磺基水杨酸合铜配合物组成和稳定常数测定实验的改进

改进了教学实验中常用的磺基水杨酸铜配合物组成和稳定常数的测定方法,提出一种使用六亚甲基四胺-硝酸缓冲溶液控制体系pH的方法,预先配制磺基水杨酸的二钠盐溶液,省去强酸强碱反复调节溶液pH的过程,简化了实验操作。在pH 5.60时测得磺基水杨酸铜配合物的条件稳定常数为3.6×10~3,并推出其稳定常数为K_(CuL)=3.6×10~9,与文献值K_(CuL)=3.3×10~9基本一致。     

Kinetics of thermal dehydration of some bis-salicylato-diaquo complexes of transition metal ions

The kinetics of thermal dehydration of bis-salicylato-diaquo complexes of VO(II), Cu(II), Ni(II), Co(II), Fe(II), Mn(II) and Zn(II) were studied. The activation energies and other kinetic parameters were evaluated. The observed kinetic parameters indicate first-order reactions. The activation energy of the thermal dehydration decreases in the sequence VO(II) > Cu(II) > Zn(II) > Co(II) > Ni(II) > Fe(II) > Mn(II), which is also the sequence for the difference in carboxyl group IR frequency.

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Zusammenfassung Die Kinetik der thermischen Dehydratisierung von Bis-salicylato-diaquo-Komplexen von VO(II), Cu(II), Ni(II), Co(II), Fe(II), Mn(II) und Zn(II) wurden untersucht. Aktivierungsenergien und andere kinetische Parameter wurden bestimmt. Die beobachteten kinetischen Parameter weisen auf Reaktionen erster Ordnung hin. Die Aktivierungsenergie der thermischen Dehydratisierung nimmt in der Reihenfolge VO(II) > Cu(II) > Zn(II) > Co(II) > Ni(II) > > Fe(II) > Mn(II) ab. In der gleichen Reihenfolge ändert sich auch die IR-Frequenz der Carbonylgruppe.

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-- , , , , , . , . VO(II) > Cu(II) > Zn(II) > Co(II) > Ni(II) > Fe(II) > Mn(II). .

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The authors express their sincere thanks to the late Dr. M. D. Karkhanawala (then Head, Chemistry Division, BARE, India), for providing the facilities for TG and DTA, and also to the UGC (India) for research fellowships to the authors (BDH and SMA).     

Kinetics of thermal dehydration of some bis-(4-aminosalicylato)-diaquo complexes of transition metal ions

The kinetics of thermal dehydration of bis-(4-aminosalicylato)-diaquo complexes of VO(II), Cu(II), Ni(II), Co(II), Fe(II) and Mn(II), were studied. The activation energies and other kinetic parameters have been evaluated. The observed kinetic parameters indicate a first-order reaction. The activation energy of the thermal dehydration decreases in the order: VO(II) > Cu(II) > Co(II) > Ni(II) > Fe(II) > Mn(II), which is also the order for the covalency in the MO bonds.     

On a low intensity <Superscript>241</Superscript>Am Compton spectrometer for measurement of electron momentum density

In this paper, a new design and construction of a low intensity (100 mCi) ²⁴¹Am γ-ray Compton spectrometer is presented. The planar spectrometer is based on a small disc source with the shortest geometry. Measurement of the momentum density of polycrystalline Al is used to evaluate the performance of the new design. The measured profile is in good agreement with the existing theoretical data and our density functional calculations.      

Electronic properties and Compton profiles of molybdenum dichalcogenides

We present the first ever experimental Compton profiles of molybdenum dichalcogenides (MoX₂; X=S and Te) using 20 Ci ¹³⁷Cs Compton spectrometer. To interpret our experimental data, we have computed the theoretical profiles, energy bands and density of states using linear combination of atomic orbitals method in the framework of density functional theory and its hybridisation with Hartree Fock. The energy bands and density of states using full potential linearised augmented plane wave method have also been computed. Both theories show the existence of the indirect band gap. In addition, the relative nature of bonding is explained in terms of equal-valence-electron-density profiles and valence band charge densities.     

Ultraviolet Light Assisted Hierarchical Porous Fe2O3 Catalyzing Heterogeneous Fenton Degradation of Tetracycline Under Neutral Condition with a Low Requirement of H2O2

The hierarchical porous Fe2O3 particles as a novel ultraviolet light assisted heterogeneous Fenton catalysts were synthesized by bio-template synthesis method using iron nitrate as precursor at high temperature of around 550℃.The hierarchical porous structured Fe2O3 was endowed with a large surface area and abundant pore volume,leading to the exposure of more active sites and rapid mass transfer.The synergistic effect of UV irradiation and hie-rarchical porous Fe2O3 improved the photo-degradation efficiency of Tetracycline(TC).The degradation efficiency of Fe203 catalyzing UV-Fenton system reached 97.4%after 60 min reaction,which was more substantial than Fe2O3 catalyzing Fenton system(7.6%)and UV/H2O2 system(59.2%).Moreover,the hierarchical porous Fe2O3 catalyzing UV-Fenton system exhibited an extremely wide pH range(from 3.0 to 9.0,from mildly acidic to slightly alkaline)for efficient degradation of TC.Simultaneously,the extraordinary higher degradation efficiency was based on 10 mmol/L H2O2 concentration,which was low requirement for H2O2,Further,the hierarchical porous Fe2O3 can be used for five consecutive cycles with over 95%of the original degradation efficiency.Ultraviolet light assisted heterogeneous Fenton reaction in the hierarchical porous Fe2O3 improved the·OH and O2·^-production and Fe(III)/Fe(II)redox cycle,which consequently achieved an excellent degradation rate.     

Some constructions of two-associate class PBIB designs

Summary Two-associate class PBIB designs, having association schemes of GD orL ₂ types, are constructed by using patterned matrices and by methods of taking unions of sets of blocks.     

Symmetry and classification of certain regular group divisible designs

In this paper it is shown that a regular group divisible (GD) design, with parametersv, b, r, k, ₁, ₂ satisfyingrk – ₂ v + 1 and ₂ = ₁ + 1, must be symmetric (i.e.,v + b). Furthermore, the parameters of such symmetric regular GD designs can be expressed in terms of only two integral parameters.Supported in part by Grant 59540043 (C), Japan.     

Synthesis of 2-Tert-butylimino-3-hepta-O-benzoyl-β-D-lactosylimino-4-S-benzyl-6-arylimino-2,3-dihydro-1,3,5-thiadiazines

A new series of synthesis of 2-tert-butylimino-3-hepta-O-benzoyl-β-D-lactosylimino-4-S-benzyl-6-arylimino-2,3-dihydro-1,3,5-thiadiazines (hydrochloride) were synthesized by the interaction of 1-aryl-5-hepta-O-benzoyl-β-D-lactosyl-2-S-benzyl-2,4-isodithiobiurets with tert-butyl isocyanodichloride. The identities of these newly synthesized N-lactosides have been established on the basis of usual chemical transformations and infrared, ¹H NMR, and mass spectral analysis.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]