Co-ordination stoichiometry,edge shift and effective nuclear charge: A novel correlation

Summary K-absorption edge shifts of the absorbing atom in its complexes have been correlated with the effective nuclear charge on the central metal ion, overall electronegativity difference between the nearest neighbours in the complexes and the ionic radius of the central metal ion; a linear correlation has been observed among them, the data subjected to the method of least squares indicated that the correlation is genuine.

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Riassunto Gli slittamenti dell’orlo di assorbimentoK dell’atomo assorbente nei suoi complessi sono stati correlati con la carica nucleare efficacie sullo ione metallico centrale, con la differenza di elettronegatività generale tra vicini prossimi nei complessi e col raggio ionico dello ione metallico centrale; una correlazione lineare è stata osservata tra loro, i dati soggetti al metodo dei minimi quadranti hanno indicato che la correlazione è genuina.

     

QSAR Study on Binding Affinity of PATs (Rodenticides) to the [3H]-Mepyramine-Labelled H1 Receptor In Rat and Guinea Pig Brain

Abstract

The binding of a series of PAT analogues (rodenticides) to the [³H]-mepyramine-labelled H₁ receptor in rat and guinea pig brain was investigated topologically using negentropy (N), molecular redundancy (MRI), first-order molecular connectivity (¹X _v ), Wiener (W), and Szeged (Sz) indices. Multiple regression analyses showed that MRI provided excellent results upon introduction of indicator parameters. Predictive ability of the proposed models was discussed using cross-validation parameters.     

A Method of Computing the PI Index of Benzenoid Hydrocarbons Using Orthogonal Cuts

The Padmakar–Ivan (PI) index of a graph G is defined as PI , where for edge e=(u,v) are the number of edges of G lying closer to u than v, and is the number of edges of G lying closer to v than u and summation goes over all edges of G. The PI index is a Wiener–Szeged-like topological index developed very recently. In this paper, we describe a method of computing PI index of benzenoid hydrocarbons (H) using orthogonal cuts. The method requires the finding of number of edges in the orthogonal cuts in a benzenoid system (H) and the edge number of H – a task significantly simpler than the calculation of PI index directly from its definition. On the eve of 70th anniversary of both Prof. Padmakar V. Khadikar and his wife Mrs. Kusum Khadikar.     

Transfer measurements for the Ti+Ni systems at near barrier energies

Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies. Coupled channel calculations incorporating couplings to 2⁺ and 3⁻ states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer were carried out for ^46,48Ti+⁶¹Ni systems. The present paper gives the results of these studies.     

Topological estimation of proton-ligand formation constants of potential antitumour agents: Salicylhydroxamic acids

Proton-ligand formation constants of salicylhydroxamic acids (SHA) and their nuclear substituted derivatives have been estimated topologically using the normalized Wiener index, referred to as mean square Wiener index (Wms). Regression analysis of the data indicates that Wms can be used successfully for estimating and monitoring proton-ligand formation constants.     

Studies on the thermal behaviour of tris-[thallium(III)]-lactate

The interaction of TL(OH)₃, with excess lactic acid indicated the formation of Tl(LA)₃ where LA stands for the anion of lactic acid. The structure of the complex was predicted from elemental analyses and IR spectra. The thermal decomposition of the complex using TG, DTG and DTA gave supporting evidence for the predicted structure. The kinetics of thermal decomposition were also studied employing various computational methods.     

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).