Zinc Powder Catalysed Formylation and Urealation of Amines Using CO 2 as a C1 Building Block †

Octanuclear Zinc Clusters in Microporous Organic Polymers: Network-Enhanced Reductive CO2 Fixation to Formamides at Room Temperature

A building block containing eight zincs and eight iodo groups (8 Zn) is obtained by the Zn complexation of a salen ligand bearing two additional hydroxy groups. Through the Sonogashira-Hagihara coupling of 8 Zn with 1,3,5,7-tetra(4-ethynylphenyl) adamantane, microporous organic polymers bearing octanuclear zinc clusters (MOP-8 Zn) are prepared, exhibiting a high surface area of 562 m2 g-1, microporosity, and a particulate morphology with an average diameter of 249 nm. The MOP-8 Zn exhibits significantly enhanced catalytic performance, compared to molecular counterparts, in the reductive carbon dioxide fixation to formamides, possibly due to the cooperative adsorption and confinement effect of networks on substrates.

Synthesis of Diverse Ureas from Amines and CO2 at Atmospheric Pressure and Room Temperature

A metal-free method is developed to perform the synthesis of urea derivatives utilizing CO2 as the C1 building block at atmospheric pressure and room temperature. In addition to diverse symmetric and dissymmetric ureas, benzimidazolones and quinazolinone can also be easily prepared using this protocol. Most importantly, the gram-scale preparation of fungicide pencycuron and antipsychotic drug pimavanserin proceeded smoothly under the mild conditions.

Study on vinyl crosslinking and related properties of silicon-containing arylacetylene resin synthesised by zinc powder catalysis

A matrix resin poly(silicon-containing arylacetylene vinyl)s (PSAV) containing vinyl at both branch and terminal chains underwent synthesis via the zinc powder catalytic method using m-diacetylene benzene and dichloromethylvinylsilane as raw materials. Vinyl in the PSAV resin was crosslinked by the free radical initiator dibenzoyl peroxide to obtain a crosslinked network structure resin (PSAV-L). This approach sought to improve the thermal properties and other related properties of the matrix resin. A series of tests, such as rotated rheometer, FTIR, DSC, TGA, Py-GC-MS and universal testing machine, characterised processing property, curing behaviour, thermal properties and mechanical properties. The rheological curve shows that PSAV-L resin has a wide processing window (40–134.5°C), endowing the resin with excellent processing performance. Thermal curing behaviour indicates that PSAV-L resin can start curing at a lower temperature, namely, 32°C earlier than PSAV resin. TGA analysis shows that the degradation temperature at 5% weight loss (Td5) of PSAV-L resin stands at 579.4°C, 45.4°C higher than that of PSAV resin due to the fact that the crosslinking of vinyl gives PSAV-L resin a network structure. The flexural strength, flexural modulus and ILSS of the quartz fibre cloth reinforced PSAV-L resin composite (QF/PSAV-L) are 184.68 MPa, 15.50 GPa and 12.40 MPa. The PSAV-L resin exhibits the comprehensive properties of good processing performance, low curing temperature, excellent thermal performance and high mechanical properties.

N-Acylbenzotriazoles as Proficient Substrates for an Easy Access to Ureas, Acylureas, Carbamates, and Thiocarbamates via Curtius Rearrangement Using Diphenylphosphoryl Azide (DPPA) as Azide Donor

A diverse range of ureas, N-acylureas, carbamates, and thiocarbamates has been synthesized in good to excellent yields by reacting N-acylbenzotriazoles individually with amines or amides or phenols or thiols in the presence of diphenylphosphoryl azide (DPPA) as a suitable azide donor in anhydrous toluene at 110 °C for 3–4 hours. In this route, DPPA was found to be a good alternative to trimethylsilyl azide and sodium azide for the azide donor in Curtius degradation. The high reaction yields, one-pot and metal-free conditions, straightforward nature, easy handling, use of readily available reagents, and in many cases avoidance of column chromatography are the notable features of the devised protocol.