Infrared spectroscopic study of the structure of the tetrabutyl S-dithiopyrophosphate complex of silver

The structure of the complex Ag·TBDTPP (tetrabutyl S-dithiopyrophosphate) formed in HNO₃ medium was studied by IR and NMR methods. The complex is involved in the isomerization of TBDTPP in the presence of Ag⁺ and NO ₃ ⁻ ions. In the IR spectra, we observe the disappearance of P−O−P band and the occurrence of new absorption bands associated with P−S−P and P=O bonds. The silver ion is coordinated to the thiophosphoryl group of the isomer molecule. The influence of HNO₃ concentration on complex formation is discussed.     

Single crystals of triglycine sulphate containing palladium

Single crystals of TGS doped with Pd₂₊ have been grown from aqueous solutions using the method of temperature decrease. It was found that the relative growth rate along thec-axis is not constant through the growth process being larger by more than an order of magnitude (in medium size crystals, ca. 30 g) than in pure TGS crystals. Investigation of the domain structure revealed that in the growth pyramids ¦110¦, the crystals are poled in one direction. The internal bias field in these growth pyramids was experimentally found to be of the order of 1 kV/cm. The high internal field excludes the possibility of spontaneous depoling and makes the Pd²⁺-doped TGS crystals suitable for pyroelectric applications.     

Power Centralized Semigroups

A semigroup is said to be power centralized if for every pair of elements x and y there exists a power of x commuting with y. The structure of power centralized groups and semigroups is investigated. In particular, we characterize 0-simple power centralized semigroups and describe subdirectly irreducible power centralized semigroups. Connections between periodic semigroups with central idempotents and periodic power commutative semigroups are discussed.     

Finite rings in which commutativity is transitive

A ring is called commutative transitive if commutativity is a transitive relation on its nonzero elements. Likewise, it is weakly commutative transitive (wCT) if commutativity is a transitive relation on its noncentral elements. The main topic of this paper is to describe the structure of finite wCT rings. It is shown that every such ring is a direct sum of an indecomposable noncommutative wCT ring of prime power order, and a commutative ring. Furthermore, finite indecomposable wCT rings are either two-by-two matrices over fields, local rings, or basic rings with two maximal ideals. We characterize finite local rings as generalized skew polynomial rings over coefficient Galois rings; the associated automorphisms of the Galois ring give rise to a signature of the local ring. These are then used to further describe the structure of finite local and wCT basic rings.     

On the Schur multipliers of finite p-groups of given coclass

In this paper we obtain bounds for the order and exponent of the Schur multiplier of a p-group of given coclass. These are further improved for p-groups of maximal class. In particular, we prove that if G is p-group of maximal class, then |H ₂(G, ℤ)| < |G| and expH ₂(G, ℤ) ≤ expG. The bound for the order can be improved asymptotically.     

Quantitative determination of UO2 and ThO2 in powdery mixtures by infrared spectrometry

Infrared spectra of powdery mixtures of UO₂ and ThO₂ were quantitatively evaluated with a computer. The computer programme was tested using the spectra of sulphates. Preliminary results are given and a possible use of this method for analyzing the mixtures of UO₂ with PuO₂ is suggested.     

Powerful 2-Engel Groups

We study powerful 2-Engel groups. We show that every powerful 2-Engel group generated by three elements is nilpotent of class at most two. Surprisingly, the result does not hold when the number of generators is larger than three. In this article and its sequel, we classify powerful 2-Engel groups of class 3 that are minimal in the sense that every proper powerful section is nilpotent of class at most 2.     

ESI‐MS/MS of expanded porphyrins: a look into their structure and aromaticity

Electrospray mass spectrometry/mass spectrometry was used to investigate the gas‐phase properties of protonated expanded porphyrins, in order to correlate those with their structure and conformation. We have selected five expanded meso‐pentafluorophenyl porphyrins, respectively, a pair of oxidized/reduced fused pentaphyrins (22 and 24 π electrons), a pair of oxidized/reduced regular hexaphyrins (26 and 28 π electrons) and a regular doubly N‐fused hexaphyrin (28 π electrons). The gas‐phase behavior of the protonated species of oxidized and reduced expanded porphyrins is different. The oxidized species (aromatic Hückel systems) fragment more extensively, mainly by the loss of two HF molecules. The reduced species (Möbius aromatic or Möbius‐like aromatic systems) fragment less than their oxidized counterparts because of their increased flexibility. The protonated regular doubly fused hexaphyrin (non‐aromatic Hückel system) shows the least fragmentation even at higher collision energies. In general, cyclization through losses of HF molecules decreases from the aromatic Hückel systems to Möbius aromatic or Möbius‐like aromatic systems to non‐aromatic Hückel systems and is related to an increase in conformational distortion. Copyright © 2016 John Wiley & Sons, Ltd.     

High-temperature conductivity of solid and liquid CdTe

Conductivity of CdTe single crystals fabricated in our laboratory by vertical gradient freeze method was studied at temperatures 400–1200°C. Two clear slopes are seen — 0.7 eV in the solid and 4.6 eV in the liquid. Experimental value of electrical conductivity at the melting point 10 Ω⁻¹ cm⁻¹ was observed. A model explaining the experimental data is suggested.