Xerogel-sequestered silanated organochalcogenide catalysts for bromination with hydrogen peroxide and sodium bromide

In the Chalcogenoxide Elimination Panorama: Systematic Insight into a Key Reaction

The selenoxide elimination is a well-known reaction in organochalcogen chemistry, with wide synthetic, biological, and toxicological implications. In this work, we apply benchmarked density functional theory (DFT) calculations to investigate different aspects of the title reaction in three (bio)chemically relevant models, spanning minimal systems of theoretical interests as well as biological or synthetic organochalcogenides. The activation strain analysis (ASA) methodology is employed along a suitable reaction coordinate to obtain insight into the role of the chalcogen and of the oxidation state, to pinpoint the factors that tune the elimination reactivity of the investigated systems. Lastly, we computationally validate the hypothesis that telluroxides eliminate more slowly than selenoxides because of a detrimental hydration process that leads to unreactive hydrates.

Organoselenium chemistry-based polymer synthesis

Novel synthesis of selenium containing polymers with pre-determined structures and applications thereof.

Selenium reagents as catalysts

Organoselenium chemistry has become an important tool in synthetic and medicinal chemistry.

Functional Enzyme Mimics for Oxidative Halogenation Reactions that Combat Biofilm Formation

Transition-metal oxide nanoparticles and molecular coordination compounds are highlighted as functional mimics of halogenating enzymes. These enzymes are involved in halometabolite biosynthesis. Their activity is based upon the formation of hypohalous acids from halides and hydrogen peroxide or oxygen, which form bioactive secondary metabolites of microbial origin with strong antibacterial and antifungal activities in follow-up reactions. Therefore, enzyme mimics and halogenating enzymes may be valuable tools to combat biofilm formation. Here, halogenating enzyme models are briefly described, enzyme mimics are classified according to their catalytic functions, and current knowledge about the settlement chemistry and adhesion of fouling organisms is summarized. Enzyme mimics with the highest potential are showcased. They may find application in antifouling coatings, indoor and outdoor paints, polymer membranes for water desalination, or in aquacultures, but also on surfaces for food packaging, door handles, hand rails, push buttons, keyboards, and other elements made of plastic where biofilms are present. The use of natural compounds, formed in situ with nontoxic and abundant metal oxide enzyme mimics, represents a novel and efficient "green" strategy to emulate and utilize a natural defense system for preventing bacterial colonization and biofilm growth.

Dibromination of alkenes with LiBr and H2O2 under mild conditions

Activation of H₂O₂ by LiBr and AcOH is efficiently achieved for dibromination of alkenes in high yields and selectivity.

Selective continuous flow synthesis of hydroxy lactones from alkenoic acids

The first in-flow selenium-mediated catalysis has been realized under eco-friendly conditions to convert alkenoic acids into hydroxy lactones with a high regio- and diastereo-selectivity ratio.

The performance of hybrid titania/silica-derived xerogels as active antifouling/fouling-release surfaces against the marine alga Ulva linza: in situ generation of hypohalous acids

Mixed titania/silica xerogels were prepared using titanium tetraisopropoxide (TTIP) and tetraethoxy orthosilicate (TEOS). Xerogel properties were modified by incorporating n-octyltriethoxysilane (C8). The xerogels catalyze the oxidation of bromide and chloride with hydrogen peroxide (H2O2) to produce hypohalous acids at pH 7 and pH 8. The antifouling/ fouling-release performance of a TTIP/C8/TEOS xerogel in the presence and absence of H2O2 was evaluated for the settlement of zoospores of the marine alga Ulva linza and for the removal of sporelings (young plants). In the absence of H2O2, differences in the settlement of zoospores and removal of sporelings were not significant relative to a titanium-free C8/TEOS xerogel. Addition of H2O2 gave a significant reduction in zoospore settlement and sporeling removal relative to the C8/TEOS xerogel and relative to peroxide-free conditions. The impact of TTIP on xerogel characteristics was evaluated by comprehensive contact angle analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy.