Molecular and electronic structures of copper-cuprizone and analogues

作者：Kundu Suman; Mondal Amiya; Weyhermueller Thomas; Sproules Stephen; Ghosh Prasanta^*

来源：Inorganica Chimica Acta, 2016, 451: 23-30.

DOI：10.1016/j.ica.2016.06.040

• Dinuclear copper(II) complex
• Copper cuprizone
• Electronic structure
• DFT calculations

A paramagnetic dinuclear copper(II) complex, [Cull(L)C1](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(L-mcpz)2]2, (cis or trans-2(NN)), is similar to 3 x 10(3) kJ/mol higher in energy than the mono-deprotonated NO-chelation, Cu(LmcpzH)2, (cis or trans-2(NO)) precluding the existence of so far reported 2(NN) products. The calculations revealed that in all isomers, due to the mixing of d(xy)(2) 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 (lambda(ex) = 375 nm; Xem = 405, 426 nm; phi) = 0.014).

• 出版日期2016-9-1