Design and Construction of Metallo-supramolecular Terpyridine Architectures

Design and Construction of Metallo-supramolecular Terpyridine Architectures
Author: Yi-Tsu Chan
Publisher:
Total Pages: 188
Release: 2010
Genre: Macrocyclic compounds
ISBN:

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Beyond molecular chemistry, supramolecular chemistry focuses on constructing highly complicated and functional systems from chemical species held together by intermolecular non-covalent interactions. Metal-ligand coordinative interaction plays an important role in construction of supramolecules; 2,2':6',2"-terpyridine (tpy) is one ligand that has been widely used in this arena. Bis(terpyridine) ligands with suitable geometry are able to form cyclic structures upon complexation with metal ions. Either by a stepwise procedure or by a self-assembled process, a series of metallomacrocyles containing tpy-M-tpy units (M = metal) has been constructed and isolated. Self-assembly using the labile tpy-Cd[superscript II]-tpy connectivity provides access in quantitative yields to hexacadmium macrocycles that were characterized by traveling wave ion mobility mass spectrometry (TWIM-MS), which enhances the resolving power of electrospray ionization mass spectrometry by adding shape-dependent dispersion and completely deconvolutes the isotope patterns of different charge states, as well as avoids isomer superposition. The self-assembly of a series of Cd[superscript II] metallomacrocycles with different sizes and architectures has been achieved by controlling the stoichiometry and shapes of the building blocks. Novel approaches to the development of artificial multivalent carbohydrate conjugate objects remain an important area of research due to their strong and specific interactions with receptors. Integrating carbohydrates with metallomacrocycles, linear or branched sugar-functionalized 3,5-di(terpyridinyl)arenes have been synthesized and shown to self-assemble using Fe[superscript II] into hexameric and pentameric macrocycles. The self-assembled nanofibers of both macrocycles were generated by slowly diffusing the nonpolar solvent hexane into a homogeneous solution of the complexes in CHCl3/MeOH/MeCN. In order to fabricate nanometer-sized materials from predesigned building blocks, a bottom-up approach has been used to incorporate Au nanorods (NRs) into multicomponent structures containing tpy-FeII-tpy connectivity. This was the first example of Au NR assembly to afford predominately end-to-end linear and branched nanoarchitectures using metal complexes, which can be disassembled under mild conditions.

Design and Synthesis of Terpyridine Based Metallo-Supramolecular Architectures

Design and Synthesis of Terpyridine Based Metallo-Supramolecular Architectures
Author: James M. Ludlow (III)
Publisher:
Total Pages: 152
Release: 2015
Genre: Chemical reactions
ISBN:

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In the field of metallo-supramolecular chemistry, the N-heteroaromatic ligand, [2,2':6',2"] terpyridine (tpy), has received considerable attention due in part to its ability to coordinate with a wide variety of transition metals; this has enabled a range of bonding strengths, properties, and molecular architectures. A variety of strategies have been employed with [tpy-M(II)-tpy] based architectures including the use of triangle-based frameworks, flexible ligands, and harnessing of additional non-covalent forces to enhance self-assembly. To achieve three-dimensional architectures, new strategies include use of meta-substitution, multi-planar vertices, flexible vertices, and by restricting the availability of planar conformations via precoordination or predesigned steric hindrance. There is also increasing focus on interconversions between supramolecular structures in response to reaction conditions and on their hierarchical self-assembly. Flexible, multitopic ligands can introduce new structural possibilities, allowing for intramolecular interactions and more adaptive systems to arise. When the semi-flexible 1,2-bis[4'-(4-ethynylphenyl)-2,2':6',2"-terpyridyl]-o-carborane is self-assembled under kinetic control, via formation of Fe(II) complexes, the main cyclic product is triangular (trimer). However, under thermodynamic control, using a labile transition metal, e.g. Zn(II), the cyclic trimer is in dynamic equilibrium with a cyclic dimer, and with adequate entropic driving force the cyclic dimer is obtained exclusively. The combination of flexible crown ethers possessing a trio of rigid, 60° ligands allows for the construction of a 3D structure (tetrahedron) under thermodynamic control. Formation of the tetrahedron is facilitated by intramolecular, pi-pi interactions. Structural confirmation utilized 1D and 2D NMR, and electrospray ionization mass spectrometry coupled with travelling wave ion mobility (ESI-TWIM-MS). 19F NMR experiments support presence of guest host interactions between anions and the supramolecular cavity.One step synthesis of the first homoleptic [tpy-Os(II)-tpy] metallomacrocycle was reported and characterized via NMR, ESI-MS, TWIM-MS, and UV-vis alongside its Fe(II) and Ru(II) analogues. Gradient tandem-MS was used to derive center-of-mass collision energies and revealed unexpectedly that the order of stability of the [tpy-M(II)-tpy] complexes was M(II) = Ru > Os > Fe. Toward hierarchical ordering of supramolecular materials, the effect of molecular geometry and amphiphilicity on the ability of self-assembled metallosupramolecular macrocycles to self-order was studied. Conversion of [tpy-M(II)-tpy] macrocycles into directional amphiphiles enhanced ordering characteristics, enabling the formation of nanoscale structures.

Design and Construction of Metallo-supramolecular Terpyridine Possessing Higher Order Structure

Design and Construction of Metallo-supramolecular Terpyridine Possessing Higher Order Structure
Author: Keqin Zheng
Publisher:
Total Pages: 59
Release: 2013
Genre: Macromolecules
ISBN:

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Abiological self-assembly has emerged as a major, active, and cutting-edge area of chemistry. Within this arena, many terpyridine-based, coordination-driven, self-assembled macrocycles have been created and studied. Investigation of potential properties and the opportunity to unveil the detailed primary and secondary structures of these materials, such as in fibers and crystals, are of particular interest. Considering that few terpyridine-based macrocyclic crystal structures have been reported, the difficulty to obtain suitable crystals for X-ray characterization is evident. Thus, drawing support from polyanionic stablization, a series of rigid, polycarboxylic acids, for example, hexakis(4-carboxyphenyl)benzene, and 3,3',3",5,5',5"-benzene-1,3,5-triyl-hexabenzoic acid (H6BHB) have been prepared to assist the crystallization of triangular terpyridine complexes and marcromolecular systems. A single crystal has been grown using the combination of a benzyl-modified, trisRu(II)-based metallomacrocycle and a 3,3',3",5,5',5"-benzene-1,3,5-triyl-hexabenzoic anion, as the counterion. Subsequently, the first successful X-ray analysis of a triangular, trisRu(II)-based, metallocycle is described.

Design and Synthesis of Heteroleptic and Heterometallic Metallo-Supramolecular Terpyridine Architectures

Design and Synthesis of Heteroleptic and Heterometallic Metallo-Supramolecular Terpyridine Architectures
Author: Rajarshi Sarkar
Publisher:
Total Pages: 162
Release: 2015
Genre: Chemical reactions
ISBN:

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Inspiration from biological assemblies in Nature has produced an extraordinary amount of research in supramolecular chemistry. Various non-covalent interactions have been employed to design and synthesize numerous sophisticated architectures with unique structural and functional properties. Metallo-supramolecular constructs are primarily synthesized in a homoleptic assembly; whereas, a preprogrammed monomer is reacted with a suitable metal ion to produce the desired, highly symmetric architectures. On the other hand, structural variance in the supramolecular materials is instilled mainly by step-wise or dynamic assembly protocols. Owing to the unavailability of suitable building blocks and lack of control over the outcome of the assembly, study of these assembly methods has been limited. Two novel terpyridine-based bimetallic triangles were synthesized via a less explored supramolecular fusion approach. Syntheses of two homometallic cyclic trimer and two metallo-squares were achieved, and they were characterized by NMR and MS techniques. Mixing of triangular and the tetrameric units produced the desired bimetallic triangular complexes in quantitative yield. The multinuclear structures were characterized by 1H, 2D-COSY, 2D-NOESY, ESI- and TWIM-MS data. Tandem MS data provided information on the stability of these triangles. UV-vis and luminiscence data indicated metal-ligand charge transfer. Three bimetallic triangles were constructed by a step-wise directed assembly method. An oligomeric trimer was synthesized from a 60o-directed bisterpyridine ligand and was characterized by NMR and MS techniques. Three heterobimetallic triangular architectures were obtained by reacting the oligomeric trimer with Zn(II), Cd(II), and Fe(II). 1H, 2D-COSY, and 2D-NOESY NMR, ESI- and TWIM-MS data confirmed the proposed structures. Luminescence data showed the emission intensities of the triangles are lower than the linear trimer indicating quenching effect of Zn(II), Cd(II), and Fe(II) centers. Synthesis of a structural mimic of first-generation Sierpiński triangle was achieved via dynamic supramolecular assembly. The two required bis- and tetrakis-terpyridine ligands were synthesized and characterized. The ligands were reacted with Cd(II) in precise 1:1:3 molar ratio to obtain the desired complex in near quantitative yield. 1H, 2D-COSY, and 2D-NOESY NMR, ESI- TWIM-MS, and collision cross-section data confirmed the presence of a Sierpiński triangle as the sole product of the reaction. TEM provided the visualization of the desired architecture, shape, and size of the observed molecules, which fit perfectly the simulated parameters.

Design and Construction of Terpyridine-based Two-dimensional and Three-dimensional Supramolecular Architectures

Design and Construction of Terpyridine-based Two-dimensional and Three-dimensional Supramolecular Architectures
Author: Xiaocun Lu
Publisher:
Total Pages: 0
Release: 2013
Genre: Ligands
ISBN:

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Supramolecular self-assembly focuses on the studies of weak interactions beyond molecules and construction of complicated, well-defined supramolecular architectures which widely exist in natural process and have been used in catalysis, chemical sensing and molecular electronics. Utilization of tpy-MsupII/sup-tpy (M = metal) connectivity to construct specific shaped supramolecular architectures has been well-developed.Bisterpyridines possessing 60° and 120° directionality can readily form triangular and hexagonal metallomacrocycles with group 12 metals, such as: Zn(II) and Cd(II), respectively. The supramolecular rhomboidal architecture could also be formed through a multicomponent self-assembly utilizing a precise stoichiometric ratio (1:1:2) of bisterpyridines with 60° or 120° directionality and metal ions (Zn2+ or Cd2+). However, the triangular construct, which is formed solely by bisterpyridine with 60° branching angle, could also be detected in the same solution. To further probe the self-sorted formation of a rhomboidal architecture, a tristerpyridine possessing three adjacent terpyridine units is used. Such tristerpyridine ligand can readily react with 60°-directed bisterpyridine ligands and metal ions (Zn2+ or Cd2+) in the stoichiometric ratio (2:2:5) to quantitatively form a center-bridged, fused-triangular shaped, rhomboidal structure. A facile heteroleptic self-assembly of hexakisterpyridine and tristerpyridine possessing 60° angles between the adjacent terpyridine moieties with stoichiometric amount of Zn2+ ions (1:6:12) leads to the formation of supramolecular spoked wheel architecture in a 90% isolated yield, which is fully characterized by ESI-MS, NMR, and TEM imaging. When the central hexakisterpyridine of the spoked wheel is replaced with two staggered tristerpyridine ligands possessing 120° angle between the adjacent terpyridine units, a three-dimensional, supramolecular, bicycle-like wheel structure is readily formed, in which two 120°-directed tristerpyridines serve as the hub and spokes and six 60°-based tristerpyridines locate outside as rims. Another analogous supramolecular spoked wheel can also be formed by further redesign of the core ligand. Two tristerpyridine ligands possessing 60° between the adjacent terpyridine units adopt a parallel-staggered conformation with the opposite orientations to replace the core hexaligand. Eight equivalent amount of such tristerpyridine ligands (two serving as core ligands; six as outer rim ligands) can readily react with twelve equivalence of metal ions (Zn2+ or Cd2+) to form a supramolecular mandoline-shaped wheel structure, which contains two vertex-connected, centrally-bridged rhomboidal moieties at the concentration of > 15 mg·mL−1. When the concentration of the Cd2+-based mandoline-shaped structure is reduced, a quasi-tetrahedron structure possessing four tristerpyridine ligands and six Cd2+ ions can be detected and it becomes the only self-assembly product when the concentration is below 0.5 mg·mL−1. The Zn2+ analogue of the mandoline-shaped structure remains intact during the dilution and there is no quasi-tetrahedron structure detected in such supramolecular system.

Modern Terpyridine Chemistry

Modern Terpyridine Chemistry
Author: Ulrich S. Schubert
Publisher: John Wiley & Sons
Total Pages: 237
Release: 2006-08-21
Genre: Science
ISBN: 3527608427

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The first book to didactically illustrate this particular, prominent class of supramolecular building-blocks covers topics ranging from terpyridine syntheses, via their chemistry and properties, supramolecular structures, and multinuclear metal complexes, right up to functionalized polymers, 3D-architectures, and surfaces. Invaluable for students and lecturers in chemistry and biochemistry, materials scientists, as well as polymer, complex and physicochemists.

Terpyridine-based Metallo-supramolecular Architectures

Terpyridine-based Metallo-supramolecular Architectures
Author: Hany El-batal
Publisher:
Total Pages: 182
Release: 2013
Genre: Macrocyclic compounds
ISBN:

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The research and applications of functional materials continue to grow rapidly in order to match the materials and energy needs of an increasing population. In this regard, perylene is a stable, organic material that possesses a rich chemistry and unique chemical, physical, and electronic properties. The molecular organization into predesigned geometries such as: cages, dendrimers, macrocycles and polymers, can add a profound enhancement to the material functional characteristics. At the heart of metallosupramolecular chemistry, tpy-M-tpy binding is a pivotal tool to construct complex and functional architectures. This dissertation reviews the chemical, structural, physical, and electrochemical properties of perylene with an emphasize on its metallosupramolecular chemistry. The synthesis of perylene-containing bis-, tetrakis-, and hexakis-terpyridine ligands along with their corresponding heteroleptic tpyRu11tpy complexes was achieved. These high molecular weight nano-dendritic architectures were characterized using 1H NMR, 13C NMR, COSY, and ESI-MS. These complexes exhibit broad absorption spectra (250-625 nm) and high molar absorption coefficients that are proportional to the number of photoactive units. The synthesis of supramolecular dyes based on tpy-Ru11-tpy motifs connected to perylene-core either in bay- or peri-positions was demonastrated. The structures of these materials were confirmed using a combination of 1H NMR, 13C NMR, COSY, ESI-MS, and their electrochemical properties were studied via Cyclic Voltametry. These dyes were utilized as active ingredients for DSSCs, of which the photovoltaic properties were described. Fluorescent cyclic metallosupramolecular architectures were obtained via tpyZn11tpy mediated self-assembly of two aminobisterpyridine containing perylene ligands that were synthesized in a multistep procedure, the chemical structure and purity of both ligands and complexes were assured using a combination of 1H NMR, 13C NMR, COSY, and ESI-MS. DOSY was utilized to investigate the dimensions of the metallocycles that were compared to the values obtained from the energy minimized molecular modeling. The photophysical properties of these macrocycles showed strong fluorescence suggesting their potential use in LED. The formation of novel cyclic complexes including trimer and heteroleptic tetramers was achieved. The UV-Vis absorption and emission spectra of these materials were studied, and their chemical structures were illucidated via a combination of spectroscopic techniques including 1H NMR, ESI-MS, and MALDI-TOF-MS. Molecular modeling simulation of these nanosized complexes revealed cavities that can be used for host-guest chemistry.

Terpyridine-based Materials

Terpyridine-based Materials
Author: Ulrich S. Schubert
Publisher: John Wiley & Sons
Total Pages: 562
Release: 2012-09-25
Genre: Technology & Engineering
ISBN: 3527639632

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In recent years, the utilization of terpyridines both in macromolecular structure assembly and device chemistry has exploded, enabling, for example, supramolecular polymer architectures with switchable chemical and physical properties as well as novel functional materials for optoelectronic applications such as light-emitting diodes and solar cells. Further applications include the usage of terpyridines and their metal complexes as catalysts for asymmetric organic reactions and, in a biological context, as anti-tumor agents or biolabels. This book covers terpyridine-based materials topics ranging from syntheses, chemistry, and multinuclear metal complexes, right up to functionalized polymers, 3D-architectures, and surfaces. Aimed at materials scientists, (in)organic chemists, polymer chemists, complex chemists, physical chemists, biochemists, and libraries.

Supramolecular Chemistry of Functionalized Terpyridines

Supramolecular Chemistry of Functionalized Terpyridines
Author: Ibrahim Eryazici
Publisher:
Total Pages: 309
Release: 2007
Genre: Ligands
ISBN:

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"Highly ordered, regularly repeating molecular architectures, constructed via self-assembly techniques, have gained importance over the last three decades due to their potential utilitarian applications. A key construction strategy has relied on the synthesis of specific building blocks capable of forming 'higher-ordered' stable structures that have useful properties that can be used as molecular and supramolecular devices. To this end, mono and bis(terpyridine) ligands have been widely used because of their well known photochemical and electronic properties, as well as their ability to facilitate directed, metal-mediated self-assembly. However, limited accessibility to unsymmetrically functionalized terpyridines has restricted their potential use in the construction of more complex infrastructures. For this purpose, methyl-, methoxy-carbonyl- and cyano-substitution patterns on the 4,4"--Positions of 4'-arylterpyridine were chosen since these functionalities afforded simple routes to a variety of useful substituted building blocks for higher-ordered supramacromolecular architectures. Single crystal X-ray studies of these terpyridines revealed that molecules of the diester terpyridine (approximately coplanar) are stacked by the overlap of the central pyridine rings in consecutive layers with mean interplanar distances of 3.4 Å (pi - pi interactions) in the solid state. Moreover, functionalized bis(terpyridine) ligands were achieved via the Kröhnke method and Pd(0) coupling strategy using either 1,3-toluenylbisboronic acid or 1,3-diethynyltoluene with meta- or para-I or Br-phenylterpyridines. A dinuclear tetracationic Fe(II) complex was prepared via metal-directed self-assembly. The chair-like molecular architecture was primarily characterized by X-ray crystallography, mass spectroscopy (ESI-MS), as well as 1H NMR, UV-vis, and CV experiments. Crystal packing of this metallomacrocycle revealed that it formed channels that encapsulated water and MeCN. The low temperature 1H NMR studies suggested that tpy-Fe-tpy moieties in the dimer were interlocked and resembled a spur gear relationship. Surprisingly, dinuclear and trinuclear metallomacrocycles were formed when 1,3-bis(2,2';6',2"-terpyridine-4'-phen-3-ylethynyl)toluene was treated with equimolar amount of Ru(II) that was confirmed by MALDI-TOF mass and NMR spectroscopy. The construction of a heteronuclear (Ru4Fe2) hexameric metallomacrocycle with methyl- and carbonyl-functionalized bis(terpyridyl) moieties was achieves by Pd(0) coupling strategy for potential solar cell applications and supramolecular aggregation of the resulting hexamers through H-bonding. Carboxylic acid functionalized mono- and dinuclear homo- and heteroleptic Ru(II) percursors were also prepared for the same purposes. The single crystal X-ray structure of a homoleptic Ru(II) complex with tetra-ethoxycarbonyl and di(iodo) groups revealed short iodo-carbonyl interactions."--abstract.