Polyhedron最新文献

A new acetato bridged 2D coordination polymer with general formula of [Mn(µ-4-ambh)(µ-OAc)(OAc)]_n (1) was prepared by the reaction of Mn(OAc)₂·4H₂O with 4-aminobenzohydrazide (4-ambh) in equimolar ratio. The reaction was done in methanol under reflux condition and the single crystals of 1 were obtained by evaporation of the solvent. The structure of this compound was determined by X-ray analysis, and its spectroscopic properties and thermal stability were also studied. These studies indicated that in this compound, the manganese ions are connected by a mixture of acetate and 4-ambh bridges to form a 2D polymeric network at the bc crystallographic plane. The intermolecular and intramolecular interactions were investigated by Hirshfeld surface analysis. Magnetic studies revealed a dominant antiferromagnetic intermetallic coupling of J = −0.78 cm⁻¹ magnitude. Magnetization measurements suggest a diamagnetic ground state and a small gap of 1.59 cm⁻¹ with the first excited state; while the axial zero-field splitting parameter, D, was calculated at −0.21 cm⁻¹.

Silver(I) complexation with boron cluster anions [B_nH_n]²⁻ (n = 10, 12) and chelating 1-substituted-2-aldiminebenzimidazoles 1-(1-methylbenzimidazol-2-yl)-N-phenylmetanimine (L¹) and 1-(1-benzylbenzimidazol-2-yl)-N-cyclohexylmethanimine (L²) in systems AgNO₃/[B_nH_n]²⁻/L and {Ag₂[B_nH_n]}_m/L, as well as with azaheterocyclic ligands 2,2ʹ-bipyridine (bipy) or 1,10-phenanthroline (phen) in the system AgNO₃/[B_nH_n]²⁻/L has been first studied. The effect of the organic ligand on the composition and structures of the resulting compounds has been shown. As a result, binuclear complexes [Ag₂L₂[μ–B_nH_n]] with bridging boron cluster anions with various combinations of coordination modes (edge-edge and edge-face for the [B₁₀H₁₀]²⁻ anion, edge–atom and nontrivial asymmetric for the [B₁₂H₁₂]²⁻ anion) have been synthesized and structurally characterized for benzimidazole derivatives L¹ and L². When using bipy or phen as ligands, polymeric complexes {Ag₂L[B₁₀H₁₀]}_m or {Ag₂L₂[μ-B₁₂H₁₂]}_m have been obtained.

Three mononuclear complexes (PtL1H, PtL2H, and PtL3H) and one binuclear complex (Pt₂L1) have here been prepared using the bis-carbene ligand of 1,3-propylene-bis(1,3-dihydro-3-butyl-2H-imidazol-2-ylidene) and one of three rigid planar ligands of dibenzo[f,h]quinoxaline (L1H₂), dibenzo[a,c]phenazine (L2H₂), and tribenzo[a,c,i]phenazine (L3H₂). These four complexes were fully characterized by nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), and elemental analyses. Moreover, the two binuclear complexes Pt₂L2 and Pt₂L3 could not be isolated, but Pt₂L3 was isolated and characterized by single-crystal X-ray diffraction (XRD). Complexes PtL1H, PtL2H, and Pt₂L1 exhibited phosphorescence in N₂-degassed dichloromethane (DCM) solution at 563 nm, 656 nm, and 624 nm, respectively. Also, Pt₂L1 exhibited triplet emission at 553 nm in a 2 wt% PMMA film, with the highest Ф of 63 % and τ of 23.8 μs. Moreover, complexes PtL1H and Pt₂L1 were deposited on quartz plates to monitor formic acid vapor and acetic acid vapor. The plates that were covered with PtL1H exhibited phosphorescent quenching in both formic acid and acetic acid. However, the plates that were covered with Pt₂L1 did only show a prompt response to formic acid, but were not sensitive to acetic acid.

In recent work, manganese ferrite (MnFe₂O₄) nanoparticles and manganese ferrite carboxy methyl cellulose (MnFe₂O₄/CMC) composite were synthesized using Salvadora persica extract (SPE). Characterization of green synthesized nanoparticles and composite was performed by different techniques such as FTIR, SEM, UV–visible spectroscopy, XRD, and EDX. These techniques evaluated the size, shape, composition, morphology, and crystallinity of bimetallic nanoparticles (BMNPs) and nano-composites (NCs). These techniques demonstrated the presence of oxygen with metals, 3.28 nm size of MnFe₂O₄ and CMC hump between the 22-26° and the spherical, cubic, and mostly irregular shape of MnFe₂O₄ nanoparticles and rougher surface of MnFe₂O₄/CMC composite. Nanoparticles and nanocomposites were utilized for the degradation of Amoxicillin (AMX). The maximum degradation of AMX occurred at optimum conditions such as adsorbent dosage (6 mg MnFe₂O₄, 2 mg MnFe₂O₄/CMC), pH (4,6) within 60 min at 5 mg/L initial AMX concentration. Results revealed that the catalytic activity of NCs (97 %) was more than BMNPs (93 %) which may be attributed to the incorporation of reduced Carboxy Methyl Cellulose (CMC). It reduced the e-hole recombination rate and enhanced the AMX degradation at ambient conditions. The nature of adsorption was illustrated by Langmuir and Freundlich models and results demonstrated that the Freundlich model followed more closely. Thermodynamics parameters described the endothermic and spontaneous nature of the adsorption process, negative Gibbs energy variation, and positive entropy and enthalpy change. The recovery and reusability of BMNPs and NCs were investigated and concluded that MnFe₂O₄ and NCs can be used many times for the AMX adsorption process.

Two novel multifunctional chemical sensor Mn-LMOF, namely, [Mn₂(TPPE)(ndc)₂(H₂O)]_n (LMOF-1) and [Mn₂(TPPE)(oba)₂]_n (LMOF-2) were solvothermally synthesized by introducing an AIE luminogens (AIEgens) ligand, 1,1,2,2-tetra[4-(pyridin-4-yl)phenyl]ethylene(TPPE), and analyzed by single crystal X-ray diffraction, thermogravimetric and powder X-ray diffraction and other methods. LMOF-1 and LMOF-2 have high stability and strong luminescence properties in solutions. The sensing experiments testify that LMOF-1 can be used as a selectively sensor for Al³⁺, with the limit of detection is 1.83 × 10⁻⁵ M. And LMOF-1 and LMOF-2 can identify Fe³⁺, CrO₄²⁻ and Cr₂O₇²⁻ ions in aqueous solution, and LMOF-1 has a higher Ksv for all three ions than LMOF-2.

On the basis of the thiophene-containing and furan-containing complexes, we design four complexes by introducing thiazole, isothiazole, oxazole, isoxazole on main ligands. The electronic structure, absorption and emission spectra, charge injection/transport properties, absorption and phosphorescence properties have been investigated by density functional theory (DFT) and time-dependent density functional theory (TDDFT). Introducing S atom to substitute O atom could enhance HOMO energy level, blueshift emission wavelength, decrease $\Delta {\text{E}}_{{\text{S}}_{\text{1}}{\text{- T}}_{\text{1}}}$ value. The introduction of N atom on furan ring and thiophene ring could decrease HOMO and LUMO energy levels and energy gaps, blueshift emission wavelength, decrease $\Delta {\text{E}}_{{\text{S}}_{\text{1}}{\text{- T}}_{\text{1}}}$ value, enhance electron transport ability. Introducing thiazole could decrease hole injection ability and $\Delta {\text{E}}_{{\text{S}}_{\text{1}}{\text{- T}}_{\text{1}}}$, and then may have higher Φ_PL. Isoxazole and isothiazole groups could facilitate the electron transition from HOMO to LUMO and enhance hole injection ability. Thiazole and isothiazole groups could increase absorption peak strength and hole transport ability.

Copper (II) complexes of the cationic ligands 1-(4′-pyridyl)-pyridinium (L1) and 1-(4′-pyridyl)-pyridin-4-ol (L2) have been prepared and characterized by single crystal X-ray diffraction and variable temperature magnetic susceptibility measurements: [Cu(L1)₂X₂]X₂ [where X = Cl (1), Br (2)], and [Cu(L2)₂X₂]X₂ [where X = Cl (3), Br (4)]. The complexes are fundamentally square planar with L₂X₂ coordination planes and long, semi-coordinate bonds to the additional halide ions. All compounds crystallize in monoclinic systems with 1 and 2 in the P2₁/n space group and 3 and 4 in the P2₁/c space group. The crystal structures are stabilized by both non-classical (in the case of 1 and 2) and classical (3 and 4) hydrogen bonds. EPR data for 1–4 support a rhombohedral structure, in good agreement with the local geometry as seen in the crystal structures. Magnetic susceptibility measurements show the presence of very weak antiferromagnetic interactions. In addition, the syntheses and magnetic properties of two neutral complexes, [Cu(L3)₂X₂]·2H₂O [L3 = 1-(4′-pyridino)-4-pyridone; X = Cl (5), Br (6)] are reported. Magnetic susceptibility data indicate the presence of moderate antiferromagnetic exchange interactions [J ∼ 28 K (5), 60 K (6)] which were well modeled by the S = 1/2 Heisenberg uniform chain model.

Toward the development of effective metal-based coordination drugs for the treatment of cisplatin-resistant cancers, we report four new ruthenium(II) coordination compounds, namely, [RuCl₂(yc1)₂(DMSO)₂] (QY1), [RuCl₂(yc2)₂(DMSO)₂] (QY2), [RuCl₂(yc3)₂(DMSO)₂] (QY3), and [RuCl₂(yc4)₂(DMSO)₂]·1.25H₂O (QY4), which contain 3-pyridin-2-yl-chromen-2-one (yc1), 8-methyl-3-pyridin-2-yl-chromen-2-one (yc2), 7-methoxy-3-pyridin-2-yl-chromen-2-one (yc3), and 2-pyridin-2-yl-benzo[f]chromen-3-one (yc4) ligands, respectively. Complex QY4 possessing a more extended planar yc4 ligand showed the highest cytotoxicity against cisplatin-resistant A549/DDP lung cancer cells (R9LC), yielding a remarkably low micromolar IC₅₀ value of 5.02 ± 0.14 μM and low toxicity against embryonic kidney HEK293 (e293) normal cells under equal conditions (IC₅₀ = 88.04 ± 1.03 μM). Notably, QY4 exhibited higher cytotoxicity than QY1–QY3, yc1–yc4, and cisplatin. QY4 and QY1, especially QY4, induced R9LC apoptosis via mitochondrial dysfunction, which involved mitochondrial membrane potential (MP) damage, ROS/Ca²⁺ activation, and apoptosis protein up-regulation. Thus, these coumarin ruthenium(II) coordination compounds are promising mitochondria-targeting anticancer agents.

In this work, a composite material (ACE@UiO-66-NH₂) has been synthesized conveniently by loading a cysteine-responsive molecular probe Acrylic acid 3-acetyl-2-oxo-2H-chromen-7-yl ester (ACE) on a UiO-type zirconium-based metal–organic framework (UiO-66-NH₂). Furthermore, the resulting ACE@UiO-66-NH₂ demonstrated to be a fluorescent turn-on probe for selective recognition of Cys from other amino acids in aqueous HEPES buffer systems. Additionally, the proposed recognition mechanism has been confirmed by ¹H NMR and TLC. The study provided a promising approach to rationally design MOF-based fluorescent sensor for Cys in aqueous system.

Three novel hexanuclear Dy^III complexes supported by polyhydroxy Schiff-base ligands, [Dy₆(hmc)₃(μ-acac)₂(acac)₃(μ₃-OH)₄(H₂O)₂]·2MeCN (1·2MeCN), [Dy₆K₂(hmc)₃(μ-CO₃)₆(μ₃-CO₃)₄(H₂O)₂]·8MeOH (2·8MeOH) and [Dy₆(hmc)₃(μ-OAc)₆(μ₃-OH)₃(H₂O)₃] (3) (H₃hmc: 1,5-bis(2-hydroxy-3-methoxybenzylidene)carbonhydrazide), have been prepared and structurally characterized by single-crystal X-ray diffraction, elemental analysis, and IR spectroscopy. Each of the hexanuclear complexes is constructed from triangular Dy₃ building blocks, with the six Dy^III ions are arranged in three different conformations. The magnetic properties of three dinuclear Dy^III complexes have also been investigated (Fig. S2). The frequency-dependent ac susceptibility is indicative of Single-Molecule Magnet behavior without and/or with optimum dc field for complexes 2 and 3.