Theoretical investigation on the effect of the ligand on bis-silylation of C(sp)–C(sp) by Ni complexes

Density functional theory (DFT) is used to study the bis-silylation of alkynes catalyzed by a transition metal nickel–organic complex; the active catalyst, the organic ligand, the reaction mechanism, and rate-determining step are discussed in this paper.

The Effect of Titanium Organic Complex on Pollination Process and Fruit Development of Apple cv. Topaz

Optimal weather conditions are necessary for the proper course of the flowering process and high activity of pollinators, which is the most important factor affecting pollination. Because weather conditions do not always favour effective pollination and because pollinators’ activities are decreasing, the application of compound stimulating pollination and fertilization may be a good perspective for increasing yield. Titanium is considered a beneficial element for plants. Preliminary studies have indicated the positive effect of titanium organic complex on pollen adhesion to the stigma and pollen germination on the stigma of tomato and cucumber. Therefore, a 2-year experiment was designed to determine the effect of titanium organic complex application on the pollination process and fruit development of apple cv. Topaz (Malus domestica Borkh.) The experiment demonstrated the positive effect of titanium organic complex on fertilization of ovules because of effective pollination, seed setting, and fruit development of apple. Application of titanium organic complex improved pollen adhesion to the stigma and pollen germination on the stigma. In addition, titanium organic complex increased the number of pollen tubes growing through the pistil style, which resulted in fertilization that was more effective, as confirmed by the higher number of seeds set in fruits. Higher numbers of seeds set in fruits positively affected their weight and size. Therefore, fruit harvested from trees to which titanium organic complex was applied were characterized by greater weight, length, and diameter compared to fruits obtained from the trees to which titanium organic complex was not applied.

Charging and ultralong phosphorescence of lanthanide facilitated organic complex

Emission from the triplet state of an organo-lanthanide complex is observed only when the energy transfer to the lanthanide ion is absent. The triplet state lifetime under cryogenic conditions for organo-lanthanide compounds usually ranges up to tens of milliseconds. The compound LaL1(TTA)3 reported herein exhibits 77 K phosphorescence observable by the naked eye for up to 30 s. Optical spectroscopy, density functional theory (DFT) and time-dependent DFT techniques have been applied to investigate the photophysical processes of this compound. In particular, on-off continuous irradiation cycles reveal a charging behaviour of the emission which is associated with triplet-triplet absorption because it shows a shorter rise lifetime than the corresponding decay lifetime and it varies with illumination intensity. The discovery of the behaviour of this compound provides insight into important photophysical processes of the triplet state of organo-lanthanide systems and may open new fields of application such as data encryption, anti-counterfeiting and temperature switching.

Tuneable photoluminescence of TBAPY-based Metal-Organic Complex

We report the synthesis of crystals of an organic metal complex based on a large redox-active ligand (tbapy) exhibiting luminescent properties. We have demonstrated the tuning of the luminescence of a Zn-based metal-organic complex, soaked in advance in dimethylformamide, with pumping light.

Sulfint – the Czech gas desulfurization technology

The article describes one of the gas desulphurisation technologies which has been developed in the Czech Republic. The technology uses washing solution of organic complexes of various metals to remove H2S from gases. H2S removal is realized by its reaction with complexes of suitable metals with organic reagents. This leads to the H2S oxidation to elemental sulfur and the reduction of the metal protected by the organic complex to a lower oxidation state, which is also bound in the organic complex. Regeneration of the washing solution is performed by oxidation of the reduced form of the complex using oxygen from the air. Complexes of iron with ethylenediaminetetraacetic acid, nitrile triacetic acid or diethylenetriaminopentaacetic acid are used for the preparation of washing solutions. The reaction of the ferric complex of ethylenediaminetetraacetic acid with H2S is accompanied by a change in the color of the washing solution from a deep red color (like red wine) to a light brown color (like coffee with milk) of the ferrous complex of ethylenediaminetetraacetic acid. When this complex is completely depleted, it begins to decompose to black ferrous sulfide by further contact with H2S. This reaction is irreversible. The ferrous complex of ethylenediaminetetraacetic acid can be regenerated by reaction with oxygen, which also takes place at normal or elevated temperatures. The rate of this reaction is much slower compared to the reaction of H2S with the ferric complex. The process was discovered and intensively researched at the Institute for Fuel Research in Prague and later also at the University of Chemistry and Technology Prague. The first pilot plant tests took place with the desulfurization of coke oven gas at the Coking Plant Vítězný únor in Ostrava, where the first operating facility working with the given technology was later built. Another operating facility working with this technology was put into operation at the Antonín Zápotocký High pressure gasification plant in Ústí nad Labem and was used for desulphurization of expansion gases from pressure purification of waste gas of the Rectisol system. The technology was named Sulfint. Both facilities operated successfully until the end of operation of the town-gas supply system in the Czech Republic in the mid-1990s.

Synthesis, crystal structure, and quantum mechanical studies regarding a new metal–organic complex based on Cd (II)

A novel metal-organic complex formulated as [Cd (phen)(dipic) (H2O)2]. 3 H2O (phen = 1, 10-phenanthroline; dipic2−= pyridine-2,6-dicarboxylate) has been hydrothermally synthesized at 150°C for 48h. The structure of Cd complex was characterized by elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and single-crystal X-ray diffraction (SC-XRD). The crystal system of Cd complex is monoclinic with space group C 2/c. The pentagonal bipyramid (seven coordinate) around Cd2+ center filled by two terminal water ligands, one 1,10-phenanthroline, and one pyridine-2,6-dicarboxylate anion. Extensive O–H···O hydrogen bonding interactions involving all coordinated water molecules, dipicolinate oxygens, and crystallization water molecules further stabilize the complex units by linking them to form three-dimensional polymeric networks. Indeed, quantum mechanical studies were performed to understand effective factors on stability of the Cd(II) complex.