10.1021/acs.orglett.8b03386
Agnieszka Mlynarska-Cieslak et al. discusses the chemical synthesis of nicotinamide adenine dinucleotide (NAD) cap analogues designed to be less susceptible to NAD-RNA degrading enzymes. The study aims to enhance the stability of NAD-capped RNAs for further biological studies. The authors synthesized a set of NAD analogues with modifications such as O-to-S substitutions at the pyrophosphate moiety and phosphorothioate/phosphorothiolate modifications. These analogues were incorporated into RNA transcripts using in vitro transcription with T7 polymerase. The modified RNAs were then tested for their susceptibility to deNADding enzymes like DXO, NudC, and Nudt12. The results identified several analogues that showed resistance to these enzymes, particularly compounds with combined modifications like a-PS and 2'-O-methylation.
10.1016/j.poly.2009.06.056
The research investigates the formation of supramolecular dimers in copper(II) complexes through hydrogen bonding and their impact on magnetic properties. The study focuses on three copper(II) complexes: [Cu(3-O2Nbz)2(nia)(H2O)2] (1), [Cu(4O2Nbz)2(nia)2(H2O)2] (2), and [Cu(4-O2Nbz)2(nia)2]?(4-O2NbzH)2 (3), where 3-O2Nbz and 4-O2Nbz represent 3-nitrobenzoate and 4-nitrobenzoate anions, respectively, and nia represents nicotinamide. These chemicals play crucial roles in the formation of the complexes. The research involves the synthesis of these complexes using copper(II) acetate, nicotinamide, and either 3-nitrobenzoic acid or 4-nitrobenzoic acid. The structures of the complexes were determined through X-ray crystallography, revealing that complex (1) forms supramolecular dimers with strong hydrogen bonds between equatorially coordinated water molecules and uncoordinated carboxylate oxygen atoms, leading to antiferromagnetic interactions. The study provides experimental evidence that hydrogen bonds extended through carboxylate bridges can serve as pathways for spin–spin interactions, as demonstrated by the magnetic properties and EPR spectra of the complexes.
Xi
