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A new application of Wiener indices in estimating x‐ray K‐absorption parameters is described. X‐ray K‐absorption parameters were correlated with Wiener indices. Some copper(II) and cobalt(II) complexes of pyrazolin‐5‐ones as ligand were used to establish this type of correlation. The chemical shift is positive, that is, it is towards the higher energy side of the metal edge in both copper and cobalt complexes. The results obtained in this study demonstrate that topological indices of the organic molecules acting as ligands can be used for estimating edge shifts theoretically. Copyright © 2000 John Wiley & Sons, Ltd.

The synthesis of novel diblock polymers containing both a potential charge transport and a non‐linear optic block has been accomplished. The synthesis exploits the living, ring‐opening metathesis block copolymerization of two norbornene type monomers, one of which contains an unsubstituted N‐carbazolyl ring while the other has a bromo substituent at the 3‐position of the carbazole ring. Conversion of the bromo functionality to a 2,2‐dicyanovinyl group introduces the non‐linear optic property. The first monomer was prepared by the previously reported efficient cation radical Diels–Alder cycloaddition of N‐trans‐1‐propenylcarbazole to 1,3‐cyclopentadiene, while the second was obtained by N‐bromosuccinimide bromination of the first monomer. For purposes of comparison, the corresponding random copolymer was also synthesized.

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X‐ray absorption fine structure studies of some cobalt(II) complexes were carried out using a Seifert x‐ray generator and Cauchois‐type bent crystal x‐ray spectrograph of 0.4 m radius. It was found that the graphical method originally proposed by Lytleet al. gives useful information about the bond length and also the environment of the absorbing atom. The phase parameters of the first coordination shell, α1 and β1, provide valuable information about the forward‐ and back‐scattering atoms, respectively. The total phase shift δ1 gives an idea of the periodicity of the x‐ray absorption fine structure. It was also found that the periodicity is affected by the presence of different ligands in the studied cobalt(II) complexes.