Photochemical reaction of gadolinium(III) tetraphenylporphyrin in toluene solution containing an electron acceptor or donor

In this paper we have studied by absorption spectroscopy the course of the steady state photolysis of gadolinium(III) complex with 5,10,15,20-tetraphenylporphyrin. The result has been compared with the photolysis of free base tetraphenylporphyrin. Irradiation of GdTPP(acac) and H₂TPP (H₂TPP ≡ tetraphenylporphyrin; Hacac ≡ acetylacetone) with visible light in the presence of triethylamine as an electron donor, leads to their photoreduction. Formation of the gadolinium tetraphenylchlorin complex and tetraphenylchlorin is observed. The process of irradiation in the presence of CCI₄ as an electron acceptor has different pathways for GdTPP(acac) and H₂TPP. The gadolinium complex is mono oxidized, giving rise to the π⁺ radical cation while, for unmetallated porphyrin, dication H₄(TPP)²⁺ formation is observed.     

Inclusive meson resonance production inK + p interactions at 250 GeV/c

A detailed analysis of the inclusive production of the vector mesonsφ,K ^*+,0(892) \(\bar K*^0 (892),\rho ^{ + ,0} ,\omega \) and the tensor mesonsK ₂ ^*0 )(1430) andf ₂(1270) inK ⁺ p interactions at 250 GeV/c is presented The data are compared with results at lower energies and with various quark-parton models. The production ofρ ⁰,K ^*0(892) and \(\bar K*^0 (892)\) increases at the same rate as a function ofs, is concentrated in the central region and is not reproduced by the models. Production of the tensor mesonsf ₂(1270) andK ₂ ^*0 (1340) is suppressed relative toρ ⁰ andK ^*0(892) by a factor of about 3.     

Reactions of commercial ruthenium chlorides with O-donor ligands. Reactions with water: u.v.-vis. investigation of soluble products; analysis,thermogravimetry and an i.r. study of precipitated solids

Summary The u.v.-vis. absorption spectra of the products of reaction of commercial ruthenium chlorides with water have been measured. Deconvolution analysis revealed that hexaaquo-, pentaaquohydroxy- and pentaaquo-chlororuthenium(III) ions are formed, in addition to four unknown compounds.Analysis of the concentration data suggests the formation of soluble oligomers of the primary products over several hours following dissolution. Storage of the solution for ca. 170 h furnishes insoluble materials, characterized by analysis, thermogravimetry and i.r. The bulk of these solids can be described as [Ru_{2n + 2}O_{3n + 3}] ·mH₂O or [Ru_{2n + 2}O_{(3n + 3) - a} (OH)_2a ·mH₂O. We suggest the existence of ruthenium hydrides in these precipitated solids.     

The structure of lanthanide complexes with five membered sulfones and the specific benzene solvation

By means of a computer program based on the pseudo-contact equation, the structures of lanthanide complexes with five-membered sulfones have been established. The compounds are 1:1 bidentate complexes with the axis of complexation nearly parallel to the bisecting line of the O-S-O angle, and with the lanthanide position being at an average distance of 2.4 A from both oxygen atoms. The Ledal model, which assumes the specific benzene solvation, has been proposed as an adequate model for molecules with planar ring structure, and the distance between the benzene and solute along the preferential axis of complexation has been established as ~ 3.0 Å. The most probable conformation of the ring was taken into account because the accuracy of location of the lanthanide or benzene molecule in these complexes depends mainly on the correct model of the molecule assumed. Detailed analysis of the Eu(fod),-induced shifts in the PMR spectrum of NTBN sulfone confirmed the advanced structure of the complexes of five-membered ring sulfones with the lanthanide shift reagents.     

Non-radiative deactivation pathways of subphthalocyanine and subnaphthalocyanine dyes and of their mixture

Subphthalocyanine and subnaphthalocyanine dyes and their mixture were investigated by means of the spectroscopic and photoelectric methods. Absorption, fluorescence, steady-state and time-resolved photothermal measurements for the dyes and their mixture were done in order to get information about the radiative and non-radiative deactivation processes as competetive processes to charge separation. It was shown that energy transfer between the dyes improved the photocurrent generation in photoelectrochemical cells (PEC) based on In(2)O(3) and SnO(2) as an electrode. The possible participation of the dye triplet states in non-radiative processes was discussed.     

Ein neuer Eiweisskörper in der Milch

Analytical and Bioanalytical Chemistry -     

Synthesis of Chiral 2,4-Chiral 2,4-Dichloro-6-menthoxy-1,3,5-triazines and 2-Chloro-4, 6-Dimenthoxy-1,3,5-triazines as Enantiodifferentiating Coupling Reagents. An X-ray Study on 2,4,6-Trimenthoxy-1,3,5-triazine

Chiral mono-di-and trimenthoxy-1,3,5-triazines ware obtained from natural menthol and cyanuric chloride and applied as enantioselective coupling reagents in the synthesis of dipeptides.     

Dielectric studies of a ferroelectric liquid crystal

Measurements of the complex dielectric permittivity in the frequency range 30 Hz-13MHz have been made for the chiral smectic C and smectic A phases of the mixture ZLI-3654. In the S*_C phase a large contribution to the electric permittivity coming from the Goldstone mode was found. For the pretransitional region S*_C-S_A, only the soft mode has been detected. It is found that the molecular relaxation originating from the reorientation around the short axis is well separated from the soft mode even in the pretransitional region. The influence of different relaxation modes on the dielectric anisotropy is presented.     

NEW NATURAL SULFOXIDES OF NUPHAR ORIGIN. STRUCTURE,CHEMISTRY, PUMMERER REARRANGEMENT

Abstract

Further studies on basic compounds from Nuphar luteum L. Sm. resulted in isolation of a new group of sulfoxides with thiohemiaminal type of structure.     

Structure and dynamics of ferroelectric liquid crystals under random geometrical restrictions

The dynamics of ferroelectric liquid crystals confined in porous nitro-cellulose membrane (Synpor) are investigated by broadband dielectric spectroscopy, and a characterization of the mesomorphism is achieved by DSC and X-ray scattering. The complex inner membrane structure of random interconnected voids can be treated as a frozen random defect disorder in the mesophases. Its influence on the molecular dynamics of the confined mesogens is negligible. However, Goldstone and soft modes of DOBAMBC (2-methylbutyl 4-(4-decyloxybenzylideneamino)cinnamate) are suppressed by the confinement and not detected dielectrically. In the short pitch and high spontaneous polarization material C7, 4-(3-methyl-2-chloropentanoyloxy)-4'-heptyloxybiphenyl, confinement has a minor influence on the soft mode, and the Goldstone mode is clearly present, although with reduced strength, broadened with respect to the bulk, and shifted to higher frequencies by more than one decade. The results are interpreted as effects of random confinement on the length scale of the helical pitch.