Experimental and Theoretical Investigations of Complex Formation of Substituted Phenylazo-Derivatives of Methylphloroglucinol

Using spectrophotometric titration technique, the processes of complex formation of some phenylazo-derivatives of methylphloroglucinol (MPG) containing hydroxo-, nitro- and nitroso-substituents were studied. The spectral criteria of neutral and ionized forms of the organic ligands in their different tautomeric forms were determined.It was detected that the complex formation is accompanied by formation of one or two chelate cycles which involve azo- or nitroso-fragments and neighboring OH-groups of the organic ligands. Different types of coordination lead to different changes in the electronic absorption spectra.The DFT-B3LYP modeling of a Ni(II) complex of α-hydroxyphenylazo MPG established the most probable coordination mode of the organic ligand: tridentate chelating dianion, distorted square coordination of Ni-cations including one water molecule.  The theoretical results are in a good accordance with the experimental data

Experimental and Theoretical Investigations of Complex Formation of Substituted Phenylazo-Derivatives of Methylphloroglucinol

Using spectrophotometric titration technique, the processes of complex formation of some phenylazo-derivatives of methylphloroglucinol (MPG) containing hydroxo-, nitro- and nitroso-substituents were studied. The spectral criteria of neutral and ionized forms of the organic ligands in their different tautomeric forms were determined.It was detected that the complex formation is accompanied by formation of one or two chelate cycles which involve azo- or nitroso-fragments and neighboring OH-groups of the organic ligands. Different types of coordination lead to different changes in the electronic absorption spectra.The DFT-B3LYP modeling of a Ni(II) complex of α-hydroxyphenylazo MPG established the most probable coordination mode of the organic ligand: tridentate chelating dianion, distorted square coordination of Ni-cations including one water molecule.  The theoretical results are in a good accordance with the experimental data

PENGGUNAAN TEKNIK MURDER PENDEKATAN METAKOGNITIF UNTUK MENINGKATKAN PENALARAN MATEMATIS MAHASISWA PENDIDIKAN MATEMATIKA PADA MATAKULIAH GEOMETRI ANALITIK

Tujuan dari penelitian ini adalah menelaah peningkatan kemampuan penalaran matematis mahasiswa yang memperoleh pembelajaran teknik MURDER pendekatan metakognitif dan mahasiswa yang memperoleh pembelajaran ekspositori pada materi garis dan lingkaran. Penelitian ini merupakan penelitian kuantitatif. Subjek penelitian adalah mahasiswa tingkat dua kelas A dan kelas B yang terdiri dari 35 mahasiswa. Metode pengumpulan data yang digunakan meliputi: (1) tes kemampuan penalaran matematis, (2) observasi, (4) dokumentasi. Data dianalisis menggunakan uji-t atau uji mann whitney. Hasil temuan penelitianin adalah: (1) Peningkatan kemampuan penalaran matematis mahasiswa yang memperoleh pembelajaran teknik MURDER pendekatan metakognitif lebih baik daripada peningkatan kemampuan penalaran matematis mahasiswa yang memperoleh pembelajaran ekspositori; (2) kualifikasi peningkatan penalaran matematis yang menggunakan pembelajaran teknik MURDER pendekatan metakognitif dan pembelajaran ekspositori masih dalam kategori sedang

Structure of Monomeric Octahedral d ²-Rhenium(V) Monooxo Complexes [ReO(L_tri)(L_bi)] and [ReO(L_tetra)(L_mono)] with Oxygen Atoms of Tridentate (O, O, O) and Tetradentate (O, O, O, O) Chelating Ligands

The structural features of four mononuclear octahedral d2-Re(V) monooxo complexes [ReO(Ltri)(Lbi)] and [ReO(Ltetra)(Lmono) with tridentate (O, O, O) and tetradentate (O, O, O, O) chelating ligands are discussed. It is shown that the Re–O(Ltri)trans bonds are elongated, whereas the Re–O(Ltetra)trans bonds are shortened as compared to the Re–O(L)cis bonds

Structure of Monomeric Octahedral d 2-Rhenium(V) Monooxo Complexes [ReO(Ltri)(Lbi)] and [ReO(Ltetra)(Lmono)] with Oxygen Atoms of Tridentate (O, O, O) and Tetradentate (O, O, O, O) Chelating Ligands

Abstract: The structural features of four mononuclear octahedral d2-Re(V) monooxo complexes [ReO(Ltri)(Lbi)] and [ReO(Ltetra)(Lmono) with tridentate (O, O, O) and tetradentate (O, O, O, O) chelating ligands are discussed. It is shown that the Re–O(Ltri)trans bonds are elongated, whereas the Re–O(Ltetra)trans bonds are shortened as compared to the Re–O(L)cis bonds. © 2019, Pleiades Publishing, Ltd

Synthesis and Physicochemical Properties of Chromium(III) and Iron(III) Complexes with Bromonitrofluorenones

Polynuclear complexes [M3O(CH3COO)6(H2O)2L]OH and Fe2O(CH3COO)4L2 2 (H2O)2, where M = Cr(III), Fe(III); L = 5-bromo-2,4,7-trinitrofluorenone (L1) and 4,5-dibromo-2,7-dinitrofluorenone (L2), were synthesized. Quantum-chemical calculation of the electronic structure and spectra of 5-chloro-2,4,7-trinitrofluorenone was performed by the Pariser-Parr-Pople method. IR and electronic absorption spectra indicate that bromonitrofluorenones are incorporated into trinuclear (μ-oxo)acetato complexes as neutral terminal ligands coordinated through the carbonyl oxygen

Инновационный подход к утилизации автомобильных шин. Проблемы и перспективы

A new method of dissolution of the used car tires in the different organic solvents at elevated temperature and pressure was tried. An efficiency rating of swelling of the car tires' samples was found: optimal proportion of solvent, rubber, the time of effective swelling and pressure. As the result it was found out that the tire is entirely swelling under such conditions and there is an opportunity of easy recovery of the metal circlet and cord from it, which increases the rubber quality and facilitate the process of recycling of the car tires

Synthesis and Physicochemical Properties of Chromium(III) and Iron(III) Complexes with Bromonitrofluorenones

Polynuclear complexes [M3O(CH3COO)6(H2O)2L]OH and Fe2O(CH3COO)4L2 2 (H2O)2, where M = Cr(III), Fe(III); L = 5-bromo-2,4,7-trinitrofluorenone (L1) and 4,5-dibromo-2,7-dinitrofluorenone (L2), were synthesized. Quantum-chemical calculation of the electronic structure and spectra of 5-chloro-2,4,7-trinitrofluorenone was performed by the Pariser-Parr-Pople method. IR and electronic absorption spectra indicate that bromonitrofluorenones are incorporated into trinuclear (μ-oxo)acetato complexes as neutral terminal ligands coordinated through the carbonyl oxygen