Физико-химические основы химии и технологии платиновых металлов и их соединений

The date of investigation on chemistry and technology of platinum metals in the large years are presented. The complexes of palladium(II) with macroheterocyclyc compounds are syntesited. The application of electrochemical processes for selection of platinum metals from solutions and applyed of concentrate of platinum metals is shownКратко рассмотрены результаты выполненных в последние годы работ в области химии и технологии платиновых металлов. Выполнен синтез комплексов палладия(II) с макрогетероциклическими соедине-ниями. Показана возможность применения электрохимического метода для извлечения платиновых металлов из растворов и получения концентратов

The physico-chemical results of chemistry and technology of platinum metals and their compounds

The date of investigation on chemistry and technology of platinum metals in the large years are presented. The complexes of palladium(II) with macroheterocyclyc compounds are syntesited. The application of electrochemical processes for selection of platinum metals from solutions and applyed of concentrate of platinum metals is show

Reversible inhibition of Escherichia coli inorganic pyrophosphatase by fluoride: trapped catalytic intermediates in cryo-crystallographic studies

Here, we describe high-resolution X-ray structures of Escherichia coli inorganic pyrophosphatase (E-PPase) complexed with the substrate, magnesium, or manganese pyrophosphate. The structures correspond to steps in the catalytic synthesis of enzyme-bound pyrophosphate (PP(i)) in the presence of fluoride as an inhibitor of hydrolysis. The catalytic reaction intermediates were trapped applying a new method that we developed for initiating hydrolytic activity in the E-PPase crystal. X-ray structures were obtained for three consecutive states of the enzyme in the course of hydrolysis. Comparative analysis of these structures showed that the Mn2+-supported hydrolysis of the phosphoanhydride bond is followed by a fast release of the leaving phosphate from the P1 site. The electrophilic phosphate P2 is trapped in the "down" conformation. Its movement into the "up" position most likely represents the rate-limiting step of Mn2+-supported hydrolysis. We further determined the crystal structure of the Arg43Gln mutant variant of E-PPase complexed with one phosphate and four Mn ions