A facile preparation method for nanosized MOFs as a multifunctional material for cellular imaging and drug delivery

<p>Tb-based metal-organic framework nanoparticles (Tb-MOF NPs) with good colloidal stability and stable fluorescence properties in an aqueous solution were prepared by a simple mechanical grinding of Tb-MOF with a biocompatible polymer surfactant (F127). The characteristic fluorescence property of Tb-MOF NPs allowed us to use this nanomaterial as a cell imaging probe. Efficient cellular uptake of Tb-MOF NPs apparently via an energy-dependent endocytosis was observed by confocal laser scanning microscopy. By taking advantage of the porous nature of the Tb-MOF NPs an anticancer drug (doxorubicin) was successfully loaded and delivered to kill cancer cells to demonstrate their usage as a drug delivery vehicle. This simple grinding method afforded a nanosized, multifunctional biomaterial that was used for cell imaging and drug delivery, and it can be extended to other MOFs to widen their applications.</p

Semicrystalline Dihydroxyacetone Copolymers Derived from Glycerol

The ring-opening polymerization of glycerol-derived six-membered cyclic dimethylacetal dihydroxyacetone carbonate (MeO₂DHAC) have been studied both in solution and bulk conditions with organic catalysts. The guanidine 1,5,7-triazabicyclo[4.4.0]­dec-5-ene (TBD) was the most active catalyst in solution, whereas the thiourea/sparteine catalytic system displayed the most predictable kinetics. Ring-opening polymerization of MeO₂DHAC or copolymerization with ε-caprolactone (CL) in the melt occurred readily with TBD as catalyst to afford random copolymers. Acetal deprotection afforded the polycarbonate poly­(dihydroxyactone carbonate) (p­(DHAC)) or poly­(carbonate ester) copolymers p­(DHAC-<i>r</i>-CL). The polycarbonate p­(DHAC) is a high-melting thermoplastic with a melting point of 246 °C. The p­(DHAC-<i>r</i>-CL) copolymers all displayed semicrystalline behavior as evidenced by DSC and WAXS analysis with <i>T</i>_g and <i>T</i>_m changing as a function of comonomer composition. These new materials could have potential use in biomedical applications or as biomass-derived thermoplastics

Selective Synthesis of Molecular Borromean Rings: Engineering of Supramolecular Topology via Coordination-Driven Self-Assembly

Molecular Borromean rings (BRs) is one of the rare topology among interlocked molecules. Template-free synthesis of BRs via coordination-driven self-assembly of tetracene-based Ru­(II) acceptor and ditopic pyridyl donors is reported. NMR and single-crystal XRD analysis observed sequential transformation of a fully characterized monomeric rectangle to molecular BRs and vice versa. Crystal structure of BRs revealed that the particular topology was enforced by the appropriate geometry of the metallacycle and multiple parallel-displaced π–π interactions between the donor and tetracene moiety of the acceptor. Computational studies based on density functional theory also supported the formation of BRs through dispersive intermolecular interactions in solution

Selective Synthesis of Ruthenium(II) Metalla[2]Catenane via Solvent and Guest-Dependent Self-Assembly

The coordination-driven self-assembly of an anthracene-functionalized ditopic pyridyl donor and a tetracene-based dinuclear Ru­(II) acceptor resulted in an interlocked metalla[2]­catenane, [M₂L₂]₂, in methanol and a corresponding monorectangle, [M₂L₂], in nitromethane. Subsequently, guest template, solvent, and concentration effects allowed the self-assembly to be reversibly fine-tuned among monorectangle and catenane structures

Coordination-Driven Self-Assembly and Anticancer Potency Studies of Arene–Ruthenium-Based Molecular Metalla-Rectangles

The two new large molecular metalla-rectangles <b>6</b> and <b>8</b> were obtained by the reaction of the two different arene–ruthenium acceptors [Ru₂(<i>p-</i>cymene)₂(μ-η⁴-C₂O₄)­Cl₂] (<b>2</b>) and [Ru₂(<i>p-</i>cymene)₂(donq)­(Cl)₂] (donq = 5,8-dioxido-1,4-naphthoquinonato) (<b>4</b>) with a symmetrical <i>N</i>,<i>N</i>′-bis­(4-(pyridin-4-ylethynyl)­phenyl)­terephthalamide (<b>1</b>) donor ligand. Both metalla-rectangles were isolated in good yields as triflate salts and were characterized by multinuclear NMR, ESI–MS, and UV–vis spectroscopy. X-ray crystallography of <b>6</b> confirmed a molecular metalla-rectangle. The cytotoxicities of metalla-rectangles <b>6</b>–<b>9</b> were established in SK-hep-1 (liver cancer), AGS (gastric cancer), and HCT-15 (colorectal cancer) human cancer cell lines. The cytotoxicity of metalla-rectangle <b>8</b> was found to be considerably stronger against all cancer cell lines, even much more effective than the well-known anticancer drugs doxorubicin and cisplatin. In addition, expressions of APC and p53, colorectal cancer suppressor genes, were significantly increased following exposure to the metalla-rectangle <b>8</b>

Banking performance’ determinants

У статті розглянуто фактори впливу на ефективність банківського бізнесу. З позиції необхідності управління ефективністю банківського бізнесу запропоновано внутрішні фактори розглядати як сукупність статусних характеристик банку та характеристик його бізнес-моделі.The article deals with banking performance’s determinants. In context of banking performance management its proposed internal factors to consider as a set of status characteristics and the characteristics of the bank's business model

Organocatalytic Synthesis of Quinine-Functionalized Poly(carbonate)s

The ring-opening polymerization of substituted cyclic carbonates with 1-(3,5-bis-trifluoromethyl-phenyl)-3-cyclohexyl-thiourea (TU)/1,8-diazabicyclo[5.4.0]­undec-7-ene (DBU) organocatalysts afford highly functionalized oligocarbonates. The fluorescent alkaloid quinine can be readily incorporated into the oligocarbonates either by initiation from quinine or by ring-opening polymerization of a quinine-functionalized cyclic carbonate (MTC-Q). Copolymerization of MTC-Q with a boc-protected guanidinium cyclic carbonate affords, after deprotection, highly water-soluble cationic copolymers functionalized with both quinine and pendant guanidinium groups. When multiple quinine groups are attached to the oligomers, they exhibit minimal fluorescence due to self-quenching. Upon hydrolysis, the fluorescence intensity increases, providing a potential strategy for monitoring the hydrolysis rates in real time

Formation of [3]Catenanes from 10 Precursors via Multicomponent Coordination-Driven Self-Assembly of Metallarectangles

We describe the formation of a suite of [3]­catenanes via multicomponent coordination-driven self-assembly and host–guest complexation of a rectangular scaffold comprising a 90° Pt-based acceptor building block with a pseudorotaxane bis­(pyridinium)­ethane/dibenzo-24-crown-8 linear dipyridyl ligand and three dicarboxylate donors. The doubly threaded [3]­catenanes are formed from a total of 10 molecular components from four unique species. Furthermore, the dynamic catenation process is reversible and can be switched off and on in a controllable manner by successive addition of KPF₆ and 18-crown-6, as monitored by ¹H and ³¹P NMR spectroscopy

A Unique Non-catenane Interlocked Self-Assembled Supramolecular Architecture and Its Photophysical Properties

A novel, interlocked, self-assembled (M₂L₂)₂ molecular architecture was constructed from an arene-Ru acceptor and a 1,4-di(pyridin-4-yl)buta-1,3-diyne donor. Two M₂L₂ units, with cavities of ∼7.21 Å, spontaneously interlock, with one unit encapsulating a twin in a non-catenane fashion. The dimeric host–guest complex thus formed is unique among two-dimensional self-assemblies and is stabilized by π–π interactions between the M₂L₂ units

Coordination-Driven Self-Assembly Using Ditopic Pyridyl–Pyrazolyl Donor and <i>p</i>‑Cymene Ru(II) Acceptors: [2]Catenane Synthesis and Anticancer Activities

Coordination-driven self-assembly of <i>m</i>-bis­[3-(4-pyridyl)­pyrazolyl]­xylene (<b>L</b>) and [(<i>p</i>-cymene)₂Ru₂­(OO∩OO)₂(OTf)₂] (<b>A</b>_<b>1</b>) (OO∩OO = 6,11-dioxido-5,12-naphthacenedione) in methanol resulted in a mixture of [2]­catenane <b>1</b> and macrocycle <b>2</b>, and self-assembly in nitromethane resulted in pure macrocycle <b>2</b>, whereas the coordination-driven self-assembly of <b>L</b> and similar acceptors [(<i>p</i>-cymene)₂Ru₂(OO∩OO)₂(OTf)₂] [OO∩OO = 5,8-dioxido-1,4-naphthoquinonnato (<b>A</b>_<b>2</b>); 2,5-dioxido-1,4-benzoquinonato (<b>A</b>_<b>3</b>); oxalato (<b>A</b>_<b>4</b>)] resulted in the formations of monomeric macrocycles <b>3</b>–<b>5</b>, respectively. All self-assembled macrocycles were obtained in excellent yields (>90%) as triflate salts and were fully characterized by multinuclear NMR, elemental analysis, and electrospray ionization mass spectrometry (ESI-MS). The structures of [2]­catenane <b>1</b> and macrocycles <b>5</b> were confirmed by single-crystal X-ray diffraction analysis. The X-ray structure of <b>1</b> confirmed an edge-to-face interaction between the tetracene moiety in parallel-displaced π–π stacks (3.5 Å), and CH···π (2.5 Å) stabilizes the [2]­catenane topology. Macrocycles <b>2</b>–<b>5</b> were assessed for anticancer activities using human cancer cell lines of different origins, and the macrocycle <b>3</b> was found to exhibit the best inhibitory effect and to do so in a dose-dependent manner. Further examination with the Tali apoptosis assay suggested the growth inhibitory effect of <b>3</b> involved the induction of the programmed cell death, and this suggestion was supported by observations of PARP and caspase 3 cleavage after treating cells with <b>3</b>. In addition, exposure to <b>3</b> increased the expression of Bax and repressed the expression of Bcl-2, thus indicating the involvement of macrocycle <b>3</b> upstream of Bax and Bcl-2 in the apoptotic signaling pathway. Macrocycle <b>3</b> also tended to repress metastasis as evidenced by changes in the transcriptional expressions E- and N-cadherin (markers of metastasis). Furthermore, a stability assay demonstrated macrocycle <b>3</b> remained stable at high concentration