Study of the correlations of the MLCT Vis absorption maxima of 4-pentacyanoferrate-40′-arylsubstituted bispyridinium complexes with the Hammett substituent parameters and the solvent polarity parameters E NT and AN

Papadakis, R; Tsolomitis, A

dc.contributor.author	Papadakis, R	en
dc.contributor.author	Tsolomitis, A	en
dc.date.accessioned	2014-03-01T01:32:00Z
dc.date.available	2014-03-01T01:32:00Z
dc.date.issued	2009	en
dc.identifier.issn	08943230	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/20012
dc.subject	Hammett equation	en
dc.subject	LFERs	en
dc.subject	Pentacyanoferrate complex salts	en
dc.subject	Solvatochromism	en
dc.subject	Substituent effects	en
dc.subject.other	Hammett equation	en
dc.subject.other	LFERs	en
dc.subject.other	Pentacyanoferrate complex salts	en
dc.subject.other	Solvatochromism	en
dc.subject.other	Substituent effects	en
dc.subject.other	Benzene	en
dc.subject.other	Chemical bonds	en
dc.subject.other	Chlorine compounds	en
dc.subject.other	Dyes	en
dc.subject.other	Ethanol	en
dc.subject.other	Ethylene	en
dc.subject.other	Ethylene glycol	en
dc.subject.other	Fourier transform infrared spectroscopy	en
dc.subject.other	Hydrogen	en
dc.subject.other	Ligands	en
dc.subject.other	Meats	en
dc.subject.other	Methanol	en
dc.subject.other	Nuclear magnetic resonance spectroscopy	en
dc.subject.other	Optical properties	en
dc.subject.other	Organic solvents	en
dc.subject.other	Salts	en
dc.subject.other	Water absorption	en
dc.subject.other	Solvents	en
dc.title	Study of the correlations of the MLCT Vis absorption maxima of 4-pentacyanoferrate-40′-arylsubstituted bispyridinium complexes with the Hammett substituent parameters and the solvent polarity parameters E NT and AN	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/poc.1514	en
heal.identifier.secondary	http://dx.doi.org/10.1002/poc.1514	en
heal.publicationDate	2009	en
heal.abstract	In this work six new 4-aryl substituted bispyridinium salts have been synthesized using 2, 4-dinitrophenyl-bispyridinium chloride as the starting material, which was arenamine exchanged via the Zincke reaction. These aromatic heterocyclic salts were used as ligands, acting as Lewis bases to form a series of 4-pentacyanoferrate-4(-aryl substituted bispyridinium complex salts in high yields. The complex salts were characterized using several spectro-scopic techniques including 1H as well as 13C NMR spectroscopy, UV-Vis and FTIR spectrophotometry. These materials present a number of interesting electronic and optical properties. Herein we mainly focused on the electronic absorption of these materials. The visible metal-to-ligand-charge- transfer (MLCT) band of these materials assigned as dπ(FeII) → π*(L) was proved to be affected by substituent changes (of the benzene ring of the complexes) but mainly by solvent polarity changes. Band shifts of even 4000 cm-1 were induced by small solvent polarity changes (e.g., water to methanol). The Vis absorption spectra were investigated in four protic solvents (water, 2, 2, 2-trifluoroethanol, ethylene glycol, and methanol). The substituent effects were then quantified using the Hammett equation which correlates the MLCT absorption wavenumbers with the Hammett constant (σx). Furthermore, two of the most successful solvent polarity parameters (the acceptor number AN and the normalized solvent polarity scale ENT) were used to quantify the solvent polarity effects on the MLCT absorption wavenumbers. The correlations obtained in all cases proved to be satisfactory. The dominant interaction responsible for the solvent polarity effects proved to be the hydrogen-bond formation between the cyano groups of the complex salts and the protic solvents. Copyright © 2009 John Wiley & Sons, Ltd.	en
heal.journalName	Journal of Physical Organic Chemistry	en
dc.identifier.doi	10.1002/poc.1514	en
dc.identifier.volume	22	en
dc.identifier.issue	5	en
dc.identifier.spage	515	en
dc.identifier.epage	521	en