Role of ancillary ligands in -nitrosothiol and NO generation from nitrite-thiol interactions at mononuclear zinc(ii) sites.

Generation of -nitrosothiol (RSNO) and nitric oxide (NO) mediated by zinc(ii) coordination motifs is of prime importance for understanding the role of zinc(ii)-based cofactors in redox-signalling pathways. This study uniquely employs a set of mononuclear [LZn] cores (where L = MePzPz/MePzPy/MePzQu) for introducing subtle alterations of the primary coordination sphere and investigates the role of ligand tuning in the transformation of NO in the presence of thiols. Single crystal X-ray diffraction (SCXRD) analyses on [LZn-X](X) (where X = perchlorate/triflate) illustrate consistent changes in the bond distances, thereby showing variations of the metal-ligand interactions depending on the nature of the heterocyclic donor arms (pyrazole/pyridine/quinoline).

Deciphering the Origin of Regioselectivity in Ru(II)-Catalyzed C-H Annulation of -Chlorobenzamides with 1,3-Diynes.

Understanding the reaction mechanism and origin of regioselectivity in transition metal-catalyzed C-H activation/annulation reactions with 1,3-diynes has remained an intriguing challenge. In this article, to establish the mechanism and decipher the origin of regioselectivity, we report a detailed computational density functional theory-based mechanistic investigation on the recently developed Ru(II)-catalyzed [4 + 2] annulation of -chlorobenzamides with 1,3-diynes for the synthesis of 3-alkynylated isoquinolone derivatives. Our calculations reveal a redox-neutral pathway for the annulation reaction.