 2 ] ( 1 ), [Cu 4 (H 2 L) 2 (L) 2 ]·4CH 3 OH ( 2 ), [MnL] n ( 3 ), [Er 2 (HL) 2 (NO 3 ) 4 ]·4CH 3 CN ( 4 ), H 3 L = 2-hydroxy-N-(2-((2-hydroxybenzylidene)amino)ethyl)benzamide], were prepared and structurally characterized. The coordination behavior as well as deprotonation of the H 3 L in the four complexes reveal considerable variations depending on the metal ions as well as counter anion. The hydroxyl-bridged dinuclear complex 1 with a Cu–O–Cu–O four-membered ring was obtained when copper chloride was used as metal source. The tetranuclear complex 2 with two Cu–O–Cu–O four-membered rings which bridged both through hydroxy and amide group was obtained using copper acetate instead. Reacting the ligand with manganese acetate yielded complex 3 which exhibits 1-D zig–zag chains only bridged through amide group. While complex 4 which holds a dinuclear one by aid of hydroxyl-bridge without nitrogen atom participating in coordination when erbium nitrate was introduced. The experimental magnetic susceptibilities indicate 1 , 2 and 4 exhibit antiferromagnetic interactions through hydroxy bridge, while 3 exhibits dominant antiferromagnetic interactions with spin canting through the amido bridge.

A new pentadentate chelate-bridging ligand possessing an inner N 2 O 3 coordination site with one amide, one imine, and two phenoxo functions, 2-hydroxy-N-(2-(((3-hydroxynaphthalen-2-yl)methylene)amino)ethyl)benzamide (H 3 L), was synthesised. Reaction it with Mn(OAc) 2 ·4H 2 O yielded a novel zigzag penta-coordinated Mn(III) coordination polymer, [MnL] n , due to the bridging ability of the amide function. The crystal structure of [MnL] n has been determined at 293 K which crystallizes in the monoclinic space group P2 1 /c (No. 14): a = 16.0601(12) A, b = 8.4048(6) A, c = 12.7168(10) A, β = 112.395(9), V = 1606.0(2) A 3 , Z = 4. The experimental magnetic susceptibilities indicates the Mn(III) coordination polymer exhibits dominant antiferromagnetic interactions between the manganese centers through the amido bridge, and spin canting is observed with a ferromagnetic transition occurring at 8.5 K.

Two new structure-related pyrazolone-type Salen ligands, N,N′-ethylamine bis[1-(4-methoxy-phenyl)-3-methyl-4-benzoylimino-2-pyrazoline-5-ol](H2LI) and N,N′-ethylamine bis[1-(4-methoxy-phenyl)-3-methyl-4-acetylimino-2-pyrazoline-5-ol](H2LII) have been designed and synthesized with the ultimate aim of self-assembling novel Zn(II) compounds with interesting fluorescence properties. Reactions of Zn(OAc)2 with the two ligands led to the formation of two new Zn(II) complexes with the formulae of [ZnLI(CH3OH)] (1) and [Zn2LII2] (2), which have been characterized by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, IR spectroscopy and thermal gravimetric analysis. Mononuclear complex 1 with the pentacoordinated zinc(II) ion hosted into the N2O3 compartment crystallized in the monoclinic space group P21/c, while the hydroxyl-bridged dinuclear [Zn2LII2] complex (2) with the pentacoordinated zinc(II) ion hosted into the N2O2 compartment crystallized in the monoclinic space group C2/c and had a Zn–O–Zn–O four-membered ring. The structure determinations show that substituted group at the 4,4′-position of the this kind of Salen ligands are important factors influencing the crystalline array. The fluorescent properties of the two compounds at ambient temperature both in solid state and solution were also investigated. The results provided interesting insights into ligand effects on the structures and fluorescent properties of zinc(II) coordination complexes.

The stepwise course of the synthesis of ZnIILnIII complexes of a new compartmental heptadentate open amide crown ether ligand has been investigated through the determination of the intermediate and final products occurring in the process. In the first step, the ligand L is reacted with Ln(NO3)3·5H2O to give the electroneutral complex [LnIIIL(NO3)3] with the lanthanide ion being linked to the N3O2 coordination site of the ligand which are fairly stable and could be isolated. Addition of Zn(NO3)3·6H2O to the [LnIIIL(NO3)3] complexes yield the desired heterodinuclear [ZnIILnIIIL(NO3)5(H2O)] complexes. In all [ZnIILnIIIL(NO3)5(H2O)] complexes, the ZnII ions invariably occupy the N3O2 site whereas the LnIII ions show preference for the carbonyl O site. Additionally, the solid-state photophysical properties of these complexes show that the sensitized EuIII- and TbIII-based luminescence can be enhanced after ZnII ion is incorporated.

The new semirigid exo-bidentate ligand incorporating furfurysalicylamide terminal groups, namely, 1,4-bis{[(2′-furfurylaminoformyl)phenoxyl]methyl}-2,5-bismethylbenzene (L) was synthesized and used as building blocks for constructing lanthanide coordination polymers with luminescent properties. The series of lanthanide nitrate complexes have been characterized by elemental analysis, IR spectroscopy, and X-ray diffraction analysis. The semirigid ligand L, as a bridging ligand, reacts with lanthanide nitrates forming three distinct structure types: chiral noninterpenetrated two-dimensional (2D) honeycomblike (6,3) (hcb, Schlafli symbol 63, vertex symbol 6 6 6) topological network as type I, 1D zigzag chain as type II and 1D trapezoid ladder-like chain as type III. The structural diversities indicate that lanthanide contraction effect played significant roles in the structural self-assembled process. The luminescent properties of EuIII, TbIII and DyIII complexes are discussed in detail. Due to the good match between the lowest triplet state of the ligand and the resonant energy level of the lanthanide ion, the lanthanide ions in EuIII, TbIII and DyIII complexes can be efficiently sensitized by the ligand.

Two new lanthanide coordination polymers based on a semirigid bridging thenylsalicylamide ligand ([Ln{sub 2}L{sub 3}(NO{sub 3}){sub 6}]·(C{sub 4}H{sub 8}O{sub 2}){sub 2}){sub ∞} were obtained and characterized by elemental analysis, X-ray diffraction, IR and TGA measurements. The two compounds are isostructure and possess one dimensional trapezoid ladder-like chain built up from the connection of isolated LnO{sub 3}(NO{sub 3}){sub 3} polyhedra (distorted monocapped antisquare prism) through the ligand. The photoluminescence analysis suggest that there is an efficient ligand-to-Ln(III) energy transfer in Tb(III) complex and the ligand is an efficient “antenna” for Tb(III). From a more general perspective, the results demonstrated herein provide the possibility of controlling the formation of the desired lanthanide coordination structure to enrich the crystal engineering strategy and enlarge the arsenal for developing excellent luminescent lanthanide coordination polymers. - Graphical abstract: We present herein one dimensional lanthanide coordination polymers of a new semirigid exo-bidentate ligand which not only display interesting structures but also possess strong luminescence properties. Display Omitted - Highlights: • We present lanthanide coordination polymers of a new semirigid exo-bidentate ligand. • The lanthanide coordination polymers exhibit interesting structures. • The luminescent properties of Tb(III) complexes are discussed in detail.

A new semirigid exo -bidentate ligand was designed, synthesized, and used as building blocks for constructing lanthanide polymers both with interesting supramolecular structures and luminescent properties. Among a series of lanthanide nitrate complexes which have been characterized by elemental analysis, X-ray powder diffraction, IR spectroscopy and molar conductance analysis, five new coordination polymers have been determined using X-ray diffraction analysis. All the coordination polymers exhibit the same metal-to-ligand molar ratio of 1:1 and the semirigid exo -bidentate ligand as a bridging ligand, reacts with lanthanide nitrates forming a zigzag chain which further interconnected to three dimensional supramolecular structure in aid of cooperative C–H⋯O hydrogen bond and π–π stacking interactions. The europium and terbium containing compounds exhibit luminescence of the referring trivalent lanthanide ions, giving a red luminescence for EuIII and a green luminescence for TbIII triggered by an efficient antenna effect of the picolylsalicylamide group.

Five new homodinuclear lanthanide(III) complexes with a new tetrapodal thenylsalicylamide ligand (L), of formulae [Nd 2 L 2 (NO 3 ) 6 (CH 3 OH) 2 ]·2H 2 O·2CH 3 OH ( 1 ), and [Ln 2 L 2 (NO 3 ) 6 (CH 3 OH) 2 ]·4CH 3 OH, Ln = Sm ( 2 ), Eu ( 3 ), Gd ( 4 ), Tb ( 5 )) have been synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and molar conductance analysis. The two arms of L ligand arranged in a complementary head to head fashion to bind two lanthanide to form a cage-like coordination dimer with the other two uncoordinated arms constructing interesting three dimensional supramolecular structures. The europium and terbium containing compounds both exhibit luminescence of the referring trivalent lanthanide ions, giving a red luminescence for Eu(III) and a green luminescence for Tb(III) triggered by an efficient antenna effect of the thenylsalicylamide group.

We present here new lanthanide coordination polymers based on a semirigid bridging furfurylsalicylamide ligand which were synthesized and characterized by elemental analysis, X-ray powder diffraction and IR measurements. The coordination polymer [Pr 2 L 3 (NO 3 ) 6 ] ∞ displays a two-dimensional honeycomb-like framework, which can be regarded as a (6,3) topological network with praseodymium atoms acting as “three-connected” centers. The photoluminescence analysis indicates that there is an efficient ligand-to-LnIII energy transfer in TbIII complex and the ligand is an efficient “antenna” for TbIII. From a more general perspective, the results demonstrated herein provide the possibility of controlling the formation of the desired lanthanide coordination structure to enrich the crystal engineering strategy and enlarges the arsenal for developing excellent luminescent lanthanide complexes of salicylamide derivatives.

Hepatocyte nuclear factor-4alpha (HNF-4a) is an important transcription factor in the liver, and regulates a large number of genes involved in many aspects of hepatocyte functions. In this study, a liver-specific transcriptional regulatory element comprised of albumin promoter (ALBp) and alpha-fetoprotein enhancer (AFPe) was obtained and cloned into the plasmid pHNF4sh-CMV(short hairpin RNA targeting HNF4α) with original CMV promoter removed, resulting to pHNF4sh-EP for liver-specific knockdown of HNF4α expression. In an attempt to verify its characteristics, pHNF4sh-EP was transfected to L02, HepG2, and COS1 cell lines in vitro and delivered into mice in vivo. pHNF4sh-CMV and pNCsh-EP were used as controls. For in vitro, the level of HNF4α mRNA and protein was decreased in all cell lines transfected with pHNF4sh-CMV whereas HNF4α mRNA and protein decreasing was only observed in L02 and HepG2 cell lines upon transfection with pHNF4sh-EP, and this decreasing was more significant as compared with pHNF4sh-CMV transfected cells. For in vivo, the decreasing of HNF4α mRNA and protein was observed in both liver and kidney tissues upon transfection with pHNF4sh-CMV. After transfection with pHNF4sh-EP, decreasing of HNF4α mRNA and protein was only found in liver tissue and this decreasing was more significant. No obvious HNF4α mRNA and protein decreasing was detected either in vitro or in vivo after transfected with pNCsh-EP. In conclusion, pHNF4sh-EP could highly-active and liver-specific knockdown of HNF4α expression liver and it will be useful for further study of the funcitions of HNF4α in liver.

Two new flexible exo-bidentate ligands were designed and synthesized, incorporating different backbone chain lengths bearing two salicylamide arms, namely 2,2'-(2,2'-oxybis(ethane-2,1-diyl)bis(oxy))bis(N-benzylbenzamide) (L(I)) and 2,2'-(2,2'-(ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl))bis(oxy)bis(N-benzylbenzamide) (L(II)). These two structurally related ligands are used as building blocks for constructing diverse lanthanide polymers with luminescent properties. Among two series of lanthanide nitrate complexes which have been characterized by elemental analysis, TGA analysis, X-ray powder diffraction, and IR spectroscopy, ten new coordination polymers have been determined using X-ray diffraction analysis. All the coordination polymers exhibit the same metal-to-ligand molar ratio of 2 : 3. L(I), as a bridging ligand, reacts with lanthanide nitrates forming two different types of 2D coordination complexes: herringbone framework {[Ln(2)(NO(3))(6)(L(I))(3)·mC(4)H(8)O(2)](∞) (Ln = La (1), and Pr (2), m = 1, 2)} as type I,; and honeycomb framework {[Ln(2)(NO(3))(6)(L(I))(3)·nCH(3)OH](∞) (Ln = Nd (3), Eu (4), Tb (5), and Er (6), n = 0 or 3)} as type II, which change according to the decrease in radius of the lanthanide. For L(II), two distinct structure types of 1D ladder-like coordination complexes were formed with decreasing lanthanide radii: [Ln(2)(NO(3))(6)(L(II))(3)·2C(4)H(8)O(2)](∞) (Ln = La (7), Pr (8), Nd (9)) as type III, [Ln(2)(NO(3))(6)(L(I))(3)·mC(4)H(8)O(2)·nCH(3)OH](∞) (Ln = Eu (10), Tb (11), and Er (12), m, n = 2 or 0) as type IV. The progressive structural variation from the 2D supramolecular framework to 1D ladder-like frameworks is attributed to the varying chain length of the backbone group in the flexible ligands. The photophysical properties of trivalent Sm, Eu, Tb, and Dy complexes at room temperature were also investigated in detail.

Cell wall-related nucleotide sugar transporters (NSTs) theoretically supply the cytosolic nucleotide sugars for glycosyltransferases (GTs) to carry out ploysaccharide synthesis and modification in the Golgi apparatus. However, the regulation of cell wall synthesis by NSTs remains undescribed. Recently, we have reported the functional characterization of Oryza sativa nucleotide sugar transport (Osnst1) mutant and its corresponding gene. OsNST1/BC14 is localized in the Golgi apparatus and transports UDP-glucose. This mutant provides us with a unique opportunity for evaluation of its abroad impacts on cell wall structure and components. We previously examined cell wall composition of bc14 and wild type plants. Here, the spatial distribution of these cell wall alterations was analyzed by immunolabeling approach. Analysis of the sugar yield in different cell wall fractions indicated that this mutation improves the extractability of cell wall components. Field emission scanning electron microscopy further showed that the orientation of microfibrils in bc14 is irregular when compared to that in wild type. Therefore, this UDP-glucose transporter, making substrates available for polysaccharide biosynthesis, plays a critical role in maintaining cell wall integrity.

In an attempt to construct a highly active, liver-specific transcriptional regulatory element, the mouse albumin promoter (ALBp) and α-fetoprotein enhancer (AFPe) were obtained. To verify its hepatic specificity and activity, the AFPe-ALBp-containing fragment was cloned into the plasmids, pVAX-S and pGL3-Luc with original promoter removed. Plasmid pVAX-AFPe-ALBp-S was then transfected into hepatic and non-hepatic cells in vitro, and delivered into mouse by intravenous injection and intramuscular injection, respectively. In addition, pGL3-AFPe-ALBp-Luc was transfected into hepatic and non-hepatic cell lines; pVAX1, pVAX1/S, and pGL3-ALBp-Luc were used as controls. The expression of hepatitis B surface antigen (HBsAg) was observed, and luciferase activity in cells was measured. For plasmid pVAX-AFPe-ALBp-S, the expression of HBsAg was observed in hepatic cell lines, but not in a non-hepatic cell line. Using pVAX-S, the expression of HBsAg was observed in both hepatic and non-hepatic cell lines. In cells expressing pGL3-AFPe-ALBp-Luc, the level of luciferase activity was significantly higher in hepatic cell lines, compared with the non-hepatic cell lines. In addition, the level of luciferase activity in cells expressing pGL3-AFPe-ALBp-Luc was significantly higher than that of pGL3-ALBp-Luc in hepatic cell lines, suggesting that AFPe could enhance target gene expression under the control of ALBp. The expression of HBsAg was detected in mouse liver, but not muscle when using pVAX-AFPe-ALBp-S. In contrast, the expression of HBsAg was detected in both mouse liver and muscle upon transfection with pVAX-S. In conclusion, the AFPe-ALBp element could be used as a tool to induce liver-specific expression of a target gene.

A new tetrapodal ligand 1,1,1-tetrakis{l_brace}[(2'-(2-furfurylaminoformyl))phenoxyl]methyl{r_brace}methane (L) has been prepared and their coordination chemistry with Ln{sup III} ions has been investigated. The structure of {l_brace}[Ln{sub 4}L{sub 3}(NO{sub 3}){sub 12}].H{sub 2}O{r_brace}{sub i}nfinity (Ln=Nd, Eu)] shows the binodal 4,3-connected three-dimensional interpenetration coordination polymers with topology of a (8{sup 6}){sub 3}(8{sup 3}){sub 4} notation. [DyL(NO{sub 3}){sub 3}(H{sub 2}O){sub 2}].0.5CH{sub 3}OH and [ErL(NO{sub 3}){sub 3}(H{sub 2}O) (CH{sub 3}OH)].CH{sub 3}COCH{sub 3} is a 1:1 mononuclear complex with interesting supramolecular features. The structure of [NdL(H{sub 2}O){sub 6}].3ClO{sub 4}.3H{sub 2}O is a 2:1 mononuclear complex which further self-assembled through hydrogen bond to form a three-dimensional supramolecular structures. The result presented here indicates that both subtle variation of the terminal group and counter anions can be applied in the modulation of the overall molecular structures of lanthanide complex of salicylamide derivatives due to the structure specialties of this type of ligand. The luminescence properties of the Eu{sup III} complex are also studied in detail. - Grapical Abstract: We present here a series of zero- to three-dimensional lanthanide coordination structures and luminescence properties of Eu(III) complex of a new tetrapodal ligand.

To explore the relationship between the structure of the ligands and the luminescent properties of the lanthanide complexes, luminescent lanthanide complexes of a new tripodal ligand, featuring N-thenylsalicylamide arms, were synthesized and characterized by elemental analysis, IR and TGA measurements. Photophysical properties of the complexes were studied by means of UV − visible absorption and steady-state luminescence spectroscopy. The results of UV − vis spectra indicate that metal binding does not disturb the electronic structure of the ligand. Excited-state luminescence lifetimes and quantum yields of the complexes were determined. The photoluminescence analysis suggested that there is an efficient ligand − Ln(III) energy transfer for the Tb(III) complex, and the ligand is an efficient 'antenna' for Tb(III). From a more general perspective, the results demonstrated the potential application of the lanthanide complex as luminescent materials in material chemistry. Copyright © 2012 John Wiley & Sons, Ltd.

By the “metalloligand” strategy, two new 3d–4f heterometallic metal–organic frameworks (MOFs), {[Ln 2 Cu 3 (IDA) 6 ] · 1.5H 2 O} n [Ln = Tb ( 1 ) and Dy ( 2 ); H 2 IDA = iminodiacetate acid], had been prepared. X-ray crystal structure analyses show that 1 and 2 possess of 3D frameworks with highly ordered 1D channels along the c axis. The highly stable skeleton and reversible de- and rehydration performance of 1 are demonstrated by thermogravimetric and powder X-ray diffraction analyses, and a low temperature magnetic study of 2 reveals a weak ferromagnetic interaction between the metal ions.

Using 1,9-salicylamide bissubstituted oxadecane ligand, 1,9-bis [2-(2′-picolylaminoformyl)-1,4,7,9-tetraoxadecane (L), two novel lanthanide complexes have been prepared and well characterized by means of elemental analysis, IR spectroscopy, UV–vis spectroscopy, TGA analysis and single-crystal X-ray diffraction. {[PrL(NO3)3(H2O)2]·CH3OH}n is a 1D zigzag polymer with three-dimensional supramolecular structure formed by hydrogen bonds, while [EuL(NO3)3(H2O)]n is a linear coordination polymer and present an interesting supramolecular double chain, which are very different from the structure of terbium complex reported before. The result reported herein demonstrated that steric crowding associated with the decreasing lanthanide ion radius causes changes of the conformation of the ligand as well as structures. Luminescence studies for the Eu(III) complexes demonstrated that the salicylamide ligand also exhibits a good antennae effect for the Eu(III) ion due to efficient intersystem crossing and ligand-to-metal energy transfer and the Eu(III) ion is well shielded from the surrounding environment.

A new polycarboxylate acid ligand (H4L = 2,2′,2 ″,2″′-[2,5-dimethyl-1,4-phenylenebis(methylenenitrilo)]tetraacetic acid) and its copper (II) complex have been synthesized and characterized by elemental analysis, IR spectra, TG analyses, cyclic voltammetry and single-crystal X-ray diffraction. The crystal structure reveals that this complex is an infinite 2D metal-organic framework and forms a 3D supramolecular architecture through the intermolecular hydrogen bonds.

A new potentially bridging ligand containing two salicylamide pendant arms separated by a 2,3-dimethoxynaphthalene spacer has been prepared and its coordination chemistry with Ln(III) ions has been investigated. An analysis of the presented crystal structures indicates that the diversity of these supramolecular structures is mainly dictated by the nature of the metal ions. These compounds represent good examples of tuning crystal structures arising from the flexibility of the ligands and the Ln contraction effect. Luminescence studies showed that the introduction of the methoxyl substituents on the naphthalene backbone lowers the triplet energy and considerably changes the luminescent behaviors of the Eual and Tb(III) complexes, which is very different from the literature data on similar compounds. In the emission spectra of the Tb complex the ligand fluorescence remains relatively important because of the back-energy transfer from the Tb(III) ion to the ligand, which to the best of our knowledge, may be the first example of salicylamide lanthanide complexes. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).