16 research outputs found
Synthesis and Characterization of Self-Assembled Nanoscopic Metallarectangles Capable of Binding Fullerenes with Size-Selective Responses
Two
new metallarectangles, <b>4</b> and <b>5</b>, were
obtained from the self-assembly of areneruthenium-based molecular
clips <b>2</b> and <b>3</b> with a new dipyridyl donor
ligand <b>1</b> containing a diamide core and ethynyl spacers.
The metallarectangles were characterized by multinuclear NMR, electrospray
ionization mass spectrometry, and UV–vis spectroscopy,
and the molecular structure of <b>4</b> was unambiguously determined
by single-crystal X-ray diffraction analysis. Because of the presence
of an extended π-electron aromatic surface, the tetracene-containing
molecular rectangle <b>5</b> was capable of binding C<sub>60</sub> and C<sub>70</sub> fullerenes as quantified by UV–vis, emission,
and <sup>1</sup>H NMR experiments, providing an example
of a supramolecular host capable of recognizing large guest molecules
Synthesis and Characterization of Self-Assembled Nanoscopic Metallarectangles Capable of Binding Fullerenes with Size-Selective Responses
Two
new metallarectangles, <b>4</b> and <b>5</b>, were
obtained from the self-assembly of areneruthenium-based molecular
clips <b>2</b> and <b>3</b> with a new dipyridyl donor
ligand <b>1</b> containing a diamide core and ethynyl spacers.
The metallarectangles were characterized by multinuclear NMR, electrospray
ionization mass spectrometry, and UV–vis spectroscopy,
and the molecular structure of <b>4</b> was unambiguously determined
by single-crystal X-ray diffraction analysis. Because of the presence
of an extended π-electron aromatic surface, the tetracene-containing
molecular rectangle <b>5</b> was capable of binding C<sub>60</sub> and C<sub>70</sub> fullerenes as quantified by UV–vis, emission,
and <sup>1</sup>H NMR experiments, providing an example
of a supramolecular host capable of recognizing large guest molecules
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, [M<sub>2</sub>L<sub>2</sub>]<sub>2</sub>, in methanol and a corresponding monorectangle,
[M<sub>2</sub>L<sub>2</sub>], 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 of 2D-Metallamacrocycles Using a New Carbazole-Based Dipyridyl Donor: Synthesis, Characterization, and C<sub>60</sub> Binding Study
A new carbazole-based 90° dipyridyl donor 3,6-di(4-pyridylethynyl)carbazole
(<b>L</b>) containing carbazole-ethynyl functionality is synthesized
in reasonable yield using the Sonagashira coupling reaction. Multinuclear
NMR, electrospray ionization-mass spectrometry (ESI-MS), including
single crystal X-ray diffraction analysis characterized this 90°
building unit. The stoichiometry combination of <b>L</b> with
several Pd(II)/Pt(II)-based 90° acceptors (<b>1a</b>–<b>1d</b>) yielded [2 + 2] self-assembled metallacycles (<b>2a</b>–<b>2d</b>) under mild conditions in quantitative yields
[<b>1a</b> = <i>cis</i>-(dppf)Pd(OTf)<sub>2</sub>; <b>1b</b> = <i>cis</i>-(dppf)Pt(OTf)<sub>2</sub>; <b>1c</b> = <i>cis</i>-(tmen)Pd(NO<sub>3</sub>)<sub>2</sub>; <b>1d</b> = 3,6-bis{<i>trans</i>-Pt(CC)(PEt<sub>3</sub>)<sub>2</sub>(NO<sub>3</sub>)}carbazole]. All these macrocycles
were characterized by various spectroscopic techniques, and the molecular
structure of <b>2a</b> was unambiguously determined by single
crystal X-ray diffraction analysis. Incorporation of ethynyl functionality
to the carbazole backbone causes the resulted macrocycles (<b>2a</b>–<b>2d</b>) to be π-electron rich and thereby
exhibit strong emission characteristics. The macrocycle <b>2a</b> has a large internal concave aromatic surface. The fluorescence
quenching study suggests that <b>2a</b> forms a ∼1:1
complex with C<sub>60</sub> with a high association constant of <i>K</i><sub>sv</sub> = 1.0 × 10<sup>5</sup> M<sup>–1</sup>
Coordination-Driven Self-Assembly of 2D-Metallamacrocycles Using a New Carbazole-Based Dipyridyl Donor: Synthesis, Characterization, and C<sub>60</sub> Binding Study
A new carbazole-based 90° dipyridyl donor 3,6-di(4-pyridylethynyl)carbazole
(<b>L</b>) containing carbazole-ethynyl functionality is synthesized
in reasonable yield using the Sonagashira coupling reaction. Multinuclear
NMR, electrospray ionization-mass spectrometry (ESI-MS), including
single crystal X-ray diffraction analysis characterized this 90°
building unit. The stoichiometry combination of <b>L</b> with
several Pd(II)/Pt(II)-based 90° acceptors (<b>1a</b>–<b>1d</b>) yielded [2 + 2] self-assembled metallacycles (<b>2a</b>–<b>2d</b>) under mild conditions in quantitative yields
[<b>1a</b> = <i>cis</i>-(dppf)Pd(OTf)<sub>2</sub>; <b>1b</b> = <i>cis</i>-(dppf)Pt(OTf)<sub>2</sub>; <b>1c</b> = <i>cis</i>-(tmen)Pd(NO<sub>3</sub>)<sub>2</sub>; <b>1d</b> = 3,6-bis{<i>trans</i>-Pt(CC)(PEt<sub>3</sub>)<sub>2</sub>(NO<sub>3</sub>)}carbazole]. All these macrocycles
were characterized by various spectroscopic techniques, and the molecular
structure of <b>2a</b> was unambiguously determined by single
crystal X-ray diffraction analysis. Incorporation of ethynyl functionality
to the carbazole backbone causes the resulted macrocycles (<b>2a</b>–<b>2d</b>) to be π-electron rich and thereby
exhibit strong emission characteristics. The macrocycle <b>2a</b> has a large internal concave aromatic surface. The fluorescence
quenching study suggests that <b>2a</b> forms a ∼1:1
complex with C<sub>60</sub> with a high association constant of <i>K</i><sub>sv</sub> = 1.0 × 10<sup>5</sup> M<sup>–1</sup>
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 [Ru<sub>2</sub>(<i>p-</i>cymene)<sub>2</sub>(μ-η<sup>4</sup>-C<sub>2</sub>O<sub>4</sub>)Cl<sub>2</sub>] (<b>2</b>) and [Ru<sub>2</sub>(<i>p-</i>cymene)<sub>2</sub>(donq)(Cl)<sub>2</sub>] (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>
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
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
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 KPF<sub>6</sub> and 18-crown-6, as monitored
by <sup>1</sup>H and <sup>31</sup>P NMR spectroscopy
A Unique Non-catenane Interlocked Self-Assembled Supramolecular Architecture and Its Photophysical Properties
A novel, interlocked, self-assembled (M<sub>2</sub>L<sub>2</sub>)<sub>2</sub> molecular architecture was constructed from an arene-Ru acceptor and a 1,4-di(pyridin-4-yl)buta-1,3-diyne donor. Two M<sub>2</sub>L<sub>2</sub> 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 M<sub>2</sub>L<sub>2</sub> units