Molecular and electronic structures of copper-cuprizone and analogues

Kundu, S., Mondal, A., Weyhermüller, T., Sproules, S. and Ghosh, P. (2016) Molecular and electronic structures of copper-cuprizone and analogues. Inorganica Chimica Acta, 451, pp. 23-30. (doi: 10.1016/j.ica.2016.06.040)

Abstract

A paramagnetic dinuclear copper(II) complex, [CuII(L−)Cl]2 (1) while LH = (E)-1,2-diphenyl-2-(2-(pyridine-2-yl)hydrozono)ethanone, an analogue of mono-hydrazone cuprizone (LmcpzH2), was isolated and substantiated by spectra, single crystal X-ray structure determination, unrestricted density functional theory (DFT) calculations and inter alia. Magnetic susceptibility measurement and EPR spectra confirmed the triplet state of 1 above 30 K because of two paramagnetic copper(II) centers. Unrestricted DFT calculations on copper cuprizone species with doublet spin state established similar electronic features and disclosed that bis-deprotonated NN-chelation, [Cu(Lmcpz)2]2−, (cis or trans-2NN), is ∼3 × 103 kJ/mol higher in energy than the mono-deprotonated NO-chelation, Cu(LmcpzH)2, (cis or trans-2NO) precluding the existence of so far reported 2NN products. The calculations revealed that in all isomers, due to the mixing of dx2−y2 orbital with a ligand group orbital as in 1, 48–50% spin density is delocalized over the LmcpzH2 ligand. In fluid solution, 1 absorbs strongly at 527 nm due to LMCT elucidated by the time dependent (TD) DFT calculations and the excited LMCT state is fluorescent (λex = 375 nm; λem = 405, 426 nm; Φ = 0.014).

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Sproules, Dr Stephen
• Authors: Kundu, S., Mondal, A., Weyhermüller, T., Sproules, S., and Ghosh, P.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Inorganica Chimica Acta
• Publisher: Elsevier
• ISSN: 0020-1693
• ISSN (Online): 1873-3255|
• Published Online: 29 June 2016
• Copyright Holders: Copyright © 2016 Elsevier
• First Published: First published in Inorganica Chimica Acta 451:23-30
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher