Tetracyanoquinodimethane complexes of copper and a 17-membered N,O-donor macrocycle

Abstract

An axially elongated copper(II) complex, CuL¹Cl₂, has been obtained by reaction of copper(II) chloride with a 17-membered N,O-donor macrocyclic ligand (L¹). In an attempt to prepare the complex from copper(II) perchlorate, crystals of L¹ suitable for X-ray were obtained as its diperchlorate salt, [H₂L¹][ClO₄]₂. Further reaction of CuL¹Cl₂ with LiTCNQ and Et₃NH(TCNQ)₂ furnished the charge transfer copper(I) complexes CuL¹(TCNQ)₂·3H₂O and CuL¹(TCNQ)₃, with TCNQ carrying partially reduced charge. The presence of a diamagnetic metallic centre was confirmed by EPR and magnetic measurements.

Keywords:

• 7,7′,8,8′-Tetracyanoquinodimethane
• Copper(II)
• X-ray structure
• Charge transfer
• Magnetic properties
• EPR

Acknowledgements

We acknowledge the financial assistance of the CSIR, New Delhi in the form of project 1(1731)/02/EMR-II to PK. We thank CDRI Lucknow for elemental analyses and BARC Bombay for variable temperature magnetic data.