Novel silver(I)N-heterocyclic carbene complexes bearing 2-(4-hydroxyphenyl)ethyl group: Synthesis,characterization, and enzyme inhibition properties

Herein, novel silver-based N-heterocyclic carbene (NHC) complexes bearing 2-(4-hydroxyphenyl)ethyl group were synthesized. Novel Ag(I)NHC complexes were synthesized from the 2-(4-hydroxyphenyl)ethyl-substituted benzimidazolium salts and silver oxide via in situ deprotonation method. The successful formation of all Ag(I)NHC complexes was proved by using ¹H NMR, ¹³C NMR, FTIR spectroscopy, and elemental analysis techniques. In addition, their inhibitory effects have been investigated of these substances on acetylcholinesterase (AChE), α-glycosidase (α-Gly), human carbonic anhydrase I (hCA I), and human carbonic anhydrase II (hCA II) enzymes. It has been seen that all compounds have a better ability to inhibit compared with existing tried inhibitors. Among these, the best inhibitor against AChE enzyme is 1g (K_i : 9.54 ± 0.98 μM and IC₅₀ : 17.40), and against α-Gly, 1c showed the highest effect (K_i 3.09 ± 0.36 μM and IC₅₀ 7.91). The best inhibitor against hCA I and hCA II enzymes are 1c and 1g compounds. For hCA I and hCA II, IC₅₀ values were calculated as 17.85 and 9.06 μM and K_i values were measured as 5.45 ± 2.02 and 8.99 ± 2.02 μM, respectively.     

Preparation of a 99mTc-labeled graft polymer and its in vitro and in vivo evaluation

Journal of Radioanalytical and Nuclear Chemistry - The aim of this study is the synthesis of a novel 99mTc-labeld graft polymer and the biological evaluation of its in vitro and in vivo properties....     

The first use of [PdBr2(imidazolidin-2-ylidene)(pyridine)] catalysts in the direct C-H bond arylation of C2-substituted furan and thiophene

Research on Chemical Intermediates - N-Heterocyclic carbene (NHC)-linked PEPPSI-type palladium complexes have recently been used in the direct C-H bond arylation of heteroarenes. However, in most...     

Thermal properties and kinetics of new-generation posterior bulk fill composite cured light-emitting diodes

In this study, the thermal behavior in terms of glass transition (T _g), degradation, and thermal stability of four commercial new-generation posterior bulk fill composites (Surefill SDR, Dentsply; Quixfill, Dentsply; Xtrabase, Voco; and Xtrafill, Voco) activated by light-emitting diodes (LEDs) was analyzed by thermogravimetric analysis (TG), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The activation energies (E _a) for the decomposition of the dental resins were calculated based on the Kissinger and Doyle kinetic models from the peaks of the endothermic curves obtained when the specimens were heated at four different temperatures (5, 10, 15, and 20 °C min^?1) during DSC. The results show that the Xtrabase composite displayed the highest T _g (120 °C at a 5 °C min^?1 heating rate) and E _a (157.64 kJ mol^?1) values associated with thermal degradation from the main chain of the polymer.     

Thermal and kinetic analyses of 2,5-bis(2-hydroxyphenyl)thiazolo[5,4-d]thiazole

Thermal behavior and UV–Vis absorption properties of 2,5-bis(2-hydroxyphenyl)thiazolo[5,4-d]thiazole were investigated in the present study. It was found that decomposition occurs in two stages which correspond to removal of both phenolic rings and degradation of remaining core structure, respectively. After the characterization of decomposition stages, apparent activation energy values of each stage were calculated using model-free isoconversional methods (FWO and KAS). Apparent activation energies of decomposition stages are determined by both methods. Their averages are calculated as 98.232 and 123.253 kJ mol^?1 in consecutive order. UV–Vis absorption properties of this compound have been determined with using different solvents.     

Constrained‐Geometry Bisphosphazides Derived from 1,8‐Diazidonaphthalene: Synthesis,Spectroscopic Characteristics,Structural Features,and Theoretical Investigations

Investigations on the Staudinger reaction between 1,8‐diazidonaphthalene and phosphorous(III) building blocks, a key step in the synthesis of superbasic bisphosphazene proton sponges, yielded a set of bisphosphazides with a constrained geometry 1,8‐disubstituted naphthalene backbone. This compound class has attracted our interest not only due to their surprisingly high stability, but in particular because of their theoretically predicted basicity in the range of their bisphosphazene analogues that can be referred to the constrained geometry interaction of two highly basic nitrogen atoms. Eleven new bisphosphazides bearing simple P‐amino groups as well as P‐guanidino substituents, azaphosphatrane moieties, P₂ building blocks, or chiral P‐amino substituents derived from L ‐proline are presented. They were studied concerning their spectroscopic properties and partly also their chromophoric and structural features. In the case of the pyrrolidino‐substituted TPPN(2N₂) (TPPN=1,8‐bis(trispyrrolidinophosphazenyl)naphthalene), the stepwise nitrogen elimination is investigated theoretically and experimentally, which led to the isolation and structural characterization of TPPN(1N₂) bearing a phosphazide and a phosphazene functionality in one molecule. Attempts to protonate the obtained bisphosphazides and to prove the computationally predicted pK_BH⁺ values through NMR titration reactions resulted in their decay, which again was rationalized by theoretical calculations. Altogether we present the so far most extensive spectroscopic, structural and theoretical investigation of constrained geometry bisphosphazides and their Brønsted and Lewis basic properties.     

Dyeing of cotton with thyme and pomegranate peel

Application of natural dyes for textiles is increasing due to awareness of environment, ecology, and pollution control. The purpose of this study is to determine the color, antimicrobial, and fastness properties of cotton fabrics dyed with thyme and pomegranate peel without a mordanting process. In this way, it was planned to avoid use of metallic mordants (heavy-metal salts) and prevent heavy-metal pollution for ecological production. Additionally, a variety of the most commonly used mordants, namely potassium aluminum sulfate, copper(II) sulfate, iron(II) sulfate, and tin(II) chloride, were used for mordanting of cotton fabrics in order to compare the differently mordanted and unmordanted dyed fabrics’ color efficiencies (K/S) and CIE L ^* a ^* b ^* color values. It was found that mordant type had an effect on color efficiency and the color coordinates of fabrics dyed with both thyme and pomegranate fruit peel. Moreover, the antimicrobial properties of the fabrics only dyed directly with thyme and pomegranate peel without any mordanting process were determined to demonstrate the usability of these natural dye sources without use of any mordanting agents. The obtained antimicrobial activities were compared with undyed samples. Undyed samples showed no antimicrobial activity, whereas significant antimicrobial activity was obtained after the dyeing procedure using thyme and pomegranate peel on unmordanted fabrics. Washing, rubbing, perspiration, and lightfastness properties of dyed fabrics were also evaluated. Thyme and pomegranate fruit peel as natural dye sources revealed sufficient results even for unmordanted samples.     

4-Vinylbenzyl-substituted silver(I) N-heterocyclic carbene complexes and ruthenium(II) N-heterocyclic carbene complexes: synthesis and transfer hydrogenation of ketones

4-Vinylbenzyl-substituted Ag(I) N-heterocyclic carbene (NHC) complexes and Ru(II) NHC complexes have been synthesized. The Ag(I) complexes were synthesized from the imidazolium salts and Ag₂O in dichloromethane at room temperature. The Ru(II) complexes were prepared from Ag(I) NHC complexes by transmetallation. The six 4-Vinylbenzyl-substituted Ag(I) NHC complexes and six 4-Vinylbenzyl-substituted Ru(II) NHC complexes have been characterized by spectroscopic techniques and elemental analyses. The Ru(II) NHC complexes show catalytic activity for the transfer hydrogenation of ketones.     

Poly(HEMA-co-NBMI) Monolithic Cryogel Columns for IgG Adsorption

Supermacroporous poly(2-hydroxyethyl methacrylate-co-1,5-naphthalene bismaleimide) [poly(HEMA-co-NBMI)] monolithic cryogel column was prepared by free radical cryo-copolymerization of HEMA with NBMI as a hydrophobic functional comonomer and N,N′-methylene-bisacrylamide as cross-linker directly in a plastic syringe for adsorption of albumin. The monolithic cryogel contained a continuous polymeric matrix which has interconnected pores of 10–100 μm size. Poly(HEMA-co-NBMI) cryogel was characterized by swelling studies, FTIR and scanning electron microscopy. The equilibrium swelling degree of the poly(HEMA-co-NBMI) cryogel was 10.5 g of H₂O/g dry cryogel. Poly(HEMA-co-NBMI) cryogel was used in the adsorption/desorption of IgG from aqueous solutions. The maximum amount of IgG adsorption from aqueous solution in phosphate buffer was 98.20 mg/g polymer at pH 7.0. The nonspecific adsorption of IgG onto plain poly(HEMA) cryogel was very low (2.79 g/g polymer). It was observed that IgG could be repeatedly adsorbed and desorbed with the poly(HEMA-co-NBMI) cryogel without significant loss of adsorption capacity.     

Synthesis, characterization and aggregation behaviour of novel peripherally tetra-substituted octacationic water soluble metal-free and metallophthalocyanines

In this study, a new phthalonitrile derivative 3 bearing 1,3-bis[3(dimethylamino)phenoxy]propan-2-ol 1, metal-free phthalocyanine (Pc) 4, metallophthalocyanines (MPcs) 5–7 and their quaternized derivatives 4a–7a were synthesized. Metal-free Pc 4 was prepared by cyclotetramerization of phthalonitrile derivate 3 and MPcs 5–7 were synthesized by heating 3 with NiCl₂, CoCl₂ and CuCl₂ in n-pentanol in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, respectively. Quaternization of the dimethylamino functionality produced quaternized octacationic water soluble metal-free, Ni, Co and Cu Pcs which were soluble in water, DMF, DMSO. The aggregation behaviour of these compounds were investigated in different concentrations of chloroform for metal-free, Ni, Co and Cu Pcs. The effect of solvents on absorption spectra were studied in various organic solvents. The novel compounds were characterized using IR, ¹H-, ¹³C NMR, UV–vis and MS spectral data.