Red-listed mosses in the Komi Republic (Russia)

The paper presents data on red-listed mosses of the Komi Republic. 114 taxa of moss species have been sug- gested for inclusion in the new edition of the Red Data Book of the Komi Republic.

Toward an Understanding of Diamond sp²‑Defects with Unsaturated Diamondoid Oligomer Models

Nanometer-sized doubly bonded diamondoid dimers and trimers, which may be viewed as models of diamond with surface sp²-defects, were prepared from corresponding ketones via a McMurry coupling and were characterized by spectroscopic and crystallographic methods. The neutral hydrocarbons and their radical cations were studied utilizing density functional theory (DFT) and ab initio (MP2) methods, which reproduce the experimental geometries and ionization potentials well. The van der Waals complexes of the oligomers with their radical cations that are models for the self-assembly of diamondoids, form highly delocalized and symmetric electron-deficient structures. This implies a rather high degree of σ-delocalization within the hydrocarbons, not too dissimilar to delocalized π-systems. As a consequence, sp²-defects are thus also expected to be nonlocal, thereby leading to the observed high surface charge mobilities of diamond-like materials. In order to be able to use the diamondoid oligomers for subsequent surface attachment and modification, their CH-bond functionalizations were studied, and these provided halogen and hydroxy derivatives with conservation of unsaturation

Chemical Characterization of the Smallest S-Nitrosothiol, HSNO; Cellular Cross-talk of H₂S and S-Nitrosothiols

Dihydrogen sulfide recently emerged as a biological signaling molecule with important physiological roles and significant pharmacological potential. Chemically plausible explanations for its mechanisms of action have remained elusive, however. Here, we report that H2S reacts with S-nitrosothiols to form thionitrous acid (HSNO), the smallest S-nitrosothiol. These results demonstrate that, at the cellular level, HSNO can be metabolized to afford NO+, NO, and NO– species, all of which have distinct physiological consequences of their own. We further show that HSNO can freely diffuse through membranes, facilitating transnitrosation of proteins such as hemoglobin. The data presented in this study explain some of the physiological effects ascribed to H2S, but, more broadly, introduce a new signaling molecule, HSNO, and suggest that it may play a key role in cellular redox regulation.Friedrich-Alexander-Universität Erlangen-Nürnberg (Intermural grant from Emerging Field Initiative: Medicinal Redox Inorganic Chemistry)National Science Foundation (U.S.)National Institutes of Health (U.S.) (Postdoctoral Fellowship