C, N and Sn NMR spectral evidence for tin five-coordination in triorganotin(IV) oxinates

The ¹³C and ¹¹⁹Sn NMR spectra of tri(1-butyl)tin(IV) and triphenyltin(IV) oxinates and 1-naphthoxides in neat liquid and deuteriochloroform, pentadeuteriopyridine and hexamethylphosphortriamide solutions, and the ¹⁵N NMR spectra of both the oxinates and 8-methoxyquinoline in deuteriochloroform have been recorded. From the comparison of chemical shifts δ(¹³C), δ(¹⁵N) and δ(¹¹⁹Sn) and coupling constants ⁿJ(¹¹⁹Sn¹³C) of the compounds it is concluded that the triorganotin(IV) oxinates, both as the neat liquid and in solution, form complexes containing five-coordinate tin atoms. In the neat liquid and in deuteriochloroform (a non-coordinating solvent) oxinates form chelate complexes with a cis-trigonal bipyramid arrangement. In coordinating solvents (pentadeuteriopyridine, hexamethylphosphortriamide) these are equilibria involving the formation of small amounts of oxinate complexes with one solvent molecule. These complexes have trans-trigonal bipyramid geometry with butyl or phenyl groups in equatorial plane and the monodentate oxinate group and a solvent molecule in axial positions.     

The structural phase transitions of aminoguanidinium(1+) dihydrogen phosphate—study of crystal structures, vibrational spectra and thermal behavior

Aminoguanidinium(1+) dihydrogen phosphate was prepared by crystallization from aqueous solution. On the basis of the results of DSC measurements, X-ray structural analysis was carried out at temperatures of 160, 215 and 293 K for three aminoguanidinium(1+) dihydrogen phosphate phases ( |Z=2|non-ferroic |melting point 408 K; II |201-222 K|(2) |Z=2|non-ferroic|-; III |<201 K|(2)|Z=4|non-ferroic|-). The triclinic unit cell dimensions (a=6.8220(2), b=7.1000(2), c=7.4500(2) Å, α=86.925(2)°, β=80.731(2)°, γ=79.630(2)°, V=350.21(2) Å³—phase I) are similar for all three structural phases with the exception of phase III, where doubling of the c-axis length leads to an increase in the volume to 692.34(3) Å³. The crystal structure of all three modifications consists of parallel layers of dihydrogen phosphate anions that are interconnected by aminoguanidinium(1+) cations through hydrogen bonds of the N-H…O type. The planar aminoguanidinium(1+) cations are oriented almost parallel to each other and are perpendicular to the anion layers. The primary differences amongst phases I, II and III lie in the location of the H atom in the short O-H…O bonds connecting the dihydrogen phosphate anions in layers. The FTIR and FT Raman spectra of natural and deuterated compounds were recorded and interpreted. The FTIR spectra were studied down to a temperature of 90 K.     

Voltammetric and X-ray diffraction analysis of the early stages of the thermal crystallization of mixed Cu,Mn oxides

Mixed Cu,Mn, Cu,Mn,Al, Cu,Mg,Mn, and Cu,Mg,Mn,Al oxides were obtained by calcination of amorphous basic carbonate (Cu,Mn oxides) or hydrotalcite-like precursors at 300–800 °C. The product composition was characterized by chemical analysis, XRD, and voltammetry of the microparticles. The XRD amorphous portion was detected indirectly by XRD and directly by voltammetry. Tenorite (CuO) and spinels were the main crystalline components of the oxide mixtures. The presence of Al shifted the onset of the crystallization of XRD-detectable tenorite and spinel to temperatures higher by 100–200 °C, and the presence of Mg shifted tenorite crystallization by 100 °C, but voltammetry was able to detect these phases even in XRD-amorphous or nanocrystalline calcines. Voltammetry is hence suitable for analysis of poorly crystalline oxides that can be used in heterogeneous catalysis.     

Über Reaktionen von Nitrosophenolen, 3. Mitt.: Reaktion von 2-Nitroso-1-naphthol mit Resorcin und Orcin

Zusammenfassung Die Reaktion von 2-Nitroso-1-naphthol mit Resorcin bzw. Orcin in Äther bei Anwesenheit von HNO₃ liefert Benzo[c]phenoxazon-(9) (I), Benzo[c]phenoxazon-(9)-12-oxid (II), Methyl-benzo[c]phenoxazon-(9) (III) sowie 11-Methyl-benzo[c]phenoxazon-(9)-12-oxid (IV). Die Struktur der isolierten Substanzen wurde durch Reduktion mittels TiCl₃ sowie durch die UV- und IR-Spektren gestützt.

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The reaction of 2-nitroso-1-naphthol with resorcinol and orcinol in ether solution in the presence of nitric acid has been studied. From the reaction mixture the benzophenoxazones I–IV have been isolated. Structures were assigned on the grounds of UV and IR spectra and partly by using TiCl₃ as a reducing agent.

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Mit 1 Abbildung     

Untersuchung der kinetik von azokupplungs-reaktionen mittels direkter injektions-enthalpiemetrie

The present paper deals with the application of direct injection enthalpimetry (DIE) in the study of the kinetics of azo coupling reactions. On the example of the coupling of diazotized aniline-4-sulphonic acid with 1,8-dihydroxynaphthalene-3,6-disulphonic acid, it was verified that the rate constants determined using DIE are comparable with those determined using spectrophotometry. Advantages result from the application of DIE in the study of the kinetics of azo coupling reactions.     

Synthesis of 3‐thiocyanato‐1H,3H‐quinoline‐2,4‐diones

4‐Hydroxy‐1H‐quinolin‐2‐ones ( 1 ) react with thiocyanogen in acetic acid to the corresponding 3‐thiocyanato‐1H,3H‐quinoline‐2,4‐diones ( 2 ) in good yields. In some cases, 3‐bromo‐1H,3H‐quinoline‐2,4‐diones ( 4 ) were isolated as minor reaction products. Compounds 2 are very reactive towards nucleophiles and easily hydrolyze to the corresponding 4‐hydroxy‐1H‐quinoline‐2‐ones ( 1 ).     

Square-Planar Nickel(II) O,O′-Dialkyldithiophosphato Complexes with Triphenylphosphine of the Type [NiX(S2P{OR}2)(PPh3)] (X = Cl,Br, I and NCS)

A series of new [NiX(S₂P{O-c-Hex}₂)(PPh₃)](X = Cl^–, Br^–, I^– and NCS^–)(1)–(4) and [Ni(NCS)(S₂P{OR}₂)(PPh₃)][R =n-Pr (5), i-Pr (6)] complexes has been synthesized and characterized by elemental analyses, f.i.r., i.r., u.v.–vis., ¹H-, ¹³C{¹H}- and ³¹P{¹H}-n.m.r. spectra, magnetochemical and conductivity measurements. A single crystal X-ray analysis of [Ni(NCS)(S₂P{O-n-Pr}₂)(PPh₃)](5) reveals the molecular structure of the complex and confirms a square-planar geometry around the central atom of nickel with the NCS anion coordinated via the nitrogen atom.     

Auger electron spectroscopy of a hydrogenated amorphous silicon

Thin layers of a hydrogenated amorphous silicon were studied by means of the Auger electron spectroscopy (AES). It was found that the spectra of the a-Si : H samples exhibit a large peak at 34 eV which was ascribed to the L₁L₂₃V Coster-Kronig transition and that the intensity of the L₂₃VV transition was lowered, due to hydrogenation. The explanation of this feature is given on the basis of the electronic structure and the transition probabilities changes in silicon, due to hydrogenation. The results on the a-Si : H layer were compared with measurement of the a-Si layer and the influence of an electron and an ion bombardment, an elevated temperature and an exposure to oxygen on both layers was studied.The author would like to expres hiss thanks to Dr. J. Zemek for supplying the a-Si and a-Si : H layers, to Dr. J. Drahokoupil and Dr. J. imnek for stimulating discussions and to Dr. V. Cháb for helpful discussions and for his help with measurements.     

Nuclear structure effect in internal conversion of the 166 kev hinderedM1 transition in139La

The internal conversion coefficients were calculated for the 165.853 keV 5/2⁺7/2⁺ hindered transition in ₅₇ ¹³⁹ La using the new computer program NICC for conversion coefficients of all atomic shells. The algorithm employed in this code is described. The analysis of precise experimental data yielded the nuclear penetration parameter=4.2±0.8. This value was found to be in accord with theoretical estimates and to correspond to the Nilsson deformation parameter=–0.056±0004 of the¹³⁹La nucleus. Using the Nilsson wave functions for above the mixing ratio ² = N(E2)/N(M1) was determined to be less than 8.10^–5, which supports the assumption of a pureM1 multipolarity of this transition.Presented at the 26th All-Union Conference on Nuclear Spectroscopy and Nuclear Structure (February 1976, Baku, USSR).We are obliged to Dr. B. N.Subba Rao for the communication of his value for the investigated transition.     

Rhodium(I) complexes with 1′-(diphenylphosphino)ferrocenecarboxylic acid as active and recyclable catalysts for 1-hexene hydroformylation

The rhodium complex trans-[Rh(CO)(Hdpf-κP)(dpf-κ²O,P)] (1), (Hdpf = 1′-(diphenylphosphino)ferrocenecarboxylic acid) was used as an efficient and recyclable catalyst for 1-hexene hydroformylation producing ca. 80% of aldehydes at 10 atm CO/H₂ and 80 °C. After the reaction, unchanged complex 1 was separated from the reaction mixture and used again three times with the same catalytic activity. The effect of modifying ligands, phosphines and phosphites, on the reactivity of 1 was investigated. The active catalytic systems containing 1 or trans-[Rh(CO)(L)(dpf-κ²O,P)] (2) were formed in situ from acetylacetonato rhodium(I) precursors [Rh(CO)₂(acac)] (3) or [RhL(CO)(acac)] (4) and Hdpf or Medpf (L = phosphine, Medpf = methyl ester of Hdpf).