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Poly(thienylene vinylene) (PTV) with high molecular weight was obtained via transition-metal-free and halogen-free polymerization, and the Brønsted acid doping of the PTV film was used for thermoelectric application.

Coordination-driven self-assembly of metal ions and organic ligands has been extensively applied over the past few decades, towards construction of various functional two-dimensional (2D) and three...

The reaction of a metallo-organic ligand (LA) in which two “V”-shaped bisterpyridines attaching to meta-position of “X”-shaped tetraterpyridine via connectivity and Zn2+ ions gave rise to 3D supramolecular architectures: octagram (Zn8LA4). However, a position varied ligand (LB) in which two “V”-shaped bisterpyridines locating at the ortho-position of “X”-shaped tetraterpyridine afforded a different 3D hexagram (Zn6LB3). Full characterizations included NMR (1H, 13C, 2D COSY, NOESY and DOSY), ESI-MS, TWIM-MS, TEM and AFM. The resulted structures were directly determined by the position of two “V”-shaped bisterpyridines attaching to “X”-shaped tetraterpyridine.

A two-ligand system composed of the predesigned multivalent and complementary terpyridine-based ligands was exploited to construct heteroleptic metallo-supramolecules and to investigate the self-assembly mechanism. Molecular stellation of the trimeric hexagon [Cd

Gigantic coordination molecules assembled from a large number of metal ions and organic ligands are structurally and functionally challenging to characterize. Here we show that a heterometallic clu...

Data carriers using spin waves in spintronic and magnonic logic devices offer operation at low power consumption and free of Joule heating yet requiring noncollinear spin structures of small sizes. Heterometallic rings can provide such an opportunity due to the controlled spin-wave transmission within such a confined space. Here, we present a series of {ScnGdn} (n = 4, 6, 8) heterometallic rings, which are the first Sc-Ln clusters to date, with tunable magnetic interactions for spin-wave excitations. By means of time- and temperature-dependent spin dynamics simulations, we are able to predict distinct spin-wave excitations at finite temperatures for Sc4Gd4, Sc6Gd6, and Sc8Gd8. Such a new model is previously unexploited, especially due to the interplay of antiferromagnetic exchange, dipole-dipole interaction, and ring topology at low temperatures, rendering the importance of the latter to spin-wave excitations.

Self-assembly of twelve pentatopic tectons, which have complementary edges or can be linked using either digonal or trigonal connectors, represents the optimal synthetic strategy to achieve spherical objects, such as chemical capsids. This process requires conditions that secure uninterrupted equilibria of binding and self-correction en route to the global energy minimum. Here we report the synthesis of a highly soluble, deca-heterosubstituted corannulene that bears five terpyridine ligands. Spontaneous self-assembly of twelve such tectons with 30 cadmium(II) cations produces a giant icosahedral capsid as a thermodynamically stable single product in high yield. Nuclear magnetic resonance (NMR) methods, mass spectrometry analyses, small-angle X-ray scattering, transmission electron microscopy, and atomic force microscopy indicate that this spherical capsid has an external diameter of nearly 6 nm and shell thickness of 1 nm, in agreement with molecular modeling. NMR and liquid chromatography evidences imply that chiral self-sorting complexation generates a racemic mixture of homochiral capsids., The icosahedron, as the polyhedron closest in symmetry to the sphere, is one of the most compelling Platonic solids for chemists to construct. Here, the authors assemble a supramolecular icosahedron from twelve pentatopic corannulene-based tectons, a strategy that was proposed over a decade ago but only now synthetically realized.

Nanosized cage-within-cage compounds represent a synergistic molecular self-assembling form of three-dimensional architecture that has received particular research focus. Building multilayered ultralarge cages to simulate complicated virus capsids is believed to be a tough synthetic challenge. Here, we synthesize two large double-shell supramolecular cages by facile self-assembly of presynthesized metal-organic hexatopic terpyridine ligands with metal ions. Differing from the mixture of prisms formed from the inner tritopic ligand, the redesigned metal-organic hexatopic ligands bearing high geometric constraints that led to the exclusive formation of discrete double-shell structures. These two unique nested cages are composed of inner cubes (5.1 nm) and outer huge truncated cubes (12.0 and 13.2 nm) with six large bowl-shape subcages distributed on six faces. The results with molecular weights of 75 232 and 77 667 Da were among the largest synthetic cage-in-cage supramolecules reported to date. The composition, size and shape were unambiguously characterized by a combination of 1H NMR, DOSY, ESI-MS, TWIM-MS, TEM, AFM, and SAXS. This work provides an interesting model for functional recognition, delivery, and detection of various guest molecules in the field of supramolecular materials.

Complementary complexation between 2,2&prime, 6&prime, 2&Prime, terpyridine (tpy) and 6,6&Prime, dianthracenyl-substituted tpy in the presence of Zn(II) ions provided an efficient strategy for construction of metallo-supramolecular diblock copolymers. To synthesize well-defined tpy-modified polystyrenes (PSs), an Fe(II) bis(tpy) complex bearing &alpha, bromoester as a metallo-initiator was applied to atom transfer radical polymerization (ATRP) to avoid poisoning the Cu(I) catalyst. Subsequently, a series of tpy-functionalized PSs was obtained after the decomplexation of &lt, tpy-Fe(II)-tpy&gt, junction by tetrakis(triethylammonium) ethylenediaminetetraacetate (TEA-EDTA) under mild conditions. The metallo-supramolecular poly(3-hexylthiophene) (P3HT)-block-PS diblock copolymers were prepared by simply mixing the corresponding terminally tpy-modified homopolymers with Zn(II) ions, and further characterized by 1H NMR and diffusion ordered spectroscopy (DOSY) experiments. The approach using metallo-initiators for ATRP offers an opportunity to construct tpy-functionalized polymers with controllable molecular weights and low polydispersities. Through the spontaneous heteroleptic complexation, a variety of metallo-supramolecular diblock copolymers with tunable block ratios can be easily constructed.

Based on the predesigned self-selective complexation, metallo-supramolecular P3HT-b-PEO diblock copolymers with varying block ratios were synthesized, and their oriented polymer films generated during solvent evaporation in a 9 T magnetic field were investigated. An anisotropic, ordered layer structure was achieved using [P3HT20 -Zn-PEO107 ] and carefully characterized by polarized optical microscopy (POM), AFM, polarized UV/Vis spectroscopy, and GI-SAXS/WAXS. The PEO-removed [P3HT20 -Zn-PEO107 ] film was obtained after decomplexation with TEA-EDTA under mild conditions, and the selective removal of PEO domains was evidenced by UV/Vis and ATR-FTIR spectroscopy. Anisotropic photoconductivity of the magnetically aligned film was evaluated by flash-photolysis time-resolved microwave conductivity (FP-TRMC) measurements. The results indicated that the presence of insulating crystalline PEO segments diminished the photoconductivity along the P3HT backbone direction.

Supramolecular cages/vesicles in biology display sophisticated structures and functions by utilizing a few types of protein subunit quasi-equivalently at distinct geometrical locations. However, synthetic supramolecular cages still lack comparable complexity to reach the high levels of functionality found in natural systems. Herein we report the self-assembly of giant pentagonal supramolecular prisms (molecular weight >50 kDa) with tetratopic pyridinyl subunits serving different geometrical roles within the structures, and their packing into a novel superstructure with unexpected three-fold rotational symmetry in a single two-dimensional layer of crystalline state. The formation of these complicated structures is controlled by both the predetermined angles of the ligands and the mismatched structural tensions created from the multi-layered geometry of the building blocks. Such a self-assembly strategy is extensively used by viruses to increase the volume and complexity of capsids and would provide a new approach to construct highly sophisticated supramolecular architectures.

We report here that energy migration during luminescence can be extremely minimized by caging the fluorescent centers in a molecular cluster of [Tb6(μ3-F)8(piv)10(Hpiv)4DMF]·xDMF·yH2O 1. Experimental and theoretical simulations reveal that bonding terbium with fluoride is the key to reducing the non-radiative multi-phonon relaxation processes, which is disparate to the common hydroxy-based lanthanide clusters.

‘Aniono’ double helicates and grids were constructed using PO43– anions and a bis–tris(urea) ligand and interconverted by changing the counter-cation., Supramolecular assembly of well-defined discrete architectures has been of great interest due to the tunable properties of these structures in functional materials and bio-mimicking. While metal-coordination-driven assembly has been extensively studied, anion-coordination-driven assembly (ACDA) is just emerging for constructing complex supramolecular structures. Herein two A2nL2n (A = anion, L = ligand; n = 1 or 2) ‘aniono’-supramolecular assemblies, i.e. double helicates and the first anion grid, have been constructed based on the coordination between phosphate (PO43–) anion and a bis–tris(urea) ligand. Moreover, the aniono-grid and double helicate motifs can be readily interconverted under ambient conditions by simply changing the counter-cation. These results redefine the power and scope of ACDA, which may represent a new approach in the assembly of well-defined architectures in parallel with the metal coordination-driven assembly of metallo-supramolecules.

Tetrafunctionalized calix[4]resorcinarene cavitands commonly serve as supramolecular scaffolds for construction of coordination-driven self-assembled capsules. However, due to the calix-like shape, the structural diversity of assemblies is mostly restricted to dimeric and hexameric capsules. Previously, we reported a spontaneous heteroleptic complexation strategy based on a pair of self-recognizable terpyridine-based ligands and CdII ions. Building on this complementary ligand pairing system, herein three types of nanocapsules, including a dimeric capsule, a Sierpinski triangular prism, and a cubic star, could be readily obtained through dynamic complexation reactions between a tetratopic cavitand-based ligand and various multitopic counterparts in the presence of CdII ions. The dimeric capsular assemblies display the spacer-length-dependent self-sorting behavior in a four-component system. Moreover, the precise multicomponent self-assembly of a Sierpinski triangular prism and a cubic star possessing three and six cavitand-based motifs, respectively, demonstrates that such self-assembly methodology is able to efficiently enhance architectural complexity for calix[4]resorcinarene-containing metallo-supramolecules.

An anion-coordination-based A(4)L(6) ("A" denotes anion and "L" is ligand) tetrahedral cage was constructed by a C-2-symmetric bis-bis(urea) ligand and phosphate anion, which showed reversible interconversion with the A(2)L(3) triple helicate as a response to the template, concentration, or solvent. Notably, an unusual "peripheral" templation was found to be critical to stabilize the tetrahedral structure. This peripheral effect was utilized to assemble an "empty" A(4)L(6) cage that allows the multi-stimuli-controlled capture/release of biologically important species such as choline and acetylcholine.

A series of stellated metallosupramolecular architectures have been assembled through three-component integrative self-sorting. Building on the complementary ligand pairing, the initial attempts to synthesize the hexagram complex from a combination of X-shaped

Three heterobimetallic metallomacrocycles were readily assembled through either a stepwise or a one-pot protocol by selective complexation of ZnII ions and PdII or PtII acceptors with the predesigned ligands possessing one 60°-bent bisterpyridine and two mono- or bis-pyridines. In the multicomponent self-assembly, the preorganized ZnII-terpyridine metallo-triangle led to the formation of the exterior macrocycles.

Predesigned complementary complexation of two 2,2':6',2″-terpyridine-based ligands was established by installing 2,6-dimethoxyphenyl substituents at the terpyridyl 6,6″-positions, which provided ancillary ion-dipole interactions in the coordination process and extra π-stacking stabilization in the resultant heteroleptic complex. The high-fidelity self-recognition ligation afforded facile access to the quantitative self-assembly of multicomponent triangle [Cd6L(3)3L(4)3] and ditrigon [Cd15L(3)6L(5)3] (that is, a hexagon with six 120° angles and two alternating edge lengths). It was found that the linear 6,6″-substituted ditopic motif (L(3)) would be directed by the ligand geometry of L(5) to selectively incorporate into the parallel homoleptic connections in the bilayered framework.

The amalgamation of different components into a giant and intricate structure that makes quantitative and spontaneous assembly through molecular design is indispensable but challenging. To construct novel metallo-supramolecular architectures, here we present an architectural design principle based on multicomponent self-assembly. Using a carefully designed hexatopic terpyridine-based metallo-organic ligand (MOL), [Ru2T2K], we report on the formation of supramolecular trapezoid Zn5[Ru2T2K]V2, hollow hexagon Zn15[Ru2T2K]3K3, and giant star-shaped supramolecule Zn18[Ru2T2K]3[Ru2X2V]3, all of which were assembled by one-pot, nearly quantitative assembly of [Ru2T2K] with the ditopic 60°-directed bisterpyridine V, tetrakisterpyridine K, and MOL [Ru2X2V], respectively. The complementary ligands were selected on the basis of the size- and shape-fit principles, actually similar to the mortise–tenon joint that aligns and locks the two complementary wood components. This strategy is expected to open the door to soph...

Spontaneous formation of the heteroleptic cadmium(II) bis(terpyridine) complex under ambient conditions can be achieved by a combination of 6,6''-di(2,6-dimethoxylphenyl)-substituted and unsubstituted terpyridine-based ligands. Building on this dynamic heteroleptic complexation, diverse metallo-supramolecular macrocycles and cages were readily assembled in quantitative yields from the predesigned multicomponent systems. The complementary ligation reinforced self-recognition to facilitate the shape-dependent self-sorting of a four-component dynamic library into two well-defined parallelograms. In addition, the subtle lability difference between homoleptic and heteroleptic complexes led to the site-selective CdII -ZnII transmetalation in the Sierpinski triangle. Facile construction of a dodecanuclear tetrahedral metallocage was also realized by using two self-recognizable tritopic building blocks. The photophysical study of the metallo-supramolecules assembled from the d10 metal ions revealed intense ligand-based photoluminescence in solution. The self-assembly strategy described here provides an efficient methodology for building pre-programmable, sophisticated supramolecular architectures furnished with photoactivity.

A series of metallo-supramolecular ring-in-ring structures was generated by assembling Cd(II) ions and the multivalent terpyridine ligands (L(1-3)) composed of one 60°-bent and two 120°-bent bis(terpyridine)s with varying alkyl linker lengths. The mechanistic study for the self-assembly process excluded an entropically templated pathway and showed that the intramolecularly complexed species is the key intermediate leading to ring-in-ring formation. The next-generation superstructure, a spiderweb, was produced in quantitative yield using the elongated decakis(terpyridine) ligand (L(5)).

The combination of conventional transition-metal-catalyzed coupling (2 e- process) and photoredox catalysis (1 e- process) has emerged as a powerful approach to catalyze difficult cross-coupling reactions under mild reaction conditions. Reported is a palladium carbodicarbene (CDC) complex that mediates both a Suzuki-Miyaura coupling and photoredox catalysis for C-N bond formation upon visible-light irradiation. These two catalytic pathways can be combined to promote both conventional transition-metal-catalyzed coupling and photoredox catalysis to mediate C-H arylation under ambient conditions with a single catalyst in an efficient one-pot process.

Self-assembly of a metallo-organic ligand, composed of an inner uncomplexed 120°-bis(terpyridine) and an outer extended free 120°-bis(terpyridine) linked with a triple connector, with Zn2+, gave rise to a discrete planar supramolecular honeycomb patterned fractal. The central metallo-hexagon was surrounded by six identical metallo-hexagons which perfectly mimicked the natural simplest honeycomb structure.

Complementary coordination of two predesigned 2,2′:6′,2″-terpyridine-based ligands to a ZnII ion led to the exclusive formation of a heteroleptic bis(terpyridine) complex under ambient conditions. This highly self-selective process was facilitated by 9-anthracenyl substituents at the 6,6″-positions of a terpyridine, which not only decelerated the formation rate of its homoleptic complex, but also provided π-stacking stabilization in the heteroleptic complex. Facile construction of metallo-supramolecular poly(3-hexylthiophene) (P3HT)-block-poly(ethylene oxide) (PEO) diblock copolymers was realized using the complementary ligand pair. The morphological studies of the amphiphilic block copolymers in solution were conducted by atomic force microscopy and transmission electron microscopy, indicating that the self-assembled core–shell morphology such as spherical and fibrillar nanostructures could be controlled by adjusting the rod–coil block ratios. The heteroleptic complexes residing at the junction between t...

How to orient polymers homeotropically in thin films has been a long-standing issue in polymer science because polymers intrinsically prefer to lie down. Here we provide a design principle for polymers that are processable into a 2D homeotropic order. The key to this achievement was a recognition that cylindrical polymers can be designed to possess oppositely directed local dipoles in their cross-section, which possibly force polymers to tightly connect bilaterally, affording a 2D rectangular assembly. With a physical assistance of the surface grooves on Teflon sheets that sandwich polymer samples, homeotropic ordering is likely nucleated and gradually propagates upon hot-pressing towards the interior of the film. Consequently, the 2D rectangular lattice is constructed such that its b axis (side chains) aligns along the surface grooves, while its c axis (polymer backbone) aligns homeotropically on a Teflon sheet. This finding paves the way to molecularly engineered 2D polymers with anomalous functions., Vertical alignment of polymers on surfaces is challenging due to their flexibility and tendency to arrange on horizontal planes. Here, the authors report a design principle allowing polymers to be arranged into 2D homeotropic orientations by using long-range dipole-dipole interactions and hot-pressing on Teflon sheets.

Two hexanuclear metalloprisms possessing three dibenzo[24]crown-8 units were generated in quantitative yields by complexation of the predesigned tetratopic 2,2′:6′,2′′-terpyridine ligand (T) with CdII and ZnII ions, respectively. The prismatic hosts were subsequently self-assembled with the trifunctional guest molecule (TriG) containing dibenzylammonium ions to afford the corresponding metallo-supramolecular pseudo-suit[3]anes. It was serendipitously found that the host–guest inclusion rates could be modulated by the subtle dynamic difference in metal–ligand frameworks, finally leading to a selective encapsulation event in the presence of both metallo-suits.

New metallomacrocycles composed of 2,2':6',2″-terpyridine (tpy) ligands and Ru(II) or Fe(II) transition metal ions were prepared by stepwise directed assembly and characterized by 2D diffusion NMR spectroscopy (DOSY), electrospray ionization traveling wave ion mobility mass spectrometry (ESI TWIM MS), and molecular modeling. The supramolecular polymers synthesized include a homonuclear all-Ru hexamer as well as heteronuclear hexamer and nonamer with alternating Ru/Ru/Fe metal centers. ESI MS yields several charge states from each supramacromolecule. If ESI is interfaced with TWIM MS, overlapping charge states and the isomeric components of an individual charge state are separated based on their unique drift times through the TWIM region. From experimentally measured drift times, collision cross-sections can be deduced. The collision cross-sections obtained for the synthesized supramacromolecules are in good agreement with those predicted by molecular modeling for macrocyclic structures. Similarly, the hydrodynamic radii of the synthesized complexes derived from 2D DOSY NMR experiments agree excellently with the radii calculated for macrocyclic architectures, confirming the ESI TWIM MS finding. ESI TWIM MS and 2D DOSY NMR spectroscopy provide an alternative approach for the structural analysis of supramolecules that are difficult or impossible to crystallize, such as the large macrocyclic assemblies investigated. ESI TWIM MS will be particularly valuable for the characterization of supramolecular assemblies not available in the quantity or purity required for NMR studies.

Construction of supramolecular architectures employing the self-assembly of predesigned building blocks has drawn considerable attention in the past decades. Based on the combinatorial library proposed by Lehn, self-assembling constructs are often an equilibrium distribution of possible assemblies possessing comparable stabilities. Assemblies with similar components resulting in an equilibrating mixture of binary or multiple entities have been reported. Under appropriate conditions, the thermodynamically most stable species can be obtained in quantitative yield. Based on these tenants, many successful strategies have been developed for the synthesis of metallocycles with triangular, rectangular, pentagonal, and hexagonal shapes. In contrast, few examples of larger polygonal structures are documented. Towards larger finite architectures, subtle variation of building blocks could result in a dramatic change to the final products. In the self-assembly of bis(terpyridine) ligands possessing a 1208 angle between two ligating moieties, only hexameric metallomacrocycles were previously reported due to the difficulty of separation and characterization. More recently, Newkome et al. successfully isolated unexpected pentameric and heptameric macrocycles from the Fe-mediated complexation of rigid bis(terpyridine) ligands. Herein, we employ kinetically stable (in which tpy=2,2’:6’,2’’-terpyridine, M=Fe and Ru) connectivity to afford a series of homoand heteronuclear metallomacrocycles by means of stepwise assembly procedures. By using metals that form strong coordinative bonds (Fe and Ru), the self-assembly process becomes kinetically controlled and irreversible, thus allowing for the formation of macrocycles other than the thermodynamically most stable hexameric ring. Further, the use of elongated bis(terpyridine) dimers as precursors introduces steric constraints and increased rotational freedom, which obstruct the formation of small metallocycles, while facilitating the construction of novel, large metallocycles that would be difficult to realize otherwise. Traveling-wave ion-mobility mass spectrometry (TWIM-MS) and molecular modeling provide unique insight into the distinct ring sizes formed and their conformational flexibility. Reaction (Scheme 1a) of 3,5-bis(4’-terpyridinyl)anisole (1) with 1.05 equivalents of FeCl2·4H2O in a mixed solvent of MeOH/CHCl3 at reflux for 18 h gave the pentamer (2 ; 6%), hexamer (3 ; 15%), and heptamer (4 ; 3%), which were isolated by column chromatography (SiO2) eluting with H2O/ MeCN/sat.-KNO3(aq) (1:12.5:1; v/v/v). Subsequently, the counterions were exchanged from NO3 to PF6 by adding a slight excess of methanolic NH4PF6 (1m). The H NMR spectrum (Figure S1a in the Supporting Information) of pentamer 2 displayed four sharp singlets at d=9.41 (3’,5’-tpyH), 8.61 (4-ArH), 8.16 (2,6-ArH) and 4.34 ppm (OCH3), supporting the presence of a single homogeneous environment for complexed bis(terpyridine) ligands, in contrast to linear oligomers that have more complicated patterns. Other supportive data included an expected upfield shift in the H NMR spectrum for the 6,6’’-tpyH protons (d=7.27 ppm, Dd= 1.48 ppm) relative to the corresponding peaks of ligand 1 and one sharp peak in the C NMR spectrum at d=57.3 ppm (OCH3). Its structure was further confirmed by the intense ESI-MS peaks (Figure S2a in the Supporting Information) at m/z 1382.7, 1000.4, 771.3, 618.6, 509.5, and 427.7, corresponding to [M nPF6] ions (n=3–8), respectively. The H NMR spectra of macrocycles 3 and 4 revealed similar patterns, but all aromatic peaks exhibited a slight downfield shift relative to the corresponding peaks in 2, presumably due to conformational changes in the larger rings. The 4-ArH signal in pentamer 2 showed a significant upfield shift (Dd= 0.13 ppm) in comparison with hexamer 3, owing to the shielding by the adjacent pyridines in the more crowded inner space (Figure S1b in the Supporting Information). A similar phenomenon was observed in our previous work. Heptamer 4 has more conformational flexibility, minimizing this shielding effect; its 4-ArH signal was shifted further downfield (Figure S1c in the Supporting Information). Macrocycles 3 (MW=5498.5 Da) and 4 (MW= 6414.9 Da) were further verified by their ESI mass spectra (Figure S2b and S2c in the Supporting Information). Hexamer 3 gave rise to eight major peaks at m/z 1229.7, 954.7, [a] Dr. Y.-T. Chan, Dr. X. Li, Dr. C. N. Moorefield, Prof. Dr. C. Wesdemiotis, Prof. Dr. G. R. Newkome Department of Polymer Science, Department of Chemistry The University of Akron, 170 University Circle-RM501B Akron, OH 44325-4717 (USA) Fax: (+1)330-972-2368 E-mail : newkome@uakron.edu wesdemiotis@uakron.edu Homepage: http://www.dendrimers.com [] Drs. Chan and Li contributed equally to this work. Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201100559.

Since the advent of nanotechnology, a primary challenge has been to assemble materials from predesigned building blocks for the fabrication of nanometer-sized materials. Metal nanocrystals (NCs) have attracted significant attention due to their unique shape and size, as well as their tuneable electrical, optical and catalytic properties. A bottomup approach has generally been used for constructing the desired multi-unit composites from individual components. Although extensive studies have been performed on spherically shaped NCs, research on anisotropic nanoparticles, for example, nanorods (NRs) with a distinct 1D or linear structure, is limited. Since the properties of NCs are mostly sizeand shape-dependent, NRs have the potential to show novel as well as improved properties, such as in surface-enhanced Raman scattering (SERS) effects or optical and fluorescent properties, when compared to isotropic nanospheres (NSs). c,3] Geometrically, the aspect ratio (the length of major axis divided by the width of minor axis) of NRs is >1 and their cofacial assembly produces more angularly complex structures than that of the NSs. Side-to-side assemblies of NRs have been achieved by introducing active sites on the sides of the rods and subsequently connecting via DNA, electrostatic interaction, and more recently with click chemistry; however, arrangement of NRs in an endto-end orientation, for example, forming chains or branched structures, requires a regiospecific functionalization. Toward this goal, the tips of NRs have been modified with different metals, which were subsequently termed nanodumbbells, for participation in direct end-to-end assembly. It is well-known that Au NRs have different crystallographic facets, which comprise the ends and side surfaces. Recently, it was found that these side facets have a higher surface energy, and in turn, adsorb more bilayer surfactant, for example, cetyltrimethylammonium bromide (CTAB); notably, the yield of these surface-modified nanorods has been shown to be supplier (CTAB) dependent. Current progress on direct end-to-end Au NR assembly has focused on using biocompatible connectors, a,w-dithiols, and synthetic polymers. As well, organometallic connections, such as bis(terpyridine)-transition metal complexes, are also of interest due to their potential to impart unique electrical, optical, and photovoltaic properties. For example, hybrid Au NCs and bis(terpyridine)–Ru complexes have been fabricated and shown to exhibit enhanced electrochemical properties. Herein, we report the first example of a bottom-up approach for the end-to-end linear and branched assembly of Au NRs into multicomponent structures using [(disulfide-modified terpyridine)2–M ] (M=Fe or Cd) interconnectors and their facile disassembly and reassembly. The synthesis of disulfide-modified monoterpyridine (SStpy) 2, the [(SS-tpy)2–M ] complexes 3 (M=Fe), and 4 (M= Cd) is shown in Scheme 1. In a typical Gabriel synthesis, 4’(4-hydroxyphenyl)-2,2’:6’2’’-terpyridine was treated with N-(3-bromopropyl)phthalimide to afford the intermediate protected amine, which was subsequently deprotected (H2NNH2·H2O) to give the amine-modified monoterpyridine 1. The structure was supported (H NMR) by signals for the new OCH2 (4.17 ppm) and CH2NH2 (3.20 ppm) moieties; a dominate peak (ESI-MS) at m/z 383.3 [M+H] further confirms the structure. Disulfide-modified monoterpyridine 2 [a] Y.-T. Chan, Prof. Dr. G. R. Newkome Departments of Polymer Science and Chemistry The University of Akron, Akron, OH 44325-4717 (USA) Fax: (+1)330-972-2413 E-mail : newkome@uakron.edu [b] Dr. S. Li Excel Polymers, 14330 Kinsman Rd. Burton, OH 44325 (USA) [c] Dr. C. N. Moorefield Maurice Morton Institute for Polymer Science The University of Akron, Akron, OH 44325 (USA) [d] Dr. P. Wang ChemNano Materials, 2220 High St. Suite 605 Cuyahoga Falls, OH 44221 (USA) [e] Prof. Dr. C. D. Shreiner Chemistry Department, Hiram College, P.O. Box 67 Hiram, OH 44234 (USA) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201000040.

Highly ordered mesoporous silicas with large accessible pores have been prepared by using pre-synthesized poly(ethylene oxide)- b -poly(methyl acrlyate) (EO n MA m ) diblock copolymers as templates. Via adjusting the chain length of EO versus that of MA, a series of silica mesostructures, including two-dimensional (2-D) hexagonal, 3-D bicontinuous ( Ia3d ), and body-centered cubic ( Im3m ) symmetries, were prepared with the use of tetraethyl-orthosilicate (TEOS) as the silica precursor under acidic conditions. The mesostructures of all materials were characterized by small-angle X-ray scattering and transmission electron microscopy measurements. N 2 adsorption–desorption isotherms reveal that the pore size ranges from 4 to 30 nm with a narrow pore-size distribution and its dimension is proportional to the chain length of MA units.

The synthesis, purification, structural analysis, and photophysical properties of a series of five-, six-, and seven-sided Fe II macrocycles and the corresponding hexameric Cd II macrocy- cle, all prepared by self-assembly of a 1208 bis(terpyridine) ligand modified with first- and second-generation 1!3 C-branched dendrons, are reported. All metallomacrocycles were fully charac- terized by 1 H and 13 C NMR spectrosco- py, traveling-wave ion-mobility mass spectrometry (TWIM MS), molecular modeling, UV/Vis absorption spectros- copy, photoluminescence, and cyclic voltammetry. A gradual increase of the collision cross sections of the Fe II met- allomacrocycles was observed with a successive increase of the number and molecular size of the ligands. The com- bination of ion-mobility mass spec- trometry and NMR techniques unveils structural features that agree well with calculations. Extinction coefficients and emission are significantly modulated by increasing the ring size and changing the metal ion center from Fe II to Cd II .

Self-assembly of specially designed building blocks has been widely employed in the construction of rigid supramolecular structures. Towards this goal, many successful strategies have been developed for the synthesis of metallomacrocycles, such as for trigonal, rectangular, hexagonal, heptagonal, and octagonal structures. In contrast, only a limited number of pentagonal shapes have been reported in the literature. Accordingly, building blocks require a suitable angle to generate five-sided motifs. For example, a carbazole unit that introduced a 1058 angle between two terpyridine ligands was readily self-assembled to give metallopentacycles. Tetragonal and trigonal metallomacrocycles formed by 608 juxtaposed bis(terpyridine) ligands possessing bendable alkyne spacers have been documented. However, the formation of unexpected products by using rigid linkers is rare. Herein, we report the isolation and characterization of a unique pentameric macrocycle, along with its anticipated hexameric homologue, generated from an Fe-mediated complexation of functionalized bis(terpyridine) ligands with a 1208 angle relative to the coordination sites. Reaction of 1 (Scheme 1) with 1.05 equivalents of FeCl2·4H2O in MeOH at 25 8C for 24 h gave the pentamer [Fe5(1)5 ACHTUNGTRENNUNG(NO3)10] (2a ; 4.3%) and the hexamer [Fe6(1)6ACHTUNGTRENNUNG(NO3)12] (2b ; 11.9%), which were isolated by gradient column chromatography eluting with H2O/MeCN/sat. KNO3(aq) (from 1:20:1 to 1:15:1; v/v/v). The H NMR spectrum of pentamer 2a revealed sharp singlets at 8.22 and 8.75 ppm for 2,6-ArHs and 4-ArH respectively, supporting the presence of the symmetric macrocycle, in contrast to linear oligomers that exhibit more complicated patterns. Other supportive data (H NMR spectroscopy) included an expected upfield shift for 6,6’’-tpyHs (d= 7.41 ppm, Dd= 1.34 ppm) and a downfield shift for 3’,5’tpyHs (d=9.65 ppm, Dd=+0.86 ppm) relative to the corresponding peaks in the uncomplexed ligand 1 (Figure 1). The H NMR spectrum of hexamer 2b exhibited a similar pattern, but the peaks of terpyridine part showed a slight downfield shift relative to the corresponding peaks in 2a presumably due to the additional metal centers in 2b resulting in added electron deficiency. In comparison with 2b, notably the 4-ArH peak of 2a has an upfield shift (Dd= 0.2 ppm) due to the enhanced crowded inner space. This proved to be a key discernable feature in recognizing, isolating and characterizing the otherwise remarkably similar fiveand sixmembered ring structures. The 2D COSY NMR spectra of the bis(terpyridine) ligand 1 and the self-assembled macrocycle 2a also ensured the proper assignments. Notably, at [a] Y.-T. Chan, Dr. M. Soler, Prof. G. R. Newkome Departments of Polymer Science and Chemistry The University of Akron, Akron, OH 44325-4717 (USA) Fax: (+1)330-972-2413 E-mail : newkome@uakron.edu [b] Dr. C. N. Moorefield, Prof. G. R. Newkome Maurice Morton Institute for Polymer Science The University of Akron, Akron, OH 44325 (USA) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.200902988. Scheme 1. Unexpected and predetermined products 2a and 2b obtained by self-assembly of 1. a) FeCl2·4H2O, MeOH, 25 8C, 24 h (each Fe II macrocycle isolated as the polyNO3 salt; see Experimental Section).

Self-assembly of 1,3-di(4′-terpyridinyl)arenes by using the labile tpy-Cd(II)-tpy (where tpy = 2,2′:6′,2′′-terpyridine) connectivity afforded access to hexacadmium macrocycles in high yield. These supramolecular assemblies were characterized by traveling wave ion mobility mass spectrometry (TWIM-MS).

Poly(ethylene oxide)-b-poly(methyl acrylate) diblock copolymer (EOmMAn) prepared via an atom transfer radical polymerization (ATRP) approach was used as a template to synthesize Ia3d mesostructured silica with thick walls under acidic conditions.

Self-assembly of novel linear and branched carbohydrate-functionalized mono- and di(2,2':6',2''-terpyridinyl)arenes afforded access to a series of twisted self-organized nanofibers.