Suchergebnisse

p-tert-Butylcalix[4]arene 1 reacts with bromoethyl acetate and LiAlH4 to form the p-tert-butyl-tetrakis(2-hydroxyethoxy)calix[4]arene 8 bearing four ethyl-spacers at the lower rim of the calixarene. Reaction of 8 with Et2NSiMe3 leads to the tetrakis-substituted derivative 9. Treatment of 9 with PF2Cl gives the stable tetrakis-fluorophosphite 10, while the reaction with 2-chloro-1,3,5-trimethyl-1,3,5-triaza-2σ3λ3-phosphorin-4,6-dione furnishes the tetrakis-substituted molecule 11. When 11 was allowed to react with SO2Cl2, formation of the tetrakis(2-chloro)ethyl substituted calix[4]arene 13 was observed. All examined calixarene derivatives are exclusively obtained in the cone conformer. Reaction of 11 with dichloro(cyclooctadiene)platinum(II) leads to the symmetrically four-times bridged dimmer 15, which exhibits a trans orientation of the atoms surrounding the platinum(II) atom and involves all eight phosphorus atoms in the bridges. When 10 was treated with (COD)PtCl2, the cis intermolecular complex 16 was obtained.

The sludge resulted from the urban wastewater treatment plants, can be used, from a circular economy, as a fertilizer for agricultural and degraded lands, for horticulture and forestry. This paper aims to propose an alternative for the use of this type of sludge in a sustainable way, with a low impact on the environment. The study consisted of experiments done to recover the stabilized sludge from the urban wastewater treatment plants in the process of degraded land rehabilitation, using the energetic willow, Salix sp. The experimental results showed that the use of stabilized sludge as fertilizer for naturally and anthropogenic degraded lands determined the improvement of nutritional characteristics of the lands cultivated with Salix sp., and allowed the growth, development, and maintenance of this plant. Taking into consideration the characteristics of the cultures and the quantities of metals accumulated by Salix sp., it can be concluded that these plants were adapted to the environmental conditions and the substrate toxically composition. The results obtained on two degraded lands indicate that Salix sp. can be used for its introduction in the economic circuit, both for salty soils and ash dumps.