Functional materials discovery using energy–structure–function maps

Molecular crystals cannot be designed in the same manner as macroscopic objects, because they do not assemble according to simple, intuitive rules. Their structures result from the balance of many weak interactions, rather than from the strong and predictable bonding patterns found in metal–organic frameworks and covalent organic frameworks. Hence, design strategies that assume a topology or other structural blueprint will often fail. Here we combine computational crystal structure prediction and property prediction to build energy–structure–function maps that describe the possible structures and properties that are available to a candidate molecule. Using these maps, we identify a highly porous solid, which has the lowest density reported for a molecular crystal so far. Both the structure of the crystal and its physical properties, such as methane storage capacity and guest-molecule selectivity, are predicted using the molecular structure as the only input. More generally, energy–structure–function maps could be used to guide the experimental discovery of materials with any target function that can be calculated from predicted crystal structures, such as electronic structure or mechanical properties

Nuevas cicloadiciones y procesos tándem intramoleculares de ceteniminas y carbodiimidas / Baltasar Bonillo Fernández; directores, Mateo Alajarín Cerón y Angel Vidal Gómez.

Texto en español, resumen en inglés.Tesis-Universidad de Murcia.Consulte la tesis en: BCA. GENERAL. ARCHIVO UNIVERSITARIO. TM 3934

Chain-Growth Polymerization of 2-Chlorothiophenes Promoted by Lewis Acids

Lewis acids promote the polymerization of several 2-chloroalkylenedioxythiophenes, providing high-molecular-weight conjugated polymers. The proposed mechanism is a cationic chain-growth polymerization, as confirmed by end-capping reactions and a linear correlation of molecular weight with percent conversion. The “living” character of this process was used to prepare new block copolymers.United States. Air Force Office of Scientific Research (FA9550-10-1-0395

Chain-Growth Polymerization of 2‑Chlorothiophenes Promoted by Lewis Acids

Lewis acids promote the polymerization of several 2-chloroalkylenedioxythiophenes, providing high-molecular-weight conjugated polymers. The proposed mechanism is a cationic chain-growth polymerization, as confirmed by end-capping reactions and a linear correlation of molecular weight with percent conversion. The “living” character of this process was used to prepare new block copolymers

Tuning Photophysical Properties in Conjugated Microporous Polymers by Comonomer Doping Strategies

The photophysical properties of conjugated microporous polymers (CMPs) are tuned using an acceptor doping strategy. This allows the fluorescence of a native polyphenylene network to be controlled by introducing low loadings (0.1-5 mol %) of an acceptor comonomer, such as benzothiadiazole (BT), bisthiophenebenzothiadiazole (TBT) and perylenediimide (PDI). Fluorescence quantum yields are around 10 times higher than analogous nonporous polymers because of avoidance of chain aggregation in the porous network. White emitting CMPs with high quantum yields are prepared using this approach. Different domain structures can be prepared by changing the addition sequence of the monomers, and this has a strong effect on the fluorescent properties. These doped porous polymers can also be used as fluorescence sensors for volatile organic compounds (VOCs)

Conjugated polymers of intrinsic microporosity (C-PIMs)

Conjugated microporous polymers (CMPs) have shown great potential for energy and environmental issues, however, poor solubility and processability of most of these materials limit their applications. Herein, a range of linear conjugated polymers of intrinsic microporosity (C-PIMs) is reported, combining for the first time the properties of conjugated microporous polymers, such as tunable electronic properties and compositional variation, with those of linear polymers of intrinsic microporosity (PIMs) allowing for solution processability and film formation. These soluble materials have a number of potential applications, for example as components in devices where large, porous interfaces are combined with extended electronic conjugation

Extended conjugated microporous polymers for photocatalytic hydrogen evolution from water

Conjugated microporous polymers (CMPs) have been used as photocatalysts for hydrogen production from water in the presence of a sacrificial electron donor. The relative importance of the linker geometry, the co-monomer linker length, and the degree of planarisation were studied with respect to the photocatalytic hydrogen evolution rate

Tunable Organic Photocatalysts for Visible-Light-Driven Hydrogen Evolution

Photocatalytic hydrogen production from water offers an abundant, clean fuel source, but it is challenging to produce photocatalysts that use the solar spectrum effectively. Many hydrogen-evolving photocatalysts are active in the ultraviolet range, but ultraviolet light accounts for only 3% of the energy available in the solar spectrum at ground level. Solid-state crystalline photocatalysts have light absorption profiles that are a discrete function of their crystalline phase and that are not always tunable. Here, we prepare a series of amorphous, microporous organic polymers with exquisite synthetic control over the optical gap in the range 1.94–2.95 eV. Specific monomer compositions give polymers that are robust and effective photocatalysts for the evolution of hydrogen from water in the presence of a sacrificial electron donor, without the apparent need for an added metal cocatalyst. Remarkably, unlike other organic systems, the best performing polymer is only photoactive under visible rather than ultraviolet irradiation