Synthesis and characterization of soluble seco-porphyrazines with bulky substituents

By cyclotetramerization of 3,4-bis(4-tert-butylphenyl)pyrroline-2,5-diimine in the presence of magnesium butanolate, magnesium porphyrazinate with eight (4-tert-butylphenyl) units on the periphery has been synthesized. Its demetalation by the treatment with trifluoroacetic acid resulted in a partially oxidized product, namely, octakis(4-tert-butylphenyl)-2-seco-porphyrazine-2,3-dione. Further reaction of this product with copper(II) acetate, zinc(II) acetate, and cobalt(II) acetate led to the metallo derivatives, [octakis(4-tert-butylphenyl)-2-seco-2, 3-dioxoporphyrazinato]M(II) (M = Cu, Zn, Co). These soluble complexes have been characterized by elemental analysis, FT-IR, ¹H NMR, UV-Vis, and mass spectral data.     

Synthesis and characterization of soluble porphyrazines bearing octakis 2-anthraquinonylmethylthio substituents

By cyclotetramerization of 1,2-bis(2-anthraquinonylmethylthio)maleonitrile in the presence of magnesium butanolate, magnesium porphyrazinate carrying eight (2-anthraquinonylmethylthio) functional groups on peripheral positions has been synthesized. The metal-free derivative was obtained by treatment with tri?uoroacetic acid; reaction of this product with copper(II) acetate, zinc(II) acetate, and cobalt(II) acetate led to the metal porphyrazinates [M?=?Cu(II), Zn(II), and Co(II)]. These new compounds have been characterized by elemental analysis, together with FT-IR, ¹H-NMR, ¹³C-NMR, UV-Vis, and mass spectral data.     

Synthesis and spectral properties of novel seco-porphyrazines with eight 4-biphenyl groups

Magnesium porphyrazinate substituted with eight 4-biphenyl groups on the periphery positions has been synthesized for the first time from cyclotetramerization of 1,2-bis(4-biphenyl)maleonitrile in the presence of magnesium butanolate. Its demetalation by treatment with trifluoroacetic acid, resulted in a partially oxidized product, namely, octakis(4-biphenyl)-2-seco-porphyrazine-2,3-dione. Further reaction of this product with copper(II) acetate, zinc(II) acetate and cobalt(II) acetate has led to the metallo derivatives, [octakis(4-biphenyl)-2-seco-2,3-dioxoporphyrazinato] M(II) (M = Cu, Zn, Co). These novel compounds have been characterized by elemental analysis, together with FT-IR, ¹H NMR, UV–Vis and mass spectral data.     

Vanadyl(IV) complexes of 4-alkoxy substituted [N,O] donor salicylaldimine Schiff bases derived from chloro-/nitro-aniline: synthesis,mesomorphism, and DFT study

Oxovanadium(IV)-Schiff-base complexes, [VOL₂] {L?=?N,N′-bis-(4-X-amino phenyl (4′-n-alkoxy)-salicylaldiminato), n?=?10, 18; X?=?Cl, NO₂}, have been synthesized from the interaction of vanadyl (VO²⁺) and the bidentate [N,O] donor in methanol/ethanol. The compounds were characterized by FT–IR, ¹H- and ¹³C-NMR, FAB-mass spectra, elemental analyses, and solution electrical conductivity. Mesomorphic behavior of the ligands and their vanadyl complexes were probed by polarizing optical microscopy and differential scanning calorimetry. The compounds are thermally stable and exhibit enantiotropic smectic A mesomorphism over the temperature range of 57–231°C. The mesophase–isotropic transition temperatures for the complexes are much higher than the ligands. Melting and clearing points of the compounds did not show any definitive trend with regards to alkoxy chain length or electronegative substituent. Variable temperature magnetic susceptibility measurements of the vanadyl complexes clearly show the absence of exchange interactions among the vanadyl spin centers. Non-electrolytic natures of the complexes were shown by conductometric measurements. A ν(V=O) of ～970?cm^?1 corroborated the absence of any V=O?···?V=O interactions. Density functional theory study carried out using DMol3 at BLYP/DNP level to determine the energy-optimized structure revealed a distorted square pyramidal geometry for the vanadyl complexes.     

A NEW PERSPECTIVE ON VANADYL TARTRATE DIMERS. PART II. STRUCTURE AND SPECTROSCOPIC PROPERTIES OF CALCIUM VANADYL TARTRATE TETRAHYDRATE

Abstract

The calcium vanadyl tartrate complex [Ca(VO)(d,l-C₄H₂O₆)(H₂O)₄] has been synthesized and characterized by spectroscopic methods. Its crystal structure was solved by X-ray methods. The compound is monoclinic, space group P2₁/c, with a = 8.0282(5), b = 17.1568(8), c = 7.6113(3)Å, β = 94.269(4)° and Z = 4. The structure consists of centrosymmetric vanadyl tartrate dimers, [(VO)(d,l-C₄H₂O₆)]₂ ^4-, and calcium cations placed between them. As a result, dimers form chains in the [101] direction. Neighbouring chains are linked by the coordination of the calcium ion to the oxygen atom of a vanadyl group of a different chain, thus forming a two-dimensional structure. Different layers are linked by hydrogen bonds. Spectroscopic studies show the existence of intra-dimeric interactions between vanadium atoms.     

Synthesis,Electrochemical and Luminescence Studies of Nickel and Vanadium Complexes Containing Tetradentate Schiff Base Ligand with N2O2 Donor Atoms

A symmetrical tetradentate Schiff base ligand was derived by the condensation of ortho‐vanillin and thiourea in 2:1 molar ratio and adjusted pH. Nickel and vanadyl complexes were obtained using the template method by the reaction of ortho‐vanillin and thiourea with Ni(OAc)₂. 4H₂O and VO(acac)₂ (2:1:1 molar ratio) in absolute ethanol and adjusted pH. The Schiff base ligand and its complexes have been characterized by FT‐IR, ¹H NMR, UV/Vis, elemental analysis and conductometry measurements. In nickel and also vanadyl complexes the ligands were coordinated to the metals via the imine N and enolic O atoms. The complexes have been found to possess 1:1 metal to ligand stoichiometry and the molar conductance data revealed that the metal complexes were non‐electrolytes. The nickel and vanadyl complexes exhibited tetrahedral and square pyramidal coordination geometry, respectively. The emission spectra of the ligand and its complexes were studied in DMSO. Electrochemical properties of the ligand and its complexes were also investigated in the DMF solvent at the 150 mVs^‐1 scan rate. The ligand and its complexes showed irreversible processes at this scan rate.     

Synthesis,characterization and α‐amylase and α‐glucosidase inhibition studies of novel vanadyl chalcone complexes

A series of chalcone ligands and their corresponding vanadyl complexes of composition [VO (L^I–IV)₂(H₂O)₂]SO₄ (where L^I = 1,3‐Diphenylprop‐2‐en‐1‐one, L^II = 3‐(2‐Hydroxy‐phenyl)‐1‐phenyl‐propenone, L^III = 3‐(3‐Nitro‐phenyl)‐1‐phenyl‐propenone, L^IV = 3‐(4‐Methoxy‐phenyl)‐1‐phenyl‐propenone) have been synthesized and characterized using various spectroscopic (Fourier‐transform infrared, electrospray ionization mass, nuclear magnetic resonance, electron paramagnetic resonance, thermogravimetric analysis, vibrating sample magnetometer) and physico‐analytic techniques. Antidiabetic activities of synthesized complexes along with chalcones were evaluated by performing in vitro and in silico α‐amylase and α‐glucosidase inhibition studies. The obtained results displayed moderate to significant inhibition activity against both the enzymes by vanadyl chalcone complexes. The most potent complexes were further investigated for the enzyme kinetic studies and displayed the mixed inhibition for both the enzymes. Further, antioxidant activity of vanadyl chalcone complexes was evaluated for their efficiency to release oxidative stress using 2,2‐diphenyl‐1‐picryl‐hydrazyl‐hydrate assay, and two complexes (Complexes 2 and 4 ) have demonstrated remarkable antioxidant activity. All the complexes were found to possess promising antidiabetic and antioxidant potential.     

A single crystal EPR study of VO ions doped in Cs2Co(SO4)2.6H2O Tutton salt

EPR spectra of VO²⁺ ions doped in single crystals of Cs₂Co(SO₄)₂.6H₂O single crystals have been studied at various temperatures (390–103 K) on X-band frequency. The detailed EPR analysis shows three vanadyl complexes with differing intensities. The g and A tensors are found to be axially symmetric. The intense vanadyl complexes in the lattice are found to occupy the Co²⁺ substitutional sites, whereas the weak vanadyl complex at the interstitial sites. The optical absorption spectrum at room temperature shows three absorption bands characteristic of VO²⁺ ions in tetragonal symmetry. By correlating the EPR and optical data, the molecular bonding coefficients and the Fermi contact interaction terms have been evaluated and discussed. The line broadening of VO²⁺ spectra on cooling the crystal is explained on the basis of spin-lattice relaxation narrowing. The spin-lattice relaxation time for the host Co²⁺ ions has been estimated at various temperatures.     

Synthesis and study of binuclear vanadyl complexes with acyldihydrazones of salicylaldehyde and dicarboxylic acids

The binuclear vanadyl(ii) complexes [(VO)₂·2Py·2EtOH]·mH₂O with acyldihydrazones of salicylaldehyde (H₄L) and dicarboxylic acids were synthesized and studied. In these complexes, two chelate vanadyl(ii) complexes with the tridentate bicyclic ligands are linked to each other by the polymethylene bridges —(CH₂) _n — of different lengths varying from one to four units. The ESR spectra of solutions of these complexes, unlike those of analogous copper(ii) complexes, have an isotropic signal with an eight-line hyperfine structure (g = 1.972, a _V = 93·10^–4 cm^–1) typical of monomeric vanadyl complexes, which indicates that no exchange interactions occur between the paramagnetic centers through the polymethylene chain.     

Solid-state interactions of vanadium and phosphorus oxides in the closed systems

Physicochemical processes during thermal treatment of vanadium and phosphorus oxides mixture (1) as well as with diammonium hydrophosphate (2) in the closed system (autoclave) have been studied. In the first case, at 300 °C, the defective structure γ-VOPO₄ is formed and in the second case, there was established possibility of synthesis of vanadyl hydrophosphate—the precursor of vanadyl pyrophosphate (the catalyst of n-butane oxidation to maleic anhydride). At the same time, various phases of mixed ammonium and vanadium phosphates were obtained at lower and higher temperatures.     

Liquid-crystalline oxovanadium(IV) complexes accessed from bidentate [N,O] donor salicylaldimine Schiff-base ligands

A series of bis[4-(n-alkoxy)-N-(4′-R-phenyl)salicylideneiminato]oxovanadium(IV) complexes (n?=?6,?10,?14,?16,?18 and R?=?C₃H₇) were prepared and their mesogenic properties were investigated. The mesomorphic behaviors of the compounds were studied by polarized optical microscopy and differential scanning calorimetry. Ligands display SmA/SmC and unexpected nematic mesophases. The complexes bearing longer alkoxy carbon chain (n?=?10,?14,?16, and 18) showed both monotropic or enantiotropic transitions with smectic A and high ordered smectic E phases. However, the complex with shorter carbon chain length (n?=?6) showed monotropic transition with an unprecedented nematic (N) phase. A density functional theory study was carried out using DMol3 at BLYP/DNP level to obtain a stable optimized structure. A square-pyramidal geometry for the vanadyl complexes has been suggested. A ν_V=O stretching value of ～970?cm^?1 corroborated absence of any V?=?O?···?V?=?O interactions. Cyclic voltammetry revealed a quasireversible one-electron response at 0.61?V for the VO(IV)–VO(V) redox couple. Variable temperature magnetic susceptibility measurements of the vanadyl complexes suggested absence of any exchange interactions among the vanadyl spin centers.     

Molecular recognition capability and rheological behavior in solution of novel lactone-based glycopolymers

Novel glycopolymers have been prepared from ethylene–vinyl alcohol copolymers, EVOH. For that purpose, three distinct aminosaccharides (N-(4-aminobutyl)-d-gluconamide (NABG), N-(4-aminobutyl)-O-β-d-galactopyranosyl-(1 → 4)-d-gluconamide (NABL) and N-(4-aminobutyl)-O-β-d-glucopyranosyl-(1 → 4)-d-gluconamide (NABM) have been synthesized. The previous functionalization of these EVOH copolymers is mandatory to activate their hydroxyl reactivity before the subsequent coupling reaction with the aminosaccharides. The activation with carboxylic acid groups by reaction with phthalic anhydride has been chosen in the current investigation because of its almost quantitative yield and the subsequent high modification extent reached (>60%). The glycopolymers that turned out water-soluble (i.e., those based on NABL and NABM) have shown a reversible network formation unusually described in glycopolymers. In addition, their capability to interact with lectins, particularly Concanavalin A and Ricinus communis Agglutinin, has confirmed the specificity of lectin recognition in these glycopolymers.     

N-(安替比林-4-基)-N'-取代芳甲酰基硫脲的合成及其生物活性

合成了12个含安替比林基的取代芳甲酰基硫脲类化合物, 用¹H NMR, IR和元素分析确证了它们的结构, 并进行了室内生物活性测试. 生测实验证明部分酰基硫脲类化合物, 比如N-(安替比林-4-基)-N'-m(或o)-甲苯甲酰基硫脲, N-(安替比林-4-基)-N-o-硝基苯甲酰基硫脲, N-(安替比林-4-基)-N'-m(或p)-氯苯甲酰基硫脲, 具有一定的细胞分裂素活性.     

The synthesis of novel dipyridazinothiazine ring systems

The synthesis of several dipyridazinothiazines have been accomplished by: (a) cyclization in concentrated hydrochloric acid solution of the appropriate intermediates; and (b) via the Smiles rearrangement in either basic or glacial acetic acid solution of the appropriate intermediates. The following ring systems have been prepared and characterized: 10H-dipyridazino-[4,3-b:4′,5′-e]-1,4-thiazine, 5H-dipyridazino[3,4-b:4′,5′-e]-1,4-thiazine, 10H-dipyridazino[4,5-b:-4′,5′-e]-1,4-thiazine, 5Hdipyridazino[5,4-b:4′,3′-e]-1,4-thiazine, and 10H-dipyridazino[3,4-b:-3′,4′-e]-1,4-thiazine.     

Synthesis and characterization of new soluble fluorinated seco-porphyrazines

Magnesium porphyrazinate substituted with eight 3,5-bis(trifluoromethyl)phenyl groups on the peripheral positions has been synthesized by the cyclotetramerization of 3,4-[3,5-bis(trifluoromethyl)phenyl]pyrroline-2,5-diimine in the presence of magnesium butanolate. Acid-mediated demetallation of the magnesium porphyrazine resulted in peripheral oxidation of one pyrrole ring to reveal the seco-porphyrazine, octakis[3,5-bis(trifluoromethyl)phenyl]-2-seco-porphyrazine-2,3-dione. Further reaction of this product with copper (II) acetate, zinc (II) acetate and cobalt (II) acetate has led to the metallo-derivatives, {octakis[3,5-bis(trifluoromethyl)phenyl]-2-seco-2,3-dioxoporphyrazinato} M(II) [M = Cu(II), Zn(II), Co(II)]. These new soluble complexes were characterized by elemental analysis, together with FT-IR, ¹H NMR, ¹³C NMR, ¹⁹F NMR, UV-Vis and mass spectral data.     

Studies on Enethiol-Thione Equilibrium of Some 1,5-Disubstituted 2,4-Dithiobiurets

Eaethiol contents of 1, 5-diphenyl 2, 4-dithiobiuret (DP); 1, 5-di-p-tolyl 2, 4-dithiobiuret (DPT); 1-phenyl 5-p-tolyl 2, 4-dithiobiuret (PPT); 1-phenyl 5-o-tolyl 2, 4-dithiobivret (POT); and 1-methyl 5-p-tolyl 2, 4-dithiobiuret (MPT) have been studied by alkali titration method in methanol and by spectrophotometric method in different solvents of varying polarities, ranging from pyridine (Z, 64.0) to methanol (Z, 83.6). Free energy of tautomerisation has been calculated. The effect of substituents on the phenyl group on enethiol contents have been studied. It has been observed that temperature has no effect on enethiol-thione equilibrium.     

Heterocyclic fused tropylium ions VII. On the synthesis of 9H-dithieno[2,1 -b:4,5-c′]tropylium fluoborate and 4H-dithieno[1,2-b:4,5-c′]tropylium fluoborate

9H-Dithieno[2,1 -b:4,5-c′]tropylium ion (III) and 4ii-dithieno[1,2-b:4,5-c′]tropylium ion (IV) have been synthesized by ring-closure of 1-(4-carboxy-3-thienyl)-2-(3′-thienyl)ethane (IX) and 1-(4-carboxy-3-thienyl)-2-(2′-thienyl)ethane (XVI), respectively, followed by bromination-debrom-ination to 9H-cyclohepta[2,1-b:4,5-c′] dithiophen-9-one (XI) and 4H-cyclohepta[1,2-b:4,5-c′]-dithiophen-4-one (XVIII), and finally by reduction and hydride transfer. The tropylium ions III and IV were less stable than the [b,b′]-fused isomers previously studied.     

Synthesis and Spectral Characterization of Some New 4-(2,6-Diarylpyridin-4-yl)-2H-chromen-2-ones

Some new 4-(2,6-diarylpyridin-4-yl)-2H-chromen-2-one derivatives 5a–l have been synthesized by reacting 4-(3-oxo-3-arylprop-1-enyl)-2H-chromen-2-ones 3a–c with appropriate 1-(2-oxo-2-arylethyl)pyridinium bromide salt 4a–d in the presence of ammonium acetate in refluxing glacial acetic acid. The newly synthesized compounds have been characterized by elemental and spectral analysis.     

19-O-Acetylchaetoglobosin B and 19-O-Acetylchaetoglobosin D,Two New Metabolites of Chaetomium globosum

Two new metabolites have been isolated from cultures of Chaetomium globosum. The structures of 19-O-acetylchaetoglobosin B ( 4 ) and 19-O-acetylchaetoglobosin D ( 5 ) are assigned. The ¹³C-NMR. spectra of chaetoglobosin A ( 1 ), 19-O-acetylchaetoglobosin A ( 2 ), chaetoglobosin C ( 3 ), 19-O-acetylchaetoglobosin B ( 4 ), 19-O-acetylchaetoglobosin D ( 5 ) and of cytochalasin G ( 6 ), a (3-indolyl)-[11]cytochalasan isolated from Pseudeurotium zonatum, have been interpreted.