Narrow Results

The replacement of the H atom at the R−H⋯Nu synthon with a Group 14 element leads to a tetrel bond (TtB), which is a weak interaction between the electron density deficient side (the so-called σ or π hole) of a covalently bonded tetrel atom (Tt = C, Si, Ge, Sn or Pb) and a nucleophilic (Nu) region in the same (intramolecular) or another (intermolecular) molecular entity: R−Tt⋯Nu [R = Tt, Pn (pnictogen), Ch (chalcogen), metal, etc.; Nu = lone pair possessing Ha (halogen), Ch, Pn or metal atom, anion, π-system, radical, etc.]. Similarly to the hydrogen, halogen, chalcogen and pnictogen bonds as well as to π-interactions, the TtB is also of utmost importance for the development of new metal-complex catalysts, sensors, molecular switches, etc. For example, the activity and selectivity of enzymes or synthetic catalysts can be highly affected by the action of the secondary coordination sphere of a metal complex in reactions involving the carbon atom of a TtB. In this chapter, we discuss a few examples, taken from the Cambridge Structural Database, in which TtB aggregates tectons into high-dimensional supramolecular architectures.

The one-pot synthesis of copper, cesium-containing ordered mesoporous alumina via self-assembly of a copper precursor and aluminumisopropoxide in the presence of a triblock copolymer (as a structure directing agent) was investigated. The resulting copper, cesium-containing mesoporous alumina possessed relatively high BET surface area, well-developed mesoporosity, and a larger pore width. In comparison to pure alumina, copper, cesium-containing alumina samples exhibited higher BET surface area, larger mesopores, improved thermal stability and a larger quantity of acid sites. Also, long range ordering of the aforementioned samples was observed for cesium molar percentages as high as 20%. The generality of the strategy used for the synthesis of copper contained alumina was demonstrated by preparation of other metal containing alumina oxides. This method represents an important step towards the facile and reproducible synthesis of ordered mesoporous alumina which contains other elements for various applications where large and accessible pores with high loading of catalytically active metal oxides are needed.

In this paper, a new cationic type asphalt emulsifier of triethylenetetraamine/formaldehyde modified lignin amine was synthesized by the reaction of lignin, triethylenetetraamine, sodium hydroxide and formaldehyde. The synthesis process was determined through the online Fourier transform infrared spectroscopy (FTIR) technique and the intermediate was identified. The synthesized asphalt emulsifier exhibited excellent surface activity and satisfactory emulsification effect, with higher storage stability. This emulsifier belongs to the group of medium-set asphalt emulsifier and it is suitable for application in road pavement construction of chip seal and tack coat.

Using the ionic liquid (IL) [(HSO3-B)2IM]HSO4 as a eco-friendly catalyst, a variety of 3- arylbenzo[ƒ]quinoline-1,2-dicarboxylates and their dehydro derivatives were synthesized by the reaction of naphthyl-2-amine, aromatic aldehydes and dimethyl but-2-ynedioate in acetonitrile at reflux by One-Pot method. The structure of new compounds was characterized by melting point, FT-IR, 1H NMR, elemental analysis. The influence of different catalysts and catalysts loading were investigated, and then the optimal reaction condition was obtained. A possible mechanism was also proposed. Furthermore, the recycling experiment of the catalyst was conducted and the green catalytic system can be recycled for four times with tiny decreases in yields and reaction rates. The present methodology offers several advantages such as mild conditions, excellent yields, ecofriendly and recyclable catalyst.

A series of alternating donor–acceptor (D-A) conjugated copolymers PCO-PDI (P1), PCEH-PDI (P2),and PCD-PDI (P3) have been successfully designed and synthesized. Carbazole was used as the donor unit and perylene diimide was used as the acceptor unit. All the copolymers exhibited excellent solubility in common solvents. The decomposition temperatures of copolymers were around 365 °C (P1), 305 °C (P2), and 250 °C (P3) respectively in the air which was adequate for their applications in polymer solar cells (PSCs) and other optoelectronic devices. All the three copolymers showed broad absorption bands, giving optical band gaps of 1.63 e V (P1), 1.65 eV (P2) and 1.68 eV (P3) respectively which matched the value (1.5-1.7 eV) of the ideal polymers for PCE values exceeding 10%. In addition, the lowest occupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy levels of copolymers were -5.44 eV and -3.81 eV for P1, -5.47 eV and -3.82 eV for P2, -5.42 eV and -3.74 eV for P3 respectively. These great properties of copolymers could make them become alternative materials for PSCs applications.