Volodymyr Senkovskyy

Zr and Hf based MOFs with enhanced pore accessibility for large molecules and good hydrothermal stability were obtained using a bent dithienothiophene dicarboxylate and Zr⁴⁺ or Hf⁴⁺ source. A modulator (benzoic acid) facilitates formation of an eight-connecting cluster leading to a new framework which adopts reo topology.

Most of conjugated microporous polymers (CMPs) prepared to date are poorly processable, intractable solids. The immobilization of CMPs onto various surfaces is strongly desirable for many applications, such as for gas storage and separation, heterogeneous catalysis, and so forth. However, the preparation of thin porous films remains a challenging task. This Letter reports Ni-catalyzed surface-initiated Kumada catalyst-transfer polycondensation of a tetrafunctional thiophene-based (AB) 2-monomer from organosilica microparticles leading to microparticles covered by thin-film (∼30 nm) layers of the CMP. A sample of unbound CMP was also prepared by a bulk polymerization of the same monomer. Thus-obtained CMP possesses a relatively high specific surface area of 463 m² g^–1. The porosity of the immobilized polymer is somewhat lower with a specific surface area of 123 m² g^–1.

Strongly electron-deficient (n-type) main-chain π-conjugated polymers are commonly prepared via well-established step-growth polycondensation protocols which enable limited control over polymerization. Here we demonstrate that activated Zn and electron-deficient brominated thiophene-naphthalene diimide oligomers form anion-radical complexes instead of conventional Zn–organic derivatives. These highly unusual zinc complexes undergo Ni-catalyzed chain-growth polymerization leading to n-type conjugated polymers with controlled molecular weight, relatively narrow polydispersities, and specific end-functions.

A ‘grafting‐from’ approach to synthesize microparticle‐supported conjugated polyelectrolyte brushes is presented. Poly(3‐bromohexylthiophene) is selectively grown from monodisperse organosilica microparticles by surface‐initiated Kumada catalyst‐transfer polycondensation (SI‐KCTP) and then ionizable amino groups are introduced by a two‐step polymer analogous transformation. Optical properties of the resulting microparticle‐supported conjugated polyelectrolyte brushes were found to be dependent on the surrounding chemical environment and thus the particles are promising materials for sensor applications. magnified image

On-surface self-assembly of several types of microgels prepared via the precipitation polymerization of (N-isopropylacrylamide) (NIPAM) with N,N′-methylenebisacrylamide (MBA), acrylic acid or acrylamide as comonomers is investigated with the aim to establish the main factors that govern the formation of periodic loosely packed (PLP) two-dimensional arrays. A core–shell structure is detected for all microgels, with the thickest shells being observed for the microgels containing acrylic acid or acrylamide. The main factor driving the formation of PLP arrays and determining the microgel separation is found to be the presence of large low-density shells around the highly cross-linked cores of the microgels. This key observation of our experiments has been explained by the developed theoretical model that proves to adequately describe the experimental findings. The size of microgel dry-state “footprints” can be reduced by making use of plasma-etching. The periodic microgel arrays are used as masks for the preparation of patterns of reactive silanes with controllable separation between the patterned features. Sputtering of gold onto the periodic microgel arrays followed by washing out the microgels in ultrasonic bath is proven to be an efficient way of preparing perforated gold films with PLP holes.

Surface-initiated Kumada catalyst-transfer polycondensation of poly(9,9-dioctylfluorene) (PFO) was performed from organosilica microparticles that resulted in PFO brushes with densely grafted PFO chains with a significantly enhanced propensity to adopt planar and ordered conformations (β-phase).

Herein, we present a new paradigm in the engineering of nanostructured hybrids between conjugated polymer and inorganic materials via a chain-growth surface-initiated Kumada catalyst-transfer polycondensation (SI-KCTP) from particles. Poly(3-hexylthiophene), P3HT, a benchmark material for organic electronics, was selectively grown by SI-KCTP from (nano)particles bearing surface-immobilized Ni catalysts supported by bidentate phosphorus ligands, that resulted in hairy (nano)particles with end-tethered P3HT chains. Densely grafted P3HT chains exhibit strongly altered optical properties compared to the untethered counterparts (red shift and vibronic fine structure in absorption and fluorescence spectra), as a result of efficient planarization and chain-aggregation. These effects are observed in solvents that are normally recognized as good solvents for P3HT (e.g., tetrahydrofurane). We attribute this to strong interchain interactions within densely grafted P3HT chains, which can be tuned by changing the surface curvature (or size) of the supporting particle. The hairy P3HT nanoparticles were successfully applied in bulk heterojunction solar cells.