This overview represents a comprehensive summary of the recent developments in the growing field of terpyridine-based, discrete metallosupramolecular architectures. The N-heteroaromatic ligand [2,2':6',2'']terpyridine (tpy) presents a convergent N,N',N''-chelating donor set and has the ability to bind diverse metal ions to form stable pseudo-octahedral tpy-M2+-tpy bonds. Use of tpy-M2+-tpy connectivity for the edges and directed organic vertices has opened the door to diverse, dynamic, utilitarian macromolecular materials. New strategies have been employed to synthesize a range of 2D- and 3D-fractals as well as novel macrocyclic constructs by employing new designer strategies, such as: triangle-based frameworks, hexagonal fractal designs, flexible polyterpyridine linkers, and noncovalent interactions for spontaneous quantitative self-assembly. Numerous examples of heteroleptic self-assembly have been described along with the synthesis of heterometallic conjugates using step-wise protocols. Utilizing multiplanar, directed spacer units in the polyterpyridine vertices, new 3D-polyhedra were obtained facilitating the assembly of hybrid fractal-dendritic materials. These constructs are shown to undergo tunable conformational transformations by responding to specific stimuli such as concentration, temperature, and counter ions. The increasing ability to exploit hierarchical self-assembly of complex, higher order supramolecular nanomaterials is discussed.

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 connectivity to form the corresponding Ru-dimer. The complexation between Ru-dimer and Fe demonstrates an unexpected temperature-dependent assembly between two irreversible isomeric 3D nanocages. Investigation of the coordination process and structural configurations of the metal-ligand framework, affected by the introduction of rigidity and in the presence of external stimuli (temperature), is reported.

We report a facile synthesis of 2,6-diethynyltriptycene (DET) in high yield. Application of DET as monomer in polymer chemistry has been shown (for the first time) in syntheses of two novel polymers via Sonogashira cross-coupling reaction in high yield. The newly synthesized polymers were characterized by FT-IR, UV–vis absorption, and NMR spectroscopic techniques. The polymers prepared using DET have interesting properties such as high solubility in common organic solvents, high thermal stability [decomposition temperatures (T d) > 495 °C], and high char yield (greater than 81% at 900 °C). Additionally, polymers are fluorescent. Host–guest interaction between triptycene-based polymers and fullerene (C60) has been studied for the first time. Fluorescence quenching of our polymers by C60 has been used to study the extent of (polymer·C60) host–guest complex formation. Fluorescence quenching studies indicate binding constant for polymer·C60 complexation on the order of 105 M–1.

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Imidazole based amphiphilic ionic liquids (ILs) were used as surfactants in miniemulsion polymerization (MEP) of styrene using a free radical process as well as reversible addition−fragmentation chain transfer (RAFT). Monodisperse polystyrene (PS) nanoparticles were obtained, demonstrating the efficiency of the amphiphilic IL as surfactant in MEP. IL stabilized miniemulsion was furthermore used to prepare polystyrene based magnetic nanoparticles (MNP). A large increase of the possible MNP content associated with very good colloidal stability was achieved using IL stabilized RAFT mediated MEP where a carboxyl functionalized chain transfer agent (CTA) was applied, allowing interaction with the MNP surface. The molecular weight and dispersity index of polystyrene, the content of MNP, and the morphologies of the hybrid nanoparticles were controlled by proper optimization of the concentration of initiator and CTA. The materials have been analyzed by NMR, GPC, DLS, SEM, TEM, and TGA. Finally, the magnetic properties of the materials were determined by vibrating sample magnetometer (VSM) analysis. ■ INTRODUCTIONPolymer magnetic composite (PMC) nanoparticles have raised a great deal of interest due to their potential use in several biomedical applications like magnetic resonance imaging, 1 nucleic acid purification, 2 enzyme immobilization, 3 drug delivery, 4 etc. The magnetic nanomaterials in the colloidal range have been successfully utilized in both therapeutic 5 and diagnostic 6 applications. The major challenge so far was the selection of suitable materials based on their various properties like particle size distribution, colloidal stability, content of MNP, presence of functionality, and most importantly toxicity. In the recent years, focus has also been turned on the synthesis of asymmetric polymer superparamagnetic composites for use as potential materials for applications in multimodal probes and biosensors. 7,8 Besides the biomedical applications, there are several demands for PMC nanoparticles in the production of toner materials 9 and also for the support and easy separation of catalyst in chemical reactions. 10 The above facts necessitate a fruitful technique to produce PMC nanoparticles in dispersion or as solid materials. Several methods have been developed which include microfluidic-based synthesis, 11 selective surface modification, 12 and different kinds of heterogeneous polymerization. 13,14 Among all these methods, miniemulsion polymerization (MEP) has been proven to be one of the most effective methods to prepare such materials. Regarding the synthesis of PMC nanoparticles using MEP, most of the work in the literature has proposed a single-step MEP process although no more than 20 wt % of MNP with respect to the polymer could be encapsulated. Landfester et al. 15 reported a strategy of multistep miniemulsion to encapsulate up to 40% MNP within the PS particles. Irrespective of the number of steps used for a successful encapsulation using MEP, several other parameters like nature of initiator, concen...

The self‐assembly of platinum complexes is a well‐documented process that leads to interesting changes of the photophysical and electrochemical behavior as well as to a change in reactivity of the complexes. However, it is still not clear how many metal units must interact in order to achieve the desired properties of a large assembly. This work aimed to clarify the role of the number of interacting PtII units leading to an enhancement of the spectroscopic properties and how to address inter‐ versus intramolecular processes. Therefore, a series of neutral multinuclear PtII complexes were synthesized and characterized, and their photophysical properties at different concentration were studied. Going from the monomer to dimers, the growth of a new emission band and the enhancement of the emission properties were observed. Upon increasing the platinum units up to three, the monomeric blue emission could not be detected anymore and a concentration independent bright‐yellow/orange emission, due to the establishment of intramolecular metallophilic interactions, was observed.

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.

The design, synthesis, and characterization of a new pyrazine-based ditopic platinum(II) organometallic complex are reported. The molecular structure of the organoplatinum pyrazine dipod was determined by single-crystal X-ray crystallography. The potential utility of this organometallic ditopic acceptor as a building block in the construction of neutral metallasupramolecular macrocycles containing the pyrazine motif was explored. Pyrazine motifs containing supramolecules were characterized by multinuclear NMR (including (1)H DOSY), mass spectrometry, and elemental analysis. The geometry of each supramolecular framework was optimized by employing the PM6 semiempirical molecular orbital method to predict its shape and size. The ability of the pyrazine-based organoplatinum complex to act as a host for nitroaromatic guest (2,4-dinitrotoluene and PA) molecules was explored by isothermal titration calorimetry (ITC). The binding stoichiometry and thermodynamic parameters of these host-guest complexation reactions were evaluated using ITC. Theoretical calculations were performed to obtain insight into the binding pattern between the organometallic host and nitroaromatic guests. The preferable binding propensity of the binding sites of complex 1 for both nitroaromatics (PA and 2,4-dinitrotoluene) determined by molecular simulation studies corroborates well with the experimental results as obtained by ITC experiments.