Inner-sphere electron transfer at the ruthenium-azo interface

Metal complexes exhibiting multiple reversible redox states have drawn continuing research interest due to their electron reservoir features. In this context, the present article described ruthenium-acac complexes (acac=acetylacetonate) incorporating redox-active...

SYNTHESIS AND PHYSICOCHEMICAL STUDY OF THE CERIUM AND CEFAZOLIN METAL COMPLEX

В данной работе коллективом авторов путём взаимодействия водных растворов хлорида трёхвалентного церия и натриевой соли цефазолина получено и выделено в твердом виде металлокомплексное соединение. Его элементный состав установлен с помощью метода рентгеноспектрального электронно-зондового анализа, описаны термические характеристики данного соединения, температура его разложения, состав и способ координации внутренней сферы данного металлокомплекса был уточнен методами термогравиметрии, и дифференциальной сканирующей калориметрии и методом ИК-спектроскопии. На основании полученных данных установлено, что внутренняя сфера металллокомплекса содержит в своем составе три молекулы цефазолина и три молекулы внутрисферной воды. Состав внутренней сферы отвечает брутто-формуле [CeCzl(HO) ]. На основании данных ИК- спектроскопии сделаны выводы о координации цефазолина к центральному иону через амидную и карбоксильную группы. In this work, a team of authors obtained and isolated in solid form a metal complex compound by the interaction of aqueous solutions of trivalent cerium chloride and sodium salt of cefazolin. Its elemental composition was determined using the X-ray spectral electron probe analysis. The thermal characteristics of this compound, the temperature of its decomposition, the composition and the method of coordination of the inner sphere of this metal complex were clarified by the methods of thermogravimetry, differential scanning calorimetry and IR spectroscopy. Based on the data obtained, the inner sphere of the metal complex contains three molecules of cefazolin and three molecules of inner-sphere water. The composition of the inner sphere corresponds to the formula [CeCzl(HO) ]. Taking into account IR spectroscopy data, the authors concluded that the most likely way of coordination of cefazolin to the central ion is through the amide and carboxyl groups.

Symbolika i funkcja postaci literackich w "Labiryncie świata i raju serca" Jana Amosa Komeńskiego

The presented research concerns the functions and symbolism of the characters in "Labyrinth of the World and Paradise of the Heart" by John Amos Comenius. In this work, the characters are largely typified and are examples that serve the author’s in-depth spiritual reflection. The negative features of the heroes are often shown by Comenius in animal costumes. Symbolic associations with the world of fauna refer to the inner sphere of man and show his moral condition.

Branch- and Enantioselective Allylic C−H Alkylation Works Well for Almost All Types of α-Alkenes

Asymmetric functionalization of alkenes represents one of the most attractive and straightforward methods to achieve precise assembly of molecular complexity from cost-effectiveness and sustainability viewpoints. Although the regio- and enantioselective transformations on the carbon-carbon double bond of alkenes have been extensively studied, those on the allylic C−H bonds of inactivated alkenes remain to be explored. Here, we report a Pd-catalyzed branch- and enantioselective allylic C−H alkylation, capable of accommodating almost all types of α-alkenes that range from feedstocks annually manufactured on million-ton scale to olefins tethering a wide scope of appended functionalities, providing unconventional access to chiral γ,δ-unsaturated amides. Notably, mechanistic studies reveal that the regioselectivity is not only governed by the coordination pattern of nucleophiles but also regulated by the ligational behaviors of ligands, highlighting the importance of the mono-ligation of chiral phosphoramidite ligands in provoking high levels of stereo- and branch-selectivity via a nucleophile-coordination enabled inner-sphere allylation pathway.

Synthesis of Aryl Sulfides by Metal-Free Arylation of Thiols with Diaryliodonium Salts

Metal-free arylation of thiols with diaryliodonium salts has been developed. The application of a strong organic base ena-bles the C–S bond formation under mild and experimentally simple conditions. The method allows for the synthesis of aryl sulfides containing a broad range of aryl groups from an array of thiols, including aryl, heteroaryl, and alkyl ones. The mechanism of the reaction was studied by DFT calculations, demonstrating that is follows the inner sphere pathway involv-ing the incipient formation of Ar2I(SR) intermediate, followed by the reductive elimination.

Competing Sorption of Se(IV) and Se(VI) on Schwertmannite

Schwertmannite (SHM) is a naturally occurring mineral that has been shown to effectively scavenge oxyanions from contaminated water. In this study, Fourier-transform infrared spectroscopy and X-ray absorption spectroscopy techniques in combination with wet-chemical techniques were used to study the competitive sorption of Se(IV) and Se(VI) at pH 3. The experiments were conducted with three types of schwertmannite obtained from oxidative synthesis, biogenic synthesis and high-pressure compaction at different initial Se concentrations and mixing ratios for 48 h and 56 days, respectively. A threshold value for the uptake mechanisms was identified, which reflects the amount of easily exchangeable sulphate (~0.5 mmol/g). At adsorbate concentrations below this threshold, an inner-sphere corner-sharing bidentate binuclear complex forms upon exchange with sulphate. At higher concentrations, both oxyanions become bound to SHM through co-occurrence of mainly inner-sphere and partly outer-sphere corner-sharing bidentate binuclear complexes with Fe(III) containing surface sites. Single species experiments clearly indicate a higher affinity of SHM for Se(IV). However, in mixed species experiments, competitive sorption occurs with equal or even preferential uptake of Se(VI) at concentrations much lower than the threshold value, presumably due to geometrical similarity between selenate and sulphate, and increasing preference for Se(IV) at high Se concentrations.