Physicochemical study of new polydentane ligand systems based on 2,6-diformyl-4-<Emphasis Type="Italic">tert</Emphasis>-butylphenol

New polydentate ligand systems, products of condensation of 2,6-diformyl-4-tert-butylphenol with 1,3-diaminopropanol-2 and carbo(thiocarbo)hydrazide, were synthesized and their structure was determined based on the data of elemental analysis, ¹H NMR and IR spectroscopy. The acid-base properties of bisazomethine I have been studied. Spatial structure and spectral properties of the ligand system were simulated using quantum-chemical calculations.     

Extraction-spectrophtometric determination of vanadium using 2,6-dithiol-4-<Emphasis Type="Italic">tert</Emphasis>-butylphenol and aminophenols

Mixed-ligand complexes of vanadium(II, IV, V) with 2,6-dithiol-4-tert-butylphenol and aminophenols have been studied by spectrophotometry. Extraction of mixed-ligand complexes is maximal at pH 1.2–4.8. The optimal conditions for the formation and extraction of mixed-ligand compounds have been found and the ratios of components in the complexes have been determined. A procedure has been developed for extraction-spectrophotometric determination of vanadium in soils.     

2,6-Diformyl-4-<Emphasis Type="Italic">tert</Emphasis>-butylphenol bis(8-quinolylhydrazone) and its transition metal complexes: Physicochemical study and quantum-chemical simulation

2,6-Diformyl-4-tert-butylphenol bis(8-quinolylhydrazone) and its transition metal complexes of the compositions [Cu₂(H₂L)Cl]Cl₂, [Ni₂(H₂L)Cl₃], and [Mn₂(H₂L)Cl₃], where H₂L is the monodeprotonated form of the hydrazone, are prepared. The conformations of the bis-hydrazone, geometries of the complexes, and parameters of exchange coupling between the ferromagnetic centers are evaluated by quantum-chemical calculations. The calculation results are compared with the results of the physicochemical study of the compounds. Factors affecting the stability of various forms of the ligand and complexes are discussed.     

Development of a one-stage synthesis of 2,6-di-<Emphasis Type="Italic">tert</Emphasis>-4-ethylbutylphenol from 2,6-di-<Emphasis Type="Italic">tert</Emphasis>-butylphenol

Investigation of the catalyzed reaction of 2,6-di-tert-butylphenol with ethanol, ethylene glycol, oligomeric glycols, and paraldehyde in a strongly basic medium permitted to develop a technologically suitable procedure for manufacture of 2,6-di-tert-4-ethyl-butylphenol, used in the synthesis of Antioxidant-425.     

Novel diphenylsulfimide antioxidants containing 2,6-di-<Emphasis Type="Italic">tert</Emphasis>-butylphenol moieties

New diphenylsulfimide derivatives containing substituents with the 2,6-di-tert-butylphenol moiety at the nitrogen atom were synthesized. Their molecular structures were established by X-ray diffraction. Antioxidant activity was experimentally evaluated by spectrophotometry based on hydrogen transfer to the stable radicals, namely, 2,2-diphenyl-1-picrylhydrazyl and the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS^·+), and using in vitro lipid peroxidation in rat brain and liver homogenates. The presence of phenol and diphenylsulfimide moieties in one molecule leads to a significant enhancement of antioxidant activity. The new compounds exhibit moderate inhibitory activity against enzymes involved in carbohydrate and lipid metabolism. The evaluation of antiglycation activity showed that the new sulfimides taken at a concentration of 100 μmol L^–1 have activity comparable with that of aminoguanidine.     

Mono-<Emphasis Type="Italic">meso</Emphasis>-<Emphasis Type="Italic">tert</Emphasis>-butylporphyrin

Summary. Treatment of meso-tetra(tert-butyl)porphyrin with sulfuric acid/n-butanol affords a mixture of porphyrin and mono-tert-butylporphyrin in relatively high yield.     

Micelle formation of polystyrene-<Emphasis Type="Italic">block</Emphasis>-poly(4-<Emphasis Type="Italic">tert</Emphasis>-butoxystyrene) in hexane

A new type of hexane-soluble polymeric surfactant based on poly(4-tert-butoxystyrene) (P ^t BSt) was prepared by the nitroxide-mediated living radical polymerization, and their self-assemblies in hexane were explored. Polystyrene-block-P ^t BSt diblock copolymers with six different P ^t BSt block lengths were obtained by the sequential living radical polymerization of styrene followed by 4-tert-butoxystyrene using 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl as the mediator; Mn(P ^t BSt block) = 13,500, 21,700, 26,600, 47,500, 91,300, and 108,000 at the constant length of the PSt block (Mn = 12,900). Dynamic light-scattering studies demonstrated that the copolymers self-assembled into monodispersed spherical micelles in hexane. The hydrodynamic diameter of the micelles increased with an increase in the P ^t BSt block length. The micellar size also increased as the copolymer concentration increased. However, the size decreased as a result of the increasing temperature due to a decrease in the aggregation number. The ¹H NMR analysis confirmed that the copolymers formed micelles with PSt cores.     

About selective methods of synthesis of 6-<Emphasis Type="Italic">tert</Emphasis>-butyl-2-methylphenol and 6-<Emphasis Type="Italic">tert</Emphasis>-butyl-2,4-dimethylphenol

Vapor phase catalytic methylation with methanol of 2-tert-butylphenol at the temperature 280–300°C proceeds selectively with formation of 6-tert-butyl-2-methylphenol. Elevating reaction temperature above 300°C leads to formation of 2,6-dimethylphenol. Reaction of 2-tert-butylphenol with methanol in alkaline medium in the presence of zinc oxide is shown to lead initially to formation of a mixture of calixarenes and methylenebisphenols that at elevated temperature exert splitting leading in future to 6-tert-butyl-2,4-dimethylphenol. Obtaining it in this reaction from 2,2′-methylenebis-(6-tert-butyl-4-methylphenol) proceeds selectively. Pathways of the reductive methylation of methylenebisphenols with methanol in alkaline medium is considered.     

Synthesis of (<Emphasis Type="Italic">E</Emphasis>)-<Emphasis Type="Italic">N</Emphasis>-(3-alkoxy-4-acyloxyphenylmethylene)-<Emphasis Type="Italic">N</Emphasis>-(<Emphasis Type="Italic">e</Emphasis>-cyclohexyl)amines

Previously unknown E isomers of azomethines (Schiff bases) were synthesized from vanillal and vanillin esters by their reaction with cyclohexylamine.     

Structure of hexaaquamagnesium (II) bis(4-<Emphasis Type="Italic">p</Emphasis>-aminobenzenesulfamido-2,6-dimethoxypyrimidinate) pentahydrate

The X-ray analysis of a single crystal of Mg(C₁₂H₁₃N₄O₄S)₂·11H₂O, where (C₁₂H₁₃N₄O₄S)^? is the anion of 4-p-aminobenzenesulfamido-2,6-dimethoxypyrimidine (sulfadimethoxine) is carried out. Unit cell parameters are: a = 19.753(4) Å, b = 34.031(7) Å, c = 13.859(3) Å; β = 125.37(3)°, C2/c, Z = 8, R(F) = 0.042. The structure is built of [Mg(OH₂)₆]²⁺, (C₁₂H₁₃N₄O₄S)^?, and water molecules and corresponds to the formula [Mg(OH₂)₆](C₁₂H₁₃N₄O₄S)₂·5H₂O. The IR bands of ν_asymSO₂ and ν_symSO₂ are bathochromically shifted as a result of their participation in hydrogen bonding, and not because of any direct coordination of sulfadimethoxinate anion to the complexing atom through oxygen.     

Synthesis and properties of tetra-(4-<Emphasis Type="Italic">tert</Emphasis>-butyl-5-nitro)phthalocyanines

The interaction of 4-tert-butyl-5-nitrophthalonitrile with a series of metal acetates has yielded the corresponding metal phthalocyaninates. The treatment of magnesium tetra(4-tert-butyl-5-nitro)phthalocyaninate with hydrochloric acid has afforded tetra(4-tert-butyl-5-nitro)phthalocyanine. Spectral properties of the prepared macrocycles have been studied. The nature of the organic solvent and the complex forming metal marginally affect the position of the Q band in the electron absorption spectra of the studied compounds. It has been demonstrated that the prepared phthalocyanines can dye polymer materials and are catalytically active towards oxidation of a model sulfur-containing compound.     

Heat capacities and thermodynamic properties of (<Emphasis Type="Italic">S</Emphasis>)-<Emphasis Type="Italic">tert</Emphasis>-butyl 1-phenylethylcarbamate

An N-tert-butyloxycarbonylated organic synthesis intermediate, (S)-tert-butyl 1-phenylethylcarbamate, was prepared and investigated by means of differential scanning calorimetry (DSC) and thermogravimetry (TG). The molar heat capacities of (S)-tert-butyl 1-phenylethylcarbamate were precisely determined by means of adiabatic calorimetry over the temperature range of 80-380 K. There was a solid–liquid phase transition exhibited during the heating process with the melting point of 359.53 K. The molar enthalpy and entropy of this transition were determined to be 29.73 kJ mol⁻¹ and 82.68 J K⁻¹ mol⁻¹ based on the experimental C _p–T curve, respectively. The thermodynamic functions, [H_T⁰ - H_298.15⁰ H_{T}^{0} - H_{298.15}^{0} ] and [S_T⁰ - S_298.15⁰ S_{T}^{0} - S_{298.15}^{0} ], were calculated from the heat capacity data in the temperature range of 80–380 K with an interval of 5 K. TG experiment showed that the pyrolysis of the compound was started at the temperature of 385 K and terminated at 510 K within one step.     

DFT-calculated structure of protonated tetraphenyl <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">tert</Emphasis>-butylcalix[4]arene tetraketone

Using DFT calculations, two of the most probable structures (A, B) of the tetraphenyl p-tert-butylcalix[4]arene tetraketone·H₃O⁺ cationic complex species were derived. The hydroxonium ion H₃O⁺, placed in the coordination cavity formed by the calix[4]arene lower-rim groups, is bound by strong hydrogen bonds to the phenoxy oxygen atoms of the calix[4]arene ligand (structures A, B) and also to one carbonyl oxygen (structure B). Correspondence: Emanuel Makrlík, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic.     

Complexes of palladium(II) and platinum(II) with 6-<Emphasis Type="Italic">tert</Emphasis>-butyl-2-thiouracil

cis-Dihalogeno complexes of platinum(II) and palladium(II) with 6-tert-butyl-2-thiouracil have been synthesized. The mode of coordination of the ligand to metal ions was established by IR and NMR spectroscopy.     

Syntheses,structures, and electrochemical properties of the tin(IV) complexes based on the 2-hydroxy-4-<Emphasis Type="Italic">N</Emphasis>-(phenyl)-3,6-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-<Emphasis Type="Italic">p</Emphasis>-iminobenzoquinone ligand

A series of the new tin(IV) complexes based on the 2-hydroxy-4-N-(phenyl)-3,6-di-tert-butyl-p-iminobenzoquinone ligand (LH) containing various hydrocarbon substituents R at the metal atom (R = Me, Et, ⁿ Bu, ^t Bu, and Ph) is synthesized. The structures of the synthesized compounds were determined by elemental analysis, IR spectroscopy, and ¹H and ¹¹⁹Sn NMR spectroscopy. The X-ray diffraction analyses are carried out for the LSnPh³ (I) and L²SnEt² (IV) complexes (CIF files CCDC no. 1557840 (I) and 1557839 (IV)). The main electrochemical characteristics in a solution are obtained for the whole series by cyclic voltammetry.     

Metal complexes of tetra(6-<Emphasis Type="Italic">tert</Emphasis>-butyl-2,3-quinolino)porphyrazine: II. Spectral properties

Quanitative spectral characteristics of Cu, Co, Zn, and Ni tetra(6-tert-butyl-2,3-quinolino)porphyrazine complexes prepared for the first time and soluble in hydrophobic liquids were measaured. Analogous spectral data of the protonated forms of complexes dissolved in sulfuric acids were also evaluated.     

Synthesis of acridinyl- and fluorenylidenehydrazido derivatives of <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">tert</Emphasis>-Butylcalix[4]arene

p-tert-Butylcalix[4]arenes substituted at the lower rim by acetic acid hydrazide residues reacted with methoxy(ethoxy)acridine and fluoren-9-one derivatives to give a series of calixarenes containing N′-fluorenylidene- and N′-acridinylacetohydrazide residues. It was found that modification of the hydrazide moiety does not affect the conformation of the initial macroring and that it can lead in some cases to unsymmetrically substituted calixarenes.     

Yttrium complexes with 3,6-bis(<Emphasis Type="Italic">tert</Emphasis>-butylcatecholate)

Heterometallic complex [K₃Y(Cat³⁶)₃(Dme)₄] (I) or binuclear complex [Y₂(Cat³⁶)₃(Dme)₃] · Dme (II · Dme) is synthesized, depending on the reactant ratio, by the reaction of YCl₃ with 3,6-bis(tertbutylcatecholate) potassium salt (K₂Cat³⁶) in 1,2-dimethoxyethane (Dme). Both complexes are characterized by single-crystal X-ray diffraction analysis (CIF files CCDC nos. 1527929 (I) and 1527930 (II)) and ¹H and ¹³C NMR spectroscopy.     

Synthesis of Mono- and Tetraalkylamide Derivatives of <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">tert</Emphasis>-Butylthiacalix[4]arene

Mono- and tetrasubstituted derivatives of p-tert-butylthiacalix[4]arene containing acrylate and acrylamide fragments are synthesized for the first time. The Michael aza-addition of benzylamine to the synthesized acrylamide and acrylate thiacalixarene derivatives is studied.     

<Emphasis Type="Italic">bis</Emphasis>(<Emphasis Type="Italic">N,N</Emphasis>-diethylnicotinamide) <Emphasis Type="Italic">p</Emphasis>-chlorobenzoate complexes of Ni(II), Zn(II) and Cd(II)

Three novel mixed ligand complexes of Ni(II), Zn(II) and Cd(II) with p-chlorobenzote and N,N-diethylnicotinamide were synthesised and characterized on the basis of elemental analysis, FTIR spectroscopic analysis, solid state UV-Vis spectrometric and magnetic susceptibility data. The thermal behavior of the complexes was studied by simultaneous TG-DTA methods in static air atmosphere and the mass spectra data were recorded. According to microanalytical results, formulas of complexes are C₃₄H₄₀N₄O₈ClNi, C₃₄H₄₀N₄O₈ClZn and C₃₄H₄₄N₄O₁₀ClCd. The complexes contain two moles of coordination waters, two moles p-chlorobenzoate and two mole N,N-diethylnicotinamide (dena) ligands per formula unit. In these complexes, the p-chlorobenzoate and N,N-diethylnicotinamide behave as monodentate ligand through acidic oxygen and nitrogen of pyridine ring. The decomposition pathways and the stability of the complexes are interpreted in the terms of the structural data. The final decomposition products were found to be as metal oxides.