Template synthesis in the nickel(II)–thiocarbohydrazide–propanone triple system

The complexing process proceeding in the Ni^II–thiocarbohydrazide (H₂N–H–NC(=S)–NH–NH₂)–propanone triple system in EtOH solution and nickel(II)hexacyanoferrate(II) gelatin-immobilized matrix has been studied. It has been found that in the first case, template synthesis leading, as a minimum, to formation of three coordination compounds of Ni^II with (N,N,S,S)-donor tetradentate ligands having NiL¹, NiL² and NiL³compositions where L¹ is 4,6,6-trimethyl-2,3,7,8-tetraazanonen-3-di(thiohydrazide)-1,9, L² is 4,6,6,12-tetrametyl-1,9-dithio-2,3,7,8,10,11-hexaazatridekadien-3,11-hydrazide-1 and L³ is 2,8,10,10,16-pentamethyl-5,13-dithio-3,4,6,7,11,12,14,15-octaazaheptadekatrien-2,7,15 is observed, whereas in the gelatin-immobilized matrix, a complexing process in the system considered does not occur.     

Chemische Vitamin D<Subscript>3</Subscript>-Bestimmung in Lebertran

The different aspects of Vitamin D₃ determination and the data reported in the literature are discussed. The spectrophotometric determination of Vitamin D₃ in cod-liver oil is carried out after the alkaline saponification, extraction of unsaponified parts, precipitation of accompanying sterols and the column- and thin-layer chromatographic purification and separation of vitamin D₃ on 40 cm plates from other vitamins. The dyestuff α-naphtholbenzein is suited well as standard substance for the better location and identification of vitamin D₃ zone on the thin-layer plate. The results obtained from the chemical method were checked through the simultaneous biological determination.     

Crystalline calmagite and a study of sulphonation effects on azo dye metal-ion indicators

Calmagite was introduced in 1960 as a stable substitute for Eriochrome Black T in EDTA titrations of calcium plus magnesium. The colour changes were the same but somewhat sharper. Indicator stock solutions were stable indefinitely. The new indicator was designed as an indicator and not as a wool dye. Azo dye impurities which may be present in some commercial supplies tend to lengthen the end-points. A simple means of removing these impurities to yield crystalline indicator has been developed. The effects of sulphonation on the performance of azo dyes as indicators have been studied.     

Adsorption kinetics and electrode processes

Prof. H. A. Laitinen (Urbana):We have used double layer capacity measurements to measure adsorption as a function of time during the life of slowly forming mercury drops. For many substances that are not extremely surface active, so that the solution concentration is 1 to 10 mM, the double layer capacity per unit area is essentially constant during the time interval of 5 to 15 sec of drop life. It appears, therefore, that adsorption equilibrium has essentially been attained during the later portions of drop life.Prof. P. Delahay:We have also used a similar method of following the differential capacity during drop life. I would agree that one can achieve conditions for which adsorption equilibrium with respect to bulk concentration is practically reached (high enough concentration and long drop time). But this is quite often not the case (drop time of 3–4 sec in polarography).Mr. G.C. Whitnack (China Lake, U.S.A.);In determination of nitrate esters in presence of phthalate esters we have observed considerable dropping of current height of nitrate ester wave before start of phthalate ester wave. Is this due to an adsorption process occurring at the DME?Prof. P. Delahay:It might well be, but I would hesitate to comment any further on this point because more information would be required. You probably have quite a complicated situation. Perhaps we can discuss the matter later?Prof. Dr. H. Fischer (Ettingen):Ich möchte hinzufügen, class es Fälle geben kann, in denen mcht allem der Blockierungseffekt don Grenzstrom verringert, sondern eine Veränderung des Diffusionsfilmes durch Sekundärreaktion des Inhibitors. Dies ist z.B. bei der Abscheidung von Wasserstoff an einer festen Elektrode (Fe) der Fall, wenn der Inhibitor sich spaltet in eine schwerlösliche Verbindung und ein Proton (RNH⁺ → [RN] + H⁺). Dies beobachtet man z.B, bei den Kationen von heterozyklischen Aminen (Acridin). Offentlich bildet sich eine diffusionshindernde Barriere aus.Prof. P. Delahay:The case of the hydrogen electrode is complicated, and I shall attempt to answer your question only in the case of an ideally smooth electrode. Then, diffusion toward the electrode (partially covered with an adsorbed substance) is little affected by adsorption because the size of “the holes” in the film is very small in comparison with the diffusion layer thickness. Of course, there is no diffusion where there is complete blocking.Prof. B. Breyer (Sydney):The importance of the chemical nature of the film adsorbed at the interface, which has been mentioned by Prof. delahay, seems to me to play a major part in the type of processes discussed. Thus it must be kept in mind that complex formation between the diachargeable ion and the adsorbed film might occur (cf. e.g. heyrovsky? and matyas, 1941). The fact that T1+ ion is little influenced by the presence of an adsorbed film at the electrode solution interface could then be partly explained by the notoriously low co-ordination tendency of that ion.Prof. P. Delahay:The difficulty involved in the “blocking” of the limiting current for thallium is due, I think, to the small size of this ion (large diffusion coefficient of Tl+ in comparison with other ions). Of course, complex ions can be relatively very bulky and this enhances “blocking”.Prof. E. Lange (Erlangen):I agree with prof. delahay that it is very important to investigate the connections between the adsorption and electrode reaction.This is easy for a steady state, e.g., each heterogeneous reaction between two phases that is accompanied by a transfer of ions or electrons, i.e. of electrical charges, from one phase to the other. In such a case, the Galvani tension does not change and the transfer between the two phases must be compensated by a corresponding transfer of charges within the phases.But in the non-steady state, also, an adsorption process may behave as an “electrode reaction” for instance, even an adsorption of a dipole molecule may cause a “transfer of charge” accompanied by a corresponding change of the Galvani tension. In this manner, it seems to me that for the non-steady state it is necessary to define precisely what one means by “electrode reaction”.Prof. P. Delahay:I entirely agree with Prof. i.ange about the necessity of clear definitions. I think that the fact that a steady state with respect to diffusion of the reductible or oxidizable substance has not been reached is not too serious because this scarcely affects the Galvani potential (large excess of supporting electrolyte).Variations in the amount of adsorbed organic substances indeed affect the Galvani potential (dipole orientation), but this effect is included in the dependence of the rate constant ks (at the standard potential) on the electrode coverage.Prof. N. Tanaka (Sendai, Japan).I am very grateful to Prof. delahay for his beautiful work on adsorption kinetics. I should like to make one comment in connection with the rotated dropping mercury electrode. The relation between log i and log t on the current — time curve was found to be 0.5 only in the absence of the surface-active substance. In the presence of surface-active substance, the slope of log i vs. log t changed at a certain point of the current — time curve. This can be explained when the slow adsorption of the surface-active substance on the surface of the electrode is taken into consideration.Prof. P. Delahay:Even for stirred solutions, adsorption equilibrium is not reached very rapidly. A simple calculation based on a model of the Nernst diffusion layer shows that perhaps 1–5 sec are required. Your conclusion is, therefore, quite correct.Prof. W. Kemula (Warsaw):We have recently published that, in several cases, the addition of extremely small concentrations of organic surface-active substances provokes at first a rise of the diffusion current, this current then being suppressed by additional quantities of the substance.     

Palladium salicylaldimine complexes containing boronate esters

Reactions of salicylaldehydes with boronate ester derivatives of aniline have been examined. Addition of these Schiff base ligands to palladium acetate or Na₂PdCl₄ afforded novel boron-containing trans-bis(N-arylsalicylaldiminato) palladium complexes.Condensation of salicylaldehyde (2-HOC₆H₄C(O)H) with H₂NC₆H₄Bpin (pin=1,2-O₂C₂Me₄) afforded the boron-containing Schiff bases, 2-HOC₆H₄C(H)=NC₆H₄Bpin (1–3a). Similar reactivity with 2-hydroxy-5-nitrobenzaldehyde and 2-hydroxy-1-naphthaldehyde gave the corresponding Schiff bases (1-3b) and (1-3c), respectively. Reaction of Schiff bases (2) and (3) with palladium acetate or Na₂PdCl₄ afforded complexes of the type PdL₂ (4,5), where L=deprotonated Schiff base. The molecular structure of the nitro-salicylaldehyde 4-Bpin palladium complex (5b) was characterized by an X-ray diffraction study. All new palladium compounds have been characterized fully and tested for their antifungal activity against Aspergillus niger and Aspergillus flavus.     

Rapid separation of phenylthiohydantoin amino acids: ambient pressure ion-mobility mass spectrometry (IMMS)

An electrospray ionization (ESI) ambient pressure ion-mobility spectrometer (APIMS) interfaced to an orthogonal reflector time-of-flight mass spectrometer (TOFMS) was evaluated for the first time as a detector for the identification of phenylthiohydantoin (PTH)-derivatized amino acids, the final products in the Edman sequencing process of peptides and proteins. The drift and flight times of the twenty common PTH amino acids were characterized by a well-defined 2-D mobility/mass spectral pattern. The combination of mobility/mass modes of analysis gave rise to a unique trend-line formation for the series of PTH amino acids. In addition, each PTH amino acid had a unique reduced mobility constant K(o), thus enabling the differentiation of all the amino acid derivatives including the PTH-leucine and PTH-isoleucine isomers. More importantly it was shown that it was possible to resolve a complete reference mixture of PTH amino acids in a single experimental run in less than 1 min. Detection limits for the PTH amino acids were found to range from 1.04 to 3.52 ng; indicating that the limits of detection were less than 17.0 pmol for all of the PTH amino acids.     

Synthesis,crystal structure and luminescent property of a novel H<Subscript>2</Subscript>O-bridged cobalt(II) polymer with one-dimensional chain structure

The coordination compound [Co(C₁₀H₇COO)₂(H₂O)₃]_2n · 4nH₂O was prepared by the reaction of 1-naphthoic acid and cobalt(II) acetate tetrahydrate in basic solution, and was fully characterized by X-ray diffraction, element analysis, FTIR, TG-DTA and luminescent spectra. In the crystal the six-coordinated Co(II) centers are linked into one-dimensional zigzag chains by water molecules, which are further assembled into a two-dimensional network through weak inter-chain C–H···π interactions. The solid complex exhibits favorable fluorescent properties similar to those of free ligand at room temperature, which can be assigned to the intraligand electronic transfer.     

Conversion of 3-benzoyl-1-methyl-4-phenyl-γ-piperidol by arylamines and arylhydrazines. Synthesis of 3-arylamino-1-oxo-1-phenylpropanes and 1,3-diarylpyrazoles and their fragmentation under electron impact

It has been established that on heating, 3-benzoyl-4-hydroxy-1-methyl-4-phenylpiperidine is ring-opened in the presence of arylamines by a type of retroaldol reaction, with subsequent transamination of the intermediate Mannich base and the formation of 3-arylamino-1-oxo-1-phenylpropanes. When using arylhydrazines this γ-piperidol is recyclized with the formation of 1,3-diarylpyrazoles and their 4,5-dihydro derivatives. The mass spectral behavior of a series of 3-arylamino-substituted 1-phenylpropanones has been studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1486–1495, October, 2007.     

The Effect of Alkane Chain Length on the Liquid–Liquid Critical Temperatures of Oligostyrene/Linear-Alkane Mixtures

Summary. Upper critical solution temperatures (UCSTs) for liquid–liquid demixing in a set of mixtures of linear alkanes (pentane (N ₁=5) to pentacontane (N ₁=50)) with an oligostyrene (1241amu, N ₂=12) are reported. We find strong correlation between the Hildebrand solubility parameters of the alkanes and the UCST. Correlations are developed which enable predictions concerning the miscibility of mixtures of compounds with longer chains.