RESUMO
Planar, terpyridine-based metal complexes with the Sierpinski triangular motif and alkylated corners undergo a second self-assembly event to give megastructural Sierpinski pyramids; assembly is driven by the facile lipophilic-lipophilic association of the alkyl moieties and complementary perfect fit of the triangular building blocks. Confirmation of the 3D, pyramidal structures was verified and supported by a combination of TEM, AFM, and multiscale simulation techniques.
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Hierarchical construction of a highly ordered supramolecular array has been, in general, a challenge due to the complexation of building blocks and the hard-to-control weak interactions. Herein, we present a type of well-ordered nanoribbon, which was self-assembled via shape complimentary and hydrophobic effects from the bowl-shaped supramolecular components, which were synthesized by combining designer terpyridine-based monomers and two different metal ions (Ru2+, Zn2+). Interestingly, switching counter ions or changing monomer concentrations, a transformation between a uniform nanosphere and nanoribbon occurred. This opens a door to fabricate readily tailorable, large-scale, supramacromolecular materials.
RESUMO
The quantitative, single step, self-assembly of a shape-persistent, three-dimensional C3v-symmetric, triptycene-based tris-terpyridinyl ligand initially gives a platonic-based cubic architecture, which was unequivocally characterized by 1D and 2D NMR spectroscopy, mass spectrometry, and single crystal X-ray structural analysis. The unique metal-ligand binding properties of the Cd2+ analogue of this construct give rise to a concentration-dependent dynamic equilibrium between cube, prism, and tetrahedron-shaped architectures. Dilution transforms this cube into two identical tetrahedra through a stable prism-shaped intermediate; increasing the concentration reverses the process.
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Synthesis of giant unimolecular dendrimers is challenging due, in part, to difficulties encountered at higher generations, in both convergent and divergent protocols because of the multistep construction/purification process. Herein, we report a hybrid synthetic procedure in which the core is constructed last. This quantitative assembly generated a metallodendrimer that is supercharged (120+), large (11.3 nm diameter), and its core was previously established. The series of complexes has been unequivocally characterized by NMR, ESI-IM-MS, and TEM techniques.
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A novel terpyridine-based, trapezoidal architecture was synthesized by a coordination-driven multicomponent assembly and features three different tpy-M2+-tpy bonds (M2+ = Ru2+, Fe2+, and Zn2+) in the macrocyclic ring. This trimetallic macrocycle introduces the construction of polymetallosupramolecular assemblies possessing multiple, differing metal centers in an ordered, predetermined pattern. Characterization was accomplished by NMR spectroscopy, mass spectrometry, and UV-Vis spectroscopy.
RESUMO
Five- and six-pointed star structures occur frequently in nature as flowers, snow-flakes, leaves and so on. These star-shaped patterns are also frequently used in both functional and artistic man-made architectures. Here following a stepwise synthesis and self-assembly approach, pentagonal and hexagonal metallosupramolecules possessing star-shaped motifs were prepared based on the careful design of metallo-organic ligands (MOLs). In the MOL design and preparation, robust ruthenium-terpyridyl complexes were employed to construct brominated metallo-organic intermediates, followed by a Suzuki coupling reaction to achieve the required ensemble. Ligand LA (VRu2+X, V=bisterpyridine, X=tetraterpyridine, Ru=Ruthenium) was initially used for the self-assembly of an anticipated hexagram upon reaction with Cd2+ or Fe2+; however, unexpected pentagonal structures were formed, that is, [Cd5LA5]30+ and [Fe5LA5]30+. In our redesign, LB [V(Ru2+X)2] was synthesized and treated with 60° V-shaped bisterpyridine (V) and Cd2+ to create hexagonal hexagram [Cd12V3LB3]36+ along with traces of the triangle [Cd3V3]6+. Finally, a pure supramolecular hexagram [Fe12V3LB3]36+ was successfully isolated in a high yield using Fe2+ with a higher assembly temperature.
RESUMO
A three-dimensional, highly symmetric sphere-like nanocage was synthesized using a terpyridine (tpy)-based, flexible tris-dentate ligand and characterized by single crystal X-ray analysis. To introduce more rigidity, one of the tpy units of the tris-dentate ligand was preblocked by stable
RESUMO
Metallomacromolecular architectural conversion is expanded by the characterization of three different structures. A quantitative, single-step, self-assembly of a shape-persistent monomer, containing a flexible crown ether moiety, gives an initial Archimedean-based cuboctahedron that has been unequivocally characterized by 1D and 2D NMR spectroscopy, mass spectrometry, and collision cross section analysis. Both dilution and exchange of counterions, transforms this cuboctahedron into two identical octahedrons, which upon further dilution convert into four, superposed, bistrianglar complexes; increasing the concentration reverses the process. Ion binding studies using the cuboctahedral cage were undertaken.
RESUMO
A Ru(2+)-connected, metallo-organic ligand (L) with three free terpyridines was designed and synthesized. L was assembled with Zn(2+) to generate a helical structure; however, when mixing L with a 1,2,3-tristerpyridine ligand (T), a thermodynamically stable 2D rhombus was assembled. Furthermore, this 2D rhomboidal structure can also be achieved through the dynamic transformation of preassembled helix H with T and Zn(2+) at room temperature.
RESUMO
The preparation of multi-metallic Au nanocluster and nanowires has been achieved using terpyridine-based metallo-organic polymers as multi-ionic templates through a straightforward counterion exchange with aqueous NaAuCl4 followed by a mild reduction in-situ with sodium citrate. The mild reduction of the [TpyFeTpy]2+ x 2[AuCl4]- complex, derived from [TpyFeTpy]2+ x 2Cl- 1 (tpy = 2,2':6',2"-terpyridine), led to the formation of Au nanoclusters (Au NC) with diameters ranging from 7.5-88 nm. Each Au NC alone contained multiple nanoparticles, with diameters ranging from 2.5-4.5 nm. 1,4-bis-terpyridine based metallo-oraganic polymer [-TpyFeTpy-TpyFeTpy-]n(2n+) x [Cl]2n- 2 was found to generate a multi-ionic metallo-polymer with AuCl4- as the counterion, after mild reduction with sodium citrate, resulting in irregular zigzag shaped Au nanowires (Au NW). The prepared Au NW from the di-metallic complex 3 should find applications within electronic devices. Both Au NC and NW were also found to possess excellent catalytic properties.
Assuntos
Nanoestruturas , Compostos Organometálicos/química , Polímeros/química , Piridinas/química , Prata/química , Catálise , Dimerização , Microscopia Eletrônica de Transmissão , Espectrofotometria UltravioletaRESUMO
Inspiration for molecular design and construction can be derived from mathematically based structures. In the quest for new materials, the adaptation of new building blocks can lead to unexpected results. Towards these ends, the quantitative single-step self-assembly of a shape-persistent, Archimedean-based building block, which generates the largest molecular sphere (a cuboctahedron) that has been unequivocally characterized by synchrotron X-ray analysis, is described. The unique properties of this new construct give rise to a dilution-based transformation into two identical spheres (octahedra) each possessing one half of the molecular weight of the parent structure; concentration of this octahedron reconstitutes the original cuboctahedron. These chemical phenomena are reminiscent of biological fission and fusion processes. The large 6â nm cage structure was further analyzed by 1D and 2D NMR spectroscopy, mass spectrometry, and collision cross-section analysis. New routes to molecular encapsulation can be envisioned.
Assuntos
Substâncias Macromoleculares/química , Metais/química , Ligantes , Espectroscopia de Ressonância Magnética , Nanoestruturas/química , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Self-assembly of a tribenzo-27-crown-9 ether functionalized with six terpyridines generated (85%) an expanded tetrahedral structure comprised of four independent triangular surfaces interlinked by crown ether vertices.
Assuntos
Éteres de Coroa/química , Piridinas/química , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Zinco/químicaRESUMO
The initial metallopolymer, derived from two different organic building blocks, is a kinetic intermediate to the final stable hexanuclear (bearing 4Ru(2+) and 2Fe(2+)) metallomacrocycle obtained through a thermodynamic dis-assembly/re-assembly route. The heteroleptic metallomacrocyclic architecture was characterized by NMR, UV, IR, CV, 2D-ROESY, DOSY, and ESI-MS.
RESUMO
Preparation of a new water-soluble, cellulose derivative via a supramolecular route is presented. In a one-step procedure, carboxymethyl cellulose (CMC) was reacted with the Cu(BF4)2 complex of 4'-chloro[2,2':6',2â³]terpyridine to generate the desired CMC-Cu(II)-terpyridine derivative. This polymeric salt was characterized by elemental analysis, ultraviolet-visible spectroscopy (UV-visible), Fourier transform infrared (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), rheological properties measurements, thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and tensile strength properties testing. In addition, antimicrobial properties were demonstrated against Gram-positive bacteria (Staphylococcus aureus and Streptococcus thermophilus), Gram-negative bacteria (Escherichia coli), and yeast (Saccharomyces cervisiae). The minimum inhibitory concentration of the prepared metallo-terpyridine CMC derivative against the studied microorganisms ranged from 6 to 8 mg/L to achieve ≥90% of microbial growth inhibition.
Assuntos
Anti-Infecciosos , Carboximetilcelulose Sódica/análogos & derivados , Complexos de Coordenação , Cobre , Piridinas , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Carboximetilcelulose Sódica/química , Carboximetilcelulose Sódica/farmacologia , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Cobre/química , Cobre/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Piridinas/química , Piridinas/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Staphylococcus/efeitos dos fármacos , Staphylococcus/crescimento & desenvolvimentoRESUMO
The iterative synthetic protocols used for dendrimer construction were developed based on the desire to easily craft highly branched macromolecules with ideally an exact mass and tailored functionality. Inspired by arboreal design and precursors of the utilitarian macromolecules known as dendrimers today, our first examples employed predesigned, 1 â 3 or 1 â (1 + 2) C-branched, building blocks. Physical characteristics of the dendrimers, including their globular shapes, excellent solubility, and demonstrated aggregation, revealed the inherent supramolecular potential. The architecture that is characteristic of dendritic materials also exhibits obvious fractal qualities based on self-similar, repetitive, branched frameworks. Thus, both the fractal design and supramolecular aspects of these constructs are suggestive of a larger field of fractal materials that incorporate repeating geometries and are derived by complementary building block recognition and assembly. Use of ãterpyridine-M(2+)-terpyridineã connectivity for the sides and tuned directed organic vertices has opened the door to other types of novel materials. This approach also circumvents the nonideality of dendrimers, since the heteroleptic, one-step, spontaneous self-assembly process facilitates quantitative outcomes.
RESUMO
A terpyridine-based, concentration-dependent, facile self-assembly process is reported, resulting in two three-dimensional metallosupramolecular architectures, a bis-rhombus and a tetrahedron, which are formed using a two-dimensional, planar, tris-terpyridine ligand. The interconversion between these two structures is concentration-dependent: at a concentration higher than 12 mg mL(-1), only a bis-rhombus, composed of eight ligands and 12 Cd(2+) ions, is formed; whereas a self-assembled tetrahedron, composed of four ligands and six Cd(2+) ions, appears upon sufficient dilution of the tris-terpyridine-metal solution. At concentrations less than 0.5 mg mL(-1), only the tetrahedron possessing an S4 symmetry axis is detected; upon attempted isolation, it quantitatively reverts to the bis-rhombus. This observation opens an unexpected door to unusual chemical pathways under high dilution conditions.
RESUMO
A novel terpyridine-based architecture that mimics a first-generation Sierpinski triangle has been synthesized by multicomponent assembly and features tpy-Cd(II)-tpy connectivity (tpy=terpyridine). The key terpyridine ligands were synthesized by the Suzuki cross-coupling reaction. Mixing two different terpyridine-based ligands and Cd(II) in a precise stoichiometric ratio (1:1:3) produced the desired fractal architecture in near-quantitative yield. Characterization was accomplished by NMR spectroscopy, mass spectrometry, and transmission electron microscopy.
Assuntos
Fractais , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Transmissão , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
A facile high yield, self-assembly process that leads to a terpyridine-based, three-dimensional, bis-rhomboidal-shaped, molecular wheel is reported. The desired coordination-driven supramolecular wheel involves eight structurally distorted tristerpyridine (tpy) ligands possessing a 60° angle between the adjacent tpy units and twelve Zn(2+) ions. The tpy ligand plays dual roles in the self-assembly process: two are staggered at 180° to create the internal hub, while six produce the external rim. The wheel can be readily generated by mixing the tpy ligand and Zn(2+) in a stoichiometric ratio of 2:3; full characterization is provided by ESI-MS, NMR spectroscopy, and TEM imaging.
Assuntos
Ligantes , Piridinas/química , Isomerismo , Espectroscopia de Ressonância Magnética , Simulação de Dinâmica Molecular , Espectrometria de Massas por Ionização por Electrospray , Zinco/químicaRESUMO
The design and construction of the first multicomponent stepwise assembly of a
Assuntos
Compostos Macrocíclicos/síntese química , Compostos Organometálicos/síntese química , Piridinas/síntese química , Rutênio/química , Compostos Macrocíclicos/química , Modelos Moleculares , Compostos Organometálicos/química , Piridinas/químicaRESUMO
The self-assembly of the o-carborane-based, bisterpyridyl monomer, 1,2-bis[4'-(4-ethynylphenyl)-2,2':6',2''-terpyridine]-o-carborane, utilizing either Zn(II) or Fe(II) in a precise metal : ligand ratio (1 : 1), generated a family of metallomacrocycles that were studied via ESI-TWIM-MS, (1)H NMR, and 2D NMR (COSY, NOESY). Under kinetic control, via formation of Fe(II) complexes, the main cyclic product was triangular, as is typical of 60°-based bisligands. Under thermodynamic control using more labile transition metal complexes, e.g. Zn(II), the ratio of cyclic species was found to be concentration and temperature dependent, and under an adequate entropic driving force, the cyclic dimer was formed. This system was probed via variable temperature NMR to reveal dynamic equilibrium between the entropically favored dimer and enthalpically favored trimer.