Results 21 to 30 of about 165 (92)
Transition‐Metal Catalyzed, Thermally Driven [2π+2π]‐Cycloadditions of Olefins and Alkynes
European Journal of Organic Chemistry, Volume 28, Issue 13, April 1, 2025.Thermally‐driven, transition‐metal‐catalyzed [2+2]‐cycloadditions provide a scalable and atom‐efficient strategy for synthesizing cyclobutane and cyclobutene frameworks. Complementary to established photochemical methods, they tolerate electronically unbiased substrates, thereby broadening synthetic possibilities for these valuable building blocks and ...
Leif E. Hertwig +2 more
wiley +1 more source
Hydrogenation at low temperatures does not always lead to saturation: the case of HNCO [PDF]
A&A 576, A91 (2015), 2015 Context. It is generally agreed that hydrogenation reactions dominate chemistry on grain surfaces in cold, dense molecular cores, saturating the molecules present in ice mantles. Aims. We present a study of the low temperature reactivity of solid phase isocyanic acid (HNCO) with hydrogen atoms, with the aim of elucidating its reaction network. Methods.
arxiv +1 more source
Improving the Photochemical Skeletal Enlargement of Pyridines to 1,2‐Diazepines with Isocyanates
Advanced Synthesis &Catalysis, Volume 367, Issue 5, March 4, 2025.Abstract In this work, we extend the one‐pot protocol to synthesize 1,2‐diazepines from commercially available and cheap starting materials. Capitalizing on isocyanate derivatives as activating agents, the photochemical skeletal enlargement occurs, while preserving key functional groups embedded in more than 30 substrates.
Clément Ghiazza +3 more
wiley +1 more source
Kinetics of aqueous media reactions via ab initio enhanced molecular dynamics: the case of urea decomposition [PDF]
J. Phys. Chem. B 123 (2019) 6851-6856, 2019 Aqueous solutions provide a medium for many important reactions in chemical synthesis, industrial processes, environmental chemistry, and biological functions. It is an accepted fact that aqueous solvents can be direct participants to the reaction process and not act only as simple passive dielectrics.
arxiv +1 more source
N‐Heterocyclic Carbenes and N‐Heterocycles as Synthetic Reagents and Building Blocks
Chemistry – A European Journal, Volume 31, Issue 12, February 25, 2025.N‐heterocyclic carbenes (NHCs) have widespread applications in synthesis as organocatalysts or ligands for organometallic complexes. This Mini‐review article focuses on an important but often neglected area of their chemistry, where NHCs and their N‐heterocyclic precursors or derivatives have been used as stoichiometric reagents or building blocks in ...
Emily Jacobs, Thanh Vinh Nguyen
wiley +1 more source
Angewandte Chemie, Volume 136, Issue 33, August 12, 2024.Well‐defined molecular transition metal complexes have been found to work as catalysts to convert N2 into NH3 under ambient reaction conditions, where involvement of both N2‐splitting pathway and proton‐coupled electron transfer has been effective for high catalytic activity. Direct electrocatalytic and photocatalytic NH3 formation, selective catalytic
Yoshiaki Tanabe, Yoshiaki Nishibayashi
wiley +2 more sources
European Journal of Inorganic Chemistry, Volume 27, Issue 36, December 20, 2024.Lithium tetrabutyl manganate can efficiently effect deprotonation of a variety of amines affording novel lithium amidomanganates(II). Structural identification of a family of amidomanganates 2–6 shows that the exact stoichiometry and constitution of lithium amidomanganates depends on the steric and electronic features of the amide ligand.
Rebecca S. Jones +2 more
wiley +1 more source
Nanostructured rigid polyurethane foams with improved specific thermo-mechanical properties using Bacterial Nanocellulose as a Hard Segment [PDF]
arXiv, 2020 Bacterial nanocellulose (BNC) was used to synthesize rigid polyurethane foams (RPUFs) based on its reaction with the isocyanate precursor (ISO route) and also by using the conventional procedure (POL route). The results indicated that at only 0.1 wt. % of BNC, drastic improvements of specific elastic compressive modulus (+244.2 %) and strength (+77.5 %)
arxiv
Molecules with a peptide link in protostellar shocks: a comprehensive study of L1157 [PDF]
, 2014 Interstellar molecules with a peptide link -NH-C(=O)-, like formamide (NH$_2$CHO), acetamide (NH$_2$COCH$_3$) and isocyanic acid (HNCO) are particularly interesting for their potential role in pre-biotic chemistry. We have studied their emission in the protostellar shock regions L1157-B1 and L1157-B2, with the IRAM 30m telescope, as part of the ASAI ...
arxiv +1 more source
Synthesis of New Silylated and N−Si−N bridged Urea Derivatives from Aminosilanes and Diisocyanates
Chemistry – An Asian Journal, Volume 19, Issue 23, December 2, 2024.Urea derivatives were obtained by insertion of diisocyanates into aminosilanes of the types Me3SiNRR′ and Me2Si(NRR′)2. Interesting differences in N‐Si connectivities are caused by steric and electronic effects of the reactants and migration of ‐SiMe3 and ‐(SiMe2)‐ moieties. Abstract Urea derivatives of the general motifs R1(N(SiMe3)C(O)NR2R3)2 and [R1(
Marlene K. Baumhardt +4 more
wiley +1 more source